Group for Earth Observation

The Independent Amateur Quarterly Publication for
Earth Observation and Weather Satellite Enthusiasts

Number 19
September 2008
Inside this issue . . .
For non-UK readers who
access EUMETCast via
C-Band, Kobus Botha
describes how to optimise
your signal strength
Newcomers and seasoned
readers alike will befascinated by Mike Stevens’
look back through thehistory of gaining data forweather forecasting, fromthe days of balloons to thesatellites we now take somuch for granted
Our Readers’ Survey
showed that the majority of
you are still APT
enthusiasts. Nigel Evanshas decided to whet yourappetites by running GEO’s
first APT Image competition
Marc Peigneux describes an
expedition to evaluate APT
imaging from a high passin the French AlpesMaritimes
Rob Alblas writes about the
new BUFR scatterometerdata that is now available
over EUMETCast, andexplains how you can use
his Xrit2Pic software tosuperimpose it overweather satellite
imagesAnd
muchmore ...

The Magazine forReal Listeners
Radio and Communications Monitoring Monthly (ISSN
1749-7809) aims to be the magazine of choice for all
serious radio enthusiasts and to serve all the specialist
areas of the hobby. ‘I am pleased to say that all our
regular columns provide more information than any
current or former alternative’, commented Editor Kevin
Nice.

Radio and Communications Monitoring Monthly isavailable from most good newsagents as well as directfrom its publishers.

Subscriptions are available world-wide
For more information contact Nice One Publishing Ltd,
Telephone +44 (0)1202 862690
or visit the website atwww.monitoringmonthly.co.uk

MANAGEMENT TEAM
Public Relations

A

fter an initially disappointing response, the GEO Readers Survey gathered
momentum following publication of the June issue. We are grateful for thisfeedback which has now been circulated to everyone on the GEO Management
Team. Comments were largely supportive of GEO but, as always, some readers
have concerns and we will do our best to address these. A summary of the main
points of the survey appears on page 10.
nother healthy outcome from Quarterly No 18 was the response to Laurence
Holderness’ article on The Current Weather Satellite Scene. Never before have
we received such a comprehensive and animated response from readers—allstrongly supporting his views. In a nutshell, it is perceived that setting up a
EUMETCast system is fraught with difficulties and that the processing andimaging software is viewed as highly complex. Almost without exception the callis for simplified software with just enough options to download a few images perday. You can read our monster ‘postbag’ from page 42.
e also hear from time to time of the problems members have of restoring afailed EUMETCast system. This is not an everyday process, and currently
one member, who had enjoyed a number of successful years of EUMETCast
imaging, spent several weeks of effort before he was able to return his system toa working state. The problem is that the process if installing and configuring all
the software is not entirely intuitive. With this in mind, now that EUMETCast is
well established, it seems the ideal time to update our Helplines service. Anyreader who now considers himself expert enough in any specific area is invited to
add contact details to our regular Helplines column in the centrefold See
Updating GEO’s Helplines on page 11.
or the die-hard EUMETCast enthusiast looking for new types of data to
analyse, both Rob Alblas and David Taylor explain how their software
packages are being extended to interpret BUFR wind scatterometer data files.
nd finally, for those with simpler tastes, Nigel Evans is running GEO’s firstever readers’ competition. Presented with a particular date, you are invited tosubmit a NOAA-18 APT image. The entry adjudged the best will be awarded
complimentary entry to GEO’s 2009 Symposium. Details on page 19.

A

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F
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Contents

GEO Report and Quarterly Question
Thunderstorm Season Begins with a Bang
Symposium 2008 Report
Total Solar Eclipse
The Curonian SpitUPS or Inverter: Power back-up systems
GEO Readers’ Survey
Help: How to solve your wxsat problems
GEO needs YOU.
Here is the Weather Forecast
Using the BUFR Format - scatterometer data in Xrit2Pic
Wind Data from EUMETCast
GEO Readers’ APT Imaging Competition
GEO Members Worldwide
Cover and Full Page Images
Computer Corner
NOAA-18 Image of the Aral Sea
APT Audio Control

General Information
John Tellick
email:
info@geo-web.org.uk

GEO Quarterly Editor
Les Hamilton,
8 Deeside Place
Aberdeen AB15 7PW
Scotland, UK.
email:
geoeditor@geo-web.org.uk

Membership and Subscriptions
David Anderson,
35 Sycamore Road,
East Leake,
Loughborough LE12 6PP
England, UK.
email:
members@geo-web.org.uk
Tel:01509 820 067
Fax:
01509 559 015

Meteorological Consultant
Peter Wakelin
email:
meteo@geo-web.org.uk

Technical Consultant (hardware)David Simmons
email:
tech@geo-web.org.uk

Webmaster and Website Matters
Ray Godden
e-mail: ray-geo@lescharriols.eu

Education Coordinator
David Painteremail:
education@geo-web.org.uk

GEO Shop Manager
Clive Finnis
email:
shop@geo-web.org.uk

International Liaison

Francis BellEUMETSATDavid Taylor
NASA Earth Observatory
Rob Denton

Mike Stevens
Rob Alblas
David Taylor
Nigel Evans
David Anderson
Douglas Deans
Anders Höök
Francis BellGEO Shop
NOAA Satellite Predictions for the UK and Western Europe
Helplines and Internet Discussion Groups
Copy Deadline for December issue
GEO Membership Renewal Form
Earth Imaging News
Ten Days in the Philippines
GEO at the 2008 AMSAT-UK Colloquium
Script Snippets: Automated Data Management
News in Brief
High Altitude NOAA Imaging
An Evening With Bill Giles
CSDSC
Optimising your C-band EUMETCAST Signal
Wintertime Disintegration of the Wilkins Ice Shelf
Feedback: Readers’ Comments
Early Summer for Northern Europe

Francis Bell,
Coturnix House, Rake Lane,
Milford, Godalming,
Surrey GU8 5AB
England.
Tel:
01483 416 897
email:
francis@geo-web.org.uk

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10
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15
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ii
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iv

Peter Wakelin
Rob Denton
David Taylor
David Taylor
Marc Peigneux
Peter GreenLes Hamilton
Kobus Botha
NASA Earth Observatory
John Tellick

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31
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34
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Peter Green‘Hollowtree’
Eggesford
Devon EX18 7QX
Tel:
01769 580 700
email:
international@geo-web.org.uk
Nigel Evansemail:
nigel@geo-web.org.uk

Publisher
The Group for Earth Observation Ltd
The Group for Earth Observation Limited is acompany in England and Wales limited byguarantee and not having share capital.
Company number 4975597.
The registered office is Coturnix House,
Rake Lane, Milford, Godalming, Surrey
GU8 5AB England.

Printing
Advent Print Group,
19 East Portway Industrial Estate,
Andover,
Hampshire SP10 3LU.

Responsibility
Every effort is made to ensure that thetechnical and constructional articles
published in this Quarterly are correct.
However, the ultimate responsibility is withthe reader to ensure the safety of
constructions and for any interfacing withother equipment. GEO cannot accept liability
for shortcomings in any published design or
any constructions carried out by members orother third parties.

Copyright GEO © 2008
The contents of this Quarterly remain theintellectual property of the Group for Earth
Observation Ltd. and its contributors.
Copying of text or images, either from theprinted Quarterly or from any electronicallystored source, is forbidden without
permission from the GEO Quarterly Editor.

GEO Quarterly No 19

Group for Earth Observation

September 2008

Francis BellI often start my Quarterly report with awelcome to new members of GEO. This is
not a superficial remark because we needto maintain or increase our membership,
not just for the sake of numbers but to havea pool of people who can share theirtechnical skills: perhaps helping beginners
who may be using weather satellite for the
first time or the more experienced users bypushing back the frontiers of what is
possible for individuals, educational andnon-commercial users of weather satellites.
If you can, please encourage others to join
GEO.
On the subject of help, I would like to refermembers to the published helplines which
are available to those seeking help withsatellite issues, either hardware orsoftware. Please use these help lines
because the people concerned haveoffered their services to our Group and it
takes some of the workload off others. For
example, our GEO Shop, which is run by
Clive and Carol Finnis; they are very busy
people dealing with the acquisition of stockand making it available to members andnon members. It would be helpful if they
were not contacted on routine mattersrelating to the operation of equipment. We
are grateful to Clive and Carol, who arecommitted to running the Shop on behalf of
GEO; they should not be further burdenedwith enquiries unless it relates to a specificorder.
Do, please, research your requirement andthen use the helplines on our centre pages
if you need advice or have problems.
At this point it may be appropriate, on
behalf on the membership, to thank all the
management team for offering theirservices to the Group. All are busy people
but offer to give up some of their time inpursuit of our common interests. And areminder that nobody gets paid for doing
this; in fact it often costs individuals money
for telephone calls, postage and travel toservice GEO. Membership subscriptions
cover little more than the cost of printing
and distributing our Quarterly.
Our Quarterly publication is perhaps thejewel in GEO’s crown but it is currently at
risk. For some time now our editor,
understandably, has indicated his wish to
retire. As best I know there have been no
offers of help from others and unless there
is, it’s likely that the format and perhaps thefrequency of our publication will change. If
two or three members were to collectively

2

share editorial duties there may be asolution. For example one person editing
text, someone else looking after the layout
and perhaps someone liaising with theprinters. This would spread the workload.
Other combinations of responsibilities may
be equally appropriate. However, members
must accept this notice that without
additional help the Quarterly is certain tochange.
On a positive note, GEO has been
particularly active recently. In May we held
our own symposium in Leicester and you
can read a report on page 4. GEO wasinvolved in the three day AMSAT-UK
meeting in Guildford in the final week-end
of July; David Taylor’s illustrated report canbe found on page 28. I also recently gave apublic demonstration of live APT reception
at the amateur radio station GB2 CPM
located close to the telecommunications
exhibition at Amberly Museum, West
Sussex. At all these events, live weather
satellite reception was demonstrated.
The Year Ahead
Thinking ahead to next year, I have been
looking for an alternative venue for our own
symposium, which has been staged at the
NSC in Leicester for the past five years. Achange of venue may be appropriate and I
am researching several ideas. Sharing our
symposium with another event may be an
attractive idea. Please let me know what
you think on this subject. A full day
conference—with lunch included—isavailable at one very attractive venue, but
the cost is likely to be about £35. I just
don’t know whether members would likethis.
EventsThe programme of events which we havearranged for the rest of this year is• September 28, 2008 - The west
London Radio and Electronic Show at
Kempton. Note this is a revised date.
• October 24/25, 2008 - The Leicester
Amateur Radio Show, Donington.
• December 8-12, 2008 - The NOAA
Direct Readout Conference, Miami,
USA. For details of this event contact
the web site atwww.directreadout.noaa.gov/miami08

Water Problems
GEO members seem to have very few
problems using the equipment they buy
from the GEO Shop and I attribute this thecompetence and technical skills of our

www.geo-web.org.uk

members. Hence it was a little surprisingwhen a PCI board was returned to theshop because it had developed a fault.
When the board in question was forwarded
to our hardware expert he suggested water
damage was a likely cause of the fault.
Perhaps water had worked its way down
the coax and on to the PCI board causing
corrosion.
Personally, I take care to wrap my external
coax connections in self-amalgamating
tape to keep them waterproof. However, tomy consternation, a temporary dish andcoax I had installed for Hot bird-6 began
losing signal strength. I had left the signal
strength meter in the circuit and lying on
the grass, which must have become wet atsome stage. Investigation revealedconsiderable water condensation inside themeter, hence the reduced signal strength. I
took the meter out of the circuit and a fullsignal was restored.
It may be better not to leave the meter inthe circuit but that is not quite the point of
the story; that was the ease with whichwater can enter joints and cause problems.
I disassembled the meter and over a periodof two days it dried out. The joints in themeter case are not waterproof and I willtake more care in future.
A final note. GEO is almost five years old
with a distinguished and talented
membership recognised internationally byagencies such as BNSC in the UK,
EUMETSAT in Europe and NOAA in theUSA. To maintain the quality of ouractivities and contributions to the world
wide observation of our planet we need
constant support from our membership.
Please consider what you can contribute to
GEO in the form of articles, images
reminiscences and wxsat experiences.

The question posed in Quarterly No 18
related to the boundary layer above Earth’s
surface, known as the thermopause. This isa rather indistinct boundary where any
given particle is as likely to drift off into
‘deep’ space as it is to remain associatedwith the Earth.
I became interested in the thermopause
because its altitude range lies close to theregion occupied by sun-synchronous polarSeptember 2008

orbiting satellites such as the NOAAs
and Metop at around 800 km andJason-2 at 1336 km. My reference
answer was taken from BNSC’s
Space:UK issue 23 which gave a figureof ‘about 690 km’. This boundary issomewhat dynamic so some research on
the Internet produced more details. Try
typing ‘thermopause’ into a searchengine such as Google and you candiscover a wealth of information.
Disappointingly, I only received three
responses, from Andreas Lubnow, Ian
Leitch and Sally Wannop. All answers I
considered to be correct although theyquoted slightly different figures. My
thanks to them for their responses: as forthe rest of the membership—well, you
can’t be too interested in the environment
in which weather satellites operate!
I have recently received the summer
copy of Space:UK, issue number 25. It’s
always a very interesting publication. If
you would like to receive a regular copy
(published three times per year), I
suggest you write to
British National Space Centre
Publications Office
Kingsgate House
66-74 Victoria Street
London SW1E 6SW

and ask to be put on their mailing list.
Alternatively email them, or visit their
web site,www.bnsc.gov.uk

The Quarterly Question for this month,
I’m pleased to say, was submitted by
EUMETSAT. I take it as a compliment onbehalf of GEO that EUMETSAT takes aninterest in GEO’s activities.
Background to the Question
Approximately 70% of Earth’s surface iscovered by water, some, marginal seas,others, major oceans. These have amajor influence on the planet’s climate:for example, the top three metres has asmuch thermal capacity as the whole of
the atmosphere—and it’s worth noting
the average depth of the sea is aboutfour kilometres.
A number of Earth observation satellites
have been specifically designed tomeasure sea surface height. This has tobe done against a background of sea
surface waves, tides and noting that the
Earth is not a perfect sphere, being
distinctly flattened at the poles. The othervariable is the observing satellite itself
and knowing its exact position when
taking measurements.
The success of high precision altimetry
started in 1992 with the
TOPEX/Poseidon mission which was
generated by international cooperation
between NASA (USA) and CNES
(France). This was followed by Jason-1.
The next satellite, Jason-2, involves

Group for Earth Observation

GEO Quarterly No 19

EUMETSAT, together with CNES, whoprovide the European contribution
towards the mission. Jason-2 wasrecently launched and is currently in thecommissioning phase. With a further
anticipated rise in sea level as a result of
Global Warming, it’s critical to secure
reliable data relating to global sea levels.
Quarterly Question 19
This question was submitted by Sally
Wannop, user support manager at
EUMETSAT, following consultation with
their resident Jason-2 expert. Well, if you
anticipate this will be a hard question,
you’re right: here it is!
What are the instruments
required to build a highaccuracy altimetry mission
such as Jason-2, giving ameasurement accuracy of 3
to 4 cm for sea surface
height?
I do have a model three-line answer fromEUMETSAT, which will be published in
the December Quarterly. However,having read the answer, it might havetaken me three years of PhD research tocome up with the correct answer. On theother hand EUMETSAT’s web site andtheir publications give most of theanswer. Visit their web site atwww.eumetsat.int

as a first step in researching any answer.
The inducement to submit ananswer is the promise by
EUMETSAT to send Jason-2
resource materials and ‘goodies’ tothose providing correct answers.
Your answers should be sent toFrancis Bellfrancis@geo-web.org.uk

not to EUMETSAT. Even a reasonablefraction of the model answer, I will judge
as correct. With the prospect of receiving
materials from EUMETSAT, please
include your name and full postal
address in any email you send to me.
If you can’t manage the main question,
here is an alternative straightforward
question.
What was the date and time,in UTC to within one minute,of Jason-2’s launch andwhat was the launchvehicle?
If you can’t manage either of the above
here is a final question.
What is the classical connection
between Poseidon and Jason?
A clue here is that my Citroen Xsara car
is a pretty blue colour which the
manufacturer describes as ‘Poseidon
blue‘. No prizes here, but email me yoursingle three-letter word answer anyway.

www.geo-web.org.uk

EUMETSATA May with record amounts of sunshine
ended with a bang in Europe as thethunderstorm season began. The
EUMETSAT Rapid Scanning Service from
Meteosat-8 became operational in early
May, in time to support observations andsevere weather warnings.
Convective activity dominates the weatherof Central Europe in the summer.
Especially during the first part of thesummer, in June and July, the frequencyof severe thunderstorms is significantly
increased and associated phenomena
such as strong winds, hail and sometimes
even tornadoes can cause serious damageand endanger lives. Such severe weather
situations are often quite small and evolve
very rapidly, making it difficult to workwith computer models. The new Rapid
Scanning Service consists of a five-minute(instead of 15-minute) delivery of
convective cloud imagery that helps tospot and monitor potentially dangerous
situations of severe weather. Accurate
forecasts of weather developments can bemade and if necessary, public safety
officials can issue warnings to travellers
on the roads, industry and the populationin general.
Germany was hit by thunderstorms andtorrential rain over the final weekend ofMay, with city streets and cellars flooded
and trains disrupted. The bad weather
spread to neighbouring countries,
thunderstorms and rain arriving from theeast over the Netherlands, with showers
ending in the North Sea. Rail lines were
hit by lightening and there were problems
with the electricity grid. A very warm
weekend in the Czech Republic wasinterrupted both days by heavy local
rainfall, flash floods and hail stones
measuring up to 2.5 cm.
This severe weather followed Saturday,
May 31, when temperatures of 32.5°C
broke a 140-year-old record in the oldest
observatory in the centre of Prague, where
measurements first began in 1775.
Similarly, the Netherlands experienced its
warmest May since measurements began
in 1901 while Denmark received moresunshine in May than it has in over 60
years: 347 hours, averaging 11 hours and
12 minutes a day. A second wave ofthunder storms and torrential rain hit
again on the Monday night and severe
weather warnings remained in effect for
the remainder of that week.

3

GEO Quarterly No 19

GEO’s 5th Symposium took place
within the National Space Centre,
Leicester on May 10 when the keynote
presentations were given by Professor
Grant Bigg, head of the geography
department at Sheffield University and
Dr John Remedios from Leicester
University’s Space Research Centre,
who heads the team which has
responsibility for the GERB instrument
aboard Meteosat and its data.
Grant Bigg’s Presentation
Grant Bigg spoke on the subject ofpolar lows and their impact on thenortheast Atlantic. His team have been
looking at images that are familiar to
GEO Quarterly readers: infrared
Meteosat images of the North Atlantic.

Group for Earth Observation

polar lows, small as they may be, is
important for shorter-term weather
forecasting. Also, they can speed up
the mixing of cold and warm water in
the Nordic Sea, which has longer-term
impacts on oceanic circulation.
John Remedios’ Presentation
John Remedios provided an excellent
and lively presentation about ‘The
Geostationary Earth Radiation Budget(GERB ) instrument aboard Meteosat’.
GERB data is not available toamateurs as it is not disseminated via
the EUMETCast system, so John’s talk
opened up new horizons for theaudience.

Dr John Remedios

Professor Grant Bigg

In particular, the lecture drew ourattention to the small weather systems
that form, mainly along the ice edge atthe very north of the ocean, where thewarm Atlantic meets cold air and waterfrom Arctic regions. The systems
formed—polar lows—are just a few
tens of kilometres across. Some ofthese are in the upper atmosphere andnever touch ground, others may beformed as part of (or contribute to) theformation of the more familiar synoptic
weather systems that are a feature of
our weather on the European Atlantic
seaboard.
These systems may be either short- or
long-lived but those that last longest
are generally formed over warmer
water. Are these little weather systems
worth watching? Well, yes they are! Ifthey touch the ground they will
significantly enhance wind speeds.
Polar lows may set off oceanic
convection that would not otherwise
have happened, thus contributing toAtlantic storms; so observations of

4John covered all aspects of the GERB
device, including the need for the
instrument; the wavebands covered(long-wave, short-wave and total); thedesign of the detectors and theircalibration; the results achieved fromthe GERB and the requirements forcomplex post processing to correct forearth-satellite-sun geometry and soforth. Although little-known, the UK
builds and operates some of the mostaccurate instruments for thesemeasurements, and of course accuracy
and long-term stability of calibration
are of paramount importance whenclimate change observations are being
made.
David Taylor
David Taylor spoke about changes overthe past year, both in terms of the newdata services which are now available
from EUMETCast and the software
required to handle them. Windows
Vista has become widely used, and thishas affected the way that software is
written and deployed. There are some
updates due from EUMETSAT soon,and these were discussed. On the
hardware side, David explained that
new USB2 DVB boxes had madewww.geo-web.org.uk

September 2008

reception of the full EUMETCast data
stream even easier because there wasno longer any requirement to open up
PCs to insert receiver cards.
Additionally, the new receivers areaccompanied by drivers which work
reliably even on the newest operating
systems. No wonder these boxes wereso popular at the GEO Shop!
GEO Shop
The GEO Shop stall manned by Clive
and Carol Finnis enjoyed brisk tradethroughout the day, selling a wide
range of items, including LNBs,
Satmeters, PICs, Bias Tees, an R2ZX
APT receiver and various antennas.
Best sellers by far, however, were John
Silver’s lightning radar board (6),which was featured in GEOQ 17 andthe new DVBWorld USB2.0 box (13).
Workshops
The remainder of the day was taken up
with informal discussions andworkshops and allowed members theopportunity to discuss his latest
software with David Taylor.
Throughout the day, live MSG systems
were on display, illustrating to theuninitiated just how spectacular 24hour animations of our weather canbe.
Other interesting hardware
demonstrations included Fred van den
Bosch’s home-built, highly portable
APT antenna, which he finds
invaluable for maintaining APT
reception while holidaying around theworld and an attempt by Arne van
Belle to rescue important data from afailing PC hard drive.
AGM
Late in the afternoon, Francis Bellpresided over the GEO AGM, coveringa variety of topics ranging fromfinances to the continued need ofsupport from readers regarding the
supply of satellite images andinteresting articles for GEO Quarterly.
This concluded with the popular raffle
which provided a wide range of‘goodies’ to be won.
The symposium was particularly wellattended, mainly from members in theUK, but we also welcomed members
who had travelled from France, theNetherlands, Italy, and Bulgaria.
Acknowledgements
Thanks to David Taylor and Robert Moore for
their contributions to this report. Photographs
courtesy David Taylor and Clive Finnis.

September 2008

Group for Earth Observation

GEO Quarterly No 19

John Remedios speaking about the specific characteristics
of different wavelengths during Symposium 2008

David Taylor’s presentation on the latest developments
and news from EUMETSAT

Photo: David Taylor

Photo: Cecilia Taylor

Marc Peigneux watching an HD replay while the PC
simultaneously processes and displays EUMETCast data

Marc Peigneux (right) and John Tellick look on as
Arne van Belle rescues data from a failing hard drive

Photo: David Taylor

Photo: David Taylor

John Tellick leading a EUMETSAT Workshop
during Symposium 2008

Left to right: Guiseppe Cico (Italy) Arne van Belle (Holland)
Marc Peigneux (France) and Rob Hollander (Holland)

Photo: Clive Finnis

Photo: Clive Finnis

www.geo-web.org.uk

5September 2008

Group for Earth Observation

GEO Quarterly No 19

David Taylor

The total solar eclipse on August 1, 2008 was captured on theextreme edge of this Metop-A pass, imaged by the AVHRR
instrument at 10:11 UT. I have processed the Metop-A data in my
HRPT Reader program to bring out the moon's shadow in the image,and rotated the image by 90° so that north is approximately at the topof the scene. The moon's shadow can be seen as a dark oval at thelower-left of the image; it appears elongated because of the very highlatitude of the region. I estimate the centre of the shadow to be at
66.5°E and 69.5°N, which is in the Yamal Peninsula. To theimmediate right of the moon’s shadow is Obskaya Guba, the gulf of
the Ob River, which reaches over 90 km in width in places. Farther

east is the estuary of the Yenisei River, the largest river flowing into
the Arctic Ocean and, at 5539 kilometres in length, the fifth longest
in the world. The prominent landmass to the northeast (right) of the
Yenisei is the Taimyr Peninsula, the northernmost region of mainland
Asia. The twin islands of Novaya Zemlya are visible halfway up theleft side of the image and in the top left corner is the ice-coveredisland of Nordaustlandet, the second largest of the Svalbard
archipelago.
My thanks to Mike Jupp for discovering the Metop pass.

www.geo-web.org.uk

Metop data copyright (c) EUMETSAT 2008.

7

GEO Quarterly No 19

Group for Earth Observation

A NASA Earth Observatory Newsroom Report

In the southeastern corner of the Baltic
Sea lies a narrow stretch of land
known as the Curonian Spit. Largely
forested, the spit separates theCuronian Lagoon from the Baltic Sea:
measuring just 3,800 meters across at
its widest point, it encloses a lagoon
with an area of 1,620 square
kilometers.
In this image, dark blue indicates deep
water, and lighter blue shallow or
sediment-laden water. Different shadesof blue distinguish the deeper Baltic
Sea at left from the shallower Curonian
Lagoon.
Vegetation appears in varying shadesof green, paved surfaces and bareground in shades of beige and gray,and sandy areas appear off-white.
Obvious sandy areas can be seen along
the length of the spit. On the Baltic
Sea side, a thin off-white band ofbeach runs the entire length of thespit; on the Curonian Lagoon side,
intermittent beaches carve their way
into the narrow strip of land.
Both the spit and the lagoon fall within
the borders of Lithuania in the northand Kaliningrad Oblast (Russia) in thesouth. The lagoon is fed primarily by
the Nemunas River, whose delta isprominent at the upper right of theimage. Between its sandy beaches,pine forests and attractive views, thearea is a popular tourist destination.
Yet the area is fragile.
Natural forces of wind and tide
constantly threaten the spit, andhuman efforts at stabilisation byreforestation are needed to preserve it.
The United Nations Educational,
Scientific and Cultural Organisation
designated the Curonian Spit as a
World Heritage site in 2000, after
receiving a joint nomination from
Lithuania and the Russian Federation.
This image, captured on July 25, 2006
by the Advanced Spaceborne Thermal
Emission and Reflection Radiometer(ASTER), flying on NASA’s Terrasatellite, captured this image of thespit, the lagoon it encloses, and part ofthe Baltic Sea.
NASA image created by Jesse Allen, using data provided
courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and the
U.S./Japan ASTER Science Team.

8

www.geo-web.org.uk

September 2008

September 2008

Group for Earth Observation

Rob Denton LZ/G4YRZ
How many times have you been receivinga satellite image and the power went off?
Or been out for the day and come home tofind your PC off due to a power
disconnection? For me, living in Bulgaria,
this tends to be a weekly occurrence—andvery frustrating, with a minimum of three
power cuts (also known as ‘brownouts’,
blackouts and outages to some) per week.
I was going through a phase where I waschanging my hard drives every othermonth due to them being damaged by the
PC not shutting down correctly.
What is needed is a system which allows
time to shut down the computer properly inthe event of a power outage. Thankfully, a
UPS (uninterruptable power supply) or
inverter offers you that opportunity.
Providing the outage is brief (15 minutes orso), a UPS will allow the system tocontinue operating normally, switching tobattery back-up in the blink of an eye. You
don't even realise it's happened except forthe beeping sound of the UPS warningthat you are running on battery power. The
UPS will switch back to mains power assoon as this is restored, again in a fractionof a second. You don't have to do anything
as the UPS is fully automatic.
An inverter can maintain power for a lot
longer than a UPS, depending on how it'sconfigured, and gives you time to shut
down your equipment safely in the event ofa longer disconnection.
In this article, I am going to compare the
UPS and inverter to help you determine
which is most suitable for your computer
system. Most people prefer to use a UPS,
which is what I would recommend in mostcases. This is what is sold in most PC
shops around the globe,
The UPSAn uninterruptible power supply (UPS),
also known as a continuous power supply(CPS) or a battery backup, is a device
which maintains a continuous supply ofelectrical power to connected equipment. It
does so by supplying power from aseparate source when utility power is notavailable. The UPS differs from an auxiliary
power supply or standby generator, which
does not provide instant protection from a
momentary power interruption. Integrated
systems that have UPS and standby
generator components are often referred toas emergency power systems.
There are three distinct types of UPS: offline, line-interactive and double conversion- email g4yrz@wxsat.org(also called on-line). An off-line UPS
remains idle until a power failure occurs
and then switches from utility power to its
own power source—almost
instantaneously. An on-line UPS
continuously powers the protected loadfrom its reserves (usually lead-acidbatteries or stored kinetic energy), while
simultaneously replenishing the reserves
from the AC power. It also provides
protection against all common power
problems, and for this reason it is also
known as a power conditioner and a line
conditioner.
While not limited to safeguarding any
particular type of equipment, a UPS is
typically used to protect computers,
telecommunication equipment and otherelectrical equipment where an unexpected
power disconnection could cause injuries,
fatalities, serious business disruption ordata loss. UPS units come in sizes ranging
from those which will back up a single
computer without monitor (around 200 watt)to units which will power entire data centres
or buildings (several megawatts). I use a
600 W and a 1500 W UPS. The 600 W
model typically supplies power for 15-20
minutes for a Pentium 4 PC with CRT
monitor.
Historically, UPS units were expensive;
they were most likely to be used on
expensive computer systems and in areas
where the power supply was interrupted
frequently. As prices have fallen, UPS
devices have become essential equipment
for data centres and business computers,
and may also be used for personal
computers, entertainment systems etc.
I purchased my 600 W model in Bulgaria,
new from the shop, for 90 leva (around£35). The 1500 W model was boughtsecond-hand in the UK on eBay for £50, areal bargain. I can recommend the APC’s
Smart UPS range, as you can download
associated software which has a monitoring
agent showing status, power outages,
voltages, battery condition etc.
Furthermore, the batteries areexchangeable when they come to the endof their life (3-5 years).
A UPS is generally very easy to use. It's
just a matter of connecting your equipment
to it, plugging it into the mains supply andaway you go, ready to use!
The Inverter
An inverter is an electrical or electromechanical device that converts direct
current (DC) into alternating current (AC).

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GEO Quarterly No 19

Inverters are used in a wide range ofapplications, from small switching power
supplies for computers to large electricutility applications that transport bulk power.
Most inverters operate from a 12, 24 or
48 volt DC source and output to 110 or
230 volt AC. My inverter has a 24 volt input
and outputs 1500 watts at 230 V. I use two
12 volt, 110 amp, deep-cycle batteries,
wired in series, which I obtained from mylocal caravan shop in the UK. They retailfor around £100 each. You can purchasean inverter with a power output to suit yourrequirements: from about 30 watt to several
kilowatts.
Please note
Before rushing out to purchase yourinverter, make sure you use deep-cycle
batteries and not normal car batteries. The
latter are not suitable for use with aninverter, whereas deep-cycle batteries are
made specifically for such a device.
There are two types of inverter: those that
output true sine wave AC and exactly
match mains AC, and the more common
inverters that produce modified sine wave
AC. The latter will work for mostapplications but do tend to give a buzzing
sound on some radios, TVs and Hi-Fi
equipment.
Without a doubt a pure sine wave inverter
is best and I recommend a firm called
Xantrex, which offers top quality models. I
use my inverter for general purposesaround the home so that I can still perform
normal duties without it making crazy while
the power is off for up to 5 hours at a time!
Of course, the inverter will usually provide
more back-up time than the UPS because
it draws on larger batteries with greater
charge capacity. The more batteries youconnect, the longer run time you will have.
SafetyWhen using an inverter, it is important that
all connections are made correctly using
the correct type of cable. Connecting
cables the wrong way round (reverse
polarity) can permanently damage yourinverter and/or equipment, and too thin acable can lead to overheating. If in doubt
consult a qualified electrician. Remember,with an inverter you are working with ahigh current, which can kill if not handled
carefully. Most inverters come with
instructions on how to connect the unit andwhat type cable to use.
More information on inverters and batteries
can be found in my book review:
Emergency Power for Radio
Communications, GEO Q10, page 4.

9

GEO Quarterly No 19

Group for Earth Observation

It’s really encouraging to report that, following our June issue,
readers have supported the GEO Reader Survey in numbers,
providing valuable feedback for the Management Team. Knowing
your likes, dislikes, and ‘wish lists’ will greatly assist us inaddressing members’ needs in the future.
Most Interesting Article
Three articles that appeared in GEO Quarterlies during the past
12 months came equal top of readers’ preferences and accounted
for over half of all selections, as listed below.
•
•
•
•
•
•
•
•
•
•
•
•
•

SatSignal Animations
Lightning RADAR
Arctic Meltdown
LRIT (Ed Murashie)
Aral Sea
Unseasonable Weather
Falkland Reminiscences
Comparison of Antennas for 137 MHz
PC Networking
Trialling the Dexatek USB box
EUMETCast Articles
Other Satellites (Peter Wakelin)
Cloud Streets

18%
18%
18%
12%
9%
5%
5%
3.5%
3.5%
2%
2%
2%
2%

Broadly, these returns suggest readers’ main priorities to be• Articles dealing with novel ways of manipulating their
EUMETCast images• Construction projects• Factual articles using satellite imagery to describe and explain
the state of our planet
Topics Requested
Requests for future topics generally fell into three broad categories.
Hardly surprisingly, more information relating to EUMETCast came
top of the ‘wants list’ but APT still retains a strong following, as dorequests for more articles related to meteorology.
EUMETCast / MSG• EUMETCast with Linux distributions (Ubuntu)• Using EUMETCast for beginners - the basics, getting started
without too much hassle• Beginners ‘step by step’ EUMETCast column/series• Other ‘Metcast systems’ coming into being.
• Cheapest way to receive data
• How to make use of the different types of data from MSG in
simple terms. A series of articles which show typical settings
for David Taylor's software and pictures of likely outcomes.
• Ground-up install and tweaking of satellite dish for
EUMETCast• Anything to simplify the computer complications of
EUMETCast (e.g. file organisation)• Descriptions of uses for the flood of secondary andprocessed data we are now getting on EUMETCast (i.e. notprimary images).
• Interpreting ATOVS data
APT
• Construction details on any APT item
• More coverage of APT and basic setups• More on APT• Weather satellite station setup for beginner (APT and HRPT)• Antenna's, receivers, demodulators, APT software• Maintenance / repair and recalibration of Az/El rotators,
particularly the Yaesu/Kenwood G5*** range
Meteorology• Maybe a little more on meteorology• Weather forecasting from satellite images

10

September 2008

• More on meteorological interpretation of images• After effects of major quakes/tsunamis on Earth structure
Miscellaneous• More construction projects• Weather satellites for beginners• PC networking for dummies• Picture manipulation, e.g. Photoshop to improve images• Hearing about other people's experiences and their set-ups• News and images from around the planets - the ultimate inimaging• Weather software

Statistics
Some general statistics offered by respondents revealed that only
15% of them were aged under 50. This comes as little surprise, but
starkly illustrates that GEO is not succeeding in attracting younger
members. It does rather appear that the demands of weather
satellite imaging, and of EUMETCast in particular, mean that many
GEO members have only found time to engage in our hobby after
retirement from work made sufficient leisure time available.
Additionally, almost two thirds of those who replied are radio
amateurs, a statistic that suggests that GEO must do much more
to attract members from the non-radio fraternity.
•
•
•
•
•

Aged 50 and overRadio Amateurs
Receiving MSG
Receiving APT
Receiving HRPT

85%
65%
57%
69%
11%

As to what readers actually receive in the way of satellite imagery,
it is clear that, even after over five years of free access to
MSG/EUMETCast, the majority remain loyal devotees of APT while
direct reception of HRPT is very much a minority interest.
General Comments
Many readers included their own comments, most of which werecomplimentary: GEO Quarterly was described several times as‘professional’ and the overall organisation of GEO received
numerous comments such as ‘excellent’, ‘1st class’, and ‘well run’.
On the down side, though, came several comments along the linesthat GEO is ‘too technical’ (related to the quantity of computer
programming featured in the Quarterly), ‘not everyone is an
Einstein’ and requests for more APT, DIY articles, kits and activities
and a regular Quarterly section on how to install EUMETCast.
There was a request that the Symposium be held closer to thesouth coast.
Some specific comments were:“Without dumbing down the excellent standard of thequarterly, perhaps the occasional ‘Idiots guide’ would not
be amiss”“Where else could one find such depth of knowledge
and experience so freely and graciously afforded to allmembers, particularly the tyros”“I find the magazine very interesting but I am a bit
overwhelmed by all the different ‘lingo’ and trying tounderstand all the programs”“Is there any way to have a members list printed so thatmembers can get in touch with each other. Since I am
new I have a lot of questions.?”“Would like to see more articles for the common layman”

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September 2008

Group for Earth Observation

GEO Quarterly No 19

The GEO Readers’ Survey did produce one rather scathingcomment, regarding the GEO Shop.
‘No backup from the GEO Shop ... Having recently
purchased the R2ZX receiver and the WXtoIMG software
I have had virtually no luck with receiving any decent
pictures. All cries for help have fallen on deaf ears.’This comment begs the question: ‘How should readers seek help?’

Over the years, we have received nothing but supportivecomments on the efforts of Clive and Carol Finnis for the GEO
Shop service that they offer. But it must be pointed out that Clive
and Carol provide the Shop service in their spare time (they run
their own full-time business during working hours) and that theirprincipal expertise lies in marketing—sourcing equipment on
GEO’s behalf, making it available at the best possible price tomembers and providing a distribution service. Neither of them isembedded in weather satellite imaging as a hobby
Getting Help from the GEO-Subscribers Internet Forum
Since GEO started, an Internet discussion forum managed by Nigel
Evans has been in existence, specifically to enable readers to
exchange information and to request help with their problems. A
multitude of difficulties have been resolved using this forum; wherea plea for help fails to turn up a solution it probably simply meansthat no-one knows the answer! In any event, your first port of callfor help on any weather satellite matter should be to the
Geo-Subscribers forum at
http://tech.groups.yahoo.com/group/GEO-Subscribers/

There are many other weather satellite related forums (including
one specifically related to WXtoImg software) listed in the centre
pages of GEO Quarterly. These offer more specific and specialised
support in a variety of fields.
GEO Helplines
Appearing regularly in the centre pages of GEO Quarterly is the
GEO Helplines column. The members listed in this column are only
a telephone call or email away if you require assistance.

The GEO Helplines section was set up over four years ago whenexpertise in the field of EUMETCast and the relevant imaging
software was in its infancy. Many GEO readers will these days bemuch more expert in this arena.
If you who would like to join the GEO Helplines, on any specifictopic of your choice—even if it is just one particular software
package that you know and understand expertly—please feel free
to email the editor with your contact details, stating the topic(s) on
which you are interested in helping, togeoeditor@geo-web.org.uk

When the December 2008 issue of GEO Quarterly appears it
will mark five full years of activity for our still youthfulorganisation.
Throughout this period, the names of Peter Wakelin and Les
Hamilton have been ever-present features of the ‘Contents
List’, indeed, more often than not with multiple entries.
Activity on this scale—researching, checking facts, sourcing
appropriate images and massaging everything into a
coherent narrative—is immensely time-consuming. Bothauthors have indicated that they wish to devote more timeto their other interests and will therefore be downscaling
their writing for GEO from this year’s end onward.
Expertise
When GEO first came into the world, EUMETCast was in its
infancy. During the years since, GEO readers haveexperienced a revolution in the manner in which weather
satellite imagery is received. It also goes without saying that
GEO must now number among its readership many who can
now be considered experts in this field, with a combined
wealth of knowledge that should stand the Group in goodstead for years ahead. GEO now needs you, our collective
cohort of seasoned experts, to take up the mantle and start
producing articles which share your knowledge andexperiences with newcomers.
Already, Mike Stevens, Rob Denton, Kobus Botha
and Marc Peigneux have risen to the challenge withofferings in this issue. But we do need a constant
supply of material to satisfy our readers’ demands
throughout each calendar year.
TopicsThere is now no secret as to what GEO readers wish to readabout in their Quarterlies. The bulleted list in the ‘Topics
Requested’ section (previous page) makes it plain where
readers’ interests lie. Initial quality of presentation need not
be a matter of concern; many are those who have initiallybeen hesitant about writing for GEO, only to be delighted
with what they see once editor Les Hamilton has processed
their material. If you have doubts, do feel free to discuss any
ideas you have with the editor first by email togeoeditor@geo-web.org.uk

As GEO is bound by the Data Protection Act, making a
Membership List generally available is not feasible. If you feel you
need help on a one-to-one basis from someone in your locality,
contact David Anderson, our Membership Secretary, atmembers@geo-web.org.uk

David may be able to put you in touch with other members in yourregion of the country, who can then offer assistance.
As far as we know, there are no Local Area GEO Groups. If you
would like to set one up in your area, contact the editor and we canpublish your contact details in our next issue.

Information Required
I seek any information (pin-outs, manuals etc.) for an
early Timestep/Griffin colour framestore and the matching
APT receiver. The board on the framestore is marked
RT403 and is 1985 vintage.
Any help appreciated. OK OK, I know it's ancient, but I'dlike to see it working!
Glenn Raineywww.geo-web.org.uk

email: geo@rainey.org.uk

11

GEO Quarterly No 19

Group for Earth Observation

September 2008

Mike Stevens (G4CFZ)
Back in the days before satellites or other means were
invented for meteorological purposes and forecasting it musthave been very difficult to make accurate weather
predictions. Something had to be done to improve thissituation.
One of the early methods used was to gather information byballoons, which soon became a feature of meteorologicalscience. One of the early ones was manned by a British
scientist, James Glaisher, in 1862; he managed to reach analtitude of almost 9000 metres, complete with several
thermometers, two barometers and a compass. At one point
he passed out due to lack of oxygen but recovered andreturned safely to Earth—albeit rather cold. Following thatexperience, it was decided to make use of unmanned
balloons, a technique that was further developed andimproved in the 1930’s into the radiosonde weather
observation system. Today there are various forms of
meteorological balloon: some remain at a constant height forlong periods; some are used to ascertain cloud height; yetothers measure high altitude winds.
Balloons also played a part in the early quantification of thehigh altitude westerly winds that we know today as the jetstreams. Between 1923 and 1925, Japanese meteorologist
Wasaburo Ooishi tracked the westerly movement of weather
balloons in the stratosphere. Unfortunately, he chose to
publish his work in Esperanto in the mistaken belief that
this would bring widespread recognition. Alas, the opposite
was true, and his work only surfaced after the discovery of
the jet stream following studies by Carl-Gustaf Rossby in
the USA during the 1940s. Rossby himself is credited withcoining the term ‘jet stream’.

the colder it becomes. Above regions such as Britain andEurope the temperatures are around -55 to -60°C.
Extending above the troposphere, to approximately 45 km,
is the stratosphere, which includes the ozone layer. Above
this comes the mesosphere, followed by the thermosphere,
which stretched between 80 and 120 kilometres above theEarth.
The satellite era started with the launch of the Russian
Sputnik-1. This was truly exciting and I well remember
listening for the tell-tale bleep it transmitted as it appeared
over the horizon and which faded away again as it passed
over. It left me wondering how it all happened and what the
future might hold. From then on satellites became the‘in thing’, and the Super Powers forged ahead, launching all
manner of satellites. There are now over 11 000 circling
above the Earth.
Weather Satellites
The polar orbiting weather satellites were the first to come tothe attention of the amateur fraternity. The composite image
below was produced from a number of photographs received
during Tiros-1’s second orbit, and show the Gulf of
St Lawrence with the St Lawrence River to the left.

There were also weather ships. Riding out the storms at sea
these could send back all the relevant information to
Bracknell and other weather centres—to be deciphered andtranslated into weather forecasts for shipping and thegeneral public. These ships have now been replaced by over
6 000 weather buoys—some moored, others drifting aroundthe seas and oceans—which send back their information tocentral weather centres, often via satellite relays.
I well remember the BBC weather forecasters relying onplastic symbols being stuck on to a plain map of the United
Kingdom. Somehow these managed to give us a basic idea of
the approaching weather, reliable for about eight hours at
most, and sometimes not even that. I marvelled that they
ever got it right with our fluid atmosphere.
The Atmosphere
The structure of our atmosphere consist of four principal
layers. Firstly we have the troposphere, stretching from sea
level to around 18 km, the layer where the clouds areformed and where the air moves both vertically andhorizontally. The contents of the troposphere are in constantmotion and are well and truly mixed; this is the part of theatmosphere that concerns us most because it’s where ourweather occurs. In the Troposphere the temperature
decreases with altitude: in other words, the higher you go

12

Figure 1 - An early composite Tiros-1 image
Credit: NASA

This was followed by the Nimbus series of research satellites
when Nimbus-1 gained orbit on August 28, 1964. The Soviet
program started shortly thereafter when Cosmos-45(September 13, 1964) returned some experimental images
and really took off with their first confirmed weather
satellite, Cosmos-122, in June 1966, to be followed by the
first of their Meteor range of weather satellites on March 26,
1969. The first sun-synchronous weather satellite, ITOS-A,
was launched on December 11, 1970, by the USA’s newly
formed National Oceanic and Atmospheric Administration(NOAA).
It was, however, very difficult to receive images from thesesatellites in those days as receivers for the frequencies
utilised were not commercially available. The only answer

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September 2008

Group for Earth Observation

GEO Quarterly No 19

Figure 3 - An April 2003 false-colour WEFAX image from Meteosat-7
Image © EUMETSAT 2003

Figure 2 - Metop image from May 24, 2008
Image © EUMETSAT 2008

Figure 4 - A NOAA-14 image taken from the 14:49 UT pass on August 9, 1998

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13

GEO Quarterly No 19

Group for Earth Observation

September 2008

was to obtain and modify a military receiver to access theinformation, but it did not stop there. You then had to
produce images, normally using a chart-recorder. It was
only the most ardent amateur with the requisite skill andexpertise who could make sense of the transmitted signals
and turn them into pictures. But they did, and it was to thecredit of these people that we have the knowledge today toreceive the data that is on offer to us.
Personal Computers
Once home personal computers became readily available
things really started to get very interesting. The BBC
Computer and the Commodore are just two of the popular
ones that come to mind. We were all keen to get our hands
on one, but to some they were just too expensive; but once
enthusiasts did acquire them, things started to move
forward very quickly indeed.
Software was, of course, required to decipher the signals
into something sensible and at that time there were very few
companies in the business of supplying software toamateurs. The first two who come to mind were Spacetech of
Portland, Dorset, and Dartcom from Yelverton in Devon.
Both were most helpful and assisted the amateurs inachieving some excellent results.
Amateur RadioI myself came into the weather satellite imaging hobby fromamateur radio and, with my interest in receiving all types ofsignals, it seemed a natural progression. As I worked for the
MoD and we had an excellent hobbies website, it did nottake long to identify other people with the same interest. I
was soon hooked on weather satellite reception.
Polar Satellites
The first satellites I received were NOAAs 12, 14 and 15(figure 4) and the Russian Meteor range (figure 5). I wellremember receiving my first images. Fantastic! The NOAA
range of Satellites are still going strong. Though several havebeen decommissioned, new ones have been launched, andNOAAs 15, 17 and 18 are still giving excellent pictures inboth APT and HRPT. Many of us started with these and arestill receiving them today as part of this fascinating hobby.
Like many, I turned my attention to David Taylor’s excellent
range of satellite software, which I use to this day. I still
wonder how he does it so well, with so much clarity anddetail. And for most beginners, APT is the easiest form ofweather satellite reception to start with. It’s relatively cheapand simple, with some stunning pictures at the end of it.
But of course the most recent orbiting satellite is Europe’s
Metop, launched on October 19, 2006 from the Baikonur
cosmodrome in Kazakhstan. Following its first orbit,
telemetry was received at the main ground station on
Svalbard. The satellite was then placed under the control of
the ESA Space Operations Centre for systems checking
before finally coming under the control of EUMETSAT.
Metop is now fully commissioned and sending down themost exciting pictures via the EUMETCast service that any
of us have ever seen. The detail is exquisite (figure 2).
Geostationary Satellites
Meteosat-1 launched in November 1977, was the first of thegeostationary satellites, heralding the beginning of a new era
in weather satellites. It marked the start of a continuous
high quality scanning service, initially covering Europe,
Africa and the Atlantic and from 1977, part of the Indian
Ocean as well. If you read the excellent article by John
Tellick in the March 2005 GEO Quarterly, he gives acomplete run down of the Meteosat programme.
Meteosat-1 failed fairly early in its life, causing quite a gap
in the service, until Meteosat-2 was launched in June 1981.

14

Figure 5 - A typical Russian Meteor image

Five more Meteosats followed, culminating with Meteosat-7
in September 1997. My first pictures from Meteosat-7 wereof course in WEFAX format (figure 3) and very different fromthe latest transmissions. WEFAX continued right up to thetime that this satellite was moved across to the Indian
Ocean in December 2005.
Meteosat Second Generation
In August 2002 came another new era with the launch of
the first Meteosat Second Generation (MSG) geostationary
weather satellite, MSG-1. There was great excitement bymany throughout the weather fraternity, but for amateurs it
looked as if it would require an expensive set of kit toreceive these transmissions.But fate played a hand, an onboard solid state power amplifier failed during thecommissioning, testing was halted and an enquiry was held
to ascertain the damage to the programme.

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September 2008

Group for Earth Observation

GEO Quarterly No 19

Rob Alblas
In meteorological circles, the BUFR format is commonlyused to interchange data.
“BUFR (Binary Universal Form for data Representation)
has been designed to achieve efficient exchange andstorage of meteorological and oceanographic data. It is aself defining, table driven and very flexible data
representation system, especially for huge volumes ofdata.”
Extracting data from a BUFR file needs an executable (theBUFR reader) and tables. The tables contain information on
how to extract the data. This allows new data types to be
defined without changing the BUFR extractor itself. There
are three main table sets, coded B, C and D. Some of thesehave the extension ‘.TXT’ and are in ASCII format, making
them readable using a text editor (although this is notintended as it’s a huge amount of figures, not easily
understandable by ‘normal humans’ ). For more information
about these tables, including descriptions of the BUFR
format, have a look at the website of the European Centre for
Medium-Range Weather Forecasts [7].
Files in BUFR format are also broadcast via the EUMETCast
system. However, up till now this format was not easily
usable for amateurs. Decoding software had been (partly)
written in Fortran, and primarily compiled for Unix systems.
KNMI Software
One of the projects of KNMI, the Royal Dutch Meteorological
Institute, is the development of scatterometer processing
software for operational use in weather and marine
forecasting. On their website [1] they offer free source code
for a BUFR translator, primarily for scatterometer data, butwith some adaptations other data types in BUFR format
should also be extractable. With some help from KNMI, I
was able to compile this software for both Linux andWindows. As a result, BUFR formatted data is now withinreach of amateurs. The name of the program is Bufr2Asc.
Scatterometer Project; ERS-2 Satellite
The Wind Scatterometer (SCAT) is a radar instrument onboard ERS-2 (European Remote-Sensing Satellite). ERS-2
was launched in 1995, but is still in operation. Metopcarries a comparable instrument (ASCAT, Advanced
Scatterometer) on board.
The received radar reflections from sea waves are used to
calculate wind speed and direction; a so-called ‘wind cell’ of
about 50 by 50 km is used for each measurement.
Measuring is done using a C-band microwave sensor, inthree directions relative to the satellite orbit: 45° forward,
sideways and 45° backwards. . Figure 1 shows how satellite
track and measurement areas are related.The C-band radar
frequency used is almost unaffected by heavy rain, so it canreturn useful wind data even from the heart of the fiercest
storms.
The ERS-2 satellite carries a lot more instruments [2]: theseinclude synthetic aperture radar to monitor vegetation,

growth, flooding and land cultivation and a microwave
sounder which provides measurements of the total water
vapour content in the Earth’s atmosphere.
For more information about the scatterometer project,including current measurements, have a look at the KNMI
website [1].
Decoding the BUFR Format
Raw data from the satellite is downloaded at Svalbard,
processed at ESRIN (ESA Centre for Earth Observation) in
Italy and then broadcast as BUFR via EUMETCast
Channel-1 (the same channel used for NOAA AVHRR and a
lot of other BUFR files).
Files are named likescatt_20080705_142916_ers2___00000_ear_o_250_ovw.l2_bufr
The KNMI BUFR translator is basically a command line
program. Executing the command
Bufr2Asc inputfile outputfile
will translate the input file (e.g. the mentioned ‘scatt_..’ file)
into ‘outputfile’. This is an ASCII file, which can be viewed
with a text editor like Wordpad. It contains a table withpositions and wind speed/directions:#Lat-62.26-62.15-62.05-61.95-61.84Lon
143.70144.13144.55144.97145.39Date
20080705
20080705
20080705
20080705
20080705

Time
1430
1430
1430
1430
1430

Speed
2.33
2.69
3.10
3.35
3.57

Dir
258.50255.90253.10255.40258.90....

etc.
The speed is stated in m/sec while the direction is codedusing meteorological convention, where 0° is south, 90° is
west, 180° is north and 270° is east.
Before executing Bufr2Asc, an environment variable has tobe set, e.g.:
set BUFR_TABLES=C:\bufr_tables/
This is to tell the BUFR extractor that it can find the tables,
necessary to do the extraction, in directory ‘C:\bufr_tables’.
(Note that there are currently some limitations on thelocation of the BUFR tables: see chapter ‘Installation’.)Using Xrit2pic to Decode Scatterometer Data.
I have adapted Xrit2Pic so it can deal with scatterometer
results. Wind speeds can be plotted as vectors on satellite
pictures from Meteosat, GOES, Metop etc., as well as on
Earth maps (e.g. from Blue Marble). Xrit2pic will deal withexecuting the BUFR translator, including setting theenvironment variable.
Figure 2 shows how the received ERS-2 data pops up in
Xrit2Pic’s main window. By selecting a line, the content(amount of numbers, location) becomes visible at the end of
the line. Sometimes the content is zero. This means that the
selected data doesn’t contain scatterometer information,

www.geo-web.org.uk

15

GEO Quarterly No 19

Group for Earth Observation

Figure 1 - Relation between satellite track and measurement areas

September 2008

Figure 3a - Scatterometer data plotted on a map of the Earth

Figure 3b - Scatterometer data plotted on a local area

Figure 2 - Decoding scatterometer data with Xrit2Pic

Figure 5 - Selecting vectors to add to an image

Figure 4 - Scatterometer data combined with a satellite image

16

Figure 6 - Identifying scatterometer data sets on a world map

www.geo-web.org.uk

September 2008

Group for Earth Observation

which is the case at times when ERS-2 isn’t above the sea.
The BUFR file is nevertheless broadcast because it also
contains other (non-scatterometer related) information. Oneor more (or even all) the available ERS-data may be selected.
Now, by simply clicking on Preview, a map is opened withthe scatterometer data plotted on it (figures 3a and 3b). Notethat vectors are plotted only at sea locations; above land
there is of course no wind data available.
In <Preferences> the background map may be defined;currently this must be a full-Earth map (gif or jpeg) in Plate
Carree projection. By default, the same map as for plotting
polar tracks is used, but this is a very low resolution
picture. It’s OK to see which part of the world the data isrelated to, but to examine the individual vectors a far-zoomin is needed. In that case a high resolution background map
like one of the Blue Marble charts [3] is advisable. Both
8 km/pixel and 2 km/pixel ones are usable, although thelatter needs some time (15 seconds or so) to set up, and a
PC with at least 1 GB RAM is advisable. See ‘Installation’ formore details.
Clicking on <Export> will simply extract the data in the
BUFR file into an ASCII file (see example above). Actually,
this option will just invoke the Bufr2Asc program. Since
Xrit2Pic also handles satellite pictures from Meteosat, GOES,
Metop etc., it can easily combine data of one of these with
the ERS-2 scatterometer data. As a result, wind vectors canbe plotted on satellite pictures.
To do this the location of the wind vector (longitude andlatitude) must be translated into picture pixel position (x/y).
If a NOAA AVHRR picture is used an appropiate Kepler fileis needed (i.e., Kepler data of about the same date as theused NOAA picture).
Metop and NOAA GAC files, which contain Kepler data, arebroadcast using the EPS format. This orbit information isused by Xrit2Pic, so a Kepler file isn’t necessary for thesesatellites. HRIT/LRIT files of geostationary satellites(Meteosat, GOES etc.) also contain all required figures tocalculate the longitude/latitude position of every pixel.
A note has to be made about whether it makes sense tocombine an image from one satellite with the windinformation from an other.
There are 2 possibilities:
1 Use a cloud free image as the background for the windvectors. This is like using the Blue Marble maps.
2 Use an image from the same date and about the sametime as the wind vectors.
Although possible, plotting wind vectors of one date on animage from another date, with completely different weather
conditions, doesn’t make any sense.
Finding a satellite image with nearly the same date, timeand position as the wind vectors for plotting purposes isonly possible with geostationary satellites. Meteosats 8/9
are particularly useful because of their high image repeat
rate. Combining images of one polar satellite with the windvectors from another polar satellite (ERS-2) at the sametime/date is maybe not feasible; for this, the positions ofboth satellites would fortuitously have to be about the same.
If Metop scatterometer data can be decoded, then of course
this would perfectly match with the images of the same
satellite. Something to work on ...
Although Xrit2Pic displays all received satellites by default, it
is possible to list only satellites of a certain type (figure 2). I
have added an option to show both ERS-2 and geostationary
satellites. Because they are listed in time order, it is easy to
select the ERS-satellite of interest and the geostationary

GEO Quarterly No 19

satellite nearest in time. Pressing <Preview> will then show
the combined picture. All features like special projections(Plate Carre, polar), colour mapping, special mappings for
dust, fog etc. are possible (figure 4).
Adding Vectors to a Predefined Image
Instead of selecting ERS-data and then choosing a nearestin-time satellite picture, it is also possible to do it the otherway round: plotting wind vectors for one or several ERS-2
datasets on to one predefined satellite image. First, selectand preview an image in the usual way. For polar satellites,
a projection (Mercator, Polar north/south, Plate Carre) has
to be chosen: for geostationary satellites this isn’t necessary.
Now, choose <Preview → View → Scatterometer>, which will
open a new window showing all ERS-data present in the‘received’ folder (figure 5). Select one or more lines, and thevectors will be plotted on the satellite picture. If the <Plot all>button is checked the wind vectors of all available ERS-2
data will be plotted. Vectors of the selected data will be in adifferent colour.
If no data is shown, or some indistinct shading appears at
the very margin of an MSG image, then the selected
scatterometer data must apply to a different part of theworld not shown in the image you have selected. To locate
the scatterometer data click on <Open map>. This will open
the same map as when previewing scatterometer data alone,
but now with all available scatterometer data plotted,
together with identification numbers. Again, selected data is
in a different colour, so you know ‘where you are’ (figure 6).
To examine the individual vectors a ‘far zoom-in’ is needed.
The length of each vector shows the wind speed. The actual
speed and direction at each location is available by clicking
on <More> at the very top-right of the Preview window. The
cursor may now be moved over the picture, and position(lon/lat) and wind speed/direction are shown. Zooming in at
the cursor position is possible by pressing shift-I.
Saving the result in a picture file is done using menu item

<File → Screendump>. Generated picture format is ppm.

The menu items <Save jpeg>, <Save pgm> etc. don’t work atpresent (they will not show the wind vectors). A screendump
was the easiest way to get the vectors perfectly into a
picture. (lines drawn in a picture may look broken if zoomed
out after adding them). The ppm format was chosen becauselines in a jpeg formatted file may look grubby.
Installation
For Windows there is a self-installing executable for the
scatterometer part, like the one for Xrit2Pic. By default the
BUFR extractor, Bufr2Asc.exe, is installed in the same
directory as Xrit2Pic (C:\Program Files\xrit). The tables are
installed by default in C:\bufr_tables. (if Windows is
installed on the C: drive). This is also the default in Xrit2Pic,
so normally, after default installation, everything shouldwork.
In the Xrit2Pic <Preferences> menu, you can choose analternative location for the tables. Note, however, thatcurrently Bufr2Asc doesn’t allow spaces in the directory
name (because as far as I know spaces are not allowed inenvironment variables). This is also the reason why BUFR
tables are not installed near the program. I’ll change that in
the future.
Another important point is that the path to the bufr_tables
folder must end with the Unix-type directory separator(forward slash). So the path must look like
c:\bufr_tables/
Xrit2Pic will take care of this, so it doesn’t matter if you

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17

GEO Quarterly No 19

Group for Earth Observation

forget or use the forward slash at the end. I just mention it
here to prevent confusion should this strange mixture of
directory separators pop up. (Xrit2Pic will use this path to
set the environment variable before executing Bufr2Asc.)
If BUFR translation doesn’t work, a message is placed in theinformation bar at the very bottom of the Xrit2Pic window.
For cases where this message doesn’t point to the problem, adebug feature is added. If the <Test BUFR extractor> button in
the Viewers tab of the <Preferences> menu is checked then,every time the BUFR extractor is executed, a window withmessages from this program pops up, which hopefully gives
a clue to what is going wrong.
Defining the background picture is done in the Files tab of
the <Preferences> menu. Blue Marble maps need first to be
downloaded from the NASA website [3]. Follow the ‘Monthly
global images’ link. Take care if downloading a 2km/pixel
map. These are very big jpeg files (21600 x 10800 pixels) andyour browser may not be able to display them. It is best to
download these by right-clicking on ‘2km/pixel’. This will
give a pop-up window where you can download by selecting
the ‘Save as’ option from the menu. Now the picture will be
downloaded without being displayed in the browser.
Using this picture needs 1 GB of RAM, otherwise things
become unacceptably slow. It’s best to start by using one of
the lower resolution 8km/pixel maps.
For installation on Linux, the tarball bufr2asc.tgz needs tobe downloaded. This contains both program and tables.
Extract it in $HOME/bin, and check the BUFR table locationin Preferences (by default $HOME/bin/bufr_tables/).
Using BUFR Extractor Standalone
The actual scatterometer extractor, Bufr2Asc, is a separate
program, so it may be used stand-alone or in combination
with other programs. The required environment variable may
be set together with the actual execute command.

David Taylor
For some time, wind data has
been available on the
EUMETCast stream, but if has
been in the BUFR format, whichhas proved rather more difficult
to decode than some of thevarious other formats such as
GRIB and HDF used forweather data. Fortunately, a
couple of programs have cometo hand which can decode the
BUFR data into a text format
which can be read anddisplayed more easily.
Data Sources
This data is available from twobasic sources—scatterometerdata from radar sensors carriedon polar orbiting satellites whichlook at sea-surface reflections
to determine the surface windspeed, and air-motion data
which is derived from the‘image’ data available from both18

polar orbiting and geostationary
weather satellites.
For the scatterometer data,
EUMETCast offers data fromthree different sources, thesensors on Metop-A, those on
the ERS-2 (Earth Resources
Satellite 2), and both the 25 km
and 100 km data from the
QuikSCAT polar orbiting
satellite.
For air-motion vector data,
EUMETCast carries both data
derived from the operational
Europe/Africa geostationary
satellite (Meteosat-9), and from
the MODIS satellites, Aqua andTerra. These latter products
cover the north and south polar
regions (although the Antarctic
station is down at the time ofwriting).

September 2008

For Windows
set BUFR_TABLES=c:\bufr_tables/ & Bin2Asc inputfile outputfile
For Linux (bash)
export BUFR_TABLES=$HOME/bin/bufr_tables; Bin2Asc inputfile
outputfile
with ‘inputfile’ replaced by the scatterometer file name totranslate.
(By the way, these are exactly the commands as executed by
Xrit2Pic.)
Future Developments
The Metop satellite is especially interesting because here
both image and scatterometer information are available fromone and the same satellite. The BUFR files seem to be a bit
different, however, and I have yet to find out how to decodethem. Furthermore, it would be interesting to see what othertypes of data in BUFR format is available, and how they may
be represented.
References
1 KNMI
http://www.knmi.nl/scatterometer
2 ERS-2
http://www.deos.tudelft.nl/ers/instruments.html
3 Blue Marble maps:
http://earthobservatory.nasa.gov/Newsroom/BlueMarble
4 Compiled BUFR extractor:
http://www.alblas.demon.nl/wsat/software/soft_msg.html
5 Orbit figures of ERS-2 can be found at:
http://celestrak.com/NORAD/elements/resource.txt
Note: This is not necessary for using the BUFR extractor! For plotting
wind vectors on a NOAA AVHRR picture the orbit figures of NOAA
itself are needed: (use the download option in Xrit2Pic, Preferences
tab Files.)
6 http://celestrak.com/NORAD/elements/weather.txt
7 Description of BUFR (and other formats):
http://www.ecmwf.int/products/data/software/

The Software
To allow readers
to visualise thisdata, I havewritten a simple
BUFR Viewing
program whichconverts the
BUFR data into
text using the
programs
alreadymentioned. Itthen displays
the text
BUFR Wind Vector Data for Hurricane Bertha
graphically as
either direction arrows (showing the direction of air motion) or the
more classic wind-barb display (showing the direction from which
the wind is coming). Once the data has been converted to text, thetext version is used for future display to save the repeatedconversions.
I had earlier been dubious about using a conversion program but,with modern PCs, there is not a lot of waiting around! The largest
files take the longest to convert, and these are the air-motion
vector files (AMV) from the full disk Meteosat-9 data.
The BUFR Viewer program may be downloaded here, and includes
a 30-day trial period before registration is required.
http://www.satsignal.eu/software/BUFR-viewer.html

www.geo-web.org.uk

September 2008

Group for Earth Observation

GEO Quarterly No 19

David Anderson

Nigel Evans
One of the frequent requests from the recent GEO Readers’
Questionnaire was for more articles relating to APT imaging. This
immediately struck a chord with me for, although I have consideredmoving on to EUMETCast, I have so far remained a 100% APT satellite
imager.
What better than to hold a competition for the best APT image
obtained by a GEO Reader on a specific date in the second half ofSeptember.
The Plan
To make sure that everyone will have received this issue of GEO
Quarterly in good time to be primed for the competition, the date is
Saturday, September 20.

Much has been said over the years about GEO’s
status as an international weather satellitegroup. So it seemed a useful exercise to reveal
just where our membership comes from.
The table opposite shows where all our members
come from, though does not include those whose
subscriptions expired with the delivery of
Quarterly No 18. We very much hope that allthese people will have renewed their subscription
by the time this appears in print.
Just over two thirds of GEO members reside in
the United Kingdom (68%). The Netherlands,
with 29 members comes next on the list, closely
followed by the USA and Germany.

The Satellite
Images should be from a daytime NOAA-18 pass. In the unlikely
occurrence of a serious NOAA-18 malfunction, NOAA-17 may besubstituted.
The ImageThe image you submit for the competition should be either• a monochrome channel-2 (visible) image or• a channel 2+4 false-colour image
Images should be as realistic as possible: this means no entries, please,with exotic colour schemes (cloud top temperatures, rainfall etc) oroverlays.
Information RequiredYour image, as a good quality JPEG file, should be submitted alongwith the following information:• Your name and postal address• Your email address• The receiver and antenna used
• The software used to process the image• The date and time (UT) of the pass
Judging and Closing Date
Images will be judged by Nigel Evans, whose decision shall be final andbinding. Closing date for receipt of entries is Saturday, October 25,
2008.
Prize
The entry adjudged the winner will earn the reader submitting it a prizeof free entry to GEO’s 2009 Symposium.
Submission of Entries
It is anticipated that readers will submit their entries by email, tonigel@geo-web.org.uk

Where this is not possible, they may be sent on disc or CD to
Nigel Evans
L’Eventail
7 Gloster Ropewalk
Aycliffe, Dover CT17 9ES
ENGLAND

Cover and Full Page Images
Front Cover
Anthony Lowe sent us a CD full of APT images acquiredsince the turn of the year. This quarter’s cover image
comes from his selection, the NOAA-17 pass at 11:00 UT
on May 7. A large region of high pressures reveals theentire British Isles, along with France, Denmark and
Norway.

Inside Front CoverThis false-colour image was created from an HDF filedownloaded from the China Satellite Data Service Center.
The image dates from 05:30 UT on May 10, 2008, andwas processed using the latest version of GeoSatSignal.
You can learn how to process such images in our article
on page 34.
Image: CSDSC

Back CoverThis fine Metop-A image sent to us by Mike Stevens dates
from May 5, 2008 and clearly shows both the Canary andCape Verde island groups off the coast of west Africa. The
Canaries can be seen generating an interesting set ofcloud vortices.

Page 6

Image © EUMETSAT 2008

This lovely Metop-A AVHRR image dating from themorning of June 2, 2008, showing much of Scandinavia
free of cloud, was submitted by Alan Banks.
Image © EUMETSAT 2008

Page 38
Mike Stevens downloaded this fine Meteosat-9 image at
13:10 UT on April 14

Page 40

Image © EUMETSAT 2008

Another image from Mike Stevens, this time from
Metop-A, imaged by the AVHRR at 10:37 UT on May 5.

And Finally
Thumbnails of all images submitted will be posted on the GEO website.

www.geo-web.org.uk

Image © EUMETSAT 200819

GEO Quarterly No 19

Group for Earth Observation

September 2008

Douglas Deans - dsdeans@tiscali.co.uk
Let me start off this quarter by expressing
my thanks to those who took the trouble toprovide some feedback on my new lookcolumn. Although only a few passed
comments, those who contacted me were
all very positive, particularly in respect of
the Q and A content. It seems that myconcerns regarding the rather simplistic
level of my first questions were unfounded.
as one reader put it ‘it is just what wasneeded.’This quarter I take a look at another few
interesting computer questions and also
have a couple of updated programs tobring to your attention.
Upgrading to Vista?
From time to time, I read comments
regarding Microsoft's latest operating
system and questions relating to the needor worth in upgrading to Vista. I can onlyoffer my own experiences with this as I
have both an XP and a Vista computer inconstant use. My XP unit is the 'receive'
computer for the EUMETCast system while
the Vista one is the processing computerfor EUMETCast data and everything elsethat I do—including typing this article using
AbiWord ....... now there is an incredibly
good free program. Sorry back to topic.
I do get asked about the merits of Vista,
whether it is worth upgrading and what
problems are encountered with drivers etc.
Firstly, let me say that I have found the‘Home Premium’ edition of Vista to besuperb. There are many useful featuresand visually, it is stunning. It is probably themost secure of all Microsoft's operating
systems but, that said, I do not think that
upgrading is the best route to follow.
Upgrading is expensive and, despite themany improvements, it is difficult to justify
the cost.
What is very attractive, however, is theprice when purchased bundled with a newcomputer. When I bought my AMD dual
64-bit 6400, Vista Home Premium (32-bit)
was provided for £59, complete with a
Microsoft CD ..... none of this recovery discnonsense: exceptionally good value. All my
programs were loaded back in without
issue, although I had to check for the latest
Vista drivers for my all-in-one
printer/scanner/copier. I really don't

20

recommend purchasing the 64-bit version
of Vista for the moment as that is not sowell supported just yet. In addition, I haveread that Microsoft will offer an upgrade totheir 64-bit software, although I have toassume it would be a ‘start again’
installation.

However, for those who may find the NTP
concept a little daunting, fear not, as there
are many other ways to keep you computer
clock sufficiently accurate for therequirements of our hobby. Indeed, youneed not look any further than the PC’soperating system itself.

So there it is! When it's time to purchaseyour next new computer, then move toVista, relatively cheaply and without issue.
It is, in my opinion, a superb operating
system, although meantime, XP will(properly kept up to date) satisfy all yourrequirements and needs.

Windows XP
If your computer is a member of a domain,
your computer clock is probably
synchronised automatically by a network
time server. If your computer is not amember of a domain, you can synchronise
your computer clock with an Internet time
server.

Computer Q and A
I am often asked about computer clock
inaccuracies and how to correct them, so
this quarter I want to have a look at thethorny issue of keeping your computer
accurately at the correct time. I also
discuss a handy utility for taking the hassle
out of issues associated with memory
upgrading, something that can be very
useful in view of those ever increasing
image file sizes.
Correcting Computer TimeFor our hobby, it is essential that computer
clocks are accurate. If we are tracking polar
orbiting (or indeed any other) satellites, it isessential that the computer time is correct
and that up to date Keplerian elements are
installed; otherwise, the satellite may
appear earlier or later than expected.
Although I have found more modern
computers to be better timekeepers, I havealways been surprised at just how poor
computer clock chips are. I have owned
computers where the clock chip was out by
minutes a day. Of course, if you are using
an older computer, firstly make sure thatthe problem is not caused by a run-down
CMOS battery. Replacement of this is astraightforward and inexpensive job.
There are a number of ways of keeping
your computer clock accurate, some better
than others and some more automatic thanothers.
One of the best methods nowadays is the
public standard Network Time Protocol(NTP). I don’t intend to discuss this option
as David Taylor wrote a very detailed article
explaining its use in the launch issue of
GEO Quarterly, which I strongly
recommend you to read.

www.geo-web.org.uk

Open <Control panel → Date and Time>and select the Internet Time tab. If'Automatically synchronise with an Internet
time server' is ticked, the clock will be
updated once per week. However, if you
don't have a continuous Internet connection
through a cable or DSL modem, theautomatic synchronisation might not always
occur. In that case, you can force an
immediate synchronisation by clicking theUpdate Now button on the Internet Timetab. This tab is only available if yourcomputer is not a member of a domain.
When you click the Update Now button,
your clock should be synchronised
immediately. If this fails, it might be for oneof the following reasons:• You have forgotten to connect to theInternet• Sometimes a firewall can prevent
synchronisation. Check yourdocumentation for a remedy.
A quick search on the Internet will reveal amultitude of programs written just to ensure
your computer clock is kept accurate. The
majority of them are free. There are far too
many to mention and most will do the job
efficiently and automatically.
Windows Vista
This is one of the few occasions where
Vista and XP are almost identical so you
should follow the same instructions as
detailed above for XP. Remember mycomments in the last Quarterly about theControl Panel viewing options in Vista.
Most of the free programs written to keep
your clock accurate will work equally wellwith Vista but check the documentation justto be sure.

September 2008

Group for Earth Observation

Upgrading Computer Memory
With the ever-increasing size of image files
for processing and viewing, and that long
list of animations to be run, extra memory
can be a huge help. Having said that, there
are limitations on the maximum amount ofmemory that can be installed and indeed
addressed by a computer. Obviously, thenumber of memory slots provided on themotherboard is one constraint, as are thetype and size of memory module
supported. So three memory slots that cantake a maximum of 512 MB modules eachwill be much more limiting than three slots
able to take 1 GB modules.

(number of slots, memory size and typeetc.) and offers a whole range of possible
update options, costs and ordering details.
It is a superb service which removes all theanxiety and hassle associated withidentifying and choosing memory. I haveused Crucial on a number of occasions
and, even ordering late in an afternoon, I
found the memory delivered (free ofcharge) the next morning. At the moment
memory is relatively inexpensive and it will
only cost about £40 to add 1 GB of fast
DDR RAM. Crucial's web site can beaccessed atAlso, whilst Windows ME, XP and Vista
support up to 4 GB of RAM, in reality, 32-bit
operating systems can only address slightly
over 3 GB RAM (in fact somewhere
between 2.75 GB and 3.25 GB depending
on setup).

where you can follow links to the Crucial
System Scanner tool and also the Crucial
Memory Advisor tool. Of course, if you
already know what you want, skip the tool
options and go straight to ordering.

For 64-bit operating systems, anything from
8 GB up to 128 GB can be supported,
dependant on the operating system itself.

Software Updates

Now some of you may have diligently kept
your motherboard booklets, but even if you
have, you may not understand the complex
references to memory specifications—latency, clock speed and DDR to mention
just a few. Without a motherboard
reference life is going to be very difficult
indeed. Remember, mixing memory types
will at best cause problems; more likely,
your PC will just not work.
CrucialCrucial, one of the top memory companies
in the UK, have an excellent website which
includes a very useful scanner tool. This
investigates your computer and provides amost detailed analysis of its architecture

http://www.crucial.com/uk/

APT Decoder v 2.0.5.83 (April 6, 2008)
Although I did a quick review of updates tothis program last quarter, a couple of newfeatures have been added since then. The
latest release of Patrick Tast's excellent
program now provides an Automatic
Restart feature and an Automatic Update
facility.
For full details of those additions and otherextras, and to download the program or
updates please visit
http://www.poes-weather.com/

XRIT2PIC v 2008.06a
Let me remind readers of this very versatile
program from Rob Alblas. The program

GEO Quarterly No 19

was initially written to decode HRIT and
LRIT files from MSG-1 and convert thedata to images.
However, Rob has, over a period of time,
continued to update the program to deal
with the multitude of data types now
available over EUMETCast. These include
Metop data, NOAA data, SAF files,
DWDSAT files and a wealth of
meteorological products, including recent
ASCAT data. The program is completely
free and is available for Linux as well as
Windows operating systems. For further
information, and to download the program
go to
http://www.alblas.demon.nl/
wsat/software/soft_msg.html

Latest Releases from David Taylor
To learn more about those programs and to
download the latest updates please go to
http://www.satsignal.eu
ATOVS Reader
AVHRR Manager
DWDSAT HRPT Viewer
GeoSatSignal
GRIB Viewer
GroundMap
HDF Viewer
HRPT Reader
Kepler Manager
MapToGeo
Metop Manager
MSG Animator
MSG Data Manager
PassControl
SatSignal
Sea-Ice & Viewer
Wxtrack

v 1.1.2
v 1.5.0
v 1.1.0
v 7.0.0
v 2.1.8
v 2.0.6
v 1.2.2v 2.8.0
v 1.3.0
v 1.1.6
v 1.2.4
v 2.5.20
v 2.5.20
v 3.1.0
v 5.1.2
v 1.3.4
v 3.6.8

Anders Höök
A spell of incredibly fine and warm weather innearly all of Sweden during July has resulted
in me obtaining some exceptionally good low
elevation APT images, compared with myusual standards. This has probably made all
humidity disappear from my antenna and alsothat the outside contacts are very dry.
The attached image, which includes the Aral
Sea itself and parts of the Caspian Sea andthe Black Sea came from NOAA 18 at 10:03
UT on July 25.
From my QTH, the elevation of the satellite
when it images the Aral Sea is between 4° and
9° and azimuth between 120° and 123°. Somenoise lines are clearly visible on the image,which isn’t very astonishing regarding the low
elevation, and also due to the fact that I havea power line roughly in this direction.
The receiver was an R2FX; decoding andprocessing were done with APT Decoder from
Patrik Tast.

A NOAA-18 image from Sweden, including the Aral Sea, from 10:03 UT on July 25, 2008

www.geo-web.org.uk

21

GEO Quarterly No 19

Group for Earth Observation

September 2008

Francis BellI have read recent emails and Internet discussion groupqueries relating to problems in setting the audio level from a
VHF receiver into a computer soundcard. This happened tome some years ago and I thought I might describe thesolution I employed then and still use today.
My first APT receiver was a Dartcom model, purchased in the
1980s. I still use it occasionally. The receiver itself has nevergiven me a problem but, in those early days, I was using a‘486’ computer and a decoding card bought from an
educational scientific supplier. It all worked well but initiallyI had difficulty adjusting the audio level for the interfacecard. The adjustment had to be made at the back of thecomputer using a tiny trimmer on the card. It was difficult
to access quickly and while receiving a live signal it was
nearly impossible.

Figure 1 - The boxed and labelled potentiometerI didn’t want to make alterations within the radio receiver
but while reading the manual I noticed the specification for
the audio output to the computer was 1 volt rms. against agiven resistance. Subsequent receivers I have used have had
the same 1 V rms. output standard.
Now, I’m not particularly technical but I thought that if I
connected the receiver’s audio output across a suitablepotentiometer I could sweep off any voltage I wished (up to
the maximum) and send that signal to the decoding card.
This worked well. I set my potentiometer to approximately
mid scale and, with an incoming signal, set the trimmer on
the card to give an acceptable image. I never touched thecard again. Further signal level adjustments were madeeasily, in real time, just by using my external potentiometer,
now in a box and carefully labelled (figure 1).
Nowadays, I have five APT receivers and several computers.
The computers now have built in soundcards. Although thedays of plug-in decoder cards are long gone, I still use thepotentiometer box for feeding in the audio signal from thereceiver. I set the initial audio input level to the computer
using the operating system’s sndvol32.exe utility, with myexternal box set in the mid position.
This is a one-off adjustment; thereafter I use the box with its
potentiometer for fine adjustments. The system has worked
well with all the receivers I have and with all the computersthat I use for APT. I even take my external control box on
my travels. See GEO Q 15 page 45 ‘Peripatetic APT’
It’s unlikely that I will make another external control box
because I now have three of them, but if I did I would makesome small modifications. First, I would use different typesof plugs and sockets for the input and out put so there wasno chance of connecting them the wrong way round. I would
also add a 1 kilo-ohm 0.25 W resistor in series with thepotentiometer, thus making it impossible to short circuit theaudio line from the receiver (figure 2).
All the APT weather display programs which I have tried
respond to the external box adjustments in real time. One
small point I have noticed is that WXtoImg takes three orfour display lines to adjust to a change is signal level.

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Figure 2 - Connection diagram for the potentiometer

Construction
Figure 2 illustrates how to construct the signal level
controller. The output signal from the receiver must beconnected across the two outer terminals of thepotentiometer (i.e. across the full 47 kiloöhms resistance ofthe device).
The output to the computer soundcard must connect
between the centre terminal of the potentiometer and one of
the side terminals.
The 1k resistor on the output line guards against a shortcircuit should the unit be connected the wrong way round.
Components• A small project box• 47k potentiometer (linear scale). Rating is not critical,
and anything from 10k to 100k would be eminently
suitable.
• 2 sockets for connecting the leads, different types
preferred• A control knob (with a scale attached) is useful• A 1k, 0.25 W resistor
This should be an easy small project. I certainly find the
product very useful.

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Peter Wakelin
TWINS Science Payloads on Classified Spacecraft
In June, 2006, the classified spacecraft code-named USA 184 waslaunched to a highly eccentric ‘Molniya’ orbit. The characteristics ofthis useful orbit were described in GEO Quarterly, No 14(June 2007), and the orbit of this spacecraft was used to illustrate
the advantages of such an orbit. It was speculated that USA 184
carried the first SBIRS (Space Based Infrared System) payload.
USA 200, launched on March 13, 2008 to a similar orbit, but in adifferent plane, is believed to carry the second SBIRS payload.

to map ocean currents, not only by satellites, but by utilising floats
and buoys as well. Advances in radar altimetry in the 1980s provedthat sea surface levels could be measured to better than 10 cm
accuracy and satellite measurements have been maintained
continuously since the launch of the joint NASA-CNES
TOPEX/Poseidon mission in August 1992. This satellite was still
operating nine years later when the technically more advanced
Jason-1 was launched into the same orbit, enabling tandem
operations to compare instrument characteristics and more thandouble the science return.

Analysts now believe that these two spacecraft also carry the
TWINS A and B payloads, designed to derive stereoscopic, threedimensional observations of the Earth’s magnetosphere, that allimportant region of high-energy charged particles trapped within
our planet’s magnetic field, which protects all life from harmful
components of the sun’s emissions.
The feasibility of magnetospheric imaging was demonstrated morethan 10 years ago and NASA’s IMAGE (Imager for Magnetopause
to Aurora Global Exploration) spacecraft, launched in March 2000,
was the first dedicated platform for making ENA (energetic neutral
atoms) measurements of Earth’s magnetosphere. The TWINS (Two
Wide-angle Imaging Neutral-atom Spectrometers) spacecraft
permit simultaneous observations from two widely-separated
vantage points at up to almost 40,000 km above Earth’s surface.
This stereo imaging is expected to greatly advance theunderstanding of the global aspects of Earth’s magnetosphere.
Final SAR-Lupe Launched
Germany’s fifth and final SAR-Lupe radar imaging satellite waslaunched by a Russian Kosmos-3M on July 22. It is identical to
SAR-Lupe 4, launched in March and described in Earth Imaging
News, GEO Quarterly 18, June, 2008.
Jason-2 Launched Successfully
This joint French-US (CNES-NASA) mission was launched onJune 20 from Vandenberg’s Launch Complex SLC2W by United
Launch Alliance’s Delta II 7320
vehicle at a time when the launchsite was passing through the planeof Jason-1’s orbit. It was reported
that the first stage underperformed
slightly but this was compensatedfor by the second stage andJason-2 entered the planned orbit
about 10 km lower than that ofJason-1. Jason-2 was thencommanded to execute a series ofmanouevres to raise its altitude tomatch that of its predecessor andposition it about one minute(500 km) ahead but slightly offset
to allow for Earth’s rotation during
Jason-2’s under test
this short interval. This was to
Credit: CNES
ensure that the nadir-pointing
altimeters on both satellites were following precisely the sameground track. This delicate operation took about a month after
which cross-calibration of the instruments on the two spacecraft
began. These checks will take about six months but even before
the end of July, valuable, high-quality data were being received
from this Thales Proteus class satellite which had a launch mass of
506 kg.
Jason-2 data will contribute to the Ocean Surface Topography
Mission (OSTM) which forms part of an integrated global strategy

Schematic identifying Jason-2’s instrument
Credit: CNES

Jason-1 continues to operate well and, once Jason-2’s calibrationis complete, the two will operate in tandem for as long as Jason-1
remains healthy. On completion of the calibration phase, the older
craft will be manoeuvred so that its ground track is mid-way
between two adjacent Jason-2 groundtracks. This arrangement will
once again increase the data two-fold and also provide valuable
data on smaller-scale ocean phenomena which would not be
possible with a single spacecraft, such as eddies and tides incoastal areas and shallow seas .
Data from the satellites, which are in orbits inclined at 66° to theequator, thereby covering almost all Earth’s oceans, are received
at three ground stations located at Fairbanks in Alaska, Wallops
Island, Virginia, and Usingen in Germany. After processing by
CNES, EUMETSAT or NOAA (depending on the type of data) the
products will be made available to users, some of them in near-realtime.
Instruments on Jason-2 are similar to those on Jason-1 but thePoseidon-3 radar altimeter will improve ocean surface height
accuracies to about three centimetres. The purpose of the other
instruments on board is to precisely locate the spacecraft in its orbit
and to determine atmospheric effects on the radar pulses. A brief
description of the instruments follows but much more can be foundon numerous websites such as
http://www.nasa.gov/ostm

The Poseidon-3 dual frequency altimeter is the main instrument on
Jason-2 and measures the distance to the sea surface. An analysisof the return radar signal can also result in reliable measurementsof wave height and surface wind speed.

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The Advanced Microwave Radiometer is an improved
version of that flown on Jason-1 and acquires
measurements in three separate frequencies todetermine the path delay of the altimeter’s radar signal
caused by water vapour in the atmosphere.
The Doppler Orbitography and Radiopositioning
Integrated by Satellite (DORIS) system provides highprecision, real-time orbit determination and beacon
positioning. Positions accurate to a few centimetres canbe achieved with DORIS. Measurements can also be
used in geophysical studies.
The Global Positioning System Payload (GPSP) is a
tracking system that receives dual-frequency navigation
signals continuously and simultaneously from several
GPS satellites to determine Jason-2’s orbit.
The Laser Retroreflector Array (LRA), developed by
NASA, reflects laser beams from several laser-ranging
stations and can measure Earth to satellite distances toan accuracy of a few millimetres. It is used to calibrate
GPSP and DORIS.
Improvements to these instruments since Jason-1 wasbuilt will permit a significant increase in accuracy inmeasuring ocean surface heights: better than 3 cm isanticipated. A new instrument, the Wide Swath Ocean
Altimeter, which was earlier planned for inclusion on
Jason-2, did not fly but three experimental payloads
were incorporated. They are Time Transer by Laser Link
and Environment Characterisation and Modelisation-2,
both from CNES, and Japan’s Light Particle Telescope.
Enhanced Imagery for China’s Flood Season
China’s primary geostationary satellite is currently
Fengyun-2C stationed at 105°E longitude from where it
routinely images every 30 minutes. FY-2D, launched in
November 2006, is located above 86.5°E and isnormally in standby mode; but during the summer floodrisk season in China, which extends from June to
September, FY-2D is being used to provide additional
imagery. By interlacing 30-minute imagery from the two
spacecraft, the China Meteorological Administration
effectively gets 15-minute imagery for the four-month
period. FY-2E is expected to be launched later this year
and is destined to go to 123°E.
Changes to NPOESS and NPP
A sensor considered critical in monitoring global climate
will be restored to the first satellite scheduled to fly in2013 in the National Polar-Orbiting Environmental
Satellite System (NPOESS). The Total Solar Irradiance
Sensor (TSIS) had been removed during the 2006
restructuring of the NPOESS programme. The decision
follows an earlier agreement to put another climate
sensor, the Clouds and Earth Radiant Energy System(CERES) on NPP, the NPOESS Preparatory Projectsatellite. CERES data will complement TSIS
measurements by shedding light on how clouds
influence the Earth’s energy balance and the role theyplay in regulating climate. Another instrument, theOzone Mapping and Profiler Suite (OMPS), formeasuring the vertical distribution of ozone, wasrestored to NPP in 2007, reversing an earlier decision
not to include it.
India Launches CARTOSAT-2A
On its thirteenth flight, the Indian Space Research
Organisation’s Polar Satellite Launch Vehicle, PSLV-C9
launched the 690 kg Indian remote sensing satellite
CARTOSAT-2A, the 83 kg Indian Mini Satellite (IMS-1)
and eight tiny nanosatellites for international customers
into 637 km sun-synchronous orbits. The rocket lifted off

24

Part of Bangalore, India, imaged by Cartosat-2
Credit: ISRO

from the second launch pad at the Satish Dhawan Space Centre in
Sriharikota, on India’s east coast, at 03:54 UT on April 28.
CARTOSAT-2A carries a panchromatic camera capable of taking monochromeimages in the visible part of the spectrum with a resolution of about one metre
over a swath 9.6 km wide. The camera is steerable both along and across the
direction of travel to facilitate imaging of any area more frequently. The highresolution imagery is being used primarily in urban and rural development
applications requiring large-scale mapping.
Indian Mini Satellite (IMS-1) was developed by ISRO for remote sensing
applications and incorporates many new technologies. It carries two multispectral cameras with 37 m and 500 m resolutions at the nadir and is
expected to operate for two years. IMS has been designed so that future craftin the series can incorporate a wide variety of payloads without significant
changes.
Six of the eight nanosatellites are within the University of Toronto’s NLS-4
project and were developed by various universities in Japan, Canada,
Denmark, Germany and the Netherlands. The other two are RUBIN-8, built by
Cosmos International in Germany, and NLS-5, built by the University ofToronto.
Satellite to Map Earth’s Soil Moisture
A new NASA satellite is being designed to collect global soil moisturemeasurements and other data seen as key to improving weather, flood anddrought forecasts, and predictions of agricultural productivity and climatechange. At present, scientists have no network for gathering soil moisture dataas they do for rainfall, winds, humidity and temperature. NASA’s Soil Moisture
Active-Passive Mission (SMAP), scheduled for launch in 2012, aims to change
that.
The SMAP mission is based on an earlier project that had been selected byNASA and scheduled for a 2009 launch but the Hydrosphere State Mission(Hydros) was axed in 2005 when funds were diverted. SMAP’s instruments
will gather both active (by radar) and passive low-frequency microwave
measurements on a continuous basis, thereby creating a map of global
surface soil moisture. The 6-metre mesh antenna will gather data along a
1,000 km swath covering the entire globe every few days. The satellite will
also detect if the surface moisture is frozen and, in forests, the freeze/thaw
state which determines the length of the growing season and hence thebalance between carbon assimilation into biomass and the loss of carbon due
to vegetation respiration. The result of this balance can tell scientists if a forest
is a net source or net sink of carbon.
Chilean Volcano Chaiten Erupts
After lying dormant for thousands of years, Chile’s 1,000 m high Chaiten
Volcano, near the Gulf of Corcovado, began erupting on May 2 leading to theevacuation of thousands of people from the area. Envisat’s Medium
Resolution Imaging Spectrometer (MERIS), with a resolution of 1,200 metres,
captured this image on May 2. It shows the ash cloud crossing the Andes
mountain range and Argentina before reaching the Atlantic Ocean.

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disasters for support. The initiative, referred to as ‘The Charter’,was founded in October, 2002 by ESA, the French space agency(CNES) and the Canadian Space Agency. It is aimed at providing
satellite imagery free of charge to those affected by disasters
anywhere in the world. Radar imagery can be especially useful inthe early stages when storm clouds may preclude optical imaging
and, as modern radar satellites can adjust their ‘look angle’, there
is a minimum of delay in assessing a disaster situation. Just a few
days before cyclone Nargis struck, Canada’s Radarsat-2 imagery
was used for the first time in an emergency situation. Public Safety
Canada activated ‘The Charter’ on April 30 after heavy rain andmelting snow caused the Saint John River in New Brunswick to
overflow and cause widespread flooding.

Envisat images the eruption of Chaiten volcano
Credit: ESA

To boost the use of Earth observation (EO) data at volcanic
observatories, the European Space Agency has started to monitor
volcanoes worldwide within the Agency’s Data User Element
Programme. The Globvolcano project, started early in 2007, willdefine, implement and validate information services to support
volcanological observatories in their daily work by integration of EO
data, with emphasis on observation and early warning.
Numerous Satellites Monitor Cyclone Nargis
Countries bordering the Bay of Bengal have experienced
numerous severe cyclones in recent decades yet, despite plenty ofsatellite imagery and several day’s warning, cyclone Nargis killedaround 200,000 people in early May, mostly when sea water
inundated low-lying areas of the Irrawaddy delta region of Burma.
On May 4, the UN Office for the Coordination of Humanitarian
Affairs asked the International Charter on Space and Major

Ikonos image of May 7 showing flooded fields in the Irrawaddy Delta region
Credit: GeoEye/CRISP

Geostationary satellites from Japan, China and India as well as
EUMETSAT’s Meteosat-7 cover southeast Asia but the two images
selected here are from the polar-orbiting Aqua and Ikonos
satellites.
EarthCARE Satellite Contract Signed
The European Space Agency and Astrium GmbH have signed acontract to provide the EarthCARE satellite, the sixth Earth
Explorer mission in ESA’s Living Planet Programme. As prime
contractor, Astrium will be responsible for the satellite’s design,development and integration.
The EarthCARE mission aims to improve the representation andunderstanding of the Earth’s radiative balance in climate andnumerical weather forecasting models by acquiring vertical profilesof clouds and aerosols, as well as radiances at the top of theatmosphere. The satellite, with a mass of about 1,700 kg, will beplaced in a 400 km sun-synchronous orbit in 2013. The four
instruments will be an atmospheric lidar, a broadband radiometerand a multispectral imager, all developed by ESA, and a cloudprofiling radar developed by the Japan Aerospace Exploration
Agency.

Cyclone Nargis in the Bay of Bengal on May 2 imaged by MODIS on Aqua

GOES-3 Still Functioning after 30 Years
GOES-3 is one NOAA’s early spin-stabilised weather satellites andwas launched in June 1978. Although no longer imaging, and lunisolar perturbations have increased its inclination to 14°, it is still
being used as a data-relay platform though not for NOAA-related
data. GOES-7 is also still relaying data but is a mere 21 years old.
One advantage of the high inclination is that for part of each daythese old satellites are accessible from polar regions.

Credit: Jeff Smaltz, MODIS Land Rapid Response Team, NASA GSFC

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GEO Quarterly No 19

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September 2008

Rob Denton LZ/G4YRZ

If I had been told that, one day, I would visit
the Philippines, I never would havebelieved it. Even now it all seems like a
dream to me. Not only was I there to meetthe girl who was my pen-pal—while I was
there I became engaged to my sweet
Filipina friend, Rosalina, from the town of
Calubian in the island of Leyte.
For those of you who are thinking ‘Where
are the Philippines?’ and ‘What's it likethere?,’ I hope this article will give yousome insight to these beautiful unspoilt
Islands. I can only describe them as
paradise on Earth, where the people are sofriendly and you can easily get lost in thedarkness of their eyes.
If you have an atlas, take a minute to findthe places I'm describing: it will help you tohave a better understanding of the weather
system there.
The Philippines, officially known as theRepublic of the Philippines, is a nation
located in southeast Asia with Manila as its
capital city. The Philippine archipelagocomprises over 7000 islands in the western
Pacific Ocean, bordering countries such as
Indonesia, Malaysia, Palau and Taiwan; itis the only southeast Asian nation to shareno land borders with its neighbours. The
Philippines is the world's 12th mostpopulous country with a population
approaching 90 million people.
The Philippines became a Spanish colonyin the 16th century then a territory of the
USA from early in the 20th century before
gaining independence in 1946. Today, thePhilippines has many affinities with theWestern World, derived mainly from thecultures of Spain, Latin America, and theUnited States.
As GEO members, I'm sure you are allinterested in the climate of thePhilippines—to see what it's like on the‘other’ side of the world. The Philippines
enjoy a tropical maritime climate,characterised by high temperature andhumidity with abundant rainfall, similar inmany respects to that of the countries ofCentral America. The Philippines lies in thepath of typhoons, as illustrated in the image
opposite, obtained by Japan’s MTSAT-1R
satellite.
Temperature
Based on the average of all weather
stations in the Philippines, excluding

26

Baguio, the mean annual temperature is
26.6°C. The coolest months fall in January(mean 25.3°C) and the warmest month is
May (mean 28.3°C). I visited in May andwish I had known this earlier. It was muchhotter whilst I was there, with a minimum of
30°C at night and much higher in the day.
Thank goodness for the air conditioning in
the hotel and vehicles.
Latitude is not a significant factor
controlling temperature variations
throughout the islands: altitude produces
greater contrasts in temperature. Thus, themean annual temperature of Baguio, at anelevation of 1,500 meters, is 18.3°C,
comparable with countries possessing atemperate climate. Because of this, Baguio
is known as the summer capital of thePhilippines.
The difference between mean annual
temperatures at the southernmost station in
Zamboanga and the northernmost stationin Laoag is insignificant. In other words,
there is essentially no difference in themean annual temperature of places in
Luzo, Visayas or Mindanao measured at ornear sea level.
Humidity
Humidity refers to the moisture content of
the atmosphere. Due to high temperatureand the surrounding bodies of water, thePhilippines has a high relative humidity.
Average monthly relative humidity varies
between 71% in March and 85% in
September.The combination of warm
temperature with high relative and absolute
humidities gives rise to high sensible
temperature throughout the archipelago. It
is especially uncomfortable during March toMay, when temperature and humidity both
attain their maximum levels.
RainfallRainfall is the most important climaticelement in the Philippines. Rainfall
distribution throughout the country varies
from one region to another, depending
upon the direction of the moisture-bearing
winds and the location of mountainsystems. The mean annual rainfall of thePhilippines varies from 965 to 4,064
millimetres annually. Baguio City, eastern
Samar, and eastern Surigao receive thegreatest rainfall while the southern portionof Cotabato receives the least. At General
Santos City in Cotabato, average annual
rainfall is only 978 millimetres.

www.geo-web.org.uk

The Seasons
Using temperature and rainfall as bases,
the climate of the country can be divided
into two major seasons, the rainy seasonfrom June to November and the dry seasonfrom December till May. The dry season
may be subdivided further into the cool dry
season from December to February andthe hot dry season from March to May.
Typhoons
Typhoons have a great influence on the
climate and weather of the Philippines. A
great portion of the rainfall, humidity andcloudiness are due to the influence of
typhoons, which generally originate in theregion of the Marianas and Caroline
Islands of the Pacific Ocean, and whichhave the same latitudinal location as
Mindanao. Their movements follow anorthwesterly direction, sparing Mindanao
from being directly hit by the majority of thetyphoons that cross the country. This
makes the southern Philippines very
desirable for agriculture and industrial
development.
Wind Systems in the Philippines
During the period from June to September,the Habagat, or southwest monsoon, blows
strongly from the southwest. Originating in
the region of Australia,
the winds initially turnto the right and headtoward low pressurenear the equator.
However, once northof the equator, theyturn left due to the
Coriolis effect andhead instead towards
low pressure overcentral Asia, passing
over the Philippines
on the way.
The SW Monsoon
From November to
February, on the other
hand, the Amihan, or
northeast monsoon,
starts as a stream ofcold air from the highpressure region over
Siberia, and moves
south toward low
pressure over the northPacific Ocean. The
Coriolis effect deflects
these winds to the left

The NE Monsoon

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GEO Quarterly No 19

Typhoon Rammasun closes in on the Philippines in this 1-km visible MTSAT-1R image acquired on May 10, 2008
Image: China Satellite Data Service Centerand over the Philippines from the northeast
as they are drawn towards the lowpressure over Australia.
Personal Experiences
Whilst I was in Leyte we just caught theaftermath of typhoon Rammasun (image
above), which brought extra rain to theregion but thankfully no loss of life ordamage. The skies always seemed cloudy,
but that did not mean it was always raining.
If there were no clouds, there would be no
shelter from the hot sun. When it did rain, it
rained heavily and provided the perfectopportunity for Rosalina and theneighbour’s children to take a cool,refreshing shower in the garden. It wasinteresting for me to see new flora andfauna, with coconut and banana trees inmost gardens and lots of interesting newplants, with huge butterflies on them.
Being a radio ham, and also having aninterest in antennas, one interesting point I
noticed was the angle of the offset dishes;
whilst almost vertical in UK, here they werepointing at a similar angle to prime focus
dishes, due to the latitude being close to
the equator at around 11°N.

Angled offset TV dish antennathat there would be lots of pager
interference, although that depends on thefrequency of the pagers. Now that I havean R2ZX, maybe next time I go I can be
portable and get some APT images. I justneed to find a portable antenna. I'm surethere will be a design in one of the backissues of GEO. Of course, one way to findit quickly could be to use the GEO index
which can be found on Les Hamilton's web
page
Taking a cool shower in the garden
during the monsoon rains

I'm not sure how APT reception would be in
the Philippines because everyone is
cellphone crazy there, texting all the time. It
seems to be the fashion. I can only imagine

www.geo-web.org.uk

http://myweb.tiscali.co.uk/
wxsatellite/software.htm

References
This article was compiled from my own
experiences and various other sources fromthe Internet, courtesy PAGASA, Learning
Haven and Wikipedia.

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September 2008

David Taylor
Once again, GEO were invited to attend the AMSAT-UK
Colloquium at the University of Surrey at the end of July, to
put on a live display of weather satellite reception andprovide a lecture for the programme.
Thursday’s Precursor
As in some previous years, two GEO members who are also
members of the Three Counties Amateur Radio Club enjoyeda visit to the club’s Field Day where Francis Belldemonstrated live APT reception, helped by John Tellick(figures 1,2) while David Simmons demonstrated both live
EUMETCast reception (almost) and live ‘plane tracking withan SBS-1 box (figure 3). Whether it was the heat or not, but
Francis’ portable PC was running out of power by the end of
the day and David Simmons’ inverter (to power his kit) gave
up before EUMETCast reception was fully established. Oh
well, ther'll be another day.
That evening was enlivened by visual observation of not one
but two ISS passes in the Bell Garden. Prediction by
WXtrack was three minutes out, leading to one GEO
member saying: ‘I always trust Heavens Above’. So a web
browser was pointed to that site and (surprise, surprise)
exactly the same predictions emerged (much to my relief as
the author of WXtrack!). So it was off to NASA’s own website,where the predictions were again identical!

which it is put. Our thanks to EUMETSAT and the BNSC
amongst others.
LectureOn the Sunday, I gave a talk to the Colloquium. Although I
had given talks to AMSAT before, the feedback has beenthat a ‘Getting Started’ talk would be welcome, as well as‘more pictures, please’. Having only a twenty-five minute slot
meant that long animations were out, which was a pity as I
had been sent an instructive animation from a French GEO
member which I would have liked to have used. So I
concentrated on the ‘how-to’ of weather satellites, trying tocover reception of APT with omnidirectional antennas andreception of HRPT with steerable antennas, although the
major part of the talk was about EUMETCast because of thequality and diversity of data which it offers. Back in
Edinburgh, Cecilia managed to capture a few screen-shotsof the BATC feed (figure 8).

Now, I know that Keplers need to be kept up-to-date, butthese Keplers were only 1.5 days old, yet gave a threeminute error—rather more than I would expect. So, for the
next ISS pass, we added three minutes, and the very bright
ISS appeared as expected. Very confusingly, it was analmost overhead pass, which I never see from Edinburgh. Itturns out that the inclination of the orbit is the same as thelatitude of Guildford, hence the potential for an overheadpass.
Later we heard that other Keplers were giving similar errors,
and elements I downloaded the next day gave spot-on
predictions. Theories please for the Great Kepler Mystery ofJuly 2008….
Demonstrations
GEO provided live EUMETCast reception throughout thethree days of the Colloquium, bringing two complete
EUMETCast systems to the event, and setting up anantenna, cables and splitter to allow both systems access tothe satellite data (figure 4). The systems were running the
popular MSG Data Manager and MSG Animator software todemonstrate geostationary satellite data and its animationand false colouring (figure 5). To show how polar-orbiter
data has been integrated onto the EUMETCast stream andwhat new possibilities this offers, the AVHRR Manager andMetop Manager software were used. There was a lot ofinterest from the delegates in viewing their home locations,seeing other places across the world and predicting whether
they would need their umbrellas on the morrow (figure 6).
Fortunately, umbrellas were not needed as it was very hot
throughout the three days—although this made it a little
uncomfortable to be in the ‘Street’ ,where GEO was located(figure 7). Opposite the equipment demonstration, GEO had
provided much literature, from a variety of sources, whichgave more detail on Earth Observation and the uses to28

Figure 1 - Live APT

A first for me, and for AMSAT, was feedback from theInternet as a result of the BATC streaming video, and I wasable to add a slide to deal with question on HRPT from
California. The first time I’ve ‘played a request’ for anyone(figure 9). There was a chuckle round the audience when I
gave an example of why now-casting was important—answering the question ‘Will it rain before the next pitstop?’. I’m obviously not the only Formula One enthusiast in
AMSAT!
Acknowledgements
Thanks to AMSAT-UK for inviting GEO to the colloquium,and to the BATC for making the event accessible across thecountry and the world.
My thanks for Francis and Nadine Bell for their excellent
hospitality during the weekend, and to John Tellick andDavid Simmons for their expertise and help.
Useful Links•••

www.geo-web.org.uk

AMSAT
http://www.uk.amsat.org/
BATC
http://www.batc.org.uk/
Three Counties ARC
http://www.radioclubs.net/tcarc/

September 2008

Group for Earth Observation

GEO Quarterly No 19

Figure 2 - Setting up the antenna for live APT reception

Figure 5 - Demonstrating false-colour imagery

Figure 3 - David Simmons’ plane tracking kit and EUMETCast dishFigure 6 - Debating the following day’s weather

Figure 4 - The EUMETCast antenna

Figure 8/9 - David Taylor speaking on the BATC feed

Figure 7 - GEO’s display in the ‘Street’

www.geo-web.org.uk

29

GEO Quarterly No 19

Group for Earth Observation

September 2008

David Taylor
Irrespective of which program you use to process EUMETCast orother data, you may wish to direct control over what data is kept
and for how long. Your processing software may not be able tokeep up with all the new data continually being introduced by
EUMETSAT, leaving you with unprocessed raw data cluttering yourhard disk and possibly slowing down your PCs performance.
Additionally, you may have software which produces daily log files
but which lacks a means of limiting the number of logs retained.
Faced with these problems, I wrote a small utility called TrimTree.
You can download TrimTree free-of-charge here:
http://www.satsignal.eu/software/disk.html#TrimTree

Please note that it is unsupported software, so ask any questions
in my SatSignal Yahoo group at
http://tech.groups.yahoo.com/group/SatSignal/

The third and subsequent parameters specify the files whichshould be deleted. Note that I have used ‘wildcard’ file specifiers,
so that any file with ‘-msg-ch06.’ or ‘-msg-ch07.’ in the file namewill match for the first example.
You would then use the <Control Panel → Scheduled tasks>
function to make Nightly.cmd run at, for example 03:05 in themorning. If your computer is not running 24 hours a day you could
make the task run when you start up the computer by placing ashortcut to Nightly.cmd in your <Program Files → Startup> folder.
Each @ECHO command sends a line of text to the screen to show
the comment following the @ECHO statement.

Downloading and Installing TrimTree
In the Zip file you download, you will find two files: TrimTree.txt and
TrimTree.exe. Open the TrimTree.zip archive with your favourite Zip
program, or use the built-in Zip management software in Windows
XP and Windows Vista.
The text file will open with Notepad and provides the latest
information about TrimTree. If you copy the executable file,
TrimTree.exe to the Windows\System32 folder, you will then beable to call up TrimTree from anywhere on your computer.
Using TrimTree
TrimTree is only partially interactive—it will display the results of its
operation briefly but does not ask for user input in the conventional
sense. Instead, the program reads its control information fromparameters passed to it on the command line; it's designed to be
run multiple times, from a batch file, with a fixed set of parameters.
You would typically run the batch file once a night or, if you switch
on your computer every day, you could run if from the Startup
menu folder.
Example 1 - Managing Image Files from MSG Data Manager

Example 2 - Managing Raw Data Files from EUMETCast
Another use for TrimTree might be to remove EUMETCast data
which you don't process, although this is actually better done byediting entries in the recv-channels.ini file. Should you decide thatany unprocessed EUMETCast data more than 2 days old is of nointerest, and that you have a default EUMETCast installation wheredata is saved to the directory
C:\Program Files\T-Systems\BusinessTV-IP\received(Note: there is a space character in ‘Program Files’)You could add the following lines into your Nightly.cmd file.
@ECHO Delete the unprocessed data which is 2 days old
TrimTree 2 "C:\Program Files\T-Systems\BusinessTV-IP\received\" *.*This would remove any files more than 2 days old which are in the
Received directory, and in any directory below it. If you have otherreceiving directories in the TelliCast tree, you can process them too@ECHO Delete the unprocessed data which is 2 days old
TrimTree 2 "C:\Program Files\T-Systems\BusinessTV-IP\received_EPS10\" *.*Because the directory names contain spaces, be sure to enclose
them in quotation marks (shift-2 on an English keyboard).

@ECHO Delete the less interesting channels after 2 days
TrimTree 2 C:\MSG\images\ *-msg-ch06.* *-msg-ch07.*@ECHO Delete the more interesting channels after 7 days
TrimTree 7 C:\MSG\images\ *-msg-ch02.* *-msg-ch09.*

Example 3 - Managing Log Files

In this example, files in the folder C:\MSG\images\ and below which
are more than 2 days old, and which match either the file namesfor MSG HRIT channel 6 or MSG HRIT channel 7 would be deleted,
as well as files more than 7 days old for MSG channels 2 and 9.
This allows you to optimise disk storage by keeping the moreinteresting data for a longer period. The lines above could beentered into a command file with a name such as Nightly.cmd.
Some Notes on the Parameters
The first parameter after the command TrimTree specifies thenumber of days which should elapse before a file is considered‘old’ and therefore a candidate to be deleted. This date is based on
the file's modification date, which is the one usually displayed byWindows Explorer. In the first example it is 2 days.

30

The second parameter is the root of the directory tree from which
you want to start the scan. I like to add the trailing ‘\’ to clarify it asa directory specification.

Here is a different example - to keep the log files from Ship Plotter,
Plane Plotter and SBS-1 BaseStation software under control.
Ship Plotter log files are retained for two weeks, and the aircraftrelated files for seven days.
@ECHO Delete PlanePlotter and ShipPlotter log files
TrimTree 7 "C:\Program Files\COAA\PlanePlotter\log files\" pp*.log
TrimTree 14 "C:\Program Files\COAA\ShipPlotter\log files\" sp*.log@ECHO Delete SBS-1 BaseStation log files
TrimTree 7 "C:\Program Files\Kinetic\BaseStation\" 20*.bst

Using the Windows Task Scheduler
If your PC is left on overnight, perhaps collecting data, you may
wish to automate the operation of TrimTree by taking advantage ofthe Windows Task Scheduler. There is more information at
http://www.satsignal.eu/software/scheduled-tasks.html

www.geo-web.org.uk

September 2008

Group for Earth Observation

Metop LRIT Abandoned
Readers will be aware that the
projected LRIT dissemination on
137.1 MHz from Metop-A nevermaterialised due to transmitter
problems. Alas, as it has proved
impossible to rectify these for the future
Metop-B and Metop-C, it has been
decided to discontinue the LRPT
operational service. On the brighterside, this presumably guarantees
NOAA satellites the use of the the137.1 MHz frequency for aconsiderable time to come.

Another GEO!
Guess what! Someone has set up arival GEO!

‘Ondes’ Magazine
Last April, French radiocommunications
and electronics magazine Ondes
carried a feature publicising GEO. The
lead page is reproduced below.

Antony Lowe spotted the culprit duringa recent visit to St Helens and took thisphotograph as evidence.

For SaleDartcom 136-138 MHz synthesised
Satellite Receiver, cased. Needs a
12-volt mains adaptor.
Unit in good working order - £45
Tel: 0117 9498258
email: dbarwood@blueyonder.co.uk

GEO member Rob Denton of
Bulgaria wishes to announce his
engagement on May 21, 2008 to
Miss Rosalina Majait, second
daughter of Rodolfo and Rosemarie
Majait of Calubian, Leyte,
Philippines, an event which,romantically, took place while sailingon a bamboo boat between the
Islands of Biliran and Leyte.

GEO Quarterly No 19... continued from page 14

EUMETCastIn April 2003, trials began to transmit thegeostationary MSG image data by means of
the operational EUMETSAT multicast system,
via EUTELSAT’s Hot Bird 6 satellite located at
13°E. As it turned out, this has been a great
success, much to the joy of amateur
enthusiasts, and in January 2004 the MSG-1
imaging service became fully operational on
what was then called the EUMETCast service.
(EUMETSAT was formed June 19, 1986.) A
typical full Earth Meteosat-9 image
downloaded at 13:10 UT on April 14 isreproduced on page 38.
(image © EUMETSAT 2008)

This was great news because now amateurs
could receive geostationary data through astandard satellite DVB broadcast system.
There were many hurdles to overcome but,once the set up was operational, you could
receive much higher resolution imagery, in
twelve channels every quarter-hour. This wasa major increase in the amount of available
meteorological data and was produced anddistributed by EUMETSAT for 24 hours perday.
Not all the devout APT enthusiasts moved on
to this service. Because of the complexities insetting up the software and gaining thenecessary licences, quite a few have been
deterred. Also, costing the new system can be
expensive, especially if you are starting fromscratch. With the current credit restrictions
and soaring fuel costs many people have toequate the priorities, and rightly so.
But given all that, I can assure readers that it
is worth it in the end because theoutstanding quality of these pictures has tobe seen to be believed. EUMETSAT have to becongratulated and thanked for producing
such an excellent service and allowing
amateurs access to the data without charge.
So please don’t be deterred by all thetechnicalities it is worth it I assure you—justlook at the amazing false colour Meteosat-9
image on the opposite page.
Back to the Weather Forecast
When you see the weather forecast on TV
nowadays, it really does have some accuracy
and credibility to it. From those early
beginnings with balloons to the latest
satellites, we have never had so muchinformation to hand, available for anyone
with appropriate hardware and software touse; and of course it enables the Met Office toproduce highly accurate weather forecasts forshipping, aviation and the general public.
Acknowledgements

Alan Banks spotted these Von Kármán vortices being shed from Jan Mayen Island in the North
Atlantic between Norway and Greenland , in this Metop-A image dated May 27, 2008.
Image © EUMETSAT 2008

www.geo-web.org.uk

I would like to thank John Tellick and Peter
Wakelin for the help they have given to me over
the years, and also to David Taylor for all his
assistance with the software.

31

GEO Quarterly No 19

Group for Earth Observation

Marc

September 2008

Peigneux

On a nice afternoon of June 2008, my son and I wereenjoying a drive in the car between St Martin Vesubie in the
Alpes-Maritimes and Barcelonette in the Alpes-de-HauteProvence. As we reached Col de la Cayolle, a 2327-metre
mountain pass on the border between the two provinces, it
was just about time for a NOAA-15 pass, so we decided tostop and take advantage of this unique opportunity. As afaithful Earth observer, I always carry with me thenecessary equipment to record an APT satellite pass.
Our temporary installation was not so difficult to build.
However I paid very special attention to the power supply
connections because a shortcut to the battery could have
had some unpleasant consequences for the car; and in theevent of a problem, we were a long way from the nearest
garage!
The main question asked by my student son was about thedifference we could see in tracking an APT satellite from ourusual ground station, which lies at an altitude of 50 metresabove sea level, compared with the Col de la Cayolle at2327 m.
I tried to explain to him that, in thissituation, it was necessary to consider
three main reception criteria: thesignal strength, the noise and thetheoretical acquisition distance (which
is linked to geometrical parameters, as
illustrated in the diagram on page 33).
Signal Strength
Receiving VHF waves at nearly 2300 m
altitude or from sea level does not havea big influence on the signal strength

The whip antenna used
to receive NOAA-15

The 15:52 UT NOAA-15 image acquired on June 20 at Col de la Cayonne
using my portable APT system and a simple whip antenna.

My son, Nicolas, at the summit of Col de la Cayolle

32

Here I am with my portable APT equipment

www.geo-web.org.uk

September 2008

Group for Earth Observation

GEO Quarterly No 19

in an isotropic environment, such as the upper
atmosphere as we are only dealing with areduction in satellite distance from 840 km to837.7 km.
In our particular situation, we had only to takeadvantage of the fact that there weren't any
obstacles which could disturb the antenna
reception for that particular northbound
NOAA-15 trajectory.
Noise
The carrier signal strength could not be
improved by our altitude. We did, however, thinkthat the denominator of the S/N ratio could be
improved by the certain attenuation of the Noiselevel. In this particular area, electromagnetic
noise was considerably reduced because thepower supply was produced by the car battery
and we were far away from cities and industrial
electromagnetic pollution.
Acquisition Distance
The simplified drawing below (exaggerated scale)shows how the acquisition distance varies withaltitude above sea level.

Peter Green
Recently, my wife and I spent a very
pleasant couple of hours in thecompany of Bill Giles OBE, former
senior weatherman at the BBC
Weather Centre for 17 years.
Bill bought his one man ‘Weather
Show’ to the Landmark Theatre,
Ifracombe, as part of the North Devon
Festival. The theatre is located on thecliffs at Ifracombe overlooking thesea: a beautiful location in this quiet
seaside town.
Bill, a son of Devon, was pleased toreturn to ‘God’s own county’ as part of
the festival. The evening was liberally
splashed with anecdotes from hisboarding school days in Crediton,near where I live, to his days at the
Met Office and BBC.

The solid horizontal line represents theacquisition distance when you are at sea level.
From the Col de la Cayolle, however, you can see
a little beyond the sea-level horizon (dottedlines), which means that the acquisition distanceincreases (because the satellite comes into range
sooner). However, for an altitude of 2 km above
sea level, this increase is negligible, being only
from 6752 km to 6760 km. Anyway, probably
due to the poor gain of my very basic whip
antenna, we didn't get a spectacular result.
Antenna
A few words about this antenna. Everybody
knows very well that, for holidays trips, our cars
boots are usually full, so I decided to bring avery simple half-wavelength whip antenna. The
whip was mounted on the magnetic base froman old citizen band antenna and placed on theroof of the car during reception. I have noticed astrong reflecting influence from the car roof,
acting as a ground-plane. Moving the antennaaway from the roof had an immediate impact,
the VHF signal strength dropping some 2 dB.
Of course, we should certainly get some better
results with a good QFH antenna. The NOAA-15
picture displayed opposite is not spectacular,
but is the result of a convivial, experimental andeducational time in a very nice location !
It is to be hoped that such an experiment could
arouse some interest in young people who arevery often curious to give a concrete expression towhat they learn at school! Hopefully they will go
on to use this type of knowledge in their vocation.

There were stories from his days atboarding school, back in those
innocent times when the boys had toshare baths with matron looking on.
Bill told how, one evening, he had toshare his bath with a boy whom hehad never met before; so, as he got
in he introduced himself: “Hello I’m
Giles”. The other boy replied: “Hello,
I’m Pidler” Bill was out the bath like arocket.
Bill first became interested inmeteorology whilst at school in
Crediton and joined theMeteorological Office, then in
Bracknell, in January 1957, on
leaving Bristol College of Science andTechnology. Later that year he wassent to Christmas Island to observe
the immediate meteorological affectsof the H-bomb tests.
Bill’s broadcasting career began in1972 when he transferred to the
London Weather Centre to become
part of the team forecasting for BBC
Radio: he moved to television
forecasting in 1975. In 1980,
promotion brought Bill back to
Bracknell, where he worked in public
relations. Finally, in May 1983, hereturned to take charge of BBC
television’s forecasting team, on theretirement of Jack Scott.
During the evening Bill related
amusing tales on a variety of topic,
including how Michael Fish missed

www.geo-web.org.uk

the 1987 hurricane, why Ian
McCaskill broadcasts without his
shoes on and why some clouds are
mistaken for UFOs.
Bill Giles has no pretensions of being
an artist, and to show how to interpreta weather forecast he portrayed
Great Britain as a triangle and Ireland
as a rectangle! He showed what toexpect from winds arriving fromdifferent areas at different times of theyear and the effects they would have.
Bill is, however, a great
communicator. He showed a film of
the BBC Weather Centre when he
was in charge and could talk on thesubject for England—and does,
having just returned from China,
where he had been talking on Global
Warming and Climate Change.
I didn’t realise that Bill had beenworking on climate change nearly
thirty years ago, getting into deep
trouble with the senior managers at
the Met Office and BBC because of
his beliefs, even though they werebacked up by maths and science.
Although he is now retired from theBBC, Bill is still very busy, giving talks
to schools as well as government
bodies and other interested groups,
perhaps like GEO. He is able to pitch
his talks to the level of knowledge ofthe audience. He is also a director of
The Weather People with his friend
from the BBC John Teather.
Following his show, Bill tookquestions from the audience, which
was again amusing. But there weresome excellent questions, even one
from an elderly lady on jet streams,
which surprised Bill as well as therest of us.
If you get the chance to see Bill Giles’show, you are guaranteed a very
enjoyable evening.
For More Information Visit
1 http://www.billgiles.co.uk/
2 http://www.weatherpeople.com/
3 Re-live the old days of BBC weather
forecasting at:
http://www.beebweather.org.uk/

33

GEO Quarterly No 19

Group for Earth Observation

September 2008

Les Hamilton
In previous issues we have described
how you can obtain AVHRR data forthe various polar orbiting weather
satellites from the NOAA CLASSArchive [1,2]. These data are available
without cost after following a simple
registration procedure. Now, a newsource of weather satellite images has
become available, the China Satellite
Data Service Center (CSDSC).
CSDSC offers both polar andgeostationary data, but be warned: the
AVHRR data comes in unfamiliar
formats that cannot be decoded by anyof David Taylor’s software. Unless you
intend to engage in softwaredevelopment, give these files a miss.
But the geostationary data fromFeng Yun 2C, Feng Yun 2D and
MTSAT-1R are another matter. These
are supplied as HDF (Hierarchical Data
Format) files which can be decoded by
the latest version of GeoSatSignal-7
and my own HDF Reader program.
Registering with CSDSC
Before you can download geostationary
satellite HDF files from CSDSC you
must register for the service by visiting
the English language version of theirwebsite at
http://satellite.cma.gov.cn/eng/

In the upper left-hand region of the
opening screen you will find the link
‘New User?’ shown in figure 1. Click on
this link to continue to figure 2 where
you must click the ‘agree’ button toprogress further.
This done, you are presented withfields where you can enter yourusername, email address, password,name etc (figure 3). Write down theusername and password that you
decide to use: you will require these in
future when you log into the site. As
far as I can tell, the Verify button
serves no purpose at present.
Although you can select the highest
user level at this point (3GB/order),you will not automatically be able todownload HDF files (which all exceed
the basic user level of 200 MB/order).
Orders will be rejected on the grounds
that ‘your shopping cart is full.’

34

Once your details are complete, click
the Submit button, whereupon you can
immediately log into the site byentering your chosen username andpassword into the fields in figure 1,
typing the security code into its box
then clicking the GO button.
Upgrading Your Subscription
To receive the higher user levels you
must now send an e-mail to

Figure 1 - Logging indataserver@nsmc.cma.gov.cn

requesting access to the FY HDF data.
They will then email you a Microsoft
Word document to complete and returnto them. In my case, this arrived the
day after I requested it and an email
confirming my upgrade was received
three days later (sent off on Friday,
received Monday). I was then
immediately able to access anddownload the HDF data files.

Figure 2 - Agreement Screen

Ordering Feng Yun HDF Data Files
Log into the site as explained above(figure 1), select FY2/SVISSR in the
Search Data drop-down menu (figure 4)
then click the Search button. The
following screen will display two menus
which allow you to select the files thatyou require (figure 5). On the left-handmenu panel select either ‘FY2C’ or‘FY2D’ (there are no FY2B files
available). On the right-hand panel you
must select ‘NOM (Normalized
Dataset)’. Don’t select the other option:although the files themselves exist, ameans of decoding them doesn’t!
It now remains to enter the start andend dates/times for the image you
require. This can be done by manually
editing the fields at the foot of figure 5;
more conveniently, clicking on either
date field opens an interactive calendar
which makes selection much easier(figure 6). When complete, click the‘GO’ button to open a screen displaying
all available files within the time span
you selected. Part of this screen isillustrated in figure 7.
Tick the box to the left of the file(s) you
require and wait for the screen torefresh. When the line of text above thelist indicates that there are items inyour shopping cart, click the link tothe shopping cart.
text continues on page 41 ...

www.geo-web.org.uk

Figure 3 - Registration Details

Figure 4 - Selecting Data TypeSeptember 2008

Group for Earth Observation

Figure 5 - Selecting the correct files

GEO Quarterly No 19

Figure 6 - Selecting the Date

Figure 7 - Ordering the data

Figure 8 - Confirming the orderFigure 9 - Order Status

www.geo-web.org.uk

35

GEO Quarterly No 19

Group for Earth Observation

September 2008

Kobus Botha
Properly aligning your satellite dish may
seem a job reserved for the professional
installer, but anyone with basic DIY skills
can achieve this themselves. Once done,
the reward will be a trouble-free MSG
experience. Excellent signal quality is ofutmost importance—it is non-negotiable forC-band reception!
C-band is Different from Ku-band
The African C-Band dissemination service
for MSG data is transmitted from theAtlantic Bird-3 satellite on a downlink
frequency of 3726.7535 MHz using lefthand circular polarisation with a symbol
rate of 11 963 ksymbol/s. Interestingly,
when I change the Polarisation setting in
my Broadlogic Vbox 2030 DVB receivercard to ‘horizontal’ instead of ‘left’, thesignal strength is still the same. I use a
Symbol rate of 11 963 ksymbol/s.
Dish Azimuth and Elevation
To determine the elevation and azimuth ofAtlantic Bird for your particular location, use
the antenna pointing tool at
http://oiswww.eumetsat.org/
antennaPointing/cgi/antennaPointing.pl

Just select Atlantic Bird-3 from the dropdown list, enter your latitude and longitude,
and click the Calculate button. Elevation
and azimuth values for your location are
immediately displayed.
The Dish
EUMETSAT recommend a 2.4-metre dish,much bigger than for Ku-Band, for the
C-band service throughout Africa. I use
two dishes, the second a standby so that I
can immediately switch over without loss ofdata should a problem arise. Both dishes
are fully equipped with an LNB and aseparate cable to my main computer. Thisis also extremely handy to eliminate signal
problems. My primary dish is a 2.4 m meshtype and the other one a 1.8 m solid model.
The 1.8 m dish produces the stronger
signal and is also much easier to handle.
Dishes of these sizes are prime-focus
antennas, where the focal point (position of
the LNB) is directly in front of the centre of36

the reflector where it is not always so easy
to adjust and work with. The small offsetfed dishes as used for Ku-band are mucheasier to install, align and work with—andmuch cheaper.

of the LNB, sometimes referred to as its
skew or tilt, in order to get the best signal
quality. With the meter still attached, slightly
rotate the LNB to left and right till you get
the strongest signal.

StormsThe LNB is totally different and extremely
sensitive to thunderstorms—much more sothan a Ku-band type. The effect of thesestorms is very often not immediately
apparent. Signal strength might remain
normal for days following a storm thensuddenly the ‘red T’ pops up and the signal
strength is negative. When this happens
you must check the alignment of the dish. If
your satellite finder/meter does not react
when you press slightly on the dish, your
LNB will have been damaged and must be
replaced. I always keep a spare.

Finally, push the LNB back and forth in its
fitting until you obtain the strongest signal(figure 2) to fine tune the focal length. Focal
length is determined from the formula

The Alignment of the DishTo receive an optimised signal, the dishmust not only have a clear line-of-sight tothe satellite but also the correct vertical(elevation) and horizontal (azimuth)alignments. Elevation refers to the angulardisplacement of the satellite above yourhorizon and azimuth to its east-west
displacement with reference to the 0°
meridian. The following steps assume you
have a handy satellite finder/meter.
First disconnect the downlead from the
DVB receiver card to prevent possible shortcircuiting. Next, disconnect this downlead
from the LNB and connect it to the ‘REC’
socket on the satellite meter then use ashort patch cable from the LNB to the ‘LNB’terminal on the meter. Reconnect the cableto your DVB card and switch on the power.
The meter should now be ready to helpaligning the dish.
First, adjust the elevation, taking the angle
calculated earlier as a rough guide. Next,
set the azimuth roughly by means of acompass then start moving the dish slightly
to east and west until the strongest signal
is achieved. Tighten the azimuth bolts andadjust the elevation up and down slightly
until the maximum signal level is attained.
Tighten the elevation bolts and again adjust
the azimuth slightly to peak the signal, thentighten all bolts.
Your dish should now be correctly aligned .
Check that you have a strong.signal on
your computer.
Optimising the LNB
You must now adjust the polarisation angle

www.geo-web.org.uk

F=D2 /16 x H
where D = diameter and H = depth of dish.
I mark my final settings on the LNB anddish with a waterproof marker, which helps
a lot with future problems. This is only arough indication since, when the alignmentof the dish is out due to strong wind, youwill not be able to see this with your nakedeye.
Errors of only a fraction of a millimetre
will produce the ‘red T’ and no signal!
Your signal should now be fully optimised.
You can now remove the meter and makesure that your fittings are properly
protected with water tight tape.
Troubleshooting
Weaker signal than normal
In a recent case, I found the problem waswith the EUMETSAT C-band service
itself.The possibility of a DVB card problem
can be checked on the YAHOO MSG
Group, where speedy notification of ‘signal
problems’ are posted.
Total loss of signal
You will have a ‘red T’ and a negative
signal to noise ratio level on your card. I
would check as follow: reboot thecomputer, check DVB card settings andcheck for an voltage output, check dishalignment cables: if need be, replace the
LNB or DVB card.
Some Final Tips
Always use the best quality cables andsockets and make absolutely sure about
the connections of sockets, grounding, etc.
Don’t under estimate the possibility ofdamp entering connections, a sure causeof a short—especially if your system has
been down for some time. This is very
important during high humidity. Open theconnections and check for moisture. I lostan LNB by not doing this!
An in-line amplifier has no noticeable
benefit.

September 2008

Group for Earth Observation

GEO Quarterly No 19

Figure 1
Make sure that the ‘biscuit’ isproperly installed inside the LNB

Figure 2
The LNB should be shifted up and down tofine tune the focal length. Please note themarks on the LNB, made for futurereference using a waterproof marker

Figure 5
Severe weather in South Africa at.12:00 UT on June 17, 2008
Image © EUMETSAT 2008

Figure 3
A different view of the finally installed LNB

Figure 4This LNB is slightly off alignment, which
may be the reason for a weak signal.

Figure 6
Severe weather in South Africa at 12:00 UT on June 18, 2008
Some areas experienced 350 mm of rainfall
Image © EUMETSAT 2008

www.geo-web.org.uk

37

September 2008

Group for Earth Observation

GEO Quarterly No 19

A NASA Earth Observatory Report
Starting late May 2008, the Wilkins Ice Shelf on the Antarctic
Peninsula started to break up. The image immediately below wascaptured by the Advanced Synthetic Aperture Radar (ASAR)
aboard the ESA’s Envisat satellite on May 30 and shows the ice
shelf at the beginning of the disintegration event. At lower right inthis image is what glaciologists describe as mélange—a mass of
ice blocks welded together in a matrix of sea ice. This portion of
the shelf actually disintegrated in 1998 but the fragments heveremained frozen in place ever since. An ice bridge connecting to
Charcot Island stabilises the ice shelf. To the north is a mixture ofvery thin sea ice, ice blocks from earlier rifting, and open water.
In the image at bottom right, acquired on July 17, the breakup of
the ice shelf continues apace. The ice mélange is much darker
and large blocks of ice can be seen drifting northward, someseparated by areas of open water.
These images focus on events in the eastern portion of the Wilkins
Ice Shelf, the western portion of the shelf having already suffered
rapid disintegration between February 28 and March 6, 2008. That
event had occurred during the southern hemisphere summer,
when summertime warmth and sunshine drive surface melt
processes. In contrast, the events shown in these images took
place during the southern hemisphere winter. As of mid-July 2008,
the exact mechanism of the winter breakup was uncertain, butwarm ocean waters appear to have played a role.

Map of the Antarctic Peninsula, showing the location of the Wilkins Ice Shelf
Image: ESA

Previous studies of this area had mapped warm ocean waters at
depths of about 400 meters beneath the ice shelf. If this warmer
water were somehow mixing with the upper waters, and coming
into contact with the underside of the ice shelf, the warmer water
may have caused basal melting of the ice.

www.geo-web.org.uk

39

September 2008

CSDSC

Group for Earth Observation

GEO Quarterly No 19... continued from page 34

You now have to tick and confirm theorder and click the ‘Submit’ button(figure 8). If you are asked ‘Submit thisform right now?’, click ‘OK’. A final
confirmation screen appears withdetails of the file(s) you ordered.
It generally takes two or three minutes
to confirm the order, after which you
receive an email with a clickable ftp
link from which to download the file.
Following confirmation, you have 72
hours to effect your download.

Figure 10 - The HDF file download link

Downloading Using a Web Browser
You can also download using your web
browser. Wait about 5 minutes, just to
be sure that the order has beenprocessed, then click on ‘My Orders’ on
the side menu. You will be taken to theorder status screen, a section of which
is illustrated in figure 9.

Download speeds do tend to varyduring the download, sometimes
dropping out completely. With this inmind, it is a good idea to set GetRight’s
download Timeout Retry interval to a
low value like 5 seconds. Figure 11
clearly shows these fluctuations in thestatus bar at the foot of the window.

If the ‘Prepare Status’ column states‘Processing’ this means your order is
not yet ready for download. Once the‘Prepare Status’ column states‘Finished’ (which takes just a few
minutes) your file is available fordownload and a clickable link will beshown in the ‘FTP Path’ column.
Clicking this link leads to the actual
download link to your specific HDF file(figure 10).

What You Get
Each HDF file contains 5 images, avisible, a water vapour and three
infrared channels, all at a resolution of
4 km/pixel. In addition, there is a
visible image at the full 1 km/pixel
resolution of the S/VISSR instrument

Clicking this link will start the
download process, which normallytakes between one-and-a-half and twohours (each FY HDF file weighs in at
215 MB). But you can easily speed up
this process using a download
manager program. I use GetRight [3],which allows me to download using
four simultaneous ftp connections,thus reducing the download time to
20-25 minutes.
Using GetRight
GetRight establishes itself as an icon inyour computer’s System Tray. Before
your first download you must configure
this program. Right-click your mouseon the GetRight icon and select‘GetRight Configuration’, followed by‘Downloads/Automatic Mode’ from the
sidebar. Set the relevant ‘Automatic
Downloading Limits’ fields to 4
connections at the same time.
To effect a download from CSDSC,
click on the provided link using theright mouse button, as illustrated infigure 10, and select ‘Copy linkaddress’ from the menu that appears.
Next, open GetRight (again with theright hand mouse button) and select‘Enter New URL to Download’. You willfind that the required address has
already been entered into its field foryou, so all that remains is to click ‘OK’and save the HDF file to a folder ofyour choice. On a good day, this willtake around 20 minutes.

Displaying the Feng Yun Images
Images from HDF files of Feng Yun-2C,
Feng Yun-2D and MTSAT-1R
downloaded from CSDSC can bedisplayed using a registered copy ofversion 7 of David Taylor’s
GeoSatSignal [4] program (use the‘File/Open one’ option). Individual
water vapour, visible and thermalchannels can all be displayed as well
as false-colour and remapped images.
If you are not a registered user of thissoftware, I have produced a free HDF
Reader program [5] which decodes all
five individual images and produces
false-colour composite images throughthe application of colour palettes.
There are only limited processing
options, and you would normally use
additional software such as PaintShop
Pro or Photoshop for final touching up.

Figure 11 - Downloading an HDF file in GetRight

Figure 12 - FY2D visible image - May 10, 2008
Image: CSDSC

CaveatThere are occasions when connections
with CSDSC are extremely slow,
particularly during weekends. Also,
they seem to go completely off-line attimes (for an entire week at one point
last May). But generally, during
weekdays, download times as
described in this article are perfectly
achievable.
References
1 http://nsof.class.noaa.gov/
2 It’s a CLASS Act - GEOQ 16, page 6
3 Get Right
http://www.getright.com/
4 GeoSatSignal
http://www.satsignal.eu/
5 HDF Reader
http://www.myweb.tiscali.co.uk/
wxsatellite/software.htm
www.geo-web.org.uk

Figure 13 - Detail from the 1 km visible image
Image: CSDSC

41

GEO Quarterly No 19

New Systems as a Challenge
Having just received the latest
edition of the GEO Quarterly I just
had to put key to type. Firstly, as
usual, it is excellent, albeit withsome professional pictures
included; the mix is just right to
add to the general articles
included.
And having read Laurence
Holderness’ article I am afraid I
tend to agree with a lot of hiscomments, but unfortunately it’s(dare I say it) progress. The
weather community within the
EUMETSAT structure required asatellite that would produce
pictures and information that would
keep them ahead of the crowd ingeneral forecasting andnowcasting for the European and
African communities. Given thegeneral opinion that Global
Warming is happening, it wasessential that a new class ofsatellite was produced and placed
into orbit to keep communities
informed of approaching storms
and varied weather patterns: so
we have Meteosats 8 and 9.
The main problem is, as Laurence
suggests, that it is very daunting tocome to terms with everything thatis required to obtain theinformation from these satellites.
Many members will be put off by
the technical requirement as wellas the cost to set the system up;
many may just give up and walkaway, especially in the current
economic climate.
I am one of those members who
considers it quite differently. If you
have an interest in a specifichobby then you go into it withenthusiasm and accept all new
systems as a challenge. How else
do we advance unless weexperiment and try new ways toreceive the information andpictures that are on offer? We arealso lucky to have David Taylor
who produces all the main
software we require to receive thedata from EUMETCast. Withoutthat it would be near impossible.
So, new members, please do not
be put off! There is a wealth of
information available to everyone
through the Group. Yes, it isdifficult and technical—but it ispossible with perseverance anddetermination. You can do it. I did.
Laurence may have started
something here with his article andsurely it is possible, with all theexperts we have within GEO, thatsomething could be devised to42Group for Earth Observation

make the hobby more attractive to
new members—but not too
technical, as that can also be a
problem with some beginners.
Kind Regards,
Mike Stevens (G4CFZ), Portland.

The Hub of our Hobby
I wish to endorse Laurence
Holderness’ article. I agree with allthat he said, in that little attention
is paid to simple 137 MHz APT,with disproportionate coverage ofthe latest high tech, PC Vista
programs, image manipulation andinterfaces. All very necessary ofcourse, but most readers andprospective new members arelooking for simple off-the-shelfreceivers, antennas and software.
APT might be ‘old hat’ to thesoftware writers and PC buffs, butthough being phased out, it still
remains the basis and hub of ourhobby and interest.
Regards
Peter Edwards GW8ARR

That 'Hands On' Experience
I have only just returned fromholiday last weekend so a delay ingetting around to reading GEO
Quarterly No 18. Again
congratulations on producing
another first class edition.
After reading the article byLaurence Holderness, I feelperhaps that some of my own
personal views would not go
amiss.
First of all I fully endorse the views
expressed by Laurence. I feel that,somewhere along the line, wehave all tended to 'go with the flow'
regarding our weather satellite
activities and have lost that 'hands
on' experience that we enjoyedbefore the advent of MSGEUMETCast. Yes, I do have amodest computer system running
MSG—and I enjoy downloading
the wonderful images when themood takes me. Getting thesystem up and running was a very
rewarding experience and I will
never forget those first complete
images.
Of late I have compared thequality of my MSG downloaded
images with similar ones in GEO
Quarterly and don't see muchdifference. The reason is of coursethat we are all using virtually thesame satellite receiving equipment
irrespective of how up-market ourPCs are. No difference to receiving
satellite TV! Another point is thatthese images, and many more,

can be downloaded from theInternet for nothing!
For the record, my own systemcost me around £350 including thelicence! This does not of course
include the cost of the requisite
software. It is possible to assemble
a budget system as I have done,
giving me all the images I need:
HRIT, LRIT and the World-FSD.
In my own case, I get most of myenjoyment from my APT system,
mainly because it lends itself more
to my experimental nature (I havebeen a licensed Radio Amateur forsome sixty odd years). Over theseyears I have built a number ofreceivers and experimented withmany types of VHF antenna,
gaining knowledge that has helped
me in the development of my own
APT equipment. The development
is an ongoing thing and I get agreat deal of pleasure from it as
there's always room for
improvement.
I would say that there is still aninterest in articles covering all
aspects of our hobby but, sad tosay, the trend of late has been astrong bias in favour of all things
MSG, irrespective of our generalinterests in weather satellites. I do
hope that, in the short term, theGroup can broaden its horizons alittle.
Just for the record, I am eighty one
years of age and still constructmost of my own equipment. I
make my own printed circuitboards and am in the process oflearning how to program microprocessors for one of my current
projects.
Philip H Cardwell GW3FXI

Pushing the Boundaries
I did enjoy Laurence’s article about
the current weather satellite scene
and will use the Initials WSS torefer to the topic header.
I must consider myself as an ‘Old
Timer’ in the WSS. My interest
was stimulated many years ago byJohn Tuke, with his articles in the
BARTG newsletters and bymeeting him and purchasing a
Barr and Stroud facsimile receivercoupled to the laughingly
described portable electronics(only if one owned a mule). I wasat that time pushing the limits ofmy knowledge far beyond mycapabilities, but I got there with thehelp of many friends andcolleagues and an endless supplyof ‘midnight oil’.
We are all pushing the boundaries
even now but there must be fewer

www.geo-web.org.uk

September 2008of us doing it because of thecomplexity of the WSS. Couple itto the black art also known as
programming, and theconsiderable infrastructure costs,
and I am surprised that so many
people are still interested.
A low cost method on the old YU3framestore concept is needed, as
Laurence has so ably stated in his
challenge. Modern end-user units
are now available which display
HD entertainment images on an
LCD screen. If you need to see
how, put ‘Popcorn Hour’ into your
Google browser and see how you
can display full HD movies without
a DVD player and a computer via
a unit the size of a hard-back
book. To my eye, it is not a world
away from picking up a direct feedfrom a dish and receiver anddisplaying it on a TV screen.
This would be a worthwhile
project—standalone, utilising adish, receiver, framestore and adisplay unit perhaps, with a USB
printer output. It would also fit thebill for a low-cost self-contained
unit, useable anywhere in theworld that had 12 volt dc and could
actually earn recognition andmaybe even money for whoever
could design, build or market it.
There must be someone in Bill
Gates territory who could take up
the challenge and cobble together
various ‘separates’ as a design
project, and come up with an
integrated all-in-one unit. We allrecognise the concept: who would
have believed 40 years ago,
standing in front of a mechanical
fax machine with the smell ofphotographic chemical in yournose, that we would be doing what
we are now.
Laurence is spot-on with his punch
line that such innovation would
attract newcomers as never before
but in my mind would also allow
emergent nations—who need aneye on the world to monitor theapproach of violent destructive
weather systems—a low-cost,easy to use unit that could help tosave lives.
Pete

EUMETCast Defeats Me
I read with interest and agreement
the comments regarding
EUMETCast reception in the June
issue of GEO Quarterly. Sometime ago, I did obtain the receiver,dish, licence and key, but to datehave only managed to obtainbrilliant television pictures fromHot Bird—alas EUMETCast

September 2008

defeats me. But at least thisproves the hardware is working.
So yes! I would be delighted tohave a simple program on thelines suggested and be more than
happy to pay for same. If there beenough like-minded persons i'msure there is someone willing towrite such a program for theongoing remuneration! I wish I
had the knowledge.
Kind regards,
Steve Hicks G0USH, Torbay.

Symposium
A note of thanks for organising asplendid symposium. It was good
to see old friends again, especiallythose I got to know in Darmstadt. I
often remember the quite fantastic
time we all had there.
The lectures and workshops weremost thought-provoking,interesting and quite likely toprove expensive to me—I have afeeling that I may have to buy an
up-to-date computer!
Thank you very much again.
Kind Regards
Tim Holdsworth
It's been a few years since I
attended my last symposium, but I
did manage to attend this year atlast. Can I say that, though I reallyknew nobody else who attended, I
thoroughly enjoyed the experienceand wish to congratulate theorganisers on making it such a
success.
I was particularly interested in thediscussion at the AGM about themagazine and the Editor’s
problems finding articles topublish. I edit, print and distributea magazine for my own club,
Buxton Radio Amateurs, and dueto the paucity of contributions fromour membership threaten quite
often to pack it in, but usually end
up writing much of the material
myself. The truth is, I enjoy the jobof producing the thing and refuse
to let it die.
One of the suggestions whichcame at the meeting was for more
items for beginners, introducing
topics. I must admit that I
personally struggle with some ofthis technology, even though I wasa scientist before retiring, so
agree with this sentiment,
although I do manage to receive
passable images in APT and from
MSG. In particular though, I know
virtually nothing about receiving
HRPT, except that the equipment,
software and setup seems to be
extremely complex and expensive.
It would be interesting to havesomeone write a step by step
guide to this topic, possibly
including the cheapest route to
take. Things like minimum size ofdishes required, software usedetc. would be helpful. Living where
I do, I don't even have any ideaGroup for Earth Observation

whether I see enough of open sky
anyway to run a system as I haveno idea of minimum acceptable
angles of elevation to getworkable images.
Tony Briggs, Buxton, Derbyshire

NewcomerI am a newcomer who first cameacross GEO when searching theInternet for a WEFAX programthat could handle noise and lossof signal: so new that the R2ZX I
bought has yet to see its first volt
and the aerial is still in the packet
it arrived in. I am thus qualified,perhaps, to comment onaccessibility for newcomers.
Even with my background (half acentury in electronics), andalthough I can understand theindividual articles, I am failing toplace each in an overall pictureand hence grade the relevance ofeach article to my central interest.
Is there a simplified block diagramthat can show what is available
and what it can or can't do foryou, so that the newcomer canpick a starting point and then
expand from there with experienceand familiarity?
There is a large amount of
information covered in acronyms
in the quarterly which, I imagine,is daunting to someone who isless versed in technology. How
about a dictionary of the acronyms
or a pointer to a web page to one
that already exists?
Other than that I think the
Quarterly hits the mark. It is varied
and interesting.
Regards,
Graeme Younger[There is an extensive list ofacronyms on the GEO website atwww.geo-web.org.uk - Ed]

Spreading the Word
Since my last letter, my wife and I
have been able to move back to
our house at Vallentuna, so now I
am back to my old APTequipment. Although I have beenable to receive very high quality
images from the CLASS archive; itis more thrilling to see the APT
images develop live even if they
are of lower quality.
There were some very interestingnotes in GEO Q18; not least from
Laurence Holderness, especiallyabout the immense flow of datathat you can get with the
EUMETCast system. I myself
would also prefer to take a nicepicture a couple of times a day(which of course is possible topick out from the EUMETCast
system).
I order to increase the interest in
satellite imaging in Sweden; I
have produced two articles; one
was a translation of an article‘Receiving weather satellite

images’ on the homepage ofJulian Moss (G4ILO) (publishedwith his kind permission) in
EterAktuellt, the magazine for the
Swedish DX Association, issued
10 times a year.
In the other article I have takenmuch from ‘about GEO’ on GEO’s
homepage. I strongly propagate
for membership in GEO. It is
published in the quarterly
magazine Väderbiten (maybe
translatable to something like
“Weather stricken”). This is amembership magazine for an
association of people gathering
weather data in Sweden. It has alittle more than 400 members. I
must admit, that I don’t have muchhope of getting more peopleinterested, but it may be worth anattempt.
But, indeed, your articles onenvironmental issues are reallyinteresting; for instance thearticles on the Aral Sea, that on
the sandstorm , Arctic meltdown
and other similar articles are very
interesting to read.
Anyhow I hope for a good future
for GEO and send my best
wishes.
Anders Höök,
Stockholm, Sweden.

MODIS
Just received the magazine andread your article on MODIS. Thishas made my day, logging on to
the Rapidfire site and seeing all
the images that are available. I’msure many will benefit from seeing
and reading about this availability.
Like many, I run a single PC
taking in MSG/AVHRR/Metop, as
well as using the computer for all
personal use, including wideband
radio communications via an Icom
PCR 1500 receiver working
through the sound-card.
I enjoy, in retirement, this hobby ofours, but at times I find it hard tounderstand much that is written
about in Group comments.
Douglas Deans article re basics
also is excellent and I believe thisis what many of us want to see
and read.
Thanks,David Tyler
I really enjoyed the June 2008
issue of GEO Quarterly, especiallythe article on MODIS. The
SmoothMODIS software andCorrectGeometry program werereally useful to me! I have been
looking at the Terra and Aqua
satellite material for a few years
now, since this is the best sourceof high-res images for the far
north of Canada: with the help of
the two programs, I am now able
to really enjoy them that much
more!
Keep up the good work! I am one

GEO Quarterly No 19of the quiet majority who enjoys
reading the magazine without
voicing my opinion too much.
Best regards
Milan Konecny, Ontario, Canada.

Setting up a Help System
I would like to suggest that GEO
sets up a list of volunteers,experienced in EUMETCast (orother) reception, willing to travel
up to say 50 miles to help fellow
members set up or resolve
problems on site. They don’t haveto be ‘experts’ or long time radio
amateurs but people like myself
who have overcome problems andsetbacks to establish a stablesystem. I often get requests forhelp via my website and it’s
obvious from the various technicalGroups that there are many
problems and people available toprovide answers.
I note Laurence Holderness’comments and a desire for a
simple system. I concur with yourchallenge.
I got into weather satellites in aroundabout way. .As an amateur
astronomer, I successfully
detected meteors by radio, usinga scanner and dipole antenna. I
then found it was possible to hear
polar orbiting satellites as theypassed overhead. These are often
observed in the early evening
when setting up ones telescope
equipment.
I built a homebrew QFHA andcould hear the satellite with thescanner but got no images. The
next step was a major hill. As
ready-built APT receivers wererather pricey, I took the bull by thehorns and built an RX2 receiver. It
worked first time. The next stage
was easier though much more
expensive—receiving MSG. A
basic setup is essentially ‘plug
and play’; the main cost is the
EUMETSAT EKU (dongle) andsoftware plus two suites of David
Taylor’s software. There appears
to be no way round paying 60
euros for the Tellicast softwarethat is essential to the receipt of
EUMETCast, even without the
EKU.
My point in all this is that a
EUMETCast system can becheaper and much easier to set
up than an APT system. For six
hourly MSG images, it should be
as easy to set up the hardware as
setting up a dish to receive TV
pictures. One PC will suffice. Rob
Albas has a free software
package. There is plenty ofsoftware out there to schedulejobs and produce final images. It
may be that your challenge canquite easily be met with what’s
already around.
CheersAlan Banks
More on page 44 ...

www.geo-web.org.uk

43

GEO Quarterly No 19

Group for Earth Observation

John Tellick
Although summer doesn’t officiallystart till June 21, summer
temperatures had already settled overmuch of northern Europe by early
June this year. The upper image on the
opposite page shows how the actual
ground temperatures between June 2
and June 8, 2008 differed incomparison with average values for thesame dates for the years 2000 through2007. These land surface data, which
are not the familiar air temperatures
normally reported in the media, wereacquired by the Moderate Resolution
Imaging Spectroradiometer (MODIS)

aboard NASA's Terra satellite.
Areas that were warmer than average
are shown as red while those that werecooler are blue. The heat that
dominated northern Europe’s weather
in early June is evident from the dark
red that covers Norway, Sweden,
Denmark and parts of Germany and
Poland. Southern Europe, by contrast,
experienced cooler than averagetemperatures during this period.

September 2008

dangerous fire conditions in
Scandinavia, and both Norway andSweden experienced a rash of forest
fires. One fire that burned for several
days in Froland, southern Norway, wasthe largest in the country for over halfa century. Before being brought undercontrol by more than 150 fire-fighters,
aided by 16 helicopters and muchneeded rain, this fire is estimated tohave destroyed around 3000 hectares
at a cost estimated to be at least sixty
million kroner.
Source: NASA Earth Observatory
NASA image created by Jesse Allen, using data obtained
from the Goddard Land Processes data archives.

The combination of intensely hot dry
weather and unpredictable winds led to
Anticipation
I read with interest the item by Laurence
Holderness in the June edition of
GEO Quarterly and was in agreement withmuch of what he said. At seventy-three I am
one of the ‘older school’ who enjoys receiving
pictures from the polar orbiting wx satellites. I
use a Proscan receiver and a turnstile aerial,and APT pictures are processed using a
registered copy of WXtoImg, and occasionally
WXSat. Like Laurence, I find enjoyment in
anticipating the passes of the satellites and theresulting pictures. I use WXtrack to keep up todate with the times of availability.
I feel I have achieved two things over theyears with polar satellites: firstly, I’ve learnt a
lot about the characteristics of satellites, orbit
times, etc, all available in the Kepler elements
available from the Space-Track website;
secondly, I’ve become familiar with the various
software programs used in processing satellite
data and might be considered reasonably
computer literate. I have followed thedevelopment of the MSG satellites withinterest but felt that I couldn’t cope with theextra outlay involved or with all the flood ofdata which requires two PCs and a lot oftechnical expertise.
As Laurence and yourself state, what isneeded is a system which isn’t too expensive,
to purchase and is fairly easy to install andmanage—and would provide images for ashort selected period of time.
Changing subject. I found the article on‘MODIS’ of great interest and now pay regular
visits to the Rapidfire site. Fascinating,Regards
Mike Ennis

Dear Francis
Thank you for sending me the latest edition of
GEO quarterly. It contains some great imagesof the dust storms. I hope that your annual
meeting was a success.
Kind regards
MichaelGEO Reader W Ford from Bristol provided this NOAA-15 image showing sunglint on the ocean west of
Portugal. The image was acquired from the 16:06 UT pass on April 8 this year using an R2FX receiverwith turnstile antenna and decoded using Patrik Tast’s APTDecoder software.

44

www.geo-web.org.uk

Dr Michael Rose
Earth Observation Programme Manager
British National Space Centre (BNSC)

European land surface temperature anomalies for the period June 2-10, 2008

That ultra wet summer of 2008 encouraged
a clematis to climbing up over the roof of his
garage on to Les Hamilton’s QFH antenna.

Mike Stevens imaged ‘Bertha’ first hurricane of the current Atlantic
Storm Season in this Metop-A segment dating from 13:26 UT on July
9, 2008.
Image © EUMETSAT 2008