Group for Earth Observation

The Independent Amateur Quarterly Publication for

Number 9

Earth Observation and Weather Satellite Enthusiasts

March 2006

Inside this issue . . .
Blue Marble—amazing highresolution planetary images
from NASA, and how you can
use them as backgrounds foryour MSG images.
The PADAT137 RQH
antenna—Ruud Jansen takes
us through the design anddevelopment stages as aprelude to describing how tobuild this rugged,
weatherproof antenna in thenext issue
QUIKScat—how NASA’s‘Seawinds’ scatterometer isrevealing the role of ocean
winds in dictating ourplanet’s weather
GeoSatSignal 5—With thetermination of WEFAX and
PDUS just weeks away now,
Douglas Deans details thebasic features of the newsoftware GEO readers must
master if they wish to
migrate to Meteosat-8 via
EUMETCast.
The Indian Space Program
part 5—Peter Wakelin
concludes his overview of thisoft-neglected contribution toplanetary meteorology
Symposium 2006
Join GEO at Leicester forwhat promises to be yet
another enthralling day in
the National Space Centre

Great News For WXSAT Enthusiasts!
Recently launched hobby radio
listeners' magazine, Radio andCommunications Monitoring
Monthly provides a regular four
page WXSAT column 'Satellites'
View' presented by Lawrence
Harris. Monitoring Monthly will also
include an annual special feature
covering WXSATs also written by
Lawrence.
"We are pleased to serve all the
specialist areas of the hobby",
commented Editor Kevin Nice, "I am
pleased to say that all of our regularcolumns provided more information
than any current or former
alternative."
The current issue of RCMM
It is the aim of Monitoring Monthly
on sale until March 23, 2006
to become the magazine of choice
for all serious radio enthusiasts. Our
initial customer feedback indicated that we are well on the way.
Radio and Communications Monitoring Monthly ISSN 1749-7809 isavailable from most good newsagents and direct from the publishers.
Subscriptions are available world-wide. For more information contact
Nice One Publishing Ltd, Tel: +44 (0)1202 862690 or visit the website
www.monitoringmonthly.co.uk

Part of the March 2004 image from NASA’s newBlue Marble series, created from MODIS images
accumulated by NASA’s Terra and Aqua EOS satellites.
See article on page 13.

Effects of the Buncfield fire on local air traffic as visualised using virtual radar. Sam Elsdon explains on page 12.

CONTACT INFORMATION

ride of place in this issue of GEO Quarterly is the first instalment
Pof a two-part article from Ruud Jansen, chairman of Werkgroep
Kunstmanen, GEO’s sister organisation in the Netherlands. In thisissue Ruud takes you through the design stages in developing the new
RQH antenna for APT and pays particular attention to impedance
matching. In the following issue Ruud will describe how to construct
his new PADAT-137 design from rugged aluminium rod and strip.

t the upper right of the facing page is what at first sight looks likea map of Europe and Africa. But in reality, this is a composite ofA
many images from the MODIS instruments aboard NASA Earth

Public Relations
Francis Bell,
Coturnix House,
Rake Lane,
Milford,Godalming,
Surrey GU8 5AB
England.
Tel:(01483) 416 897
e-mail: francis@geo-web.org.uk
General Information
John Tellick
e-mail: info@geo-web.org.uk
EditorLes Hamilton,
8 Deeside Place
Aberdeen AB15 7PW
Scotland, UK.
e-mail: editor@geo-web.org.uk

Observation satellites. These images are readily available with ground
resolutions of 2- and 8-km/pixel and can already be incorporated into
two software packages as backgrounds for your weather satellite
images—see articles on pages 13 and 43.

Membership and Subscriptions
Nigel Evans,
L’Eventail, 7 Gloster Ropewalk, Aycliffe,
Dover CT17 9ES
England, UK.
e-mail: members@geo-web.org.uk

T

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

he 3rd GEO Symposium is booked at the National Space Centre,
Leicester for Saturday, April 29 when meteorology will provide thefocus. Among the speakers will be Sally Wannop (EUMETSAT) andDoug Mansfield (a senior forecaster with the Met Office). Many of the
GEO Management Team will be staying overnight in the Campanile
Hotel, Leicester. If you are planning an overnight stay, take advantage
of GEO’s preferential booking rates: details on page 19.
inally, we welcome the appearance of a new magazine to the newsF
stands, Radio Communication and Monitoring Monthly. As you canread opposite, this new venture includes regular monthly articles on

the weather satellite scene from Lawrence Harris, and should be ofinterest to GEO readers.

Contents
GEO Report
GEO Symposium - 2006
Buncefield Explosion Smoke Plume Images
Developing the PADAT 137 RQH Antenna
Effects of the Buncefield Fire on Local Air Traffic
Blue Marble
Fiddler’s Ferry
Earth Imaging NewsGEO Symposium - Hotel Accommodation
Imaging for Margarine
Exclusive GEO Shop APT Receiver Deals

2
4
5
Ruud Jansen
6
Sam Elsdon
12
Les Hamilton
13
Robert Moore
16
Peter Wakelin
18
19
Kimberley Loh Ying-Ying 21
Clive Finnis
22

Webmaster and Website Matters
Ray Godden
e-mail: webmaster@geo-web.org.uk
Education Coordinator
David Paintere-mail: education@geo-web.org.uk
GEO Shop Manager
Clive Finnis
e-mail: shop@geo-web.org.uk
International LiaisonPeter Green‘Hollowtree’
Eggesford
Devon EX18 7QX
Tel:(01769) 580 700
e-mail: international@geo-web.org.uk

Francis BellGEO Shop Page
NOAA Satellite Predictions for the UK and western Europe
Helplines and Internet Discussion Groups
Copy Deadline for GEO Quarterly No 10 (June 2006)
GEO Membership Renewal Form

i
ii
iii
iii
iv

News in Brief
Werkgroep Kunstmanen
Birds of a Feather - Members’ Photographs
QuikSCAT - NASA’s Eyes on Ocean Winds
Arctic Front
Indian Space Program, part 5
GeoSatSignal 5 - the basic functions
Meteosat-8 Radiometer Decontamination
Tracking Hurricanes in Digital AtmosphereBook Review: ‘MSG in Orbit - In Use’More about 3D images
Software Showcase‘Far East’ Competition

23
24
24
26
29
32
34
39
41
42
42
43
44

Fred van den BoschLes Hamilton
Robert Moore
Peter Wakelin
Douglas DeansDavid Taylor
Fred van den Bosch
Francis BellFred van den Bosch
Douglas Deans

PublisherGroup 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
Printing
Advent Colour Ltd., Unit 1, Crown Way,
Walworth Industrial Estate
Andover, Hampshire SP10 5LU.
Responsibility for Constructional
Projects and Software
Every effort is made to ensure that the technicaland constructional articles published in thisQuarterly are correct. However, the ultimate
responsibility is with the reader to ensure thesafety of constructions and for any interfacingwith other equipment. GEO cannot accept
liability for shortcomings in any publisheddesign or any constructions carried out bymembers or other third parties.
Copyright GEO © 2006
The contents of this Quarterly remain theintellectual property of the Group for Earth
Observation Ltd. and its contributors. Copyingof text or images, either from the printed
Quarterly or from any electronically stored
source, is forbidden without permission from theeditor.

GEO Quarterly No 9Group for Earth Observation

March 2006

Francis BellGEO is now just into its third year of existence.
If you have just joined for the first time and thisis your first GEO Quarterly, welcome to atalented and resourceful group. I am pleased
with the way we have evolved during our shortlife and although it would be rather indulgent toattempt to list all our achievements, there is one
which I would like to identify.
It has been GEO’s policy to develop andmaintain good relations with the weather
satellite operators EUMETSAT, NOAA andother agencies. I think we have achieved this,resulting in mutual benefits. The satellite
operators know that GEO represent a
substantial user community embracing many
countries and GEO members benefit by being
kept in touch with satellite developments. Just
one example here is not out of place.
NOAA-18 Frequency Change
When NOAA-18 was launched, it started
transmitting its APT on 137.9125 MHz. Thisfrequency is adjacent to high-power terrestrial
pager transmissions in the UK, and interference
from them made NOAA-18 reception almost
impossible in many places. Because of GEO's
feedback to NOAA, by reporting members
experiences, personal contacts in the USA andother forms of communication, NOAA
recognised the problem we were experiencing
and on an experimental basis have switched
the APT downlink to 137.1 MHz. Without thebackground of our collective representations
perhaps this change would not have been madeOur formal thanks to NOAA for responding toour problems in the UK. But why was thisnecessary?
Frequency Allocations
The frequency allocation conflict came about asa result of licensing high powered pager
transmission within a frequency band which, byworld agreement, was allocated to weather
satellite transmissions. This is my interpretation.

other frequencies, including amateur radio
allocations seem under threat. I have read thedetailed submissions made by RSGB and
AMSAT-UK in response to the Ofcom
consultative document and more recently
RSGB's joint response to the European plans toallocate Ultra Wide Band (UWB) transmissions
encompassing computer technology into themicrowave band. These are warning bells towhich we should all be alert. Of course, the RF
spectrum is a valuable natural resource andthere will be a never-ending change in its use,
but along with the administration of thisresource goes responsibility.
Meteosat Changes
Members should not forget that Meteosat-7 isscheduled to stop WEFAX and PDUS
transmission next June. If you wish to start
receiving live transmissions from Meteosat-8,
you will have to migrate to EUMETCast
reception. Do not wait until June 2006 and say:‘Oh dear, what's happened to my satellite
signal?’There is an exciting year ahead. MSG-2 waslaunched in December 2005 and is currently
being commissioned and a the new polar
orbiting MetOp satellite launches in June. Shortof being a national meteorological office, thebest framework enabling individual user
stations to keep abreast of these changes iswithin the GEO membership, where
information, advice and support are available.

Unfortunately, there may be more to follow as

2

I was naturally pleased to receive complimentsfrom visitors to our stand, who stated that it was
attractive and informative. We did sign up somenew members and also prompted somerenewals. ‘Oh! I forgot to renew my membership- I’ll do it now’. I didn’t try to count the number ofvisitors we had but David Simmons, who wason the stand with us all day, quite unprompted,
said to me: ‘We must have had about 200
visitors to the stand’. We were busy from 9.30
pm to 4.00 pm.

GEO at Rallies
About 60% of the GEO membership haveamateur radio callsigns and I expect many ofthese members will have been to radio rallies,
which nowadays, quite understandably, are
combined with computer interests. Until recently
GEO has not been represented at any of theserallies but in November 2005 the decision was
taken to have a stand at the West London Radioand Computer Show at Kempton Park.

As a matter of UK Treasury policy, enacted via
the Radiocommunication Agency (RA) —now
Ofcom—as much revenue as possible is to be
extracted from licensing the use of the radio
spectrum: in this case regardless of the existing
international allocation.
Now the unforgivable element. The UK
Prime Minister goes to Kyoto and signs up
for a 'World Environmental Accord' yet,while he's away, his Treasury, via the RA,
is selling off a frequency allocation which
encroaches
onweathersatellite
reception; those very frequencies which
are used to monitor our planet. Does
anybody know a better definition ofinternational hypocrisy! Or can somebody
explain it to me differently!

before the rally to establish the dish positionand orientation also to set the cable runs. On
the day everything went well as we ran live
signals into two systems which generated aneye-catching display. John manned the stand all
day with David Simmons looking after oursoftware requirements.We also had on display
some back issues of GEO Quarterly andexamples of the hardware available from the
GEO Shop. EUMETSAT very supportivly
provided us with technical leaflets and postersof Earth images; some of the technical literatureremained at the end of the day but all the image
prints were taken by visitors. I know some ofthese will be displayed in radio shacks, studies
and on children's’ bedroom walls. The very bestuse for such stunning images of our planet.

David Simmons and John Tellick on the GEO
stand ready for the day’s influx of visitors
The GEO stand was in the main exhibition hallwith access to a window through which we ran
co-ax to an outdoor dish to run live Meteosat-8
reception. We judged that setting up on themorning of the rally for live reception was a bit
speculative, so John Tellick and I went the day
www.geo-web.org.uk

John Tellick in animated discussion with agroup of enthusiastic visitors to the GEO stand
Provisional Rally Program
As a result of our experience at Kempton, GEO
have arranged a possible programme of eventsfor 2006, as follows:• West London Radio and Electronics
Show, Kempton Park (Sunday, May 7).
• GEO’s own symposium at the National
Space Centre (Saturday, April 29)• Hamtronic Friedichshafen, located on the
shores of Lake Constance, Germany(June 23-25)• GEO hopes to be invited again to the
AMSAT colloquium in Guildford (July 2628)• Leicester Amateur Radio Rally,
Donington (October 2006, dates to be
confirmed)• West London Radio and Electronics
Show, Kempton Park (Sunday,
November 19)
GEO very much looks forward to meeting its

March 2006

member at these events. If you can attend, yoursupport will be very much appreciated.
Meetings in The Netherlands
In addition to these events, members may wish
to note the meeting dates of our Dutch friends
Werkgroep Kunstmanen. Their meetings areheld in Utrecht and the dates for 2006 (allSaturdays) are:••••March 11
May 13September 9
November 11

I’m sure support for our Dutch friends would beappreciated. Utrecht is an attractive historical
town and is worth visiting anyway with theadded bonus of attending a meeting with ourtalented Dutch friends.
Symposium 2006
As you can read on page 4, GEO is holding its
Symposium at the NSC, Leicester, on April 29.
As well as providing the opportunity to listen to
key speakers it’s a chance to meet friends, andas always, the key aspect of the day’s
proceedings will be member participation. If you
have not been to Leicester before, at leastconsider joining us in 2006.
To help us plan the Symposium, it would be
useful to know in advance of any topics
members would like to discuss. If you cannot
come yourself but have a topic for discussion,please let me know by e-mail or post and I will
ensure it appears on the agenda. Advancenotice will enable time for GEO to research any
background details or issues involved.
However, any member may raise any topic for
discussion on the day itself.

Group for Earth Observation

60 nations with their government support
looking at a 10 year time frame for aninternational coordinated plan for monitoring the
Earth. Last year the group produced a 210 page
book (650 g ) outlining a 10-year plan ofobservation and data use. I obtained a copy ofthis book which I found informative, outlining thebackground issues and presenting an ambitious
10-year plan within their established framework.
The book has a wide perspective covering
environmental issues and their observation. In
some parts this publication is not light reading
but I found the first half of the book very
interesting, colourful and well illustrated. Afterthat it was rather heavy going because it
addresses issues of international policy,
implementation and performance indicators. Allof which are important of course.
To obtain a copy of this book, which is free ofcharge, write to:
ESA Publications Division
ESTEC
PO Box 299
2200 AG Noordwijk
The Netherlands
There may be an e-mail address you can use
but my advice is to write a letter saying you
would like a copy of this book. You will probably
be rewarded for your effort. That's what I did
and I recommend other GEO members to do
the same.

Any GEO reader who would like to make apresentation or run a workshop or
demonstration at Symposium 2006 is welcome
to get in touch with me. Please do so as soon
as possible so that you may be incorporated
into the programme.

You may remember my question in the last
Quarterly which asked: ‘What is the surface
level of the water in the Caspian Sea withrespect to Mean Sea Level?’
From a personal perspective, I was surprised
when I noted this level from an old map I was
studying while on a cruise in the Black Sea. The
map gave the water level as –25.5 m and also
showed extensive areas of surrounding land
below sea level. I know small areas of North
Africa and North America are below sea levelbut the elevation, or lack of it, for the CaspianSea had escaped me.
I’m unsure whether the water level of the
Caspian sea is changing. I know it’s adjacent to
the much smaller Aral Sea (Lake Aral) which is
falling. Water abstraction from the rivers feeding
the Aral Sea have resulted in too little water
entering the sea to match evaporation from its
surface. The shrinkage of the Aral Sea shows
up well from satellites images. Wouldsomebody please send to GEO’s editor an
example image of the Aral Sea.
There were several entries to the competition. I
did exactly as promised and picked a winner on
December 25. The winning entry was from Fredvan den Bosch from The Netherlands who
submitted an answer of –27 metres. Thisequated quite closely to the old 1953 Philips
atlas I had used and which gave a level of –25.5
m. However, if both figures are exact it means
the Caspian Sea as well as the Aral Sea is
evaporating more water that its feeder rivers
provide to maintain an equilibrium water level.

MSG - In Orbit, In Use

Finally, my usual sincere thanks to the support
we all derive from friendships and sharedexperiences within our interest area and ofcourse to those who contribute to our Quarterly
publication.

At about the same time as GEO was formed
another organisation, called Group on Earth
Observations, was also constituted. In spite of
the similarity of the names, which aredescriptive of the mutual interest area, thesimilarity stops there. We are an amateur
educational and non-commercial groupwhereas ‘Group on Earth Observation’ is a
United Nations sponsored group comprising of

The December Quarterly Question

Fred or his nominee receives the free entry to
GEO’s annual symposium in Leicester this year.
And a thank you to all the other readers who
sent in entries.

Workshops

The Quarterly question this time is related to a
publication I received recently and relates to astatement in it about which I was not previously
aware. Many members may be able to give ananswer from their own background knowledgeof our Earth’s weather systems but for me theinformation came as a surprise. The answer tothe question can be found on page 75 of ‘Global
Earth Observation System of Systems’. Here issome background to this publication.

GEO Quarterly No 9

The Question
Page 75 of the above book contains aphotograph of a typical Cumulonimbus cloud
and the caption to the photograph reads:‘The hottest air mass in the world from May toAugust is generated over ‘this area’ and affects
the seasonal and inter-annual variation of the
Asian monsoon. The very active water cycle‘over this’ area sometimes associated withcumulonimbus clouds, plays an important rolein the atmospheric heating process and thenthe Asian monsoon variability.’
The question is: Where is ‘this area’?
Answers to me either by post or e-mail. As
usual the winner, or their nominee, will receivea free admission to our annual symposium at
Leicester. I will pick a winner six weeks after our
GEO Quarterly 9 is dispatched to members.

www.geo-web.org.uk

EUMETSAT have produced a superb 120
page colour A4 brochure which explains theentire MSG system and its instruments as wellas possible applications of the delivered data.
You can read a review of this publication on
page 42. GEO readers so wishing may obtaina copy as follows:• If you live in the UK, send Francis Bella written request, clearly stating yourreturn address and enclosing seven firstclass stamps to cover the cost of
postage.• If you live in the EU, send Francis Bella written request, clearly stating yourreturn address and enclosing a fiveeuro banknote to cover the cost of
postage• If you live elsewhere in the world, I
suggest you contact EUMETSAT
directly—their postal address is:EUMETSAT User Services, Am
Kavalleriesand 31, D-64295 Darmstadt,
Germany. You could also make anemail request via ops@eumetsat.int.
I will take some copies of the brochure to the
Kempton Radio and Computer rally in Marchand also to our GEO Symposium in Leicester.
The brochure is also available as a 4.9 MB
PDF download from the EUMETSAT website:

http://www.eumetsat.int/
Follow the link to ‘Brochures’ then scroll down
the page to reference ‘MSG.02’.

3

GEO Quarterly No 9Group for Earth Observation

Francis BellThe GEO Symposium will be held on
Saturday April 29, 2006 at the National
Space Centre (NSC), Leicester. The
venue is conveniently located in central
England with easy access by road, rail
and the nearby East Midlands Airport.
There is ample free car parking at the
NSC. To find out more about the venue
visit the NSC website at:www.spacecentre.co.uk
Although there are developments inprogress at the NSC, we will be using
the same rooms and lecture area as wehave in the past. These suit us well,providing display areas, space forworkshops, a room for lectures andpresentations as well as access to thesky for live satellite reception.

e-mail: francis@geo-web.org.uk

Last year we had a very full but
enjoyable programme; the main complaint was that there just was not time
to do everything justice. So this year’s
programme has been reduced a little toallow more time for workshops,
interaction with other members andmore opportunity to visit the NSC’s own
exhibition halls. The quality of the draft
programme, shown in the panel
opposite, is outstanding, and should not
be missed.
Registration
The cost of attending is £12.00, whichjust covers the cost of hiring thefacilities within the NSC. Please pay
your £12.00 at GEO’s registration deskon April 29. Please be prepared to pay bycash or cheque please—we will not havecredit card facilities available at the
NSC.
Pre-registering
If you are planning to attend, please preregister by post or e-mail to myself
because this makes administration alittle easier on the day (details on
page 1). All I require is your name sothat I can establish an expected delegate
list.

The GEO Shop display at Symposium 2005

Reaching the NSC is quite easy. It is
located one mile north of Leicester city
centre and there are numerous helpful
brown ‘spaceship’ direction signs at roadjunctions around the city, regardless ofthe direction from which you approach.
More details, with an explanatory map,can be found on the GEO website at:

Of course, you are welcome to come on
the day without pre-registration, butthere is a slight risk we might be fully
subscribed by then. Health and Safety at
the NSC places an upper limit on thenumber of people using their facilities.
We have never had to refuse anyone yet,but prior registration does guarantee
your place and also provides you withcomplementary access to the NSC’s
exhibition halls.

www.geo-web.org.uk/sym06.html
Accommodation and transport must beleft to each individual delegate toorganise. Food may be purchased inside
the NSC. Alternatively,
there arerestaurants and pubs within walking
distance of the centre. My usualapproach is to take a few sandwiches
and a drink with me, thus avoiding a
protracted lunch during the midday
break when other matters are morepressing.

4

March 2006

Provisional Programme
09.00 Doors open. Anybody withdisplay or demonstrationmaterials may set up
Registration
10.00 Opening remarks by a memberof GEO’s management team
10.10 Douglas Mansfield from the UK
Met office. A presentation about
the practical application ofsatellite data for weather
forecasting
11.00 Sally Wannop, User Support
Manager at EUMETSAT User
Services. Sally will give an
introduction to EUMETSAT’s
activities, an overview ofoperational services and a live
demonstration of their new
website12.30 Lunch break and time for theworkshops. David Simmons will
be demonstrating the almost
unbelievable data rates comingfrom Hot Bird-6. You may
remember David from last year;with a new computer, card andsoftware, he had a Meteosat-8
station running inside 30
minutes. Others will run
workshops.
14.30 Darrell Robertson, our guest
from NOAA, will deliver theafternoon presentation: ‘NOAA’s
Plans for the Coming Years’.
15.30 Tutorial / Workshop run by David
Taylor, GEO’s software
consultant. The time of this andother workshops is flexible andto some extent will be judged on
demand.
16.00 GEO AGM
17.00 End of programme
18.00 We must have the rooms
cleared and be away by 6.00pm.
Symposium 2006 will be a day wellspent. I encourage all members to cometo Leicester; if you have friends who are
not members of GEO they will also be
welcome so long as there is room. The
mostimportantaspectoftheSymposium is that it is a meeting of likeminded friends.
Contact
To pre-register, of for further details
about Symposium 2006, contact:

Dish pointing workshop at Symposium 2005
www.geo-web.org.uk

Francis Bell,
Coturnix House, Rake Lane,
Milford, Godalming,
Surrey GU8 5AB England.
e-mail: francis@geo-web.org.uk

March 2006

Group for Earth Observation

GEO Quarterly No 9

The two images on this page illustrate the giant
plume of thick black smoke that followed the
explosion and fire at the Buncefield Petrol
Depot in Hemel Hempstead, England.
The 300 metre resolution image at the top of thepage was acquired by the Medium Resolution
Imaging Spectrometer (MERIS) aboard
Envisat, Europe’s largest environmental
monitoring satellite, at 10:45 UT on December
11, 2005. The smoke cloud was 140 kilometreswide at this point.
The fire followed a massive explosion that
occurred at about 6 o’clock in the morning local
time on Sunday, December 11, 2005 and which
continued to burn for the best part of thefollowing three days. The explosion, which was
detected as far away as the Netherlands, rattled
windows, blew doors off of homes and caused
several thousand residents to be evacuatedfrom the area because of health concerns. A
high pressure regime which prevented thesmoke from dispersing was responsible for thelateral spread of the smoke plume across muchof the London and surrounding areas.
Image: ESA

GEO reader Chris Waddington caught the
13:45 UT NOAA-18 APT image reproduced atleft using his RX2 and a turnstile antenna thenprocessed the image using SatSignal. Even
with its maximum ground resolution of only
4 kilometres per pixel, this image shows thesmoke cloud very clearly.
www.geo-web.org.uk

5

GEO Quarterly No 9Group for Earth Observation

March 2006

by Ruud Jansen PA0ROJ - ranslation by Chris van Lint
This article is a follow-up to my earlier
one relating to the PITA137 [1] weather
satellite antenna. The 137 MHz signaltransmitted by a weather satellite is
directed towards the Earth’s surface
with circular polarisation and ourantenna must therefore be able toreceive this signal without noise bands
regardless of the position of thesatellite above the horizon. The
PITA137, which was constructed using
lengths of steel from a measuring tape,
was intended to be taken along on
holidays or to hang up in an attic
indoors. This antenna is notparticularly storm resistant and during
my visit to Brazil in December 2004 [2],when I took along my complete
receiving equipment, gusts of windmade my nice antenna look more like atangle of messed up measuring tapes
than a cylindrical RQHA (Resonant
Quadrafilar Helical Antenna). Since I was(and still am) very satisfied with thistype of antenna—which in comparison
to the Turnstile, Lindenblad and otherdesigns, frankly stands out as thebest—I wanted to build a rugged
outdoor version of the RQHA. I call thisthe PADAT137.
Copper Tube Design
My very first solid-state antenna wasconstructed from 12 mm copper tubing.
In contrast to antennas based on large
and small loops [3], I wanted toconstruct my antenna with two equally
sized loops. The required 90° phaseshift would be achieved by making one
loop effectively ‘longer’ by connecting an
inductor (coil) in series with it while
making the other loop effectively‘shorter’ by means of a series capacitor(similar to the PITA137 design). Since I
wanted maximum sensitivity at thehorizon, I opted for a long, thin design
with a diameter/length relationship ofabout 0.25 [4], and duly constructed theantenna from copper tubing.
Unfortunately, it turned out that the
impedance of this rather thin antenna
was around 15 Ω and it was very
sensitive to its design specifications.
Minor mechanical alterations (making
the antenna flatter or rounder) changed

6

the impedance; additionally, the phaseshift between the loops was no longer
90°.
Soldering
was
also
quite
challenging due to the critical shaperequirements and I had to construct acomplete mechanical jig to hold all thepieces of copper tubing in place during
the soldering process. Following a couple
of weeks of effort I decided to design aless critical antenna.
To construct a good antenna for my own
use was no problem and after aconsiderable amount of effort I did
obtain a useful result. However, thepurpose of my design was to allow others
to copy my antenna successfully, eventhose without access to the electronic
measuring equipment I had at mydisposal. My account of how the
PADAT137 aluminium strip RQHA wasdeveloped now follows.

Figure 1 - Phase shift

Aluminium Strip Design No 1
The PADAT137 was to be a stormresistant aluminium version of the
PITA137, using 12 mm aluminium rod
for the horizontal sections of each loop
and 15 x 3 mm aluminium strip for thevertical parts. My first design consistedof two equal loops, each making a turn, and using a capacitor and an
inductor to obtain the 90° phase shift
between them. An advantage of thisdesign is that the dimensions of all thehorizontal elements are identical, as
are those of the vertical ones. A
disadvantage was the requirement for
two different components (capacitor andinductor) to achieve the 90° phase shift.
Aluminium Strip Design No 2
My second design utilised two equal
extra-long loops, in which one loop was
effectively ‘shortened’ by means of asmall series capacitor. By making thedimensions of both loops extra-long(giving a resonant frequency lower than
137.5 MHz) and then rendering just oneof them shorter in this way, I was able
to dispense with the inductor.
I measured out the vertical components
to be a couple of centimetres longer
than those of the older PITA137 thenshortened the vertical strips until, at
www.geo-web.org.uk

Figure 2 - Smith chart

137.5 MHz, the phase shift between thereal resistance and the imaginary
resistance was +45° (figure 1). This is
only true when the real resistancevalue of this loop is equal to its positive
imaginary value. Refer to themeasurements in the Smith chart(figure 2).
The impedance value I determined inthis case consisted of a real value of
31 Ω and an imaginary value of +j 31 Ω.
The formula is Z = 31 + j 31 Ω. The loop
is inductive and hence too long (as we
knew already). I then measured theresonant frequency (pure impedance)and resistance of the loop at resonance.
Although the Smith chart initially looks
very complicated, this method ofpresentation exceeded expectations [5].
I next mounted a second loop, with thesame dimensions as the extra-long loop,
parallel to the first one. In order toMarch 2006

obtain a 90° phase shift between these
two loops we have to make this loop
‘shorter’ (i.e. capacitive) by inserting a
19 pF capacitor in series with it.
Connecting the two loops in parallel
ensures that, at a frequency of
137.5 MHz, the antenna represents apure impedance and the phase shift
between the currents in both loops is90°.
A major disadvantage arises from thecritically low 19 pF series capacitance.
Any mechanical deviation, however
small, or any variation in theconnecting cables and/or capacitor
value, will result in a considerable
difference in the phase shift and
impedance between the two loops. In
practice this was really an unusable
design.
Aluminium Strip Design No 3
Another attempt to obtain the required
phase shift was to really make thesecond loop smaller. When I
constructed a test antenna in which theheights of both loops were identical, butwhere the diameter of the second loop
was smaller, it caused problems: thereal impedance of the smaller loop wasless that of the ‘fatter’ one, so that the
impedances of the two loops were notequal at the resonant frequency.
Additionally, the diameter/length
relationships for the two loops were nolonger equal, resulting in a nonsymmetrical radiation pattern. Since
the radiation pattern is determined by
the diameter/height ratio, among otherfactors, the radiation patterns of theloops were not the same.
Aluminium Strip Design No 4
In my final test antenna I modified
both the height and diameter of thesmall loop so that the diameter/height
relationship of both loops became
identical—giving rise to identicalradiation patterns. The two loops also
shared the same centre point. Thissolved the problem of the differingradiation patterns. The difference
between the real impedance of the ‘thin’
loop and the ‘fat’ loop were now lessthan for Designs 2 and 3 at less than
2 Ω. The disadvantage of this design
was that the horizontal components ofthe two loops were now at different
heights and had unequal (plus andminus) impedances at resonant
frequency, although the difference wassmaller than in Design No 3.
The Action Plan
I decided to build all four designs andcarry out measurements on them. One
problem is that I can make general

Group for Earth Observation

antenna measurements in my attic;
however because of the adjacent walls
and electrical wiring, etc. suchmeasurements are not reliable. For afrequency of 137 MHz I should ideallyhave a free space of several dozen
meters around the antenna: but
unfortunately I don’t. I had therefore to
wait for a few dry days in order to set
up my measuring equipment in thegarden (figure 5).

GEO Quarterly No 9

Figure 3 - First results (graph)

In order to build these four designs andperform measurements on them I
constructed an antenna where theheight of both loops and theirdiameters, as well as the relationshipbetween the loops, could be adjusted bymeans of interchangeable horizontal
and vertical components (figure 6). To
reduce or extend the vertical strips, I
started off with strips which were all
extra-long, but which, by means of predrilled slots or holes, could be mounted‘shorter’ (figure 7).
To adjust the loop diameter, I prepareda number of short lengths of aluminium
rod which could be used to extend eachexisting 240 mm horizontal component(figure 8). By using a larger or smaller
piece of rod every time, I was able toreduce or enlarge the diameter in 2 mmsteps.
Measurements
Years ago, I measured my first RQHA’s
in the HF-laboratory of the school
where I worked (The Haarlem College
of Advanced technology). The complete
measuring set-up consisted of General
Radio gear, most importantly their
1602 UHF Admittance Bridge.
The measuring process is very involved
and results have to be corrected toadjust for the electrical cable length, aprocess which has to be repeatedfollowing every change to the antenna.
In order to be independent from theschool equipment, I have managed tocollect similar equipment of my own
from flea markets and second-handshops. Although reasonably happy withmy measuring equipment, themeasuring methodology was toocomplicated. After searching for acouple of years, I managed to trackdown an HP 8410-C/8411-C Network
Analyser with 8414A Polar Display
unit, which produces a graphic
representation of the resonant
frequency and the impedance (figure 9),
and an HP 8620 sweep generator.
Once the dry weather arrived, I moved
my measuring equipment from the attic
to the garden and set the gear up. I
www.geo-web.org.uk

Figure 4 - First results (Smith chart)

made sure that all co-axial cable was asshort as possible, as cable attenuationinfluences the measurement results.
For my first measurement I chose anantenna with a diameter/height ratio(D/h) of 0.33. On the one hand I wanted
to have as large a D/h ratio as possible(with real resistance between 30 Ω and38 Ω), whilst on the other hand there
was a need for a small D/h ratio toallow for greater sensitivity at thehorizon [6,7,8].
I started with a diameter of 360 mm
and measured the resonance frequency
and impedance at 137.5 MHz. Next,
whilst maintaining the D/hrelationship, the loop was shortened
step by step and more measurements
made. The results appear as a graph infigure 3 and as a Smith chart infigure 4. After a few days of assembling
and measuring, I had collected dozens
of tables with measurement results,
which I could use to construct the fourtypes of antenna, viz.
1 An antenna with two equal loops(resonant frequency 137.5 MHz),one loop with a series capacitor andthe other with a series inductor(± 45° phase shift).
2 An antenna with two large loops,
one loop only with a series capacitor(-90° phase shift)
3 An antenna with two loops of equal
height, but one with a wide diameterand the other a narrower diameter.
4 An antenna with both a large and asmall loop (± 45° phase shift).

7

GEO Quarterly No 9Group for Earth Observation

March 2006

Figure 9 - The Polar Display

Figure 10 - The Outdoor Testbench

Figure 5 - In the garden

Figure 11 - Impedance on the X-Y Plotter

Figure 13 - A section from the 13:06 UT
November 11, 2005 NOAA-18 pass. Despite
the PADAT137 antenna being located indoors
below Ruud’s tiled attic roof, and surroundedby all his electronic equipment, it produced an
excellent horizon-to-horizon image.

Figure 6 - The adjustable antenna

Figure 7 (above, left)
Pre-drilled slots in the ends of the verticalantenna elements allow them to be shortened.
Figure 8 (above, right)
Short lengths of drilled aluminium rod bolted
on to the ends of the horizontal elements tomake the antenna loops wider.

8

Figure 12 - PASAN screenshot showing antenna/receiver impedance matchingwww.geo-web.org.uk

March 2006

The Final Design
After a further couple of weeks sawing,
drilling, turning on the lathe andheaving measuring equipment back andforth between attic and garden, only one
design finally remained, No 4.
For this, I left the top horizontal
components at equal heights with adistance of 40 mm between the twolower horizontal components; thedistance between the mid-points of thetwo loops was thus 20 mm. This
resulted in a very small difference inradiation pattern between the twoloops, which in practice could be
ignored. The impedance of this ultimate
antenna was measured using the set-up
shown in figure 10.
By sweeping the signal generator
output between 132 and 142 MHz, boththe impedance and resonance could beread directly on the display of the
Network Analyser; and by connecting
an X-Y plotter to its output, theimpedance curve was plotted on paper(figure 14). Figure 11 shows thescanned plotting paper with thefrequencies written in, indicatingclearly that the antenna has a purely
resistive value at about 137 MHz (andis consequently resonant) and that the
impedance is 35 Ω. The antenna had
now reached its final form, and inpractice was producing excellent
weather images (figure 13). It now
remained to match the antenna to theasymmetric co-axial cable and the 50 Ω
input impedance of my receiver.
Matching the Antenna
There are two factors that can have anegative influence on the properties ofan antenna.
1 The absence of a matching system
to achieve a good match between asymmetrical RQHA and an
asymmetrical co-axial cable bymeans of a linking ‘balun’(balanced-unbalanced).
2 The mismatch between theantenna receiver impedances.
1. Matching to the Co-ax
Why is matching a symmetricalantenna to an asymmetrical co-axial
cable so important? If the match isabsent or incorrect, a ‘skin’ current willflow along the outside of the co-axial
cable (‘i3’ in figure 16). The outside
braid of the cable will thus become partof the antenna, as a result of which theantenna will exhibit an asymmetricalradiation pattern. The resultant effectis shown in figure 15. When a signal isGroup for Earth Observation

GEO Quarterly No 9transmitted without correct matching it
is not distributed in a symmetricalfashion. The antenna would thenexhibit rather ‘cross-eyed’ behaviour
and in the case of a RQHA it would bedirectional [9].
Secondly, part of the transmitted signal
will be transmitted through the outsideof the co-axial cable shield. Since inmost cases the antenna co-ax runs fromthe top to the bottom, part of this signal
will be transmitted through the cable ina vertically polarised fashion. When ahorizontally polarised signal isreceived, the receiver input will not
only contain the dipole signal, but
additionally, the signal received fromthe vertically acting component in the
co-axial cable.
In practice this means that a good (butincorrectly connected) antenna will be
subject to considerable interference(usually from vertically polarised
signals such as pagers) which willinterfere with the desired signal andresult in unwanted noise bands. In thecase of our PADAT137 antenna thiswould make it directional and thus
lacking all-round circular sensitivity.

Figure 14 - Impedance on the X-Y Plotter

Figure 15 - The Skin Current (i3)The length of the co-axial cable also
influences both of these sensitivities. As
a result, a well constructed RQHA
could turn out to be a disappointment(insensitive and/or directional and noisebands).
Figure 16 - An asymmetrical radiation pattern

Options
There are a number of options toprovide a proper match.
The trifilar wound 1:1 transformer
This device is used in short-wave
applications and a number of types I
built for 137 MHz produced goodresults. The capacitance between thethree windings has a considerable
influence on the correct functioning of
this balun; the best results wereobtained with a small ferrite toroid
with three 0.1 mm diameter windings(figure 17).

Figure 17 - Trifilar balun

Note: Whilst perusing some Amidon
documentation, I came across asentence in the text, which
recommended that the three wires
should be twisted in order to avoid
mutual capacitive influences. This issomething I will need to follow up!
The Bazooka
The bazooka (figure 18) consists of acopper or tin cylinder, -wavelength
long, where the bottom side isconnected to the outer shield of the cowww.geo-web.org.uk

Figure 18 - The bazooka balun

9

GEO Quarterly No 9axial cable. When such a cylinder istightly mounted around the plastic
insulation of the co-ax, a so-calledvelocity factor has to be applied.
Depending on the plastic shield(polythene or Teflon) this -wavelength
needs to be multiplied by 0.66 or 0.7. If
a larger diameter of cylinder is used, sothat the space between the cylinder andthe co-ax consists of air, there is noneed to apply a correction factor.
However you must remove theinsulation from that part of the co-axial
cable which is inside the cylinder.
The 2-Element Bazooka
The 2-element bazooka is anotherpossibility (figure 19). Instead of using
a cylinder around the co-axial cable, asecond length of co-axial cable (with thesame outside diameter as that used forthe antenna) is mounted parallel to theco-ax. Since the efficiency of this balun(similar to previous designs) depends
on mechanical construction, I have notpursued construction of this type.

Figure 19 - The 2-element bazooka balun

The Inductively Wound Cable Choke
This type, a balun (RFchoke), has quite often
been used in earlier
published construction
notes for an RQHA but
is not very effective at
137 MHz. It was often
used in short-wave
applications but it is lessuseful at higher
frequencies, since themutual capacitance
between the windings
has a negative effect on
Figure 20
performance. Such
A woundwindings must not be
cable chokeplaced adjacent to one
other. After some experimentation I
also discarded this approach (figure 20).
The Ferrite Toroid Balun
This design does not really constitute areal balun. In reality it is a ‘ferrite
loaded co-axial RF-choke’, but it does
effectively result in a 1:1 current balun.
The use of ferrite toroids or tubularcores is not cheap but does offer many
advantages with respect to otherbaluns. This balun is simple toconstruct, is not frequency dependentand its usable frequency ranges several

10

Group for Earth Observation

dozen MHz. According to details
provided by Amidon [10] the appropriatematerial is designated as ‘Type 43’. This
provides the greatest degree ofattenuation between 100 and 300 MHz.
The total length of ferrite tubes or rings
threaded on to the cable will determine
the impedance and hence the balun
choke function.
Measurements indicate that extending
the total ferrite length in excess of wavelength does not provide any
benefit. When RG58 cable is used,
many different types of cores are
suitable. Since an impedance of 800 to1000 Ω is sufficient to suppress any
skin effect currents, the number ofcores to be used depends on the lengthof the cores themselves. When using
Amidon cores, 25 of type FB-43-2401
and 12 of type FB-43-6301 are required.
The total length of these cores isaround 12 cm. You can also use thecheaper Richcom cores. The innerdiameter of these cores is around 5 mm.
If it proves to be impossible to threadthem over the co-ax cable, theinsulation over the outer shield of theco-axial cable will have to be removed.
I finally decided on using the ferrite
ring balun. I have used both ferrite
toroids and tubes in my experiments;
the use of tubes is cheaper than toroids
since fewer units are required. The
baluns were constructed from 25
Amidon toroids (or 15 Richcom tubularcores). At 137.5 MHz, these cores havea per unit impedance of around 35 Ω
(Amidon) or 65 Ω (Richcom). Whenthese are connected in series the
impedances of individual cores must be
added together. Such cores are often
offered cheaply at amateur radio fielddays. Just make sure that the material
is Type 43.
2 - Matching with the Receiver
The measurement results showed theimpedance to be somewhere between
33 Ω and 35 Ω at 137.5 MHz. Most
receivers have an input impedance of
50 Ω so, to obtain the maximum
transfer of the energy received at theantenna to the receiver, the antenna
impedance needs to be transformed to50 Ω. If the input impedance of thereceiver is around 70 Ω (as it is in our
HRX137 and many home-brew
receivers), an effective match can beobtained by simply adjusting the coaxial feed cable to a multiple of wavelength (electrical). No actual
impedance adaptation should benecessary as the impedance at the endof the cable should be around 71 Ω.

www.geo-web.org.uk

March 2006

A further possibility is to use anantenna amplifier, though not generally
needed except when a very long lengthof co-ax is in use. By adjusting theimpedance of the RF input to 70 Ω, agood match can be obtained.
Further possibilities involve the use of
stubs, lengths of co-ax sticking out fromthe main downlead. The length andcorrect placement of these stubs can becalculated [11]; their efficacy depends ontheir precise dimensions andpositioning, which is very difficult toachieve without appropriate measuring
equipment.
Another solution would be the use of animpedance transformer. Such a device
consists of aelectrical wavelength coaxial circuit. The impedance of thiscircuit may be calculated from theformulaZt = Za x Zl
where Zt represents the impedance ofthe transformer, Za that of the antenna
and Zl the combined impedance of theco-axial cable and receiver input(figure 21).

Figure 21 - Impedance transformer

ExampleZ antenna is 36 ΩZ line is 50 Ω
Z transformer is √ (36 x 50) = 42 Ω
The dimensions of the impedance
transformer can be calculated with theformulaZt = 138 log b/awhere ‘b’ is the innerdiameter of theoutside conductorand ‘a’ is the outer
diameter of the innerconductor (figure 22).

Figure 22

Using Pasan Software
The first impedance matching system I
used consisted of pieces of 50 Ω RG58 U
co-axial cable. I used the ‘Pasan’software to explore a number ofpossible matching approaches using
combinations of 50, 75, and 93 Ω.
Pasan, developed by Marien vanWesten, is a great aid when calculating
and constructing such a matching
device.
A basic guide to using Pasan for
impedance matching can be foundin the sidebar on page 11.

March 2006

I recommend first aiming to use a 0.101
wavelength piece of 50 Ω co-ax for‘Component 1’ and a 0.038 wavelength
piece of 25 Ω cable for ‘Component 2’. If
we assume a co-ax velocity factor (Vf)equal to 0.67 we will need a 147 mm
length of 50 Ω cable and a 54.6 mm
length of parallel-soldered 50 Ω co-ax.
Note
Although it is very difficult to obtain coaxial cable of 25 Ω impedance, you canjoin two 50 Ω pieces in parallel to obtain25 Ω.
If desired, you can use a longer piece of
50 Ω cable at the top of the antenna sothat more room is available to facilitate
installation of a bazooka or ferrite ringcore balun. A possible alternative
solution to the matching problem would
then be to use a 505 mm length of 50 Ω
cable (0.349 λ) together with 62.4 mm
of 93 Ω network co-axial cable.
It is also possible to make an impedancematching circuit with a combination ofjust 50 Ω co-ax and a capacitor or coil(inductor). In my latest experiments I
decided on a combination of 487 mm of
50 Ω and 101 mm of 75 Ω cables.
Note
In all the above examples, I am
assuming a velocity factor (Vf) of 0.67
(for RG58 and RG59). If a 75 Ω satellite
cable is to be used (which gives lessattenuation), be aware that Vf would be
increased to around 0.70.
If you have any questions related to the
Pasan program (operation, adjustmentetc.), please contact me at
ruud@farbridges.net
For those of you who are keen to learna bit more about baluns, Smith charts
and RQHA’s, Walter Maxwell W2DU
has written a book [12] on this subject.
He is also the designer of the
Quadrafilar antennas on board the
TIROS, ESSA and NOAA weather
satellites.
Part 2 of this article, in the JuneGEO Quarterly, will describe theconstruction of the PADAT-137
References

Group for Earth Observation

GEO Quarterly No 9

A Simple Guide to Impedance Matching with PASAN
You can download Pasan from Marien
van Westen’s website:
http://members.home.nl/mvanwesten/
Click the link to Electronics in themenu panel, then Pasan. Be sure to
download the new version of the
program, PasanSE.
Define your circuit in the Diagram
panel at the top right of the Pasan
screen; it will consist of two
components—the two lengths of co-ax
you need to match. Click the rightmouse button once on the empty
square above ‘1’ then once in the box
above ‘2’ to define components 1 and 2
as lengths of co-axial cable (figure 23
on page 12).
Select <Options → Preferences> from themenu-bar and fill in the fields from
Table 1, as illustrated in figure 24.
Check the Save current settings box
then click ‘OK’ to store these values as
your default Pasan settings.
You are now ready to start thecalculations to match the two
impedances. In the data panel at lower
right of the main Pasan screen(figure 25), under ‘Z load’, enter ‘0.35’
for ‘Re:’ (followed by the Enter key) and‘0’ for ‘Im:’ (this is the antenna
impedance). You will now see that agreen dot has appeared on thehorizontal mid-line of the Smith chart,with the value ‘35’ (figure 12).
Click on the button with the ellipsis(...) beside the entry labelled ‘1 Line’ inthe data panel (figure 25). This opens
the Transmissionline data window(figure 26), where you must enter theCharacteristic impedance as ‘50’ andthe Velocity factor as ‘0.67’ (this value
applies to RG58 cable). This windowshows a length for the co-ax and theequivalent electrical length in λ. (thesewill be adjusted correctly later: you
don’t need to change any of the otherfields at this stage). If you click<Options → Bode plot> you can view the

1 Ruud Jansen - De Pita137, De Kunstmaan, April 2000
www.jendela.nl en www.kunstmanen.nl
2 Ruud Jansen - De Kunstmaan, February 2005, p 16; GEOQ 6, p 24.
3 Rob Hollander - RQHA, Technote 1999-1 (www.kunstmanen.nl)
4 Rob Hollander - Article on radiation patterns, GEO Q3, page 26.
5 http://www.microwaves101.com/encyclopedia/smithchart.cfm#smith
The ARRL Antenna Book, chapter 28. ISBN: 0-87259-904-3
The Antenna Experimenter’s Guide, G3LDO. ISBN 1-872309-36-4
6 H.S.C. Wang - IEEE transactions on antennas and propagation, vol.
39, No 8, August 1991

circuit attenuation in a pop-up window.
Click on the ellipsis (...) button labelled‘2 Line’ and this time enter theCharacteristic impedance as ‘25’ andthe Velocity factor as ‘0.67’.
The Smith chart display now shows
the curves for the 50 Ω line and 25 Ωline (figure12). The selected component
is shown in red, any other ones blue.
Making the Match
Now comes the final trick! Click themouse on the number ‘1’ below the 1stgraphic (figure 23), then move themouse over the Smith chart (figure 12)
and click at various positions insidethe upper hemisphere of the left-handpurple circle until Length in the‘1 Line’ field is approximately 150 mm.
Next, click on the number ‘2’ below the
2nd graphic (figure 23) and click themouse on the very centre of the Smith
chart (on the value ‘50’). Repeat these
two steps, making small adjustments,
until the values on both the ‘Zin’ fields(figure 25) show exactly ‘50’. Once youachieve this the value for SWR should
be exactly ‘1.00’. Any final adjustment
is most easily made by editing theactual value in the ‘1 Line’ field infigure 25.
You can now read off the two co-ax
cable lengths required for matching(and their associated electrical
wavelengths) by clicking the ellipsis
buttons and referring to the Transmissionline data windows (figure 26). You
can also view the total attenuation in
the Bode-plot window.
Because the antenna impedance has
been converted to 50 Ω you can now
use a length of 50 Ω co-ax as thedownlead to connect your antenna to
the receiver. If you use 10 metres ofdownlead, you can add a third ‘line’element to Pasan, enter its length as
10 m, and determine the overallattenuation due to all three lengths ofco-ax from the Bode-plot window.

7 C.C.Kilgus - The Microwave Journal, December 1970
8 Rob Hollander - Technical Note 2004-1
ftp://ftp.kunstmanen.nl/pub/technotes/RQHA/RQHA 2004-1.pdf
9 http://www.poynting.co.za/tech_training/tut_balun.shtml
10 Amidon (http://www.amidon.de/ferritrinkerne.htm) and ELECTRON,
September 1991 page 468-469 (VERON).
11 http://www.circuitsage.com/matching.html andhttp://www.ee.surrey.ac.uk/Personal/D.Jefferies/jefferies-stub.html.
12 ‘Reflections II’ By M. Walter Maxwell, ISBN 0-9705206-0-3

www.geo-web.org.uk

11

GEO Quarterly No 9Group for Earth Observation

March 2006

Sam Elsdon
Figure 23 - Defining the circuit in PASAN

Figure 24 - PASAN default parameters

Sam Elsdon, who works less than a mileaway from the Buncefield oil storage
depot that caught fire so spectacularly
last December, not surprisingly took aparticular interest in the event. The
lower colour image on the inside front
cover of this issue was provided by Sam
and uses virtual radar to illustrate theeffect that the conflagration had on air
traffic in the neighbourhood.
Sam takes up the story ...
Here is a different kind of remote imaging.
The image shows a plot of what was
happening to air traffic in the Hemel
Hempstead area at the time of the
Buncefield fuel depot fire on December 11,
2005. The orange trails show the paths ofsome passing aircraft—not all aircraft are
fitted with equipment that transmits theirlocation so these cannot be plotted. The
Buncefield depot is indicated by the red
pentagon near to the Bovingdon VOR*
(shown by the legend ‘BNN’) at the centreof the image where the result of an air
traffic exclusion zone can be clearly seen
as a large gap in the trails. The few trails
that do cross the gap would have done so
at high altitude.

Figure 25 - Calculation panel in PASAN

Figure 26 - Transmissionline data panel
Frequency
Up/Down steps
Zn
Q factor
Start Frequency
Stop Frequency
Number of steps
Major
Minor
Show Smith chart normalised
Full screen

137.5 MHz
10 MHz500123.8 MHz151.3 MHz100
1 MHz
200 kHzunchecked
unchecked

Table 1 - Pasan default parameters

12

Heathrow can be easily located due southfrom Buncefield, just over half-way
towards the bottom of the image. It isrepresented in grey with many orange
trails (arriving aircraft) leading to it fromthe east. The grey shape becomes a mapof the airfield if zoomed far enough. On
December 11, traffic was arriving anddeparting Heathrow towards the west.
Normally, when arrival traffic at Heathrowis heavy, aircraft from the northwest areplaced into a holding pattern at
Bovingdon, one of four holding points for
Heathrow. The other three, at Ockham,
Biggin and Lambourne can be clearlyseen to the south, SE and NE of Heathrow
respectively. To approach Heathrow fromthe east, Bovingdon traffic would normallybe routed to the south east, through theexclusion zone, and merged with traffic
from Lambourne so the gap would usually
be covered with aircraft trails. On thisoccasion, Bovingdon traffic was routed to
the Ockham hold, making it very busy
indeed, whilst some traffic was routed
around the north and east sides of thezone. With all of the changed routings, airtraffic controllers had their work cut out,
particularly those controlling the southern
approach to Heathrow from Ockham andBiggin.
www.geo-web.org.uk

Image Background
The image was created on a Kinetic
Avionics SBS-1 virtual radar system. The
antenna is mounted approximately 30 feetabove the ground giving a range of around
190 nautical miles in all directions apartfrom the west, where the Welsh hills andmountains slice off everything past central
Wales. Naturally, aircraft altitude greatly
influences the range but from my location,
aircraft can be tracked into Luton andStanstead until they are almost on the
ground, and into Heathrow and City
airports down to about 1300 feet.
*VOR: VHF Omni-directional Radio Range. A
ground based, air navigation beacon thattransmits both its identity, and signals that
permit airborne receivers to determine thebearing from the aircraft, to the beacon. A very
good description of the VOR system can befound at:http://en.wikipedia.org/wiki/VORDavid Taylor
Here's a slightly more unusual image of the
Buncefield fire. It is a night-time pass fromNOAA-17, using the user-mode RGB
processing in my HRPT Reader software toallow channel-3 (the mid-IR data) to show the
hot-spot from the fire itself. The two plumes,
the main one blowing approximately south,
and the secondary one blowing approximately SSE are clearly visible. The remaining
details are due to slight differences in the land
surface temperature. The fire-fighting had notstarted when this data was collected.

This segment from the 21:25 UT NOAA-17 passover southern England on December 11, 2005
clearly shows the hot-spot from the Buncefield
fire as a white spot north of London.

March 2006

Group for Earth Observation

GEO Quarterly No 9

Add impact to your MSG images with MapToGeo, a new program from David Taylor
Les Hamilton
What is Blue Marble?

MapToGeo

The description ‘Blue Marble’ wasoriginally coined to describe the stunning
full-disc colour photographs of Earth taken
by astronauts during the Apollo-17 mission
to the moon (figure 1). In 2002 the concept
was extended by combining four monthsof Terra MODIS observations, collectedduring the previous year, into a seamlesstrue-colour mosaic covering the entire
planet at resolution of one kilometre per
pixel (figure 2).

Apart from being intrinsically beautiful
realisations of our planet, the Blue Marble
images may now be put to practical use bymeans of MapToGeo, a new offering fromDavid Taylor (Satsignal Software) devised
following discussions with Ferdinand Valk.

This year NASA has gone a stage further,with the creation of a set of high-definition
cloud-free Earth images in plate carrée
projection [1] at a maximum resolution of
500-metre/pixel. These images are alsoavailable at lower resolutions of 2-km/pixel
and 8-km/pixel. These new Blue Marble
images may be downloaded from thefollowing URL, which is Case Sensitive, byfollowing the link to ‘Monthly global
images’.
http://earthobservatory.nasa.gov/
Newsroom/BlueMarble/
Unless you have access to a powerfulmainframe computer, do not eventhink about ordering a 500 metre
image. Your PC will be totally unable
to display it. Indeed, even a 2-kilometre
image, which measures 21600 x 10800
pixels and occupies 20 megabytes as a
JPEG image, is so large that most PC
imaging software will struggle todisplay it adequately. Even theseimages are recommended for use on
only the very highest specification
modern PCs.
The lowest resolution Blue Marble images(8 km) are the ones to aim for. These
measure a not inconsiderable 5400 x 2700
pixels and are provided for download as
JPEG images of around 1.5 to 2 MB each;even these are highly impressive.
Images are available for each month of
2004, plus others which offer topographic
and bathymetric shading. Part of the
March 2004 Blue Marble image appearson the inside front cover of this issue.

MapToGeo allows the user to manipulatea plate carrée Blue Marble image andconvert it into an Earth view seen from thelocation of any of the current geostationary
weather satellites. These modified images
can be used as attractive backgrounds for
GeoSatSignal, and combined with cloud
patterns from current MSG images, as an
aid to weather presentation.
The great thing about this technique is thatrealistic images can now be generated byboth day and night; there is no longer any
need to wait for a daylight MSG image.
This greatly extends the ability of
GeoSatSignal to generate easily understandable data around the clock.
Program Installation
MapToGeo is available as a 30-day timelimited evaluation fromhttp://www.satsignal.net
by following the link to ‘MapToGeo’ anddownloading it as a ZIP archive. Create an
new folder called ‘MapToGeo’ and extract
the ZIP file into this. It should be notedfrom the outset that MapToGeo is intended
for use on a PC with the minimum
specification of a 1 GHz processor with
1 GB of RAM running Windows XP or
Windows 2000. MapToGeo may run on
earlier Windows platforms but this isneither supported nor guaranteed.
Using MapToGeo
Run MapToGeo and from the ‘File’ menu
select <Open plate carrée image ...>. Click<Full world image ...>, navigate to thefolder containing your BlueMarble image
and double-click its filename to load it into
the program. All that remains is to selectthe <Remap> option to create the view thatyou require (figure 3). The front cover ofthis issue displays the March 2004 Bluewww.geo-web.org.uk

Marble full Earth image remapped to theview you would see from the location ofChina’s Feng Yun-2C satellite.
GeoSatSignal Backgrounds
When creating a Job in GeoSatSignal, oneof the available options allows the use of abackground image which, when used in
combination with an appropriate Land-Sea
Mask colour lookup table (CLUT), can bemade to show through those parts of theimage that are not obscured by cloud.
To implement this feature, save copies ofappropriate background files (created in
MapToGeo) in your GeoSatSignal folder,then, in <Options → Job setup ...>, select‘Background’ from the ‘False Colour’ dropdown selection menu. Next, select a CLUT
designed for transparency from the‘Vis ch.’ selection menu. The CLUT usedin figure 4 was called ‘LutBlueMarbleTest’.
GeoSatSignal will now intelligently selectthe correct background for the image
being processed without further userintervention (provided you have located itin the GeoSatSignal folder). Figure 5
illustrates a full disc channel-9 Meteosat-8(10.8 µm infrared) image on the main
GeoSatSignal ‘False colour’ tab; likewise,
figure 6 displays part of a Feng Yun 2C
image—note that GeoSatSignal has
automatically loaded the new backgroundto reflect the appropriate satellite.
The Transparent CLUT Filter
The filter CLUT is a small 24-bit truecolour BMP bitmap image just 2 pixels
high and 361 pixels wide. GeoSatSignal
interprets such files as representing
temperatures ranging from -120°C at theleftmost pixel and incrementing in 0.5°C
steps to +60°C at the farthest right pixel. In
the case in point the left 240 pixels in eachrow represent half-degree increments
between -120° and 0° and are coded
between 100% white and a moderate grey
selected to produce the most realistic
visual effect on the final product. The
rightmost 121 pixels in each row represent
positive temperatures (0° to + 60°) and aremade solid red. This results in these pixels

13

GEO Quarterly No 9Group for Earth Observation

March 2006

Figure 1 - Earth from Apollo 17 on December 7, 1972.

Figure 2 - Blue Marble 2002 image of the Western Hemisphere

Astronaut photograph AS17-148-22727, courtesy NASA Johnson Space Center

Image: Reto Stöckli and Robert Simmon, NASA Goddard Space Flight Center

Figure 3 - Selecting ‘Remap’ mode in MapToGeo

Figure 4 - Selecting the background in GeoSatsignal

Figure 5 - Blue Marble background with Meteosat-8

Figure 6 - Blue Marble background with Feng Yun 2C

14

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March 2006

Group for Earth Observation

Figure 7 - A regular IR ‘Europe’ view from Meteosat-8

GEO Quarterly No 9

Figure 8 - The same Meteosat-8 with a Blue Marble background

Image © EUMETSAT 2005

Figure 9 - A full disc IR image (left) and with added Blue Marble background (right)

Figure 10 - Tropical Storm Zeta at 12:00 UT on January 3, 2006

Figure 11 - A segment from an MTSat image, showing Australia

Figure 12 - The standard Land-Sea Mask CLUT used for Europe
www.geo-web.org.uk

15

GEO Quarterly No 9Group for Earth Observation

March 2006

being filtering out (made transparent) from the MSG
image so that the background image shows through.
Note that temperatures below -80°C are rarely
encountered in Earth’s atmosphere, so that all the pixels
in the -120° to -80° range are normally coloured 100%
white. An image of this CLUT appears in figure 12.
This CLUT works fine for most of the year in northernlatitudes. In colder conditions it may be necessary to use
a CLUT where the ‘red region’ extends a few degrees intothe ‘negative temperature’ part of the bitmap, while torepresent hot tropical areas you may find a CLUT with ashorter ‘red region’ to give more realistic results.
The Results
Figure 7 on the previous page is a regular infrared view ofEurope from Meteosat-8 dating from November 27. Thereis a considerable degree of cloud throughout the image,
and without the superimposed country boundaries, itwould be quite difficult to interpret. With a Blue Marble
background applied (and using the standard CLUT filter)the overall scene is much clearer. The match between thetwo images is pretty good and certainly fit for weather
presentations.

Robert Moore
Following an extended autumn in the UK, winter at last arrived on
November 17, plunging the country into freezing conditions as an
anticyclonic regime prevailed. The NOAA-18 HRPT image on the
opposite page shows most of Britain free of cloud during the satellite’s
12:48 UT pass. Robert Moore took advantage of the conditions to spot
evidence of human activity near where he lives. Robert takes up thestory ...
Fiddler’s Ferry is a coal-fired power station near Warrington in Cheshire.
According to Friends of the Earth, ‘It has no sulphur controls (technology
which cuts acid rain causing sulphur dioxide) so mostly burns imported
low sulphur coal.’ FoE suggest that Fiddlers Ferry is a ‘dinosaur … wellpast its sell by date’.

Figure 9 shows a similar comparison for a world view.
Since the world view of necessity focuses almost
exclusively on the warmer areas of the Earth, a ‘tropical’version of the CLUT has been employed. The filter
adjustment does depend a bit upon the area under
scrutiny, but in practice the demarcation position between
cloud and land/sea (in the CLUT bitmap) is around 15°C
(this concept has its restrictions over desert areas during
night time though).
Figure 10 is an interesting combination of a GOES-12
and a Meteosat-8 image over a Blue Marble backgroundto create a viewpoint that you would never normallyexperience. Finally, figure 11 is an example taken from a
MTSAT-1R image, showing Australia. Again a a small
degree of CLUT filter adjustment has been made to suit
this particular region.
In Conclusion

Figure 1 - Steam rising from Fiddler’s Ferry power station

These Blue Marble maps are great fun to view and workwith and really can improve the impact of your MSG
images, particularly those from overnight infraredtransmissions. They cannot of course, from an analytic
standpoint, be considered as a replacement for genuine
MSG-1 imagery. The addition of a Blue Marble
background is primarily useful as a tool for presenting
practical daily meteorological information in an
informative and attractive way; when used in the creationof animations there is no other mechanism that cancompare with this method because it produces consistent
results 24 hours per day.
Acknowledgements
Thanks to David Taylor and Ferdinand Valk for invaluable
help and discussion during the compilation of this article:
also to Ferdinand for making available all the MSG
images on page 15.
References
1. Plate Carrée
A map projection (similar to Mercator) where lines of latitude
are regularly spaced apart by the same distance as the lines
of longitude.

16

This power station is a major landmark, its eight towers being visible from northWales and large parts of Cheshire and southwest Lancashire. Fiddlers Ferryemits regular plumes of steam from its towers, which provide shade in theimmediate locality. For observers living further afield and in clear weather theplumes provide a useful indication of weather conditions; notably the height of thetropopause and the presence of upper level wind shear. The much more modern
Queensferry power station on the south of the Dee—just inside north Wales—
provides an interesting comparison point with Fiddlers Ferry when the plumes arevisible at both locations.
The photograph above
was taken shortly after
midday on
November 17 when
the plumes of steam
could be seen risingvertically before
generating a small lineof cumulus cloud. Thisfeature was not visible
in Meteosat-8 imagery
but is just visible in the
NOAA-18 HRPT
image. The photograph was taken at
about the same time.

www.geo-web.org.uk

Figure 2 - Location of the steam plumes (arrowed)
Image: NOAA CLASS Archive
Processing: HRPT Reader

GEO Quarterly No 9Group for Earth Observation

March 2006

Peter Wakelin
Japan Launches Advanced Land Observing Satellite
The eighth H-IIA launch vehicle lifted off from Tanegashima at
01:33 UT on January 24 carrying Japan’s Advanced Land
Observing Satellite (ALOS). First stage thrust was supplemented
by two SRB-A strap-on motors and two smaller Castor IVL strapon motors. The second stage made a single 524 s burn to place
the payload, which is known as ‘Daichi’ in Japanese, into theplanned 700 km circular sun-synchronous orbit.

operating in the conventional mode, PALSAR can use ‘ScanSAR’
which permits a much wider swath but at the expense of spatial
resolution.
NPOESS First Launch Delayed until 2012
The first spacecraft in the USA’s next-generation polar-orbiting
weather satellites, NPOESS (National Polar Orbiting Operational
Environmental Satellite System) will not be launched for at leastsix years.
The NPOESS project was born out of the US Presidential
Decision of May 5, 1994 which directed the Departments ofCommerce and Defense to converge their separate polar-orbiting
environmental satellite programmes into a single programme toserve both military and civilian needs. By 1996 the programme
was taking shape and the first NPOESS launch was then
expected in 2007. Such predictions are invariably optimistic and
it is worth pointing out that, also in 1996, EUMETSAT expected
the first MetOp launch to be in 2002.

Artist's impression of ALOS in orbit

JAXA (Japan Aerospace Exploration Agency) was the prime
contractor for the spacecraft but other contractors involved
include Mitsubishi, NEC and Toshiba. ALOS will continue thework done by its predecessors JERS-1 and ADEOS but withmore advanced sensors. The three advanced sensors are
PRISM, AVNIR-2 and PALSAR.
The Panchromatic Remote-sensing Instrument for Stereo
Mapping (PRISM) is a panchromatic radiometer with 2.5 m
resolution at the nadir and will provide a digital surface model ofhigh accuracy. There are three independent optical systems
looking forward and backward, as well as at the nadir, to produce
stereoscopic images along the 35 km-wide swath.

ALOS within its huge fairing
atop the rocket

ALOS on its way

The Advanced Visible and Near Infrared Radiometer type 2(AVNIR-2) is to be used for land-coverage maps and land-use
classification maps for monitoring regional environments. Its 10 m
resolution is an improvement on the 16 m attainable at the nadir by
the original AVNIR flown on ADEOS.
The Phased Array type L-band Synthetic Aperture Radar(PALSAR) is an active microwave sensor using L-band to achieve
day and night land observations even through cloud. As well as

18

The one remaining launch in the NOAA polar-orbiting series,
NOAA N’, will be NOAA-18’s replacement in the afternoon orbit.
In addition, DMSPs 17, 18, 19 and 20 remain to be launched overthe next few years; all are destined for morning orbits. These four
are the last of the Defense Meteorological Satellite Program’s
polar-orbiters and, although direct read-out is not available tocivilian users, the spacecraft are now operated by NOAA and thedata from them are widely distributed. So, notwithstanding any
serious malfunctions, these and existing spacecraft, together withthe upcoming MetOp and NPP (NPOESS Preparatory Project),should ensure that there is no data gap before NPOESS
becomes operational.
The GOES-N Saga Continues
GOES-N was originally scheduled for launch in 2001 but
construction and launch were extended to 2003 as the on-orbit
satellites were in good health. In 2003 the launch was set for
December 2004—and then January 2005. In February 2005 it
was rescheduled to May to avoid the spring eclipse season. In
April there was concern about the Delta IV rocket and launchslipped to late June whilst some tanks were replaced. Further
rocket concerns, and checks for possible lightning damage,delayed the launch till August. On August 16 the launch wasaborted during the final countdown and rescheduled for earlyNovember. Since then, strike action by some Boeing employees
has prevented launch. May 2006, after the spring eclipse season,is the next likely launch target.
This strike action has delayed other Delta launches too, including
the imaging satellites Cloudsat/Calypso and DMSP-17.
MSG-2 Successfully Launched
Arianespace continues its string of successes with the launch ofvehicle number 525, a standard 5GS model, which put MSG-2
and INSAT-4A into a transatmospheric orbit. After first-stage
separation, a single burn of the upper stage pushed the payloads
towards a 620 x 35853 km geostationary transfer orbit inclined at
3.9° to the equator where the payloads and their Sylda adapter
were separated. Meanwhile, the first stage reentered the

www.geo-web.org.uk

March 2006

atmosphere over the Pacific Ocean. ESA
took control after spacecraft separation
and began the Launch and Early
Operations Phase (LEOP), manoeuvring
the spacecraft to its commissioning
location above 6.5° west longitude on theequator, aligning its spin axis with the
Earth’s and stabilising the spin rate at 100
revolutions per minute.
EUMETSAT took over control of MSG-2 onJanuary 2 and immediately started
commissioning activities by activating theonboard instruments and beginning thecheck out of all systems. The
commissioning phase is expected to last
until June but the routine dissemination ofdata is likely to begin before that forevaluation purposes.
On completion of the commissioning
activities in June, Meteosat-9 (as MSG-2
will then be known) will be moved to zero
degrees longitude and become fully
operational. The service currently provided
by Meteosat-7 will then be terminated andthis satellite will be moved to the IndianGroup for Earth Observation

Ocean to replace Meteosat-5.
Some users of the WEFAX service from
Meteosat-7
maybeexperiencing
interference to their images caused by
MSG-2 commissioning activities. Turning
the receiving antenna slightly to the east
may help but, as this service is ending
soon, the solution is to move to the
EUMETCast or Internet service.
MSG-3 is built and is currently in storage
and the fourth and final one is underconstruction. This second-generation
series is planned to operate for at least
another 12 years.
Fiery End for Sich 1M nears

Sich 1M was launched into a useless orbit
following an under-performance of an
upper-stage rocket in late 2004. Significant
atmospheric drag at its low perigee has
steadily reduced the apogee from theinitial 600 km and by late January, 2006
the orbit was just 248 x 382 km. Final orbit
decay will be rapid and the spacecraft willsoon burn up in the atmosphere.

GEO Quarterly No 9

Symposium 2006
Accommodation
If you are planning to attend the GEO
Symposium on April 29 and intend tostay overnight in Leicester on the
Friday, you may be interested to learn
that GEO has made arrangementswith the Campanile Hotel, Leicester.
Many of the GEO Management Teamwill be staying at the Campanile
overnight. Why not come along andjoin them?
The special room rate is £46.95 for a
double room including breakfast for
two people, a saving of £12.50 on thenormal rate. Ample parking isavailable.
To take advantage of this rate, bookquoting the reference ‘GEO’. Contact
details are:Mark Smith & Sue Wilson
Campanile Hotel
St Matthews Way
Bedford Street North
Leicester LE1 3JE
Tel: ++44 (0)116 261 6600
Fax : ++44 (0)116 261 6601
E-mail:leicester@campanile-hotels.com

This January 30, 2006 NOAA-17 channel-2 HRPT image shows high pressure bringing sub-zero temperatures to most of the UK
Image: CLASS archive (http://www.class.noaa.gov)

www.geo-web.org.uk

19

GEO Quarterly No 9Group for Earth Observation

March 2006

Figure 3 - The writer photographed amongst young oil palms on the
Guthrie estate amidst the rolling hills of Negeri Sembilan.

Figure 1 - Landsat Thematic Mapper image (bands 13, 45 and 57)
showing oil palm estates in Sumatra, Indonesia
Image: NASA

Figure 4 - Kim indicating fruit in the crown of a palm tree

Figure 2 - This 250-metre MODIS Terra image of the Sumatra coastline
facing the Strait of Malacca shows plumes of fire-haze

Figure 5 - The Sungai Muar river which meanders across the town ofMuar on its journey towards the Strait of Malacca.
This river is prone to flooding, affecting surrounding fruitorchards, rubber estates and oil palm plantations.

Image: © CRISP

Image © SpaceImaging

20

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March 2006

Group for Earth Observation

GEO Quarterly No 9

Kimberley Loh Ying-Ying
Oil palm plantations occupy more than 3.3
million hectares, about 40% of all
cultivated land in Malaysia. Nowadays,
synthetic aperture radar sensing andremote satellite imaging are playing animportant role in helping plantation
managers to maintain a competitive edge
over their competitors. Plantations need toknow fruit and frond sizes, bunch
numbers, photosynthetic efficiency, landdrainage in oil palm plantations besides
other production factors (figure 1).
Counting the Trees
Oil palm owners count tree stocks on theirplantations in order to know the value andproduction of their assets. Manual stock
keeping is tedious and unreliable; acommon method is to walk through dozens
of oil palm estates
conducting bunchcounts in batches of
10 trees and thus
estimating the total
number present. A
more
modernapproach is to count
IKONOS image ofthe palm trees fromspace, as their tree crowns used forcrowns are clearly recording trees in oilpalm plantations
visible in 1-metre
IKONOS imagery
resolution IKONOS© Space Imaging
imagery.
Classifying the Trees
High-resolution IKONOS imagery also
helps to distinguish between young andmature oil palm trees. Mature trees
generally appear darker in tone with wellformed canopies, while the young ones
are lighter in colour with well-separated
individual tree crowns. Synthetic apertureradar microwave energy can penetrate
planted vegetation and detect the crowns
and trunks of oil palms. In the C-band,backscattered energy is correlated mainlywith the crown constituents such as theleaves, twigs and small branches. Further,using a texture-based image-processing
algorithm, IKONOS can accurately classify
oil palm age at estate level from its satellite
images.

density in a surrounding grove is about
100 trees per hectare, then the manager
can infer that more trees could have grown
healthily were it not for unfertile soil or tree
fungi.
Identifying Sites for Trees
Oil palm trees demand land with welldrained soil. Land covered by water canaffect yields. IKONOS imagery has helped
to identify areas subject to flooding during
bad weather conditions. For example, astream flowing through an oil palm
plantation may cause the tree trunks to becovered, and possibly rot, during a rainyseason (figure 5)
Planning Tracks among the Trees
Plantations also have to plan routes totransport harvested fruits to the mills.
Typically, newly planted palms are planted
parallel to contour lines and tracks throughthe plantations appear bright against thegreen tree background. However, inmature plantations the palm canopies
often close up obscuring the road network
layout and route lines can then becomputed from IKONOS images through apixel-based classification algorithm which
can clearly show up large-scale land andlogistics development (figure 6).
Destruction of the Trees
When oil palms have matured the
traditional procedure is to fell the trees. On
undulating land in the forests, commercial
plantations burn their trees as a cheap way
towards replanting. This has caused air
pollution with drifting smog affecting
neighbouring countries (figure 2).
Oil palm crop yields are reduced by haze if
less than one third of the sunlight reaches
the leaves—this is the critical level forphotosynthesis—because the palm fruits’
ripening process is significantly affected.
The low oil extraction rate experienced
during the first 5 months of 1998 wasdirectly related to haze produced between
September and October 1997 as shown in
the table below.

Figure 6 - This IKONOS image clearly shows
tracks through the palm-tree canopy in the
Sandakan district of Sabah, Borneo.
Image © SpaceImaging

Harvesting the Trees
The harvesting of the oil palm, Elaeis
guineesis, for palm olefin conversion into
food and cosmetic products, and using byproducts as biofuel or nutrients for animal
feeds and mushroom cultivation, are well
documented.
There are about 340 palm-oil mills
throughout Malaysia, processing palm
olefin for the food and health careindustries. Malaysia is the world largest
producer of oil palm products and byproducts.
The Dutch planted the first oil palms in
Buitenzorg (now Bogor) Botanical Garden
in Java, Indonesia in 1848. The first batchof oil palms from Africa was received in thethen Malaya through the Royal Botanic
Gardens in Kew, England in the 1870s.
The commercialisation of oil palms in
Malaysia was largely due to Frenchman
Henri Fauconnier, who used seedlings
obtained from palms in Sumatra in 1911
and 1912.
You can read more at:

http://www.mpopc.org.my/abtegfu2.htm
What is less well known is the role of the ‘soft’ingredient of remote imagery in oil palm
cultivation.
In conclusion, one must say that it is more thana ‘light’ product whenever margarine is spread.
Acknowledgement

Locating Unhealthy Trees

A thank-you to Puan Suhaila, biology teacher at
the Seri Bintang Utara school, Kuala Lumpur
and my private tutor, Cik Noraini, for guidanceon the draft of this article.

Plantations management must also ensure
healthy plants to produce fine endproducts like margarine. The location andsurrounding area of a plantation’s vacantland may signify poor planting, unsuitablesoil or disease. For instance, if the tree

This paper is part of a research assignment on
the Fourth Form subject: ‘English for Scienceand Technology.’

www.geo-web.org.uk

21

GEO Quarterly No 9Group for Earth Observation

March 2006

Clive Finnis
We are delighted to report that the GEO Shop has secured
exclusive deals to be the sole UK distributor of two Germanbuilt APT weather satellite receivers, the Vierling‘Weatherman’ and the R2FX, both of which have beenreviewed in recent GEO Quarterlies [1,2].
GEO is the exclusive UK agent for both receivers. You
cannot purchase either anywhere else in the UK.
R2FX ReceiverComplete ‘Weatherman’ System
This comprises the APT Receiver, QFH Antenna and Windows
based computer control software. The complete system isavailable as a special introductory offer for a limited period,
offering considerable savings on purchasing the receiver and
QFH separately.
• GEO Members• Non Members-£349.00 (saving £69.00)£369.00 (saving £79.00)

Diminutive in size, but packed
with features, the new R2FX APT
receiver is ideal for the newcomerto the hobby or for the experienced
user who wants a convenient portable receiver for mobile use.
Full computer control is built in (compatible with WXtoImg)
and a novel feature is the twin antenna sockets. The receiverwill automatically select the antenna with the strongest signal
to provide long fade-free passes. Fully cased and ready to go, afull APT system (including antenna and all cables) is available
for under £200 by purchasing the R2FX with the optional
accessories pack described below.

Martelec MSR40 EPROM

R2FX Accessory Pack

Prices for the above are listed below. They all include carriage
and packing to UK addresses. Readers in EU countries areadvised to purchase direct from the German manufacturers;
they will certainly save on carriage charges [3,4]. Readersresiding in the rest of the world are advised to contact the GEO
shop for a quote if they are interested in making a purchase.

This contains everything required to implement a complete
APT receiving system when used with the R2FX receiver. It
comprises:
•
•
•
•
•
•

137 MHz Turnstile Antenna
UK plug-in power supply
PC audio lead + PC Serial ‘computer control’ lead
Aerial lead (20 metres long with fitted connector)
CD of PC shareware starter software
Instructions

Just brilliant value for money!
Note: in some areas of the country this receiver has
experienced pager intrusion on 137.91MHz, but generally
performs well on 137.1, 137.5 and 137.62.

Following the invaluable help and assistance of Chris Pretty,
the original designer of the Martelec range of receivers, GEO
can now offer an EPROM for the Martelec MSR40 receiver tocover the two NOAA18 frequencies of 137.1MHz and137.9125 MHz.
Initial tests have shown the MSR40 to be a very sensitive
receiver whilst having excellent resistance to pager
interference at 137.9125 MHz. Fitting instructions areincludedPricesGEO Members

Non Members

R2FX receiver only

£135.00£149.00

R2FX Accessories Pack

£59.00£69.00Vierling 'Weatherman' receiver£239.00£259.00

Vierling 137 MHz QFH Antenna

£179

£189

Vierling - Complete system

£349

£369

All prices include post and packing to UK addresses

The Vierling ‘Weatherman’
Professional APT Receiving System
A very impressive professional receiver,the German designed and built
Vierling, will satisfy the requirementsof the most dedicated enthusiast. Itfeatures an LCD display and has
proved to have excellent resistance topager interference. Extensive testing byJohn Tellick from his pager ‘hot-spot’ insouthwest London showed it to bebarely affected at all.
Also available separately is the Vierling
QFH antenna with excellent
performance at a very competitive
price.

22

Martelec MSR40 EPROM

UK

EU

Rest ofWorld£10.00£10.75£11.25QueriesIf you wish to make a queries about any of the above items,
please e-mail them to:
shop@geo-web.org.uk
References
1 R2FX APT Receiver - GEO Q7, page 19
2 Weatherman - GEO Q8, page 19
3 http://www.df2fq.de
4 www.vierling-group.com/weatherman

www.geo-web.org.uk

March 2006

Group for Earth Observation

GEO Quarterly No 9

Manager: Clive Finnis
e-mail: shop@geo-web.org.uk
FAX: +44 (0) 1202 893 323

PRICE LIST

TechniSat SkyStar 2 PCI CardUK

EU

A 'free to air' DVB satellite TV and data
receiver card as recommended by
EUMETSAT. This card requires
installing inside the computer andcomes with comprehensive installation
instructions and CD-ROM of driver
software.

RoW

R2FX APT Receiver- see page 22 Vierling Weatherman APT Receiver- see page 22 Vierling QFH Antenna- see page 22 TechniSat SkyStar 2 PCI Card49.50 51.00
Technisat Skystar USB box
109.50 121.50
Telestar 80 cm dish with LNB
49.00
Telestar Ku band universal LNB
11.00 12.50
Technisat Satfinder alignment meter 21.50 24.50
Dartcom high quality QFH antenna 259.00 279.00
Turnstile APT antenna
36.00
GEO-PIC 1.0
7.00
7.40
8.30
GEO/Dartcom EPROM v 1.3
10.00 10.75 11.25
GEO 2004 CD (back issues)
8.00
8.40
9.30
GEO 2005 CD (back issues)
8.00
8.40
9.30
Printed Back Issues
GEO Quarterly Back Issue(only Nos 2 to 8 available)

3.50

4.20

TechniSat SkyStar USB Box
If you do not feel confident about
installing cards inside your computer
you can use the external USB version.

Telestar 80 cm dish (or similar model)
and Ku-band LNB

5.10

All prices are in £ sterling and include postage and packaging

HOW TO PLACE YOUR ORDER
Orders should clearly state your name and address, including
postcode, and contact telephone number and e-mail addressin case we need to contact you about your order. Items orderedshould be clearly described and quantified.
It is preferred that you submit your order on a copy of the official
Shop Order Form, which you can download from the GEO
website at:
http://www.geo-web.org.uk/Orderform.pdf(Of course, we will also accept handwritten or typed orders)
Please mail your orders to:
GEO Shop
44 Disraeli Road
Christchurch BH23 3NB
Dorset, EnglandTechniSat SatFinder
Alignment Meter
A very useful and sensitive
meter which is a great help insetting up and aligning the dishfor maximum signal. The metercomes with full instructions

GEO PIC 1.0 for
RX2

GEO/Dartcom
EPROM v 1.3

This PIC comes
programmed withthe two new
frequencies to be
utilised by theforthcoming NOAA18 and NOAA-19
satellites.
Note: Check yourRX2 synthesiser
chip before ordering(see GEO Quarterly
No 5, page 16)

Recent tests haveshown the Dartcom
APT receiver to be
one of the best
regards pager
immunity in the UK.
This NEW EPROM
for the Dartcom
APT receiver adds
the two new NOAA
frequencies to thescan list in memory
page 0.

If you are paying by credit card, you can FAX us your order to:+44 (0) 1202 893 323
Turnstile APTantenna

TERMS AND CONDITIONSPayment Methods

Payments from UK Members can be accepted by Personal
Cheque, Postal Order, Credit Card and Debit Card. Paymentsfrom EU and Rest of World members can be accepted by Credit
Card or Debit Card.
Cheques and Postal Orders must be made payable to ‘Group for
Earth Observation’
VISA, Mastercard, Switch and Switch Solo are all accepted, butplease note that you must state• the cardholder’s signature• the type of card, card number and expiry date
• the issue number (for Switch and Switch Solo only)

Dartcom
QFH antenna

GEO 2004 CD
Back issues in PDF
format - so that new
members can catchup on last year.

All credit cards are authorised before goods are despatched.
Please include your e-mail address or telephone number in case
we need to contact you about your order. In the event ofproblems with items purchased from GEO-Shop, please contact
Clive Finnis (contact details at top of page).
Ordering and Shipping
We will ship by post, so please allow 28 days for delivery although wehope UK and EU orders will take just a few days; orders to the Rest of
the World may take a few weeks.

www.geo-web.org.uk

Items from the GEO shop are available only to
paid up GEO membersiMarch 2006

Group for Earth Observation

GEO Quarterly No 9

MSG-1
A forum dedicated to Meteosat-8 (formerly MSG-1), where members
can share information about the reception hardware and software.

GEO Helplines

e-mail: MSG-1-subscribe@yahoogroups.com

Douglas Deans, Dunblane, Perthshire, SCOTLAND
All aspects of weather satellites from APT, HRPT to Meteosat-8
DVB/EUMETCast systems.
• telephone:(01786) 82 28 28• e-mail: douglas@dsdeans.freeserve.co.uk
John Tellick, Surbiton, Surrey, ENGLAND
Meteosat-8 advice - registering for the various MSG services,
hardware and software installation and troubleshooting. John will also
field general queries about any aspect of receiving weather satellite
transmissions.
• telephone: (0208) 390 3315
• e-mail: info@geo-web.org.uk
Keith Holland, London, ENGLAND
Specifically, help for APT users (137 MHz band) and Meteosat-7
wefax.
• e-mail: geo@koholland.plus.com
David Strickland, Truro, Cornwall, ENGLANDDavid has set up his own wireless network system of three computers.
He has interests in electronic design and prototyping, generalcomputing, microchip processors with various facilities and of course
MSG satellite imaging. He will be happy to discuss any of the above
topics, and to help anyone local, including viewing his setup.
• e-mail: David@Strickland.uk.com
Geoff Morris GW3ATZ, Shotton, Flintshire, NE WALES
Geoff has lots of experience with aerial, co-ax,connectors, mounting
hardware etc. and has also done a lot of work with the orbiting
satellites. Geoff has been a EUMETCast Meteosat-8 user for sometime and is familiar with David Taylor’s MSG software; he should be
able to share his experiences with newcomers to this branch of thehobby.
• Tel: (01244) 818252• e-mail: gw3atz@btopenworld.com
Guy Martin G8NFU, Biggin Hill NW Kent, ENGLAND
Guy is prepared to advise anyone who wishes to receive MSG underWindows 2000. He also runs Meteosat-7 SDUS.
• agm@tonbridge-school.org
Hector Cintron, San Juan, Puerto Rico, USA
Hector is prepared to field enquiries on HRPT, APT, WEFAX, EMWIN
and NOAAPORT• Phone: 787-774-8657• e-mail: n1tkk@hwic.net
E-mail contact can of course be made at any time, but
we would ask you to restrict telephone contact to the

Useful Internet
Discussion Groups
There are a number of Internet-based discussion groups available toweather satellite enthusiasts. You can join any of these by sending an
e-mail to the appropriate address, with a request to subscribe. Indeed,a blank e-mail containing the word ‘subscribe’ in its Subject line is all thatis required. Some of the more useful groups and their contact addresses
are listed below.
GEO-Subscribers
This is a group where GEO members can exchange information relating
to either GEO itself or Earth observation satellites and related matters.

Weather Satellite Reports
A group providing reports, updates and news on operational aspects ofweather satellites.
e-mail: weather-satellite-reports-subscribe@yahoogroups.com

WXtoImg
Users of the WXtoImg software package for capturing and imaging
NOAA APT can air their problems, discuss its features and ask
questions about it.
e-mail: wxtoimg-subscribe@yahoogroups.com

Copy Deadline
for GEO Quarterly No 10

Tuesday, April 22, 2006
The Editor is always on the lookout for articles and images for inclusion
in GEO Quarterly. These can relate to any aspect of Earth Imaging,
especially:• Technical articles concerning relevant hardware / software• Construction projects• Weather satellite images• Reports on weather phenomena• Descriptions of readers’ satellite imaging stations• Activities from overseas readers• Letters to the Editor• Problems and Queries for our experts to answer
Contributions should of course be original and, where possible, should
be submitted to the editor in electronic format (floppy disc, e-mailattachment, CD). But of course we will also accept handwritten or
typed copy should the need arise.
Please note, however, that major articles which contain large numbersof satellite images, photographs or other illustrations should besubmitted well before this date so that they can be prepared andmade up into pages in time for publication.
Images and Diagrams
Images can be accepted in any of the major bitmap formats, e.g. JPG,
BMP, GIF, TIFF etc. Images in both monochrome and colour are
welcomed for inclusion. Line drawings and diagrams are preferred in
Windows metafile and postscript formats.
We can also scan original photographs, negatives and slides.
If your article submission contains embedded images and diagrams,
please note that we do also require, in addition, individual copies ofeach image or drawing which is not embedded within the article, formake-up purposes.
Submission of Copy
All materials for publication should be sent to the Editor, Les Hamilton,
8 Deeside Place, Aberdeen, AB15 7PW, Scotland.
Materials may also be sent as attachments to the following e-mailaddress:e-mail:GEO-Subscribers-subscribe@yahoogroups.com

editor@geo-web.org.uk

Satsignal
An end-user self help group for users of David Taylor's Satellite
Software Tools including the orbit predictor WXtrack, the file decoders
GeoSatSignal and SatSignal, the ATOVS and HRPT Reader programs,
the remapper GroundMap, and the MSG Data Manager
e-mail: SatSignal-subscribe@yahoogroups.com

Larger attachments (1 Mb to 10 Mb) are best sent to:editor.geo@googlemail.com

And finally . . . if you do have material ready for the next GEO
Quarterly, please submit it as soon as it is ready—do not wait till thedeadline before sending it in. This simply creates an editorial log-jam.

www.geo-web.org.uk

iii

Subscription is valid for a period of one
year from your date of application, andwill entitle you to all the privileges ofmembership of the Group for Earth
Observation, including four issues of
GEO Quarterly.

Please note that your subscriptioncommences with the issue of GEO
Quarterly current at the time of yourapplication. Back issues, whereavailable, are advertised in your copy of
GEO Quarterly.

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iv

www.geo-web.org.uk

March 2006

Group for Earth Observation

GEO Quarterly No 9

New NOAA-18 Frequency
Following extensive lobbying from many UKbased weather satellite enthusiasts, NOAA
have implemented a trial NOAA-18 APT
frequency change. Darrell Robertson, from the
NOAA Satellite Data Services Satellite andInformation Service stated:‘A NOAA-18 APT frequency change wascollectively requested by several APT users
in the United Kingdom. This action is being
implemented to help mitigate high power
pager transmissions in the UK on the 138
MHz frequency, that are impacting direct
readout ground stations operating on thecurrent NOAA-18 APT frequency of
137.9125 MHz.
NOAA will re evaluate the NOAA-18 APT
frequency change following the MetOp-A
launch scheduled for June 30, 2006 as partof the U.S.A. and EUMETSAT cooperative
Initial Joint Polar System (IJPS) agreement.’
Effective from January 4, 2006, NOAA-18
switched from 137.9125 MHz (VTX-2) to 137.10
MHz (VTX-1). Early reports indicate that APT
enthusiasts the length and breadth of the UK—
many for the first time—are now receiving
perfect NOAA-18 images on the new frequency

Updated EUMETCast
Registration Form
Once MSG-2 is fully commissioned, the existing
WEFAX and PDUS services from Meteosat-7
will cease forever, leaving many weather
satellite enthusiasts without real-time access togeostationary data. GEO members keen tocontinue their activities in this sphere arestrongly advised to register for MSG data
access. The EUMETCast Registration form,
updated last December, is available from the
GEO Website at:
http://www.geo-web.org.uk/eumreg.html

along with a convenient guide to filling in all theimportant sections.
You can also hunt it down on the EUMETSAT
website at:
http://www.eumetsat.int
although it is a major logistical exercise to
locate it. Here’s how it works ...
1. Click the link ‘ACCESS TO DATA’ at the
top of the page
2.Click the link ‘Delivery Mechanisms’ in theside menu
3. Click ‘EUMETCast Dissemination
Scheme’4. At the very foot of this page, click the link
‘EUMETCast Registration form’
5. At the foot of this page is a table headed‘Registration Forms’
6. Click on the first link in the table, ‘REG
01’ and download the PDF document
7. Once you have got your breath back,print out this form and complete it.
(Now you know why we placed the direct link on
our website!)

Eric Dean sent in this fine Meteosat-8 HRV image showing the smoke plume over southeast
England following the Hemel Hempstead oil depot fire on December 11. You can view the eventfrom the perspective of polar orbiting satellites on page 5.

MSG-2 Safely in Orbit
The second of EUMETSAT’s new generation ofgeostationary weather satellites (MSG-2)
enjoyed a successful launch from Kourou,
French Guiana, on an Ariane-5 GS launchvehicle on December 21 last. Commissioning
commenced on January 2 and continues until
summer. First images from the new satellite
were expected late January.

Fame!
It transpires that some of the craft competing inthe 2005-2006 Round the World Volvo Ocean
Yacht Race use David Taylor’s GeoSatSignal
software to process their weather data during
the race. Competitors set out last November
and can expect to be at sea for nine months andcover some 60 000 kilometres before the race
ends. Awareness of current and future weather
conditions is an important aspect of day-to-day
planning and preparation for the teams involved
and it is fascinating to learn that the software
used by amateurs plays such an important roleon this stage.

Record Hurricane Season
The 2005 Atlantic Hurricane Season broke allprevious records with the final ‘encore’, Tropical
Storm Zeta, still clinging to life into the first few
days of 2006!
Zeta was the record 27th named storm of theseason, smashing the previous record of 21
dating back to 1933. There were also 13
hurricanes, three of these reaching Category-5.
Of these, Hurricane Katrina was the costliest

www.geo-web.org.uk

ever Atlantic Hurricane, causing damage anddestruction estimated at $80 billion, three times
greater than that from the previous recordholder, Hurricane Andrew (1992).

Cover Colour Images
Front cover
A Blue Marble visualisation of the Earth fromthe perspective of China’s Feng Yun 2C
satellite. This global view was created using
David Taylor’s new MapToGeo software (readour article about Blue Marble and MapToGeo on
page 13).
Inside Front CoverUpper: An unmodified Blue Marble image of the
Earth in plate carrée format.
Lower: A virtual radar image showing the (lackof) air traffic around the Bouncefield area during
last December’s great fire.
Inside Back CoverUpper: NOAA-12 images from David Taylor
illustrating how his SatSignal 5 software can
add a Blue Marble background to an APT
image. There is more information in Software
Showcase on page 43.
Lower: An image of the Caspian Sea from Rob
Denton: more on page 43.
Back Cover
Wolfgang Baschant took his Vierling weather
satellite kit with him on his holiday on Madeiraand captured this unusual NOAA-17 APT image
dating from 13:42 UT on October 24, 2005.

23

GEO Quarterly No 9Group for Earth Observation

March 2006

Fred van den Bosch
Five times a year, in every odd month except July, the Dutch‘Werkgroep Kunstmanen’ [1] organises a meeting in Utrecht.
The November 2005 meeting was a special one, our first joint
meeting with ‘Vereniging voor Weerkunde en Klimatologie’(Organisation for Meteorology and Climate) [2]. The meeting’s
programme included topics of common interest to members ofboth organisations. The day began with introductions fromboth chairmen about themselves and their organisations andfollowing some general announcements (satellite status etc.)
the presentations started
Kees Floor
The first speaker was Kees Floor, who has worked for morethan 20 years at KNMI (The Royal Dutch Meteorological
Institute). For some years now he has been working as ascience journalist and is the author of several meteorologicalbooks. Kees started by showing some animations to explain
the difference between polar and geostationary satellites. We
were then treated to a display of many individual images,
mainly from the MODIS satellites, and enjoyed Kees'interpretation of them. Kees also included some animations toillustrate the theory behind terms like high and low pressure,warm and cold fronts etc. Many of the images are in his latest
book ‘Het Weer op Satellietbeelden’ (The Weather from
Satellite Images [3]), which contains many more beautiful
examplesaccompaniedbydetailed
explanations.
Unfortunately, at the moment, the book is only available in
Dutch. Kees has a fascinating website [4], although mainly in
Dutch, which is well worth a visit.

sandstorms in Africa and fires in Portugal. He ended with acalculation of the costs and the time that is needed for
obtaining the licence and the EKU (Eumetsat Key Unit).
Jacob Kuiper
Jacob came to the meeting following only a few hours sleep
following his night shift at KNMI and presented us with theweather forecast for the next couple of days, making direct useof an MSG animation that Arne had made earlier during themeeting. Jacob pointed out a number of phenomena andexplained what he expected would happen. Of course his talkraised some discussion in the audience. His presentation was
so clear and easily understood that, when it ended, there wasonly one question boiling in my mind: ‘Why don't I see all thesethings when I look at my images?’
Finally
Though the programme was rather full, I think we all learned
a lot about each other's interests. I have always beeninterested in receiving images from satellites but less so ininterpreting their meaning for weather forecasting. The
stories from the above speakers have already had good effects:
I now feel curious and stimulated to know more about what theimages can tell about our weather. After such a meeting you
feel encouraged and your hobby is broadened… Who knows, it
may happen to you too if you join us for the next meeting of
Werkgroep Kunstmanen.
References

Arne van BelleArne's presentation was about how to receive MSG. He
explained in detail, step by step, how to set up the different
parts of a receiving station and mentioned the difficulties you
may face. He showed some impressive animations—like

1. Werkgroep Kunstmanen
2. KNMI
3. Het Weer op Satellietbeelden
4. Kees Floor- http://www.kunstmanen.nl/- http://www.vwkweb.nl/- ISBN 903891625 6, September 2005
- http://www.keesfloor.nl/

Last issue, Francis Bell launched a light-hearted competition
for GEO members to present photographs of the greatest
number of birds photographed on an antenna. The leading
entries are reproduced opposite.
Mike Jupp was the first to submit a photograph (left) for thislight-hearted competition. Mike caught these starlings
perched on his 144 MHz 13-element Cushcraft antenna. Mike
wrote: ‘Sometimes I count over 60 starlings. I have seen more
but this is the most caught on camera’.
Roy Quantic was next with his submission (far right)
showing no fewer than 133 common starlings (Sturnus
vulgaris) perched on the various elements of his antenna. Roy
tells us that the starlings favour the 6-metre beam and thelinear loading tubes on the HF aerial. Again, Roy claims tohave seen more. Can anyone beat his total?

24

www.geo-web.org.uk

March 2006

Group for Earth Observation

GEO Quarterly No 9

The attentive audience during the meeting

In discussion: left to right, Rob Hollander, Frans Schmal, Ben
Schellekens, Jaap Rusticus and another member.

Arne van Belle explains how to set up an MSG station

Kees Floor making his presentation

Birds on antennas: photographs submitted by GEO Quarterly readers

www.geo-web.org.uk

25

GEO Quarterly No 9Group for Earth Observation

March 2006

Les Hamilton
Winds, particularly those which blow over Earth’s oceans, playa major role in every aspect of our planet’s weather; they
directly affect the turbulent exchanges of heat, moisture andgreenhouse gases between atmosphere and ocean. SeaWinds,
a state-of-the-art radar scatterometer carried aboard NASA’s
QuikSCAT [1] satellite, measures the roughness of the oceans,thus providing climatologists, meteorologists and oceanographers alike with detailed daily snapshots of the windsthat constantly swirl above their waters.
Wind and Waves
Although a general idea of wind circulation around the planet
is apparent from the movement of clouds in the atmosphere, as
perceived from weather satellites, wind is itself invisible. The
only realistic method of making accurate determinations ofwind-speed must therefore derive from the effects of the windon an other entity, specifically, the surface waters of ouroceans. Winds create surface roughness on the oceans and thiscan be measured by microwave scatterometry and accurately
correlated with the speed of the wind.
Wind, of course, produces waves, which range from the merest
ripples on the surface of a rock pool to the 30-metre monsters
that characterise the fiercest ocean storms. There are two
distinct types of wind-induced waves—gravity waves andcapillary waves [2].
The ‘normal’ waves observed on the sea surface—those which
eventually break on to the shore—are gravity waves, socalled because the principal force trying to level them resultsfrom gravity. Such waves typically have wavelengths
measured in hundreds of metres. For example, waves arrivingon a beach with a frequency of one every 10 seconds travel atover 50 kph and have a wavelength of 156 metres.
As wind blows over the ocean it also deforms the surface intomuch smaller rounded waves known as capillary waves,
where the principal restoring force tending to smooth them out
is surface tension; such waves, by contrast, must have awavelength of less than 1.73 centimetres. Capillary waves
characteristically have rounded crests but sharp V-shaped
troughs which cause small-scale roughness over the sea
surface and allow the wind and water to interact more
efficiently. The entire ocean surface, including gravity waves,is in fact covered with capillary waves, but we fail to noticethem because they are so small. It is the small-scale roughness
due to capillary waves (not the large undulations of gravity
waves) that is harnessed by the SeaWinds scatterometer.
QuikSCAT and SeaWinds
NASA’s Quick Scatterometer satellite (QuikSCAT) was
launched on June 19, 1999. It is a 970 kg, 3-axis stabilised
craft which flies in an 803 km sun-synchronous orbit. Built ina record time in just 12 months, QuikSCAT was a replacement
for the Japanese ADEOS satellite which failed in June 1997
(and which carried NASA’s earlier NSCAT sea-surface

26

scatterometer). Dubbed NASA's next ‘El Niño watcher’,
QuikSCAT is leading to a better understanding of global
weather abnormalities and is an aid to improved weather
forecasting. The mission, which was originally designed for a
3-year operational lifetime, remains fully functional after
more than six years in orbit.
QuikSCAT carries the SeaWinds instrument [3,4], a specialised
radar that transmits high-frequency microwave pulses
towards the ocean surface and measures the back-scattered(echoed) pulses that return to the satellite. By sensing
capillary wave ripples caused by winds near the oceans’surfaces, scientists can compute windspeed and direction.
SeaWinds acquires hundreds of times more surface windvelocity observations every day than older traditional methods
using ships and buoys, and because radar normally passes
through clouds relatively unhindered, it is the only remotesensing system with the ability to provide continuous,accurate and high-resolution measurements of near-surface
wind speed and direction regardless of cloud conditions.
SeaWinds uses a 1-metre rotating dish antenna which emits
two pencil beams of 13.4 GHz (Ku-band) microwaves thatsweep in circular patterns at slightly different incidence
angles (40° and 46°). The dual-pulse microwave antennaradiates across broad regions of Earth's surface employing asimilar wavelength to that of the capillary waves on the ocean.
Data is collected in a continuous 1800 kilometre-wide swath
with a horizontal resolution of 25 km, making approximately
400,000 measurements and covering 90% of Earth's surface
every day.

The Reflection of Microwaves
In common with light, microwaves also reflect from smoothsurfaces. The left-hand drawing above illustrates how amicrowave beam angled down on to a perfectly smooth ocean
surface would reflect away from QuikSCAT with none of thereflected rays returning to the SeaWinds sensor. But when thesea surface is covered by small ripples (i.e. capillary waves,right-hand drawing), the microwaves intercept their surfaces
at many different angles and reflections take place in a
multiplicity of directions (scattering). Consequently, some ofthe scattered radiation will now reach the sensors aboard

www.geo-web.org.uk

March 2006

Group for Earth Observation

QuikSCAT. The rougher the sea surface, the stronger thesignal that returns to the satellite sensor.
The Mission
QuikSCAT is tracked from polar ground stations in Svalbard(Norway), Poker Flats (Alaska), Wallops Island (Virginia) andMcMurdo (Antarctica). High-quality research data products
are produced at NASA’s Jet Propulsion Laboratory (JPL) anddistributed to the science community within two weeks ofreceipt; operational data products aimed at the international
meteorological community are produced at National Oceanic& Atmospheric Administration (NOAA) within 3 hours of datacollection.
QuikSCAT’s primary mission objectives include

GEO Quarterly No 9

agriculture and water reserves. The ability to accurately
predict El Niño would be of great benefit to countries, not justthose surrounding the Pacific basin, but around the world.
Ice Detection and Monitoring
In addition to its primary role of wind analysis, the SeaWinds
radar also finds use in mapping ice sheets and icebergs in thepolar regions. Again, its ability to cut through cloud, and to
image during the southern winter are its most valuable
attributes. Figure 1 is a composite image of Antarctica
constructed from a full day of scatterometer data. The brightcentral area of the image is the Antarctic icecap while thedarker rim represents the seasonal ice surrounding thecontinent. Figure 2 is an enlarged section showing theicebergs B15 and B16.

• Acquisition of all-weather, high-resolution measurements ofnear-surface winds over global oceans• Determination of atmospheric forcing, ocean response, andair-sea interaction mechanisms on various spatial andtemporal scales• Combination of wind data with measurements fromscientific instruments in other disciplines to help gain abetter understanding of the mechanisms of global climatechange and weather patterns• The study of both annual and semi-annual rain forest
vegetation changes• Studying daily, seasonal sea ice edge movement andArctic/Antarctic ice pack changes• Improving weather forecasts near coastlines by using winddata in numerical weather and wave prediction models• The improvement of storm warning and monitoring.
Storm Prediction
Information on global sea-surface windspeed and direction
obtained by scatterometry has proved invaluable in predicting
both global and regional weather patterns, as well as helping
in the determination of the location, direction, structure andstrength of hurricanes and typhoons [5]. Our ability to detectand track severe storms has been dramatically enhanced by
the advent of weather satellites, and data from scatterometerslike SeaWinds now augments satellite images by adding direct
measurements of surface winds to compare with the observed
cloud patterns. Advance warning of strong winds now allows
shipping to be re-routed to avoid heavy seas and strong
headwinds.

Figure 1 - A composite SeaWinds radar image ofAntarctica dating from October 2, 2000
Image: NASA/JPL.

El Niño
El Niño [6] is a phenomenon affecting the trade wind patterns
over the Pacific Ocean, and which is now understood to haveworld-wide effects on climate. Under normal conditions, tradewinds blow westward, driving warm water towards Indonesia;
this is accompanied by an upwelling of cooler, nutrient richwater off the coast of Equador. The temperature difference isof the order of 8°C. During an El Niño episode, these tradewinds weaken, reducing the upwelling with drastic effects on
marine ecosystems and commercial fisheries off the SouthAmerican Pacific coast. Rainfall patterns also reverse:
Indonesia and Australia suffer drought while the Pacific coastof South America can experience unseasonable heavy rains
and flooding.
One of the design objectives for SeaWinds was to be part of a
global monitoring system to observe the tropical oceans andhelp to predict El Niño and other irregular climatic variations.
Ocean scatterometry improves man’s ability to anticipate how
climate and weather may change, both seasonally and fromyear to year, leading to better management of global

Figure 2 - Image of Icebergs B15 and B16 off the Ross Ice Shelf
Image: NASA/JPL.

Accuracy and Errors
SeaWinds measures windspeeds of between 3 m/s and 20 m/s
with an accuracy of 2 m/s, its direction with an accuracy of 20°

www.geo-web.org.uk

continued on page 44 ...

27

GEO Quarterly No 9Group for Earth Observation

At the time that QuikSCAT acquired this image of Hurricane Katrina on
August 28, 2005, the National Hurricane Center was reporting winds ofover 250 kph. This image depicts relative wind speeds swirling aroundthe calm centre of the storm. The highest wind speeds, shown inshades of purple, circle a well-defined eye with gradually weakening
winds radiating outward. The barbs reveal wind direction, and the whitebarbs show heavy rainfall.

March 2006

Mountainous islands and steep coastal topography can modify thesurface wind field for many hundreds of kilometers. This is well illustrated
from SeaWinds data acquired from a QuikSCAT pass by South Georgia on
September 13, 1999. Ocean winds blocked by the island’s mountainous
spine have produced a long ‘shadow’ of low winds to the lee of the
obstruction; it stretched some 500 kilometers in this image produced
using data from SeaWinds
Image: NASA / Jet Propulsion Laboratory (JPL)

NASA image courtesy the QuikSCAT Science Team at JPL

This colourful image superimposes measurements of wind direction overwind speed. QuickSCAT collected this image over the south Pacific on
February 15, 2005, showing two large cyclones moving steadily closer toeach other in a potentially dangerous dance.

When QuikSCAT imaged Hurricane Wilma at 23:31 UT on October 18
sustained windspeed was 130 kph. During the following twelve hours
Wilma’s power increased dramatically as she developed into a
Category-5 hurricane with sustained winds of 280 kph! At that point,
Wilma had become the most powerful Atlantic storm ever recorded, in
terms of both wind speeds and air pressure. Ground measurements of
the wind strength of Hurricane Wilma showed sustained windspeeds
somewhat higher than those shown by QuikSCAT observations. This isbecause the sheer power of the storm made accurate radarmeasurements difficult.
NASA image courtesy of David Long, Brigham Young University, on the
QuikSCAT Science Team, and the Jet Propulsion Laboratory

28

It is very unusual for south Pacific cyclones to occur so close together
and it is hard to predict how the storms will interact. One possibility is thatthe weaker storm will be tugged off course by the large-scaleatmospheric circulation of the other. Eventually, the weaker storm willseem to ‘orbit’ the stronger one. A second possibility is that the outflow
from one storm will impede that of the other, weakening it. Regardless of
the interaction, the storms posed a potential threat to American Samoa
and the Cook Islands, which are indicated as small grey dots.
At the time this image was acquired, ‘Olaf’ was a strengthening
Category-4 cyclone with steady winds of 250 kph and gusts up to
305 kph. ‘Nancy’ was beginning to weaken with winds of 160 kph andgusts of 210 kph. The strongest winds, shown in pink, circle the centresof the storms. Even without any sort of interaction, the two large storms
could pack a dangerous one-two punch to the island nations of the South
Pacific.
NASA image courtesy Timothy Liu, Wendy Tang, and Xiaosu Xie, of the QuikSCATScience Team at the Jet Propulsion Laboratory

www.geo-web.org.uk

March 2006

Group for Earth Observation

GEO Quarterly No 9

Robert Moore
The passage of a vigorous arctic front on November 24
provided weather observers with an opportunity torecord the event simultaneously with a range of
instruments, including the ‘Mark I Eyeball’. I receive theNorthwood (Admiralty) chart by radio fax, in black andwhite, of course. When I asked for permission to use thecharts FWOC kindly sent me coloured copies. The chart
for 0600Z (chart 1) shows a northerly air-stream withtwo cold fronts ahead of troughs. The first of the fronts
passed my weather station in north Wales at about 0800
as is shown by the thermograph trace (chart 2), although
it is barely visible in the barograph trace (chart 3).
At about noon the sky turned very dark and lights had tobe switched on indoors. Low dark clouds could be seen
approaching rapidly from the north (figure 1, page 30).
Shortly after this photograph was taken, rain started
rattling against the windows (chart 4). That this really
was a very vigorous front may be seen from the dramatic
drop in the air temperature at midday. There was also avery brief rise in barometric pressure, immediately
followed by a continuation of the rapid fall that had
started about 24 hours earlier. The wind shifted fromwest to north-west.

Chart 2 - Air temperature

Having looked at the satellite imagery (figure 3), I
confidently told a visitor that the wind and rain would
soon be replaced by bright skies. Unsurprisingly, thisproved to be so. The second photograph was taken at
13:45. At this time we passed into cold and clear Arctic
air, which gave almost unlimited visibility—the peaks of
the Lake District could easily be seen from north Wales.
I have an especially good vantage point to observe
weather coming from the north, but we can all use oureyes and ears to observe the weather (see for example myreport of a similar event in GEOQ 3, page 42). Watching
the barometer or the smoke from neighbours’chimneys—low-tech activities—can add to our understanding of our high-tech satellite imagery. Some
additional instruments, like an outside thermometer anda barograph, enable us to tie our observations together
even more cogently. On a day-to-day basis we relate oursatellite imagery to general conditions outside, as shownin the weather charts. In the UK this mainly means thepassage of Atlantic lows or the presence of blocking highs
which are typical features of our annual pattern ofweather change; we are less likely to be able to follow
very short term or local changes. The events ofNovember 24 were not typical or routine incremental
changes however, but sudden and sufficiently dramatic
to hit the headlines in the press and television. Using oursatellite imagery and relatively simple instruments, plus
our normal human senses, gives us insight into such
weather events, as they happen, and enables us to do
local short-term forecasting of our own. This may evenenable us to beat the television forecasters to the punch!
www.geo-web.org.uk

Chart 3 - Barometric pressure

Chart 4 - Rainfall

29

GEO Quarterly No 9Group for Earth Observation

March 2006

Chart 1 - The MSLP 0600/24 (Image: Commander-in Chief Fleet’s Weather and Oceanographic Centre, Northwood.)

Figure 1 - View North at 12:00

Figure 3 - Meteosat-8 HRV at 12:00
Figure 2 - View North at 13:45

30

Image: © EUMETSAT (2005) Processing: GeoSatSignal

www.geo-web.org.uk

Gerry Berg sent us this NOAA-18 APT image decoded from the 13:40 UT pass on January 20.While Russia was enduring temperatures
low asas-30°C, high pressure over the North Sea kept the big freeze at bay from the British Iles.. Image processing was with WXtoImg,
using the MSA
mode (channels 2+4) with added precipitation colouring. The darker the colour (orange, red, black) the greater the probabilityof rainfall.

GEO Quarterly No 9Group for Earth Observation

March 2006

Peter Wakelin

This final part in the series details some recent events in the
Indian Space Programme and looks at some of the exciting
plans for the future.
CARTOSAT-1 Launched from New Facility
A newly completed second launch pad at the Sriharikota range
was used to launch the 6th commercial flight of the Polar
Satellite Launch Vehicle (PSLV) on May 5, 2005. The 1,600 kg
payload comprised CARTOSAT-1 and HAMSAT, both ofwhich were placed in 632 x 621 km sun-synchronous orbits.
Lift-off occurred shortly after ignition of the core first stage
and four of the six strap-on boosters; 25 seconds later, the tworemaining boosters ignited and, subsequently, booster
separation, first stage separation, second stage ignition,
payload fairing separation, second stage separation, third
stage ignition, third stage separation, fourth stage ignitionand cut-off all went exactly as planned. CARTOSAT-1 wassuccessfully released from the fourth stage 1078 seconds after
launch and, 40 s later, HAMSAT left the equipment bay.
CARTOSAT-1 is the eleventh satellite in the Indian remotesensing series. It carries two panchromatic cameras that takestereoscopic images in the visible part of the electromagnetic
spectrum with a ground resolution of 2.5 metres in a swathe
30 km wide. A 120 gigabit solid-state recorder is also on board,
enabling imagery to be returned from well beyond the range ofground stations within India and at Bearslake (Russia),
Mauritius and Biak in Indonesia.
Radio Amateurs Develop Transponders for HAMSATThe 42 kg HAMSAT, launched with CARTOSAT-1, is India’s
contribution to the international amateur radio community.
One of the transponders was developed by Indian amateurswith some help from the Indian Space Research Organisation(ISRO).

INSAT-4A

MSG-2. The first stage vehicle was sub-orbital and re-entered
the atmosphere over the Pacific Ocean. A single burn of thesecond stage took it, with its massive payloads, to a 620 x
35853 km geostationary transfer orbit (GTO), inclined to theequator at 3.9°, where the satellites and the Sylda adapter
were released. Three orbit-raising burns of INSAT’s
propulsive system took the 3080 kg spacecraft into
geostationary orbit where the solar arrays were successfully
deployed. When commissioning is complete, INSAT-4A will
operate alongside INSATs 2E and 3B at 83° east longitude.

A second transponder was developed by a Dutch amateur
radio operator who is a graduate engineering student at theHigher Technical Institute, Venlo, Netherlands. It is ISRO’s
hope that this spacecraft will help to popularise spacetechnology throughout the region.

Built at ISRO’s Satellite Centre (ISAC) in Bangalore,
INSAT-4A is the first of a new series of Indian
communications satellites. It carries 12 Ku-band transponders
with a footprint covering mainland India and 12 C-band
transponders with expanded radiation patterns extending
eastwards to the western Pacific region
Satellite
Location
and westwards to support the large
48°E
GSAT-2
Indian population in the Persian Gulf
55°E
INSAT-3E
area. The 15 m-span solar cell array
74°E
EDUSAT
provides 5.5 kW of electricity and there
74°E
KALPANA
are three 70 Ah nickel-hydrogen
74°E
INSAT-3C
batteries to continue operations during
83°E
I
N
S
A
T
2
E
solar eclipses. Other satellites in the
83°E
I
N
S
A
T
3
B
INSAT series which are currently
I
N
S
A
T
3
A
9
3
.5°E
operating, some of which incorporate
meteorological sensors, are listed in the panel at right.

INSAT-4A, ISRO’s Heaviest Satellite Launched

New Propulsion Systems under Development

The 169th flight of the Ariane launch vehicle (an Ariane-5G
version) lifted off from Kourou, French Guiana, on
December 22 carrying ISRO’s INSAT-4A and its co-passenger

ISRO successfully ground-tested an improved version of thesolid-propellant strap-on motor for the PSLV on December 29.
At present, each of PSLV’s six strap-on motors carry 9 tonnes

HAMSAT32

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March 2006

Group for Earth Observation

GEO Quarterly No 9

of propellant but the new motor, designated PSOM-XL, with alength of 13.5 m, has a 12-tonne capacity which will permit asignificantly increased payload mass.
Work is at an advanced stage in developing a cryogenic upperstage for ISRO’s Geosynchronous Satellite Launch Vehicle(GSLV) which uses extremely cold liquefied hydrogen andoxygen. These cryogenic engines are far more efficient thanconventionally-powered ones but huge technological problems
hinder their development. A brief ‘potted history’ of the
background to this development follows:
In the late 1980s, various problems delayed development of
the International Space Station. The US wanted to fly their
Space Shuttles to the up-and-running Russian Mir Space
Station. At about this time ISRO wanted to acquire foreign
cryogenic engines as it knew it did not have the capability todevelop its own, so it placed a contract with Russia to provide
the engines and technical assistance. The US Clinton
Administration did not want India to have cryogenic
technology and forced Russia to cancel the contract for engines
on the grounds of ‘weapons proliferation issues’. The Russians
retaliated by raising the cost of Shuttle/Mir flights to recoup
the (greatly exaggerated) losses allegedly incurred bycancelling the engine contract. Eventually, some Russian
engines were permitted to go to India but now ISRO hasdeveloped the technology and it poses no military threat.
Ground tests have been successfully completed and a test
flight of the new cryogenic stage is to be conducted on adevelopmental flight of the GSLV this year. The uprated
vehicle will be known as the GSLV-Mk III and will be capableof putting more than 4,000 kg into GTO. It will obviate theneed to purchase foreign launch services to orbit heavy
payloads such as the recent INSAT-4A launch conducted from
Kourou as well as create many highly-skilled jobs for Indians.
ISRO’s Vikram Sarabhai Space Centre at Thiruvananthapuram,has successfully carried out the design, development andrealisation of the Supersonic Combustion Ramjet(SCRAMJET). Through a series of ground tests, a stable,supersonic combustion has been demonstrated for nearly
7 seconds with a Mach 6 inlet airspeed. To date, only the US
has conducted an in-flight SCRAMJET demonstration but thepotential benefits the technology offers are enormous. If ahighly efficient SCRAMJET could be developed for a launchvehicle’s first stage, the need to carry oxidiser for the fuelwould be eliminated and the payload could be significantly
increased. The development of reusable hardware would
dramatically reduce launch costs too. A flight test using
ISRO’s two-stage RH-560 sounding rocket, modified to take anexperimental SCRAMJET is planned, but will not take placesoon.
Some Forthcoming Launches
The year 2006 is likely to be a busy one for ISRO with several
spacecraft being prepared for launch as well as the test launchof the new cryogenic engine.
CARTOSAT-2 is scheduled for a July lift-off although one
source suggests a delay until August or September. It is an
updated version of CARTOSAT-1, already in orbit, with an
improved resolution of only one metre. The payload of thisPSLV launch will also include SRE-1 and ANUSat. The
former is a small Space capsule Recovery Experiment (SRE),
developed by ISRO to carry out zero-gravity experiments inthe fields of metal melting, composites and microbes forbiological tests. A capsule will return the experiments to

CARTOSAT-1

Earth after a few weeks. ANUSat is a co-operative microsat
mission of Anna University of Chennai and ISRO. Anna
University is the first in India to take up space technology,
with emphasis on microsat development, in its engineering
curriculum.
INSAT-4B is another 3,000 kg communications satellite
scheduled for a July lift-off from Kourou on an Ariane-5
vehicle.
INSAT-4C is somewhat lighter than 4B, making a launch on a
GSLV from Sriharikota in August possible.
ISRO has launched several small foreign satellites as‘piggyback’ payloads on its rockets but, for the first time andpossibly as soon as May, the Italian satellite AGILE will be
the lone passenger on a PSLV launch. The financial details of
the multi-million dollar contract have not been disclosed.
AGILE (Astro-rivelatore Gamma a Immagini LEggero) will
provide a powerful and cost-effective observatory for gammaray astrophysics. Its sensors will be the first to be sensitive tophotons above 30 MeV.
GSAT-4 is an ISRO-built, experimental, communications
satellite destined for a ride to geostationary orbit on a GSLV
later this year. Bolted to its side will be a rotatable platform
carrying the Tel Aviv University Ultra Violet Experiment,
TAUVEX. The TAUVEX is a telescope operating in the ultraviolet region and will help to answer astrophysical questions
in areas such as star formation, history of galaxies, physics ofgiant black holes etc. Indian scientists will also use the data inpreparing themselves to receive and analyse the data fromtheir own UV imager on the forthcoming ASTROSAT (seebelow).
INSAT-3D is a dedicated meteorological satellite to belaunched by a GSLV in October.

www.geo-web.org.uk

concluded on page 39 ...

33

GEO Quarterly No 9Group for Earth Observation

March 2006

Douglas S Deans.
The development of this program by David Taylor began in 2001
and I consider myself privileged to have witnessed at close hand
its progress from a simple joining program through to thesophisticated package of today. Let me make it quite clear fromthe offset that my involvement was merely one of providing a very
eager test computer and, with my many years of geostationary
reception experience, the odd useful suggestion. The program
was born from a need to provide post reception processing for
geostationary weather satellite imagery. Much of the software
provided with geostationary hardware packages, while excellent
for many things, was less good for subsequent image
processing. Anyone familiar with the 9 sectored format ofMeteosat WEFAX would realise that it was screaming out for an
automated way of joining adjacent sectors……incredibly nothing
was available until David Taylor embarked upon GeoSatSignal(GSS).

What I would like to do in this, the first part of my article, is to givean insight into the more basic aspects of the program including
setting up and to look at some of the more common day to day
chores. It is essential that you become familiar with the basic
functions before tackling some of the more advanced features
which I will be looking at in Part 2 next quarter. I was fortunate inthat I have used the program over a long period of time with many
features being added progressively. Many of you will come to thefull program from day one and that is perhaps a little more
daunting.
There is a basic version of GeoSatSignal which is provided as afree program, but for support and to enjoy many of the moreadvanced features, registration is required. Quite frankly given
the not unreasonable cost of the program and the additions
available, registration is a must. By all means use the free
software to assess if it is what you want but if so please register.
Do remember that software authors have to earn a living and we
all want our programs updated from time to time. Many of you will
already know of the incredible support that David provides for his
full range of registered software. With this in mind my review isbased on the fully registered version. Of course it is not possible
in an article of this size to cover all aspects of suchcomprehensive software but I do hope it will be helpful in setting
new users on their way and for others perhaps offering a lightrefresher course. The program can be downloaded from David
Taylor’s web site at :http://www.satsignal.net
under ‘Satellite Tools’ and following the link to GeoSatSignal. It isalso available on the GEO Software CD, GS1 along with many ofDavid’s other programs.
The File System.

Figure 1 - Combining WEFAX segments

Figure 1 shows a composite WEFAX D1/D2/D3 joined using an
early version of GSS. As received WEFAX images could be a
pixel or two out of registration the program provided a nudge
facility to perfect the join. This was particularly useful whereimages were being utilised for animation purposes.
As many of you know WEFAX will be coming to an end verysoon. Indeed it is already dead in America. It seems likely that
there will be many enthusiasts migrating to the new digitalformats which have been available, from a range of sources, forseveral years. This is where the current GeoSatSignal 5 program
comes into its own and is part of the reason for my undertaking
the article at this time. Of course I hope it will also act as arefresher for others, including myself ! I do not want to spend any
more time discussing the original versions of GSS but I did want
to reminisce for a moment and remind everyone of the simple
beginnings of this program. Does make you appreciate thedevelopment even more ! Of course all the facilities first provided
in those early versions of GSS are still there along with the more
recent developments.

34

GeoSatSignal is designed to work with a vast range of file types
and as such can be used by those employing direct reception
methods including EUMETCast, or utilising Internet data andother methods of file reception. There are too many formats tomention here but the table below shows the most important ones.
Formats supported
General Images
Timestep images
Dartcom images
FY2C data as small IR images
FY2C data as 133 MB HDF files
GMS-5 data in the Taiwan FDK and LCC formats
GSFC Meteosat 7 data
MSG-1 data as image files
Orbit/SSB files
PDUS files in the Dundee Level-1 format
PDUS files in Timestep format
PDUS files in DTP MET format
PDUS files in Rob Alblas format

Filetype extensions.JPG, .BMP, .PNG, .TIF
.DAT
.ASD
.JPG
.HDF
.FDK, .LCC
.ARA
.JPG, .PNG
.HRM
.PDU
.MPD
.MET
.RAH

The simplest way to use GSS is to utilise the <File → Open> menu
and load the required file. If you have the colour option selected in
the Job set up and you choose a visible channel then the program
will automatically look for and load a corresponding IR and WV

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March 2006

Group for Earth Observation

GEO Quarterly No 9

Figure 2 - The GeoSatSignal MSG browse window

channel if it is available. If an IR image is loaded the program
does not look for any other files. Another useful option is theability to drag-and-drop files on to the panels provided. Thosepanels can be seen on the left of Figure 2 where it says ‘drop a
file’. This can be useful where, for example, filenames of multiwavelength images are not matching and so would not be pickedup automatically by the program for the colour setting. It also
allows some experimentation by providing user control ofwavelength mix. However, that is probably for more experienced
users.
Under the <File> menu there are a couple of handy browse
options where large thumbnails can be viewed for either the
EUMETCast system or for WEFAX. For obvious reasons I will
look at the EUMETCast system. This option gives you a visual on

the whole range of EUMETCast image data including 12 channelsof HRIT, 5 channels of LRIT and the Foreign Satellite Data (FSD)
channels. Figure 2 shows an example of the EUMETCast browse
window where HRIT and FSD have been selected. Under<Options> you can choose which (or all) of those categories you
want and there is a further option to re-sample. Usefully there isa ‘Browse latest’ button which will do just that for the categories
you have already set up but there is also an option to choose a
specific date and time if that is required. Double-clicking on theimage filename will load it into the currently selected Job (seelater) and process it in accordance with that Job’s settings.
Choosing a Job other than the current one is achieved by simply
right clicking on the image of your choice, selecting the desired
Job (from a menu) and hence processing suite: could not beeasier. The ‘Browse’ button provides a useful visual alternative towww.geo-web.org.uk

35

GEO Quarterly No 8Group for Earth Observation

December 2005

loading in a file and is particularly handy when there is a large
selection of channel options, or where a quick first look might
influence the image choice.
‘Job’ Hunting
One of the most fundamental and important concepts to be
grasped, because it makes life so easy, is <Jobs>, which can befound on the upper taskbar between <Options> and <Tools>.
Forty-nine Jobs are provided—more than enough for even themost active enthusiast to set up. GSS is able to offer a huge
range of processing options including false colour, overlays,
zooms, animations and remapping to mention just a few. Jobs will
involve some or all of those processes and so can be quite
complicated, and hence time consuming, to set up. Not
something that you want to do on a regular basis.
However with the Job arrangement you only need to do this once
for each process package you wish to set up—and the work isdone. Thereafter when you wish to use that package, simply load
the image or images into the appropriate Job and the operationis completed automatically. Simplicity itself. As an example
Figure 3 is a coloured, orthographically remapped close-up of theUK with geographic outlines and grid lines employing the use of
several images. With the Job option, it was produced by simply
loading a single channel-12 HRV, HRIT image from Meteosat-8
into the appropriate Job name. You can even animate thesecomplex images ... but I am getting ahead of myself here!

Figure 4 - The Job setup window

Job Name

Job Setup.
Let us now look at setting up Jobs. For the moment, I willconcentrate on the basic functions then deal with the moreadvanced options in Part 2 of this article. There are manysettings that are clearly self-explanatory, and as space is limited,
I will leave you to look at those yourself. Setting up a Job is verystraightforward: firstly select a new Job number then go to<options → Job setup>. Notice at this point that there is also
<options → Common setup> for basic items which are relevant to
all Jobs. I will come back to that later in this article.
A typical setup window is shown in figure 4 with the General tab
highlighted. The most important options from the General andProcessing taps are listed in the tables 1 and 2 on this page.

Annotation text
Path to Data Files
Path to Results
Files
Wildcard
Specification for
Latest File Name
Fire Threshold

Multi-channel Files

CLUT (Coloured Look Up Table)

Table 1 - Job Setup: General tab options

This option from the Processing tab merits special mention. The
concept is a little more difficult to grasp and I strongly recommend
reading the program help file provided as there is an excellent
write up on this. It is possible to make up your own CLUTs but I
would suggest that the majority would use those alreadyprovided. Other experts such as Ton Lindemann have produced
additional CLUTs for specific tasks and those can be freely
downloaded from David Taylor’s GSS page (address on
page 33).

Fire

A CLUT is a small bitmap where pixels along the vertical axis
control the greyscale of the visible image, whist colours on thehorizontal axis can represent either brightness values ortemperatures for the IR image, dependent on the width of thebitmap. The point is that you have full control of combining visible
and IR channels into your chosen colours at each level ofcombination. This can be most useful in highlighting specificconditions and can, for example, be used to differentiate subtle
temperature variations in high cloud that may not otherwise beeasily visible.

Boundaries

False Colour

Thermal FC(Thermal false
colour)

CLUTs must reside in the GeoSatSignal folder and when this isdone they will be available for use in the CLUTs and ‘Vis ch.’windows. This is an area that requires some reading and

36

Very straight forward but choose an easily recognisable
description for the package you are setting up. Once you
have another 48 of them you will appreciate clarity ! For
the example given above and shown in figure 3, a suitablename might well be UK HRV Colour.
Simply decides whether you want black or white text.
The program needs to know the location of your Job files
The program needs to know where you want the final
processed images to be saved.
Open latest is dealt with elsewhere in the article but thisoption tells the program which image is required for theprocess and this will ensure the most recent will be used.
A particularly useful function.
Only relevant if a channel of appropriate wavelength isused. I recommend leaving the default value but more
information on this option is discussed later in theparagraph under the Processing tab headingThis refers only to multi-channel digital data such as
PDUS and simply dictates whether the visible and WV
channels should be displayed.

www.geo-web.org.uk

Select 'Normal' if you want a colour image made up fromvisible and IR images: 'None' for no colour. Other options
will be discussed under advanced usage in Part 2.
Choose this option if you want the IR image overlain on acolour land/sea mask. The resulting image appears on the
Thermal FC tab and an example showing a Meteosat- 8
full disc can be seen in figure 5.
This option can only be used for channel-4 (3.9 µm) MSG
data, which is particularly good at detecting forest fires
and hot spots. If ‘Fire’ is ticked for a colour option,
channel-4 will be substituted for the WV channel andprocessed in accordance with the fire threshold settingreferred to above. Any hotspots will show up on the colour
image as a red dot. The threshold setting, discussed
earlier, can be adjusted although the value provided bydefault is probably best left until further experience isgained. Simply put, increasing the threshold is more likely
to produce more hot spots and more false positives. An
example of such fires using this option is shown infigure 6, where plumes of smoke are also clearly visible.
If you want geographical outlines displayed in the final
image then this box should be ticked. Other settings suchas the colour of the outlines are dealt with in Common
Setup.

Table 2 - Job Setup: Processing tab options

March 2006

Group for Earth Observation

GEO Quarterly No 9

Figure 3 - A coloured, orthographically remapped close-up of the UK

Figure 5 - A full disc IR image from Meteosat-5

Figure 6 - Fires in Portugal

Figure 7 - Calibrated IR image from Meteosat-5

Image processed by Arne van Belleexperimentation. There are some unexpected results. As an example, I
find that full disc IR images can be visually more pleasing when they
have the black surround associated with the visible images: perhaps not
for the purist but a pleasing result nevertheless. More importantly, thecalibrated data within the disc is not compromised so accurate
temperature readings can still be read with the mouse. Figure 7 showsa full disc IR image from Meteosat-5 over the Indian Ocean, processedin this way. CLUTs can be used for both IR and visible imagery and aseparate selection point is provided for each.
Common Setup.
As I mentioned before there is also a 'Common setup' for settings thatwill be valid for all Jobs, in other words not Job dependant. Again I do
not intend to waste reader's time by going through each and every
option, as many of those are also self explanatory. However let me pickout a few that perhaps merit special mention and where a hint or two
may be of help to first time users.
Options under the 'General' tab
Admin notice folder: This is the location for your admin messages which
are put out by Eumetsat on a daily basis, giving details of satellite
www.geo-web.org.uk

Figure 8 - A world view processed in GSS

37

GEO Quarterly No 9Group for Earth Observation

problems or warnings for future outages and planned
maintenance. There is a range of sources for those messages
including wefax, Internet, and Eumetcast. Simply add in thesource for your admin files and the latest message will be
displayed automatically during the first run of the day of GSS. If
you do not wish to see it again for that day simply tick the 'Don't
remind me again' box and there will be no further display until thefollowing day.
Auto reprocess: This was one of my pet hates or was until David
kindly offered the option of not having it. Auto reprocessingmeans that if you change jobs it will automatically re-processusing the new job but with the file selected for the previous job. If
you were moving from a coloured composite job (where
Meteosat 8 channel 2 was required) to an IR job (where Meteosat
8 channel 9 was required) then it was a real nuisance. There areundoubtedly times when this could be a labour saving feature but
my experience is that more often than not it is the very opposite,
so unless you find a particular use for it I recommend leaving it
unselected.
Drop priority: This allows you to run CPU-intensive processes ata lower priority to avoid interfering with sensitive tasks such as
DVB reception. This would almost certainly be recommended if
you were using just the one computer for both reception andprocessing.

required to be residing in your computer to achieve this are three
Meteosat-8 channel images from the same fifteen minute scan;channel-2, channel-4 and channel-9. If 'fire' was not ticked thenthe WV channel-5 would be required in lieu of channel-4.
How do we set up this Job?
First pick a new Job number and under <options → Job setup> goto the ‘General’ tab and name it. Perhaps ‘MSG full disc colour’
would be a suitable description for this package. The following
settings will be required and those not listed should be left as
default.
Processing tab
False colour
Thermal FC
Fire
Brightness adjust
CrispenSea threshold
CLUT
Visible channel
Boundary

Job name
Path to data files
Path to results files

Although you can decide whether to have country outlines on a
per-Job basis, this common setup provides the source and thecolour requirements when outlines are selected.

Fire threshold
Zoom

The Presets tab
Let me say something quickly about the ‘Presets’ tab as its use
can be a very handy time saver. Sixteen preset options areprovided for a range of satellites, covering both visible andthermal data.
Once set up, access to loading the files is via <View → Latest IR>
or <View → Latest Visible> and provides very rapid access to thispredefined data. As can be seen in the set-up there is also an
option to associate each preset with a specific Job number which
ensures that not only can you quickly load the latest data, but it
can also be automatically processed in accordance with yourchosen Job package. The presets provide are :AI/AV
BI/BV
EI/EV
JI/JV
WI/WV
XI/XV
M8 FD I
M8 FD V- full disk, Meteosat 7- European sector, Meteosat 7- full disk, GOES-E- full disk, GMS-5 (MTSAT-1R)- full disk, GOES-W- Indian Ocean, Meteosat 5- Meteosat 8, full disk, infra-red- Meteosat 8, full disk, visible

MSG full disc colour.
Ensure correct location(my one is c:\msg-1\images\hrit\2005\11\25\)ensure correct location. (my one C:\Program
Files\David J Taylor\GeoSatSignal)64
1:4(This will ensure that the entire disc can be seen in
the image window. Of cours,e at any time, you canzoom in and out to look at detail)Now open the appropriate Job, load in the channel-2 file andvoila!
Useful Tips.
There are certain functions in programs which, after months andyears of use, you find almost indispensable. At the time those areoften simple, innocuous additions but ones that prove to havehuge benefit and labour saving. Let me pass on a few that I havegrown to appreciate over the years.
Help Files
It may seem obvious but the help files provided within the program
are superb and should be the first port of call if you have aproblem or need some specific help to understand a more difficult
concept such as CLUTs.
Open Latest
I touched on this earlier in the article but suffice to say that in myopinion this has been the most labour saving addition to theprogram. Prior to this being provided, the normal File>Open
option had to be used for all situations. Consider late in the day
going to the end of a browse window filled with files for 12channels at 15 minute intervals. Quite a task when almost always
the wanted file is at the end of the list, in other words the latest.
A very simple addition but with huge benefit.
Auto reprocess

Full Example
For those new to the program and anxious to see its qualities,
here is a simple example of Job settings to give a full discMeteosat-8 coloured image with geographical outlines, andshowing possible fires. A thermal FC image is also wanted. This
uses many of the basic settings discussed in the article. The data

38

NormalTickedTickedChoose to suit time of day and preference
0
0
None
None
TickedGeneral tab

Options under the ‘Cartography’ tabCountry boundary data file: Most readers who are already using
David's WXtrack program should provide the location for thecountries.dat file. There are other high resolution options whichusers can download and those are referred to in David's web site.
If those are to be used ensure the correct file location is provided.
Select the colours of your choice for each of the options ofBoundary colour, Grid colour and City marker colour.

March 2006

I mention this one as it can be both useful and frustrating to havethis selected. Simply put, if this is ticked then when you change
Jobs the file used before will be loaded into the new Job
automatically, whether you want it or not. Personally I rarely want
this to happen so I leave it unticked.

www.geo-web.org.uk

concluded on page 44 ...

March 2006

Group for Earth Observation

GEO Quarterly No 9

The Indian Space Programme... continued from page 33

David Taylor
If you regularly download Meteosat-8 imagery via
EUMETCast you would have noticed that the flow of dataceased completely for a spell on January 9; when it resumed
after a short break, only the visible channels were enabled.
This was a consequence of the satellite radiometers being
decontaminated.
The IR sensors aboard earth observation satellites have to becooled to operate effectively and consequently, even in theirhighly rarefied surroundings, they do eventually start tosuffer from a build-up of ice and other condensates. Once or
twice a year it becomes necessary to power down the coolant
and actually heat up the radiometer assembly for several
days to vaporise these deposits. During this exercise, theinfrared and water vapour detectors cannot be used. As aresult, only the visible light channel data is retransmitted(during daylight hours) during these periods.

The last scheduled ISRO launch this year is a PSLV due up
in November carrying Singapore’s first remote sensing
spacecraft, X-Sat. Designed at the Satellite Engineering
Centre of Nanyang Technical University, Singapore thespacecraft is unique in that it carries a very large processing
capacity to process raw data on board thus reducing the
bandwith needed to get the imagery down to Earth.
2007 and Beyond
Unless ISRO can achieve what no other launch authority has
achieved, not all the launches planned for this year will
actually take place; delays are inevitable for various reasonsand some will slip to 2007 or beyond. Several launches are
already scheduled for 2007 but just two space sciencesatellites will be mentioned here:
ASTROSAT is an astronomical research spacecraft withsensors designed to detect X-rays over a wide range of energy
levels. It will be placed in a low-inclination orbit, probably
around 20° at an altitude of 600 km. Also on board will be a
40 cm aperture ultraviolet telescope with a high resolution
array of photon counters at its focal plane. Other countries
have been invited to fill some spare capacity on thespacecraft and experiments from Bulgaria and NASA havebeen accepted.
CHANDRAYAN-1 is an ambitious project to place asignificant science payload in orbit around the moon.
Improvements in the PSLV’s performance in recent years
means that it has the required power and accuracy for thetask. ISRO has made it clear that the lunar mission will not
be an exercise in re-inventing the wheel but will utilise newtechnologies to probe the moon’s mysteries. Dr Nair, ISRO’s
Chairman, points out that a lunar mission can provide
impetus to science in India, a challenge to technology and,possibly, a new dimension in international co-operation.
Conclusion
More than three decades ago, Dr Vikram Sarabhai, the architect of the Indian space programme, outlined what he considered should be India’s objectives in space:

EUMETCast data throughput (January 5-14, 2006)

You can clearly see the break in transmission on Monday,
January 9, plus the subsequent reduced data from just thevisible channels, in the above graph of EUMETCast data
throughput.
The daily variation of data flow is caused by the differing
image content in the compressed visible data between day
and night. The decontamination process proceeded until
Thursday, January 12, when the imaging was again stopped
while the cooling for the IR detectors was restored. Once thedetectors had cooled down, imaging was restored.
To restore fully calibrated operation takes a further 24hours, so the derived meteorological products were notavailable until the Friday afternoon.
You can read more about the functionality of the twelve MSG
radiometer channels in GEO Quarterly No 7, page 14.

‘We don’t have the fantasy of competing with theeconomically advanced nations in the exploration of
the moon or manned flights. But we are convinced thatto play a meaningful rôle nationally, and in thecommunity of nations, we must be second to none in
the application of advanced technologies to the real
problems of man and society which we find in ourcountry’
However, in the context of the recent rapid strides by India
in many disciplines, such as computing technology, nuclear
energy, medical research, etc, the lunar probe is but areflection of the nation’s will.
Acknowledgements
I am indebted to ISRO and the Nation Remote Sensing
Agency for making so much information available on theirwebsites:www.geo-web.org.uk

http://www.isro.org

http://www.nrsa.gov.in
39

GEO Quarterly No 9Group for Earth Observation

March 2006

Figure 1
The annotated track of Hurricane Wilma (red) is added to the DA basemap by means of the ‘wtnt’ warning file from NOAA.

Figure 3
Similar to Figure 1, but this time an actual satellite image has been usedas the background.

Figure 2
The same image again, with isobars added

Figure 4
Similar to Figure 2, with an actual satellite image used as the
background.

GEO recently received thisattractive postcard from
Miroslav Gola, whomanufactures theRX137141 APT weather
satellite receiver.

The receiver is available
both as a kit, and a built
product.

The receiver has beentested by Francis Bell, andthough it suffered pager
interference on the ‘old’
137.91 MHz frequency, it
gives excellent results on
the new 137.10 MHz
frequency.

40

www.geo-web.org.uk

March 2006

Group for Earth Observation

GEO Quarterly No 9Fred van den BoschThe 2005 Hurricane Season ended on a very stormy notewith the arrival of Hurricane Wilma [1]. With a new
hurricane season starting at the beginning of June, I present
here some ideas for tracking hurricanes with DAWS. Peter
Green explained in his article Hurricane Forecast Feeds [2]how you can set up a system to keep yourself informed about
when a hurricane is coming. As soon as there is a forecast
you first go to:
http://weather.noaa.gov/pub/data/raw/wt/
This is the site where the hurricane forecasts used by DAWS
are to be found. Look for the five hurricane warning files named
wtnt21.knh.tcm.at1.txt through wtnt25.knh.tcm.at5.txt. Be
sure to note which file has the most recent date as the files arecontinually recycled—the ‘wtnt25’ file is not necessarily thecurrent hurricane.
You can open the file with notepad to check if it’s the hurricane
you want to display. If so, close the file and open DAWS; clickon the Retrieve Data icon (5th from the left end of the toolbar)
then scroll down till you see the 5 lines ‘Hurricane track #1 fromNHC (Atlantic)’ to #5. Tick the line where the number
corresponds with that of the most recent hurricane warning file;e.g. if ‘wtnt24’ is most recent one then tick track#4. Now retrieve
the data.
Generating Maps
Load (or generate) a base-map of the area where the hurricane
is active and select <Data → Hurricane tracks → Official forecast>
to display the estimated track of the hurricane over the map.
Unfortunately it is not always possible to plot only one specifichurricane if several are active at the same time.
If you tick all five ‘hurricane’ lines then all five tracks will be
displayed, some of them out of date and not relevant to thecurrent situation.
ExamplesI present some examples of Hurricane Wilma. The parametersof the map I used are listed in the table below.
Digital Atmosphere

GeoSatSignal

Latitude20° Parallel

20°

Longitude-83° Meridian

-83°

Scale

3170 Span

35

Size

768 x 576 Size

768 x 576

In both cases, the map projection is orthographic.

Hurricane Wilma off Florida on October 20, 2005
Image © EUMETSAT 2005

Figure 1 shows just the track of Wilma over the DAWS basemap and in figure 2, isobars have been added.
Figure 3 is similar to figure 1, but a Meteosat-8 image including
Hurricane Wilma has been used as the background: isobars
have been added for figure 4. I used a satellite image for the
day before the warning file in order to show the eye of thehurricane. If you use an image from the same day, you will seethat the first red dot on the hurricane track exactly covers theeye.
Provided you have ingested both the ‘wtnt’ warning file and acontemporary synoptic file into DAWS, a script that draws thehurricane track is shown in the gray panel below. For details of
making such a script refer to GEO Q7 [3]. Of course, you would
choose your own names for the base-map and satellite image.
References
1. Unique finale to the 2005 hurricane season, GEO Q8, page 7(2005).
2. Hurricane forecast feeds, Peter Green, GEO Q8, page 11 (2005).
3. Using scripts with Digital Atmosphere Workstation, Fred van den
Bosch, GEO Q7, page 30 (2005).

erase
load,d:\Program Files\DigitalAtmosphereWS\maps\MSG Amerika-Midden.dmf
import,d:\Products\MSG\DAWS\DAWS-Amerika-midden.jpg
basemap
hurricanestamp
www.geo-web.org.uk

A simple DAWS script for adding ahurricane track to a satellite image called‘DAWS Amerika-midden.jpg’.
‘MSG Amerika-Midden.dmf’ is thecorresponding DAWS base-map.

41

GEO Quarterly No 9Group for Earth Observation

anybody interested in our Earth’s
atmosphere is that they obtain a copy ofthis book. It may become a reference
document for many years to come.

Francis BellEUMETSAT have recently published aquality, 120 page paperback book in A4
format entitled MSG Meteosat Second
Generation In Orbit - In Use. I don’t very
often read technical literature from cover
to cover but this one I did.
If any user wants to learn about thescope and application of MSG data
(currently Meteosat-8), this is the book to
read. It is informative, technical andattractively produced with illustrations andexamples on almost every page. I think
the best way to indicate its scope andcontent is to read the contents page,
reproduced at the foot of this page withEUMETSAT’s permission. There is

GEO members’ weather satellite interests
cover a broad spectrum: the technicalchallenge of being able to receive anddisplay the satellite data and translatethese data into images; the pleasure ofjust looking at the images; colouring
images, contrasting and highlighting
them; pushing what is possible to receive
on a home PC with minimum cost; and ofcourse looking at the weather systems
across the planet. My interests fall into allthese categories and this book helped
explain to me what I am receiving.
My recommendation is that every
existing user of MSG, any potentialuser, or anybody with an interest in
the Earth’s atmosphere, should
obtain and read this book.
The conclusions of the book read as
follows:‘The information in this publication has
been based on data generated over a
period substantially less than one fullyear of operation. Nevertheless, thehuge potential is obvious and it is clearthat many other specific uses will
emerge in the coming years as greater
understanding is obtained of thecomplex data streams. With a total, now,of four satellites of this type approve, it islikely that their data will be used forpossibly the coming two decades, withnew applications continuing to emerge
and older ones improved. Thispublication is not the last word on theuse of MSG, rather it is just the
beginning.’

information about MSG’s instruments, thedata they produce and the subsequent
applications of these data.
My strongest recommendation for any
existing user of MSG, potential user or
1. Images from MSG
Imagery Basics
Images of Clouds and surface
Images of the AtmosphereHigh Resolution Imagery
Presentation Methods
Impact of HRV Imagery
Impact of Multi-Channel
Sensing
Impact of 15-Minute Imagery
2. The MSG System
System Overview
The SEVIRI Radiometer
The GERB Instrument
Search & Rescue Services
Satellite Application Facilities

42

I have secured a bulk supply of the bookfor distribution to GEO’s membership. I
will take some copies of the book to the
Kempton radio and computer rally in
May and also to our GEO Symposiumin Leicester on April 29. If you are patient

Meteorological Product
Extraction Facility
Data Dissemination via the
EUMETCast System
3. Forecasting the Weather
Forecasting Uses of Images
and Products
Nowcasting and Very Short
Range Forecasting
Forecasting for Aviation,
Marine and Land Transport
Prediction and Monitoring ofHazardous Weather
Monitoring Convection
Synoptic Scale Systems
Hurricanes and Tropical
Cyclones

March 2006

you can collect a copy directly from methen free of charge.
If you would like a copy before this, I canmail you a copy for the cost of postage(the brochure weighs 500 grams). In thiscase, refer to the options at the foot ofpage 3.
I recommend everyone to obtain a copy.
You will be rewarded with an excellent
reference book for MSG satellites.

Fred van den BoschIn my previous article (Geo Q8, page 24),
I described how to make 3D images using
Bas Relief. By chance I found out that thiscan be done much more quickly.
The step <smooth> can be skipped. Afterloading an MSG image into both the
Image and Depth map windows, you cancontinue generating a 3D-image by simply
clicking on <Anaglyph image>. You cannot
see differences between images with andwithout a generated depth map. It looks
like smoothing also happens automaticallyduring the generation of the image, as you
can see under ‘progress’.
You can also experiment with using IR
images for the depth map. In fact thebrighter the cloud the higher it is.
Information from KNMI (Royal Dutch
Meteorological Institute) indicated thatchannels 9 (10.8 µm) and 10 (12.0 µm)
are the best for this purpose. This because
here the brightness of the clouds, which
relates to their height, is the best. So
combinations of channel-1 with either
channel-09 or channel-10 for the depth
map give the most natural effect.

Data for Numerical Weather
Prediction
Diagnostics for Numerical
Weather Prediction
Support Products
4. Climate Applications
Earth Radiation Budget
Surface Radiation Budget
Archive and Long-Term Data
Sets
Global Data Sets
Validation of Climate Models
5. The Atmosphere
CloudsCloud Properties
Cloud Top Heights

www.geo-web.org.uk

FogWind Vectors
Water in the Atmosphere
Precipitation
Condensation Trails
Dust and Aerosols
Volcanic Ash Plumes
Stratospheric Ozone
6. The Surface Environment
OceansSea Surface Temperatures
Land Surface Products
Snow Cover
Environmental Data
Vegetation Mapping
WildfiresMarch 2006

Group for Earth Observation

GEO Quarterly No 9

Douglas Deans - douglas@dsdeans.freeserve.co.uk
This quarter sees a major update to one
of David Taylor’s most popular
programs, SatSignal. Whilst thiscolumn was in preparation, David
forewarned me of the imminent releaseof SatSignal 5, allowing a brief review
to be given below.
Before undertaking the reviews, some
information regarding the NASA WorldWind program which readers will beaware was added to the GS2 CD lastyear. I have decided for a range ofreasons to remove this program fromthe Software Collection. I am consciousthat one of the fundamental reasons for
Software Showcase, apart from
reviewing shareware relevant to ourhobby, is to offer those with no Internet
facilities or just dial-up options the
chance to enjoy programs or image dataof a much larger size. At over 180 MB,
World Wind admirably fits thatcategory. However NASA have now
altered the program function to reducethe download size but this now meansthat there are many other items thatmust be downloaded after the program
is up and running, including for somethe Microsoft .NET environment. In
addition, the program’s operation now
requires you to be on-line with quiteconsiderable downloads occurring as thesoftware is used. In short, broadband
really is a necessity to run this program
properly and its provision on GS2 may
cause confusion and disappointment tothose expecting it to work smoothly
from the CD.
SatSignal 5
SatSignal has been about for a very

long time; indeed it first surfaced inearly 1999 and is still recognised as theforemost program for demodulating thesignals from polar orbiting weather
satellites and providing considerable
options for post image processing. The
program has just had a major upgradewith the addition of Background Modeto the EasyOverlay facility and is now
known as SatSignal 5. The first thing
you will notice when you install the
program is that you have 30 days to try
the software. If you do not register it
before the 30 days are up then the
program automatically reverts to thefree shareware version. Quite frankly,
given the cost of the software and thequality and usefulness of the additionalfeatures provided with registration, you
would be mad not to register. For those
who have a previously registered

GS1 All David Taylor's weather satellite programs and libraries, including the current releases of WXtrack, Satsignal, HRPT Reader, GeoSatsignal, GroundMap, RX2
PassControl and many other program extras. This disc also contains a large quantity of sample files, many of high-resolution data, for use with these programs.
WXtrack
Satellite Tracking Programv 3.5.2
SatSignal

Creates images from wave files

v 5.0.0

HRPT Reader

Converts raw HRPT data files into images

v 2.6.2

GroundMap

Rescales satellite images

v 2.0.0

RX2 PassControl

Computer control program for the RX2 receiverv 3.0.6

GS2 A wide range of software for all aspects of weather satellite reception, including tracking, receiving, monitoring and image manipulation. Content is detailed
below but many other extras are provided. Titles correspond with folder names. * implies a DOS program.
Collection D02
Recall (wave file recorder), Palette (modifies Wxsat colour palettes).
Collection D03

Scanner recorder v 1.8 (wave file recorder), *NOAA95/*FENG99 (software for the NOAA 95 HRPT project)

Collection D04

Wxsat (wave file recorder/decoder), Satmon (wave file recorder).

v 2.59AGSatTrack

Satellite tracking programv 1.33

APTDecoder

Program for capturing APT audio and processing images

CirkitDocuments for the Cirkit Wxsat receiver and the UOSat receiver (PDF format)

v 1.0.2.70

Element Manager

2-line element manager

v 1.59

Footprint

Satellite tracking programv 2.10Irfan View

Image/slideshow viewer

v 3.80

JVcomm32

Evaluation version (APT/FAX/SSTV decoder)Macintosh kepler editor

Edits verbose AMSAT format elements. Mac OS X and OS9 only.

NeoPaint

Image processing program (30 day evaluation)

OrbitronSatellite Tracking Program

Paintshop Pro

Image processing program (30-day evaluation)

v 3.70

PhotoFiltre

Image retouching program with many extras

v 6.1.5

Satscape

Satellite tracker and wave file recorder

v 2.02

Space-Track TLE Retriever

Generates TLE files in 'Celestrak' style from data sets recovered from Space Track

Splitter

Utility program for splitting and reuniting large files

WXtoImg

WAV file recording and decoding program with many options.

v 2.7.3

GS3 3DEM Package for 3D Terrain Visualisation
This CD includes the full set of GLOBE Tiles to allow you to produce excellent images and flybys from HRPT inages. Also included is a selection of Mars MOLA
files, sample images and helpful guides by Ed Murashie.
GS4 Image CD
A wide selection of high-resolution remote images from a range of satellites, including stunning imagery from the Space Shuttle missions. A full description andsource if provided for each image.
GS5 Mars Rover Panoramics
A chronological account, in panoramic images, of the NASA Mars Rovers' progress across the Martian Terrain

www.geo-web.org.uk

43

GEO Quarterly No 9Group for Earth Observation

version there is a specific upgrade offer.

March 2006

APTDecoder v 1.0.2.70

There are quite a number of updates to the program andhopefully, at a future date, these may be part of a fullsoftware review. With limited space here let me concentrateon the main change which is the incorporation of the
Background Mode to the Easy Overlay facility. You canchoose your own backgrounds provided they fall within thecriteria specified. However one of the more attractive options
is the use of the recently released Blue Marble Next
Generation with it stunning Earth images. This allows nighttime weather satellite images to look as if they were daytime
ones by careful blending of temperature data from the IR
channel. Cloud details and temperature readings are now
available over a background of blue sea and natural landcolours. The outcome is quite stunning and a double image
showing the original IR and the resulting composite coloured
background can be seen on the inside back cover of this issue(image courtesy David Taylor).
SatSignal 5 is available on GEO software CD GS1 or for
more information and to download the program yourself go
to:http://www.satsignal.net
and follow the link to Satsignal under the ‘Satellite Tools’
section.
For further information on Blue Marble Next Generation go
to :http://earthobservatory.nasa.gov/
Newsroom/BlueMarble/

This program by Patrik Tast from Finland was reviewed in
depth by Les Hamilton in GEOQ 8. The upgrade includes a
critical bug fix to NOAA 18 data and new to the software is
updated Kepler elements being archived in two line format.
The program is available on GEO software CD GS2 or for
more information and to download go to :http://www.ptast.com/apt/decoder/

How to Purchase CDs
Write to the address below requesting GS1, GS2, GS3,
GS4 or GS5. Prices are £5 for any single CD, 2 for £8, 3 for£11, 4 for £14 or all 5 for £17. Please enclose cash or
cheque (made payable to Douglas Deans—not GEO) for
the appropriate amount. Nothing else is required.
The cost includes the CD, packaging, posting and a small
donation towards the cost of overheads. No fee is asked
from overseas members although an exchange of softwareor interesting satellite images is always welcome.
Orders are normally dispatched on the day of receipt.
Order your CDs from:
Douglas Deans, 17 Montrose Way,
Dunblane, Perthshire FK15 9JL, Scotland.

QuikSCAT (... continued from page 27)

GeoSatSignal 5 (... continued from page 38)

and wind vector resolution of 25 km. Falling rain can influence theaccuracy of results on two counts. Firstly, rainfall can itself contributeto sea-surface roughness, while secondly, very heavy rain can cause
scattering and attenuation within the radar beam itself, effectively
reducing accuracy by degrading the data during transmission.

Mouse Controls

References
1. QuikSCAT Mission
http://winds.jpl.nasa.gov/quikscat
2. Ocean Waves
http://hyperphysics.phy-str.gsu.edu/hbase/waves/watwav2.html
3. QuikSCAT Overview (Earth Observatory)
http://earthobservatory.nasa.gov/Library/QuikSCAT/printall.php
4. NASA Winds Website
http://winds.jpl.nasa.gov
5. Applications of Scatterometry
http://winds.jpl.nasa.gov/aboutScat/applications.cfm
6. El Niño
http://www.pmel.noaa.gov/tao/elnino/el-nino-story.html

And finally

The mouse wheel can be used with images to zoom inand out and if it is pressed down and dragged will movethe image within the scroll. Another very useful timesaving option.
In Part 2 I will be looking at some of the more advanced
features of GeoSatSignal 5, including remapping,animations (both manual and automatic), the use of
RGB mode and the rather impressive World View.
As a small taster of things to come have a look at
figure 8, where a world view processed in GSS has
been used in WXtrack GL, another of David’ Taylor’s
programs, to give cloud cover viewable for any part of
the world.
Acknowledgement
All Images © EUMETSAT 2005

‘Far East’ Competition
Rob Denton has a fascination for pushing his weather satellite
equipment to the limits—by striving to acquire sharp APT
images farther and farther to the east from his location in
Worksop, England.
Rob is convinced that other GEO readers in England,particularly those who live nearer the east coast, could do evenbetter, so he is offering a small prize to the best image that44

‘sees’ farther east than his NOAA-17 image opposite. The prize
will be a copy of Pocket Guide to Weather and Forecasting by
Storm Dunlop and Francis Wilson, a 160-page hardback
containing lots of illustrations.
Images should be submitted to the Editor in the first instance,
and will be passed on to Rob, who will decide the eventual
prizewinner. Let’s see GEO readers rising to the challenge!

www.geo-web.org.uk

NOAA-15 at 05:55 UT on December 18, 2005,
processed using Satsignal to produce its conventional
channel B thermal image

The same NOAA-15 pass produced in SatSignal-5
using its false background mode, with a Blue Marble
background image (see page 43)

Another amazing ‘far east’ NOAA-17 image (July 15, 2005 at 08:30 UT) from Rob Denton which includes much of the Caspian Sea.
Rob writes: “I’m still waiting for someone to take up my challenge of how far east they can image with basic equipment. Again
captured in WXsat with my Dartcom System II receiver and Wimo crossed dipole antenna (no preamp used). Located in Worksop,
Notts. 53.3°N, 1.1°W. I'm sure that someone who is further east from me in the UK can get a better image, as I'm central, so comeon, lets see what can be done!”