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The GEO Quarterly

GEO MANAGEMENT TEAM
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Tel:
01483 416 897
email: francis@geo-web.org.uk
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Publisher
Published by The Group for Earth
Observation Limited, a company in Englandand Wales, limited by guarantee and nothaving share capital.
Company number 4975597.
The registered office is Coturnix House, Rake
Lane, Milford, Godalming, Surrey GU8 5AB
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Responsibility
Every effort is made to ensure that thetechnical and constructional articles publishedin this Quarterly are correct. However, theultimate responsibility is with the reader toensure the safety of constructions and for any
interfacing with other equipment. GEO cannot
accept liability for shortcomings in any
published design or any constructions carriedout by members or other third parties.
Copyright GEO © 2010
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 fromthe Editor.

March 2010

Editorial: Peter Greenelcome to GEO Q25, I hope you enjoy my first issue as editor. I would liketo thank Les Hamilton for his invaluable help in producing this Quarterly.
Over the last year he has gone out of his way to write me tutorials on how to
produce the magazine and over the last few weeks has been my constantfountain of knowledge to get to the publication day.

W

he Quarterly is your magazine, the flagship of GEO and should reflect yourinterest; however it will be nothing if you don't submit your articles andimages. Please don't just send me an image or a web link 'saying this would
make a good article'. I haven't got the time to write the articles and that's not theeditor's job. I would like to use more of members images throughout the
Quarterly so please send them in, to aid the finished printing please submit
them in the highest quality format you can.

Thilst we in Europe were shivering in the one of the coldest winters for years(as seen in our cover image) and the UK came to a standstill with a few
inches of snow Steve Ross in Potomac Falls had a few inches more read about it
on page 38

Wn a warmer area, the Caspian Sea is effectively the largest lake on Earth. Les
Hamilton has prepared an illustrated article describing this intriguing body ofwater.

I

he Envi-ham Project has launched with some images producing results down
to 300 meters, Francis Bell reports on the start of this project.

T

PT is still the most popular area of our hobby with many people getting great
images and pleasure from receiving directly from the satellite. Mike
Donnachie has improved his reception with a Cubical Quad antenna for APT andtells you how to do it in this issue.

A

Contents
GEO Report
Cover and Full Page Images
Caspian Sea
Mobile Internet for your weather station
Cubical Quad for APT
Envisat North Atlantic Depression
Envisat raw data showing the Strait of Gibraltar
Reminiscences of early days at Dundee
Envi-Ham ProjectLightening and Surge Protection

Francis BellLes Hamilton
Rob Denton
Mike Donnachie
John Tellick
Francis Bell
Francis Breame
Francis Bell
Arne van BelleGEO Shop
Helplines and Internet Discussion Groups
Copy Deadline for the next issue of GEO Quarterly
GEO Membership Renewal Form
Metop Images North America’s Great Lakes
Marine APT in the South Atlantic
AVHRR and SEVIRI a comparison
Tropical Cyclone Laurence
Potomac Falls Blizzard
Faeroe Islands DisturbanceKatabatic Winds Rake Antarctica’s Terra Nova Bay
Computer Corner
Sky: A review of Storm Dunlop's new Book
Feedback

2
3
4
6
7
8
9
10
12
18

i
iii
iii
iv
Robert Moore
Francis Bell
Marciano Righini
Dale Hardy
Steve Ross
Anders Höök
NASA Earth Observatory
Douglas Deans
Robert Moore
Readers’ Letters

23
24
26
36
38
39
40
42
43
44

GEO Quarterly No 25

Group for Earth Observation

March 2010

Francis Bell

There is the prospect of an exciting year ahead for thosemembers who are prepared or able to take advantage ofthe new dissemination service being offered by ESA via
their new Envi-Ham project.
I have written an article about my introduction to thisproject. It is partly a diary of events but I hope it
contains enough technical information to allow acompetent individual to start receiving this stunning
new service. No doubt over the coming year we will beable the share experiences, allowing many more of us toachieve successful home, school, or other institution
reception of the Envisat images. Although I am receiving
high definition images from Envisat, I still consider
myself a beginner and am still learning to display them
to best effect.
I wish to record my thanks to Stefano Badessi andothers at ESA-ESRIN Frascati for the help and guidance
enabling me to successfully receive their new service. If
I understand their hierarchy correctly, Stefano Badessi
is the Principle Investigator of the Envi-Ham project, but
this is in addition to other duties he has within ESRIN.
Editor
GEO now has a new editor for our Quarterly and in
anticipation of looking after us for the near future a big‘thank you’ to Peter Green. A cautionary word here to
the membership that the life blood of the Quarterly
relies on your contributions.
It is not the role of the editor to create the copy but toedit other contributions. Please submit to the editor
anything that you think would be of interest. Material
could be anything from personal anecdotal experiences
to highly technical articles. However, the warning is thatwithout such input there will be nothing for the editor
to edit and hence no Quarterly publication. Please besupportive of our new editor.
To just say ‘thank you’ to our retiring editor seems
inadequate. Our Quarterly has been our group’s
flagship since the ‘Launch Issue’ in 2004 and its quality
has been attributable to our editor who not only hasedited the content with meticulous accuracy but also
composed it page by page ready for the printer. I know
Les wishes to spend more of his time on his otherinterests but for the legacy he has left and thestandards he achieved on our behalf, I can only say‘thank you’.
International Liaison
As Pete has taken over the job as Editor he has
relinquished the role of International Liaison for GEO.
This is a great opportunity for one of our members to
support GEO and help develop its International
membership. It you are interested in this opportunity or
any other role please contact me.
Posting and Distribution.
A further ‘thank you’ must go to Peter Wakelin, who has

2looked after the distribution of the quarterly since theLaunch Issue. I think, over the years, Peter must havemailed about 14,000 copies of GEO Quarterly to ourmembers in the UK and abroad. He was always prompt
with his service and kept the management team up-todate with mailing costs and current membershipnumbers.
This position is now vacant and any member who may
be willing to undertake this role should contact me fordetails.
Please do not ignore this request if you think you may
be able to help. Please contact me at
francis@geo-web.org.uk

GEO Shop
The shop is another jewel in our crown because it
makes available to our membership equipment which
would otherwise be impossible to buy elsewhere. A‘thank you’ to Clive and Carol Finnis who have run the
shop for five years, and sourced receivers and otherequipment from abroad.
Thanks also to David Simmons who now looks after the
initial processing of orders and the technical side ofshop enquiries.
Events for 2010
Our friends in The Netherlands are holding their regularmeetings on the following dates in 2010:
Saturday March 20
Saturday May 8
Saturday September 11
Saturday November13
The venue for their meetings is the Nimeto, Utrecht in
The Netherlands. I feel sure GEO members would be
welcome at their meeting but check first for details on
their website at
http://www.kunstmanen.net/

UK Space Conference
GEO will be represented at the UK Space Conference inGodalming, Surrey between March 24-28,
demonstrating live APT reception together with a standof informative posters and literature. It’s just possiblethat we may also be able to demonstrate Envisat
reception too. This is a major four-day conference anddetails can be found atwww.ukspaceconference.org

AMSAT-UK are holding their annual colloquium at theHoliday Inn Guildford. The dates are:Saturday 31st July and Sunday 1st August

www.geo-web.org.uk

March 2010

Group for Earth Observation

To keep in touch with the programme andaccommodation for this event visit the
AMSAT-UK web site atwww.uk.amsat.org

Plans still have to be agreed but I would
like GEO to be represented at this meeting
to demonstrate reception of the new EnviHam project.
GEO attended the RSGB / Lincoln Short
Wave Club National Hamfest last year.
Our stand was busy for two days and wehope to be there again in 2010 perhaps
demonstrating Envi-Ham reception but
more certainly live weather satellite
reception. The dates are Friday 1st
October and Saturday 2nd October
I judged this to be a very worthwhile event
last year: hopefully it will be again in
2010.
The Royal Meteorological Society areholding a special weather satellite
conference in early September at alocation on Reading University campus.
GEO have been asked to take part in thisevent and at the moment we anticipate
giving presentations, workshops and live
weather satellite reception. It could be amajor event for us, perhaps offering theopportunity to hold our own AGM. Details
still have to be confirmed so please watch
the GEO website for the latest news
relating to this event.
A venue for our own annual symposium
has not been chosen yet although it isbeing actively researched. Again, watch
our web site for the latest news. I mustnote here that, in spite having a stunning
programme of speakers at our 2009
symposium, attendance by UK members
was very disappointing and provided noreal stimulus to run a similar event in
2010.
The Quarterly Question
Readers of our last Quarterly may haveread the question which related to thenumber of member states in EUMETSAT.
The question was prompted by something
said by Gordon Bridge in his presentation
at our 2009 symposium.
He slipped in the comment that, with two
new member states, EUMETSAT was not
short of money. Wow! There cannot bemany organisations who can say this but,with two new members, I guess this eases
their finances. Gordon showed us a list ofmember states and cooperating states. At
that time the number of member states
was 24 and this was the number I waslooking for as an answer. To confirm thisnumber read a recent EUMETSAT
publication which usually lists themember states or visit their web site atwww.eumetsat.int

GEO Quarterly No 25

other countries have joined so the current
number is 26.
This Quarterly Question has beensynthesised from my recent experiences inSouth America, where I managed to obtainsome APT images of the River Plateestuary; the emailed New Year greeting I
received from Carlos Cotlier of the Remote
Sensing Centre, Rosario, Argentina; andthe Envisat images I downloaded from
ESA of the River Plate estuary, one ofwhich appears on page 13. The Envisat
image of the River Plate clearly shows
Montivideo and Buenos Aires but thequestion is this:Cover and Full Page
ImagesFront CoverThis Modis image from NASA’s
Terra satellite captures the scene
on January 6, 2010 as Scotland
shivers under a layer of snow and

Can Rosario been seen on this sameimage?
If your answer is yes, give me an
indication of its location. For example,
using 10 units for the width of the images
and 10 units for height what would be thex,y coordinates of Rosario, if it‘s shown?

ice. Further south, England isunder siege as snowfalls in thesouthern counties approach half ametre in depth.
Image: NOAAThe greeting card from Carlos Cotlier(page 44) may or may not help you.

Back CoverAnswers to me by email at

Arne van Belle captured thisfrancis@geo-web.org.uk

before the publication deadline for
GEOQ 26.

EUMETSAT Announces
EO Portal

corrected Envisat image on
January 30th 10:51 UTC showing
snow inclination for the Uk. Image
received over the Envi-Sat Project
Copyright ESA

We have received the following
announcement from EUMETSAT:‘EUMETSAT is pleased to announce thelaunch of the Earth Observation Portal(EO Portal) which will allow you to manage
on-line your subscriptions to the data,
products and services provided by
EUMETSAT. As of January 28, 2010, youwill be able to login to the EO Portal at

Inside Back Cover
Douglas Deans shows the resultof using Google Earth to display
Eumetcast Multi-sensor

http://eoportal.eumetsat.int/userMgmt

Precipitation Estimate data (MPE)with a temporary user ID and password.

for the 0 degree and IODC data

After logging in using your new user ID
and password, you will have thepossibility to view and modify your user
profile, service subscriptions and licencearrangements.

Image:Google/Eumetsat

Please note that the information you willfind is based on your previous registration
details. Should you require any further
assistance, please contact the User
helpdesk by visiting
http://www.eumetsat.int/

and following these three steps.
• Select ‘Access to Data’ from the menubar• Select ‘User support’ from the page menu
• Select ‘Helpdesk service’ from this menu

Page 41
George Newport alerted us to thisfine image of Typhoon Nida,
imaged by Metop-A on November
27, 2009. At that time, mean
windspeed was 165 mph, gusting
to 200 mph.
Image: NOAA CLASS Archive

My thanks to the relatively small numberof members who emailed me with thecorrect number 24. Subsequently two

We hope you will enjoy using the new EO
Portal’3

GEO Quarterly No 25

Group for Earth Observation

March 2010

Les Hamilton
South and east of the Urals lies a vast, low-lying inlandbasin comprising much of Kazakhstan, Uzbekistan andTurkmenistan. In former times, during the mountainbuilding era that raised many of the surrounding ranges
some 50 million years ago, this basin contained the shallow
Paratethys Sea (an ancient northern gulf of the Tethys
Ocean, which linked the Pacific and Atlantic oceans before
North and South America drifted together); the Paratethys
stretched from north of the Alps, east as far as the presentday Aral Sea. Now long gone, the Paratethys has left behind
an inland basin which, since becoming landlocked about
5.5 million years ago, has pooled water from more than 130
rivers (80% of it from the Volga) at its lowest point to form
the Caspian Sea.

these in turn are affected by cycles of the North Atlantic
Oscillation. Thus levels in the Caspian sea relate toatmospheric conditions in the North Atlantic thousands ofmiles to the north and west.

The Caspian Sea, the largest lake on Earth with a surface
area 50% greater than all five North American Great Lakes
combined, is divided into three regions of roughly similararea. The northern part is the shallowest, with a mean
depth of just 7 metres and rarely exceeding 10 metres in
depth. It contains less than one percent of the Caspian’s
total water volume. The middle region holds approximately
35 percent of the lake’s volume and has an average depth of
174 metres while the southern Caspian, holding 64% of its
water, plunges to 1025 metres at its deepest.
Occupying a large depression north of the Elburz
Mountains, the Caspian is an endorheic (terminal) lake,
which means that its water never reaches the oceans.
Because of this, evaporation has resulted in mineralsbuilding up in the water and rendering the lake saline, witha salt content around one third of that found in the oceans:consequently, it is generally referred to as a sea. The salinity
does, however, vary considerably within the Caspian,particularly in the shallow northern region where inflow
from the Volga lowers salinity to freshwater levels. The
Caspian measures approximately 1,030 kilometres from
north to south with a width ranging between 196 and 435
km; it boasts a total coastline of over 7000 km, a surface
area of 386,400 km2 and contains some 78,000 km3 ofwater. To the east of the Caspian lies the prominent
Kara-Bogaz-Gol, a shallow gulf with just 3% of the area ofthe main Sea. Its surface lies several metres lower than thelevel of the Caspian itself, and water that constantly drains
into it quickly evaporates, rendering its salinity between ten
and twenty times that of its larger neighbour. The region
surrounding this gulf is largely uninhabited because of thesalinity, and vegetation consists only of salt tolerant plants.
The level of the Caspian has had a history of both shortand long-term variations in level and has fallen and risen,
often quite rapidly, many times in the past: currently it
stands at 26.5 m below mean sea level. Over the centuries,
Caspian Sea levels have changed in synchronicity with theestimated discharge of the Volga, which in turn depends on
rainfall levels in its vast catchment basin. Precipitation isrelated to variations in the number of North Atlantic
depressions that reach the interior of the continent, andIce up to two metres in depth covers the northern reaches of the
Caspian Sea in this Terra MODIS image dating from December 16, 2002
Image: MODIS Rapid Response Teamat NASA GSFC

Between 1930 and 1957, prolonged drought in its
hinterland, coupled with the construction of large hydromechanical irrigation projects on the Volga and Kura rivers,
reduced the surface area of the Caspian from 430,000 to
382,000 km2, at the same time lowering its surface to-28 metres and turning much of its shallow northeasternregion into dry land or marsh. Between 1977 and 1995 thelevel rose by 3 metres, in part as a result of opening sluices
in river dams during 1991. Since 1995, smaller oscillations
have continued to take place.
ClimateDuring winter, mean temperatures throughout the Caspianbasin are around the –10°C mark and the shallow northernpart of the Sea freezes from November to March, the ice
often attaining a thickness of two metres. During thesummer months the waters can rival those of theMediterranean, with surface temperatures of 24°C to 26°C
in the north, rising to 29°C in the south. Rainfall over the
Caspian Basin averages about 200 mm per annum,
significantly less than the annual evaporation of 1000 mm
per year.
Opposite Page
A true colour Aqua MODIS image of the Caspian Sea
acquired on January 15, 2008.
Image: MODIS Rapid Response Teamat NASA GSFC

4

www.geo-web.org.uk

GEO Quarterly No 25

Group for Earth Observation

Eurasia Canal Project
It has been proposed that a canal be created joining the
Caspian Sea with the Black Sea to foster trade between Asia
and Europe. If it comes to fruition, the Eurasia Canal, will
stretch for 650 kilometres through the northern Caucasus
to link the two seas. It is estimated that construction of thecanal would take take five years and cost $6 billion. If built,
the canal would be four times longer than the Suez link
between the Mediterranean and Red seas and eight times
the length of the Panama canal connecting the Pacific andAtlantic oceans. It would turn Kazakhstan into a sea powerand bring benefits to other countries in Central Asia which
are rich in oil, gas and mineral resources but lack transport
links to world markets. Such a canal would cut some1000 km from the current waterway where ships must travelfrom the Caspian to the Black Sea via the Volga river, theVolga-Don Canal, the River Don and the Sea of Azov.
Oil
Huge oil fields are now known to lie beneath the CaspianSea. Oil exploration in this part of the world began as long
ago as the mid-1870s, in the Baku region of Azerbaijan, andby the start of the twentieth century, these represented an
estimated 10% of the world’s total supply. Kazakhstan
began exploiting a major oil reserve along the Caspian in
1979 and oil and gas extraction, along with transportationand industrial production, have been the source of severe
air, water, and soil pollution in the region. Currently,
Azerbaijan and Kazahkstan have seen the biggest increasein oil production—some 70% since 1992—with a total
production of 1.6 million barrels per day, a figure that is
expected to triple by the end of this year.
References
1 The Caspian Sea (Lake Basin Management Initiative Thematic
Paper) - Nicolai Aladin and Igor Plotnikov – June 28, 2004.
http://www.worldlakes.org/
uploads/Caspian Sea 28jun04.pdf

March 2010

For those of you who are thinking Mobile Broadband is justfor laptops and vehicles, think again! There is absolutely noreason you cannot run it on a desktop PC as long asprecautions are taken, in fact it can save you a small fortune
as the market is more competitive. I don’t know how it is in
all the countries but just think, for our UK members thatmeans no £120 line connection or £11 a month line rental.
Has that got you thinking yet? Yes, all those extras, including
one off payments soon add up.
When I’m talking about precautions I mean this – Your
desktop can emit a lot of RF (interference) which can affectthe performance of your USB dongle (the thing that plugs into
your PC) so we need to get it as far away from the PC as
possible. I use a 1 meter extension cable with a stand on one

end which lifts the dongle into the clear for trouble free
reception (remember your internet arrives via radio waves so
the stronger the signal, the faster the connection) but be
careful when looking for extension cables, those Pound Shop
specials can be very lossy so seek a good quality one. There
are some nice usb extension cables on Ebay for a few pounds,
euros or whatever currency you trade in (I know GEO hasinternational members)
Don’t be afraid to experiment, trying your dongle in different
parts of the room, vertical as well as horizontal, try it near thewindow, it’s amazing how much the signal can be attenuatedby a brick wall etc. I even placed my dongle on a metal tray
which acted as a groundplane, it DOES work! Most internet
providers include a signal meter in the software so you can
see the results, but give it time to update, move it slowly whenseeking the best location.

Mobile Internet for your Weather
StationRob Denton G4YRZ rob@wxsat.org

Whose idea was it to move back to UK? Just when I got settled
in my Beautiful Bulgaria I find I’m heading back “home” toRobin Hood Country. I sure will miss the beauty andtranquillity of that place but, been there, got the t-shirt and
now it’s time to move on again

There are some excellent external (outside) antennas which
can be plugged into your dongle and these are really effective,
but again, for best results go for the ones with higher gain, atleast 11dBi. I am currently in the process of experimenting
with one. Please note: In most cases these external outside
patch antennas are not necessary, it’s just that I’m in an areawith very poor to no reception, most towns and cities havesufficient signal for just the dongle alone to suffice.

On arrival back in UK it’s time to find a new place to live,
being an old weather satellite enthusiast I thought carefullyand decided to settle somewhere in the country where I got
the least possible interference to my APT imaging.
Wrong!
I made a big mistake there. No internet to publish my weather
satellite images automatically to the web, at least none
without it costing me fortune for the extra “boost” required forthe land line signal. That’s when I decided to search foralternatives. It’s not that I’m tight with my money, simply thefact that I don’t have any!
After some thought and 4 or 5 hours searching the net I foundthe answer. Yes, the light bulb came on in those old grey cells.
Mobile Internet!

6

Anyway, to sum up, think about what you are paying for yourinternet and see if this will save you a shilling or two, it’scertainly great fun and inexpensive compared to fixed
broadband.
I have cut my internet bill in half, just by going mobile
broadband instead of a fixed landline and I can even go
portable with it now just take it with me when I try receivingfrom a remote location, which can also send straight up on
the website!!!
Enjoy the hobby.

www.geo-web.org.uk

March 2010

Group for Earth Observation

Cubical Quad for APT Reception(The EFJ Beam)
Mike Donnachie MM0EFJ

GEO Quarterly No 25

My location has a steep hill to the south which blocks off
the signals a little so I am unable to receive a signal
further than the south of Spain on a good pass but can
get pretty far to the north.
Some of my images now show the eastern seaboard of
Canada which was the subject of Quarterly Question No
23 which I was too late to submit at the time.

I read with interest the recent article in the December
2009 edition of GEO entitled “Which is the Best Antenna
for APT Reception?” I thought I would participate in theensuing discussion and put forward my own findings.
Having purchased a RX2 some time ago complete withpreamp and home made QFH antenna I set up thesystem and was disappointed with the significant amountof pager interference I was encountering.
I did a bit of research on various homemade antennas
including turnstiles etc to look for an alternative.
At the time I had been doing a bit of experimentation andconstruction of multi element cubical quads for 2 metre(144 MHz) operation.
At this point, since not all Weather Sat enthusiasts areradio hams, perhaps I should digress and explain what a
cubical quad antenna is. In simple terms it is adirectional antenna made up of one radiating element,
one reflector element and optional director elements
which concentrate the directivity of the antenna, generally
the more elements the more directivity. Each element iscomposed of a 4 sided square, hence the term quad.
Construction details including sizes etc can be found at
http://www.softcom.net/users/kd6dks/quad.html which
gives a very good calculator for element lengths. This
however is only a guide and each antenna will require a
bit of experimentation with minor variations to element
lengths to tune to the correct frequency. For those of you
wishing to construct a quad antenna I would advise you
to beg borrow or steal an Antenna Analyser such as a
MFJ 259 or 269 which makes quick work of the tuning. I
constructed my Quads using copper wire (2.5 sq mm
cross section) with spreaders made from 6mm wooden
dowels and boom of 25mm square timber. No balun isrequired and the driven element of the antenna can beconnected direct to the coax
Anyway like many of my efforts on Ham Radio projects
things did not go entirely as planned. I had adjusted thedriven element size for lowest SWR and the antennae
seemed to work well. I should point out that all myantennae are in the loft of the house and none visible toneighbours !
I noticed however that I was receiving, and transmitting,strong signals off the side of the beams, for example I
found I could get an APRS signal easily into ISS when it
was South of me and my beam pointing East !!
It then occurred to me that, if this was the case, a
Cubical Quad tuned to 137 MHz, and pointing straightup and down might work on the APT weather sats.
I set about construction, and in order to further reducethe directional gain I only made a 2 element unit.
I set this up and, would you believe it, excellent signals
with the antenna in the loft and pager noise virtuallyeliminated !

www.geo-web.org.uk

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GEO Quarterly No 25

Group for Earth Observation

John Tellick
This Envisat image
dating from November
2, 2009 captures a
depression covering
most of the North Sea.
Depressions arestorms that rotate
around a central areaof extreme lowpressure, pulling in air
from the surrounding
regions. Winds begin
rushing inwards andupwards around thislow-pressure zone
and, as this air rises, itcools to form clouds
and precipitation.
The area of low
pressure developed
overnight to thesouthwest of Britain
and heavy rains
spread throughEngland (visible),
Wales (partly visible),
Northern Ireland andScotland (partly
visible) on thefollowing morning.
Scotland was one of
the worst hit areas,
with 13 flood warnings
issued. According to
the UK Met Office, 53
mm of rain fell in the
Scottish city ofAberdeen in justtwelve hours, nearly
three-quarters of themean total rainfall forthe entire month.
The various colours ofgreen visible in thesea around the River
Thames in England
are due to sediments
being transported in
the water.
Envisat's Medium
Resolution Imaging
Spectrometer (MERIS)
optical instrument
acquired this image
working in Full
Resolution mode toprovide a spatial
resolution of 300 m.

Image: © 2009 - European
Space Agency.

8

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Group for Earth Observation

GEO Quarterly No 25

This Envisat MER_FRS image showing the Strait of Gibraltar was received by Francis Bell’s ground station on 4th February
2010. It is a raw unprocessed image using channel 12 data. The full data set offers great scope for further processing,enhancement and colouration according to preferred objectives. See back cover for an example.
Image courtesy ESA

www.geo-web.org.uk

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March 2010

Francis Breame - vf1012@btinternet.com

Dundee: January 28, 1975. It was wet andvery cold. I was standing on the edge of aroof pulling on a rope, but thoroughly
enjoying it. This memory was brought backto me recently when I discovered some oldphotographs.
Many of you will know of the Dundee
University weather satellite receiving
station and archive atwww.sat.dundee.ac.uk. Although they
have been running a continuous archive
since 1978, the station had actually been in
operation for some time before that. I firstencountered it in 1975 when I was a finalyear electrical engineering student at
Dundee. I managed to get allocated a finalyear project on the station and this waswhen my interest in meteorological satellite
reception first started. It has continued, withlapses, ever since.
Up until then the station had been
operating on 137 MHz APT only, using alarge helical antenna, usually tracked byhand (figure 1). Dundee had recently
supplied a ‘home-made’ APT system to the
Met Office (the ‘Met Box’ as it was known),
and the local station was very similar tothis. When I was there, much of the drive
was to equip the station for high-resolution
HRPT reception from the VHRR instrumenton the new NOAA 4 satellite, launched in
November 1974.
Figure 2 - An infrared NOAA-3 APT image from a pass at 10:45 UT on October 24, 1974

Figure 1 - The HRPT and APT antennae

The station was entirely hardware based;
there was no idea of using software forrunning the station or processing theimages. Indeed, the only computer
involvement was an occasional batch run
to generate satellite predictions. If you
wanted to adjust how the images looked,
you had to provide hardware to do it.
Nearly all the actual image chain was
analogue, although digital electronics were10

creeping in: for instance, in sync pulse
detection and clock generation. The only
image processing which used digitaltechniques was the lineariser, whichremoved the distortion caused by thecurvature of the Earth, such as is now doneby the ‘Save with correction’ function ofDavid Taylor’s HRPT Reader. This
employed a 1024-byte shift register (a lot ofstorage in those days) read-out at a
variable clock rate held in a PROM (forgive
me for going on about this bit but myproject was in this area).
Figure 2 shows an APT infrared image fromNOAA-3 dating from 1974. A depression as
usual, but at least it shows that my projectworked, as the scan is linearised between
the black lines.
No commercial equipment was available.
The station may have been professional,
but virtually everything was hand-made in
the lab, providing a good source of student

www.geo-web.org.uk

projects. The only storage possible was torecord the analogue baseband signal. A
good-quality domestic tape recordersufficed for APT; however, HRPT required ahigh-speed instrumentation recorderscrounged from somewhere.
The only means of output, since no TVscan displays existed, was an exnewspaper wire-photo machine about thesize of a small upright piano. This started
life with, I think, the Daily Record
newspaper in Glasgow. Because of its
origins, it had very high resolution, andproduced excellent results. However, to use
it required a light-tight cassette to be loadedwith photographic paper in the darkroom,
followed by a return trip to develop it before
you could see the results of a pass. There
was no looking at the image as it wascoming in and tweaking it. Because of this,we depended a good deal on tape playback
to get things set up properly.

March 2010

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GEO Quarterly No 25

Figure 3 - The main station hardware

Figure 4 - The wire-photo machine

Figure 6 - Lifting HRPT antenna dishFigure 3 shows the main stationequipment: the APT receiver, antenna
controls, and recorder are in the right handrack with the processing electronics in thecentre rack. The left hand rack contains the
HRPT equipment. Figure 4 features thewire-photo machine (in the foreground) witha rats-nest of rear rack cabling behind.

It looks from Dundee’s web site as though
this dish is still in place, although now
surrounded by many more.

record the event. Finally, everything was inplace. HRPT reception started very
successfully and has continued ever since.

January 1975 was cold and wet in Dundee.
The crane arrived first to place the dishmount (figure 5) engineered by the
Mechanical Engineering Department,
followed by the dish itself (figure 6).

Not long after I left Dundee, I set up an APT
station at home, cribbing some of thecircuits. It shows the rate of change indigital electronics in the 70s and 80s that
this was based on a pair of Motorola 6800
8-bit microprocessors and relied on
software (written in assembler code) for
most of the signal processing. Now, ofcourse, we only have to plug a few bits ofelectronics into a PC, install a lot ofsoftware, and we have a constant flood of
meteorological data. Not really as much fun
as pulling ropes with frozen hands, though!

Today, anyone can put up an 80 cm Kuband dish for EUMETCast reception for a
few pounds, or your local satellite TV
installer will quickly do it for you. Things
weren’t quite so simple then. It wasdeemed necessary to use something like a
10 to 12 foot S-band dish for HRPT. A
second hand one duly arrived fromsomewhere (perhaps a donation from theoil industry) and had to be mounted on theroof of the Electrical Engineering
Department. Fortunately, this has a towerlike lift motor room on top, which, whenreinforced, acted as a good mounting base.

Figure 5 - Lifting the HRPT antenna base

At some point it was decided that
temporary counterweights were needed.
Fortunately, these were readily available in
the form of students, including myself, on
the ends of ropes. So what if a few went
over the edge—plenty more where theycame from. No health and safety to worry
about then (figure 7).
My main memory of that day is being
frozen solid but very pleased to be
involved. Even Grampian TV arrived to

Do you have any recollections from theearly days of weather satellite
reception? If so, I’m sure that the editor
would like to hear from you.

Figure 7 - What health-&-safety officer? (River Tay in background)www.geo-web.org.uk

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GEO Quarterly No 25

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March 2010

Francis BellThe following text briefly relates my firstencounter with ESA / ESRIN's EnviHam project for the live reception ofimages from the largest earth
observation satellite ever launched,
Envisat. I hope this text includes
enough information and guidance forothers who may wish to participate inthis project.
I was initially surprised and ultimately
delighted to receive a telephone call in
mid October 2009 from Stefano
Badessi. Stefano was calling from
Frascati, Italy.
I know that the European Space Agency(ESA) have a centre at Frascati which islocated a few miles south east of Romebut I was not expecting a personal
telephone call from them. I had not
spoken to Stefano before and I knew
nothing about the project he was about
to explain. He first told me that he had
obtained my telephone number fromthe GEO web site. About two minutes
into our conversation I became quite
excited because Stefano was explaining
to me a new ESA project which would
allow interested users to directly accessimages from the dedicated earth
observation satellite Envisat.
The data / images would not originate
from the weather satellites I am used todealing with but from a dedicated earth
observation satellite carrying multispectral imagers giving
a potential
ground resolution of 300m instead of
the 2-3 km resolution generated byweather satellites. In other words
images with about ten times moreground detail than weather satellites.At
present we can only receive a small
selection of Envisat data in the high300m resolution. Of course I wasinterested in what Stefano was tellingme and I quickly said so.
I did know something of ESA's Envisat
satellite because I attended a lecture
given by Mark Doherty who is based in
Frascati. His lecture was part of the
British Science Festival last September
and the venue was University of Surrey.
I didn't know at that time I may be able
to receive images from the satellite Mark
Doherty was describing.
Stefano quickly explained to me that asubset of the imaging satellite's data12

was being relayed to user stations in asimilar way to the EUMETCast system.

paper copy of this form signed it andthen posted it to Stefano in Frascati.

That is, live Envisat satellite data
which is received at the Frascati
ground station Italy or their groundstation in Kiruna Sweden is quickly
processed and then a subset being
disseminated via a commercial
communication satellite. Strictly
speaking the data is not live but may
be just a few minutes old just like weare used to with EUMETCast.

However, to expedite my participation in
the new user group I also scanned thisand other forms and when completed I
emailed them to Frascati.

Stefano told me the project Envi-Ham
had been initiated to make satellite
data more readily available tointerested competent individuals,
technical user groups and those witheducation interests. A decision had
been made by ESA to issue 100
licences in the first instance: 42
licenses had already been issued butthat still left scope for others toparticipate in the project. I was toldthat provided I complied with theiruser conditions and had a suitableground station I was welcome to join
the Envi-Ham project completely freeof charge.
Before our conversation ended I gave
Stefano my email address which hesuccessfully tested with some brief
messages even before we had finishedour conversation. Having establishedthe email, link he promised to send me
background literature and technicaldetails relating the Envi-Ham project.
Within 24 hours I had this information
which I printed thus creating my new
Envi-Ham user file.
The papers not only contained
technical details of the Envi-Ham
projectbut
also
contained
questionnaires relating to the groundstation I would use. Very importantly
there was a document which I had tosign agreeing to the conditions
attached to the project. The form was'Specific Terms and Conditions' Ref
TIA-ESRIN-0906-007.
These
conditionwereverystraightforward - use the data only for
scientific, technical, self training or
education use and don't sell theimages for commercial gain. I printed a

www.geo-web.org.uk

A brief note here about references to auser station Internet connection towhich the technical papers referred.
Within the project there is a facility torequest retransmission of missed
packets of data. I understand why thismight be important for researchestablishments following critical image
patterns but for myself it represented
anunnecessary
complication.
Subsequent enquiry to Frascati
revealed that the Internet link is notnecessary for the passive reception
which I anticipated using. Just to
confirm this issue you do NOT need an
Internet connection to passively receive
Envi-Ham data.
Within a few days of my conversation
with Stefano I was issued license
number 43 together with the necessary
software to receive the Envi-Ham data. I
decided to use a computer which I had
previously used for EUMETCast
reception and dedicate it Envi-Ham
data. I had already installed and usedsuccessfully the DVB World receiverand its software on this computer. I
installed the new software into a DDS
folder which the software created forme. DDS is the abbreviation for ESA /ESRIN's 'Data Dissemination System'
for this Envi-Ham projectAs with much of this project I was on alearning curve and in this particularcase it related to the MAC address
which my DVB World receiver used tocommunicate with the computer. The
MAC address is a 12 digit hex number
and is displayed on the menu screen of
the DVB World software. This number
had been transparent to me before but
apparently the first six digits relate to
the external device and the second six
relate to the computer address.
Whatever the detail, I was asked by ESA
to provided this unique address.
This was a security measure so that thelicenses they issue together with theirMarch 2010

Group for Earth Observation

GEO Quarterly No 25

This is an Envisat MER-FRS image of the River Plate estuary. It shows the potential for processing the raw data received in
the Envi-Ham project into a high resolution colour image. This image is also part of the Quarterly Question by trying to
Image courtesy ESA
identify the town of Rosario, Argentina.

Screenshot showing with the smaller swath width of Envisat certain locations can only be captured once every 3
days.BEAM-Visat-worldmap-20091113+14+15

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GEO Quarterly No 25

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March 2010

software can only be used on the licensee's computer.

This measure is understandable thus preventing theuncontrolled distribution of the Envi-Ham's materials. I duly
sent Stefano the MAC address used by my system andpromptly received an email file with my MAC key which I
copied into my DDS folder. The 'DDS.key' file which ESA sent
to me encoded my MAC address and it was necessary tolocate this file in the same folder as the 'Site.key' which waspart of the software package which I had already received. At
this point my system was ready to receive Envi-Ham data via
the communications satellite they were using
The details of the satellite used by the Envi-Ham project are
give in their literature.
Satellite name. Eutelsat W2A:- Note this is a new satellite for
the Envi-Ham project not W1B
Position 10 degrees East
Transponder F3
Frequency 12.621 GHz
Polarisation Horizontal
Symbol rate 5732 k Sym/s
FEC 5/6
PID 230 and 231 decimal
These details need to be entered into the DVB World software.
It should be noted that the pattern of data entry is identicalto EUMETCast reception from Eurobird 9 at 9 deg E only thevalue of the specific parameters are different.

Envi-Ham 1M dish with 0.2 LNB for Eutelsat W2A
10 degs Eastestablished and my system is now receiving Envi-Ham data
most of the time. The location of Eutelsat W2A carrying theEnvi-Han signal is only one degree displaced from Eurobird
9 at 9 deg. E carrying the EUMETCast signals. This is bothan advantage and a nuisance. The strong signal for Eurobird
9 can be used to initially align the dish to just one degree from
Eutelsat W2A but also there may be some overlap of signals,
which without a sensitive meter may make it difficult to
identify the weaker Eutelsat W2A signal.
However, trial and error and much meter reading established
Envi-Ham reception.
Computer software

The computer
The Envi-Ham project do give guidance for minimum
specification for a computer. I think the specification is quitemodest. They suggest:Pentium IV 1.8 GHz or better
RAM 512
Lots of memory and disc space
Operating system - Windows 2000 Professional Server, XP
Home Professional or Vista.
I expect Windows 7 will be compatible.
The Dish!
There are statements in the Envi-Ham literature that a 1m or
1.2m diameter dish will be needed for satisfactory signal
reception and they also recommend a short cable run fromthe dish to the computer. I have noted in the past that
EUMETSAT recommend a dish size of 80 / 85 cm for
EUMETCast reception from Eurobird 9 but I haveconsistently managed perfect reception on much smaller
dishes.
Arrogantly or optimistically I thought I would manage EnviHam reception using a dish smaller than recommended but
this turned out not to be the case. The map showing thefootprint of Eutelsat W2A indicates my location, 30 miles
south west of London, is within the main footprint of thesatellite with a signal strength of 48 dBW, I noted the signal
strength is less for northern England and Scotland. I started
to experiment with an 80 cm dish but the results were at best
marginal or negative. My response was to buy 1m dish from a
local supplier and was given / lent a 0.2 db LNB. I have theadvantage of having access to my experimental dish close to
my house front door on a small paved area at ground levelalso benefiting with a clear view of the southern sky. Only 10
m of coax was need to connect the LNB to my DVB World
receiver. With much experimentation and help from friends
with sophisticated signal meters a satisfactory signal was

14

Unlike the EUMETCast data packets I am used to receiving
and see instantly displayed on the screen the Envi-Ham files
are not instantly displayed on the computer monitor. They are
stored as data files for later display and processing.
Somebody clever at writing software may be able to generateinstant image displays but for the time being I am using thevery sophisticated display software supplied to me by ESA.
The display software is called Beam/VISat which is a 'Toolbox
for Analysis and Processing Earth Observation Data' .The
Beam display software has many facilities and I am on a
sharp curve learning using its many sophisticated menus.
For the most part I am just content to display certain
segments of the transmitted images which I can recognisefrom coastal outlines or other visible geographical features. Of
course I can resort to reading the latitude and longitude data
but that seems like cheating or the last resort. The detail ofsome of the images I have received is stunning and I'm stilllearning.
If you want to participate in the Envi-Ham project please readthe following carefully.
Please do not make a trivial request to be included in the
project. Before you apply make sure you have a groundEnvi-Ham receiver available from the GEO shop

www.geo-web.org.uk

March 2010

Group for Earth Observation

station which will be capable of receiving Envi-Ham signals
from satellite Eutelsat W2A at 10 deg. E.
You will need a 1m dish or larger and a clear view of thesouthern sky. You should be able to demonstrate acommitment to the project, that is, don't clutter up ESA's
administration with casual license requests.

GEO Quarterly No 25

ERSIN Overview

If you decide you want to participate in the Envi-Ham projectcontact Stefano Badessi at ESA. Email Stefano at
Stefano.Badessi@esa.int
orthe'Envi-Ham
Project
Coordinator' at tta@esa.int

ERSIN is the European Space Agency establishment locatedin Frascati near Rome. The centre was created in 1966. One
of its chief tasks is the utilisation of the data obtained
through the earth observation missions performed by ESA's
own satellites and those of other countries through the
Earthnet programme. To carry out this task ERSIN operates
ground infrastructures consisting of some 30 data reception
stations scattered around the world. Received data is filed
before it is processed and distributed to final users on acommercial or scientific basis. In the framework of theEuropean earth observation programme, ERSIN is also
responsible for the development and operations relating to
the Envisat satellite's Payload Data System. This mission
with its complex payload of advanced instruments
transmits earthwards an enormous quantity of data whichmust be processed for various fields of application. Envisat
was launched in 2002 and is the largest Earth Observation
satellite ever built. It was designed to explore land surfaces,
the earth's atmosphere, oceans and ice caps.

Postal address for your project conditions form is:-The Envi-Ham Project Abstract

Stefano Badessi
Application Engineer ERSIN Office and Labs
European Space Agency ESRIN
Via Galileo Galilei s.n.c.
1-00044 Frascati ( RM )Italy
Try to establish as much background to the Envi-Ham projectby visiting their web site www.dwlinkdvb.esrin.esa.it/DDS/
and www.envisat.esa.int

Some categories of non-professional users such as
Education, Radio Listening and Earth Observation
Enthusiasts have shown interest in receiving in near realtime Envisat data via the Data Dissemination System(DDS).
The major objective of the Envi-Ham project shall be widen
the knowledge of ESA's Earth Observation missions among
non-professionals and retrieve possible observations doneby users and to coordinate in a single non-commercial
project a whole group of users.

Please can I repeat; research as much information as possible
about ESA, Frascati, Envisat and their DDS BEFORE making
a license application.

The Envi-Ham project principal investigator is within ESA
while others shall appear as co-investigators but will sharethe same obligations about the use of the data.

I did say in conversation to Stefano Badessi that GEO would
not overwhelm ESA with license applications so only apply if
you feel committed to receiving the Envi-Ham data. However,I think there may be a trade off here where both the EnviHam licensees and ESA are both winners. I think ESA would
like their data and the earth image products generated by the
project to be more widely distributed and in the very best
tradition of GEO and amateur involvement in cutting edge
technology, ESA may welcome participation by a broadly
based skilful, imaginative none commercial individuals orgroups.

Envisat distributed data are from instruments which may
easily generate a viewable image, with freeware software. At
the moment ESA is disseminating the global Envisat datafrom the multi-spectral instruments Medium Resolution
Imaging Spectrometer ( MERIS RR, AATSR) and the MERIS
full resolution (300m) sensed over the European Continent.
As a condition to participate every co-investigator must
declare a competence to autonomously carry out theactivity. The cost of the receiving ground station will beborne by the co-investigator.
ESA's undertaking is to provide the project with a limited
number of free licenses for DDS reception, necessary
software and an associated decryption key.

You will need a suitable receiver either as a PCI card or aseparate boxed receiver. I use a DVB World receiver. This
receiver is available from our GEO shop at £55.00. Other
receivers such as a TechniSat SkyStar 2 PCI card should beequally suitable. I expect there are others.
The computer needs to be reasonably up-to-date but need not
be the latest highest spec computer. Say 2.0 GHz processor
and enough memory to store and process the images.

My thanks to the following people who helped me establish aworking Envi-Ham ground station:Stefano Badessi, ESA-ESRIN Frascati - he was a great help inestablishing my license and forwarding necessary software.
Arne Van Belle, The Netherlands for his advice.
David Simmons and John Tellick, Surrey, for the use of theirsignal meters, David Taylor, Scotland, for configuring mycomputer both manually and remotely from Edinburgh.
I will try to report in the next Quarterly the progress I havemade with this exciting Envi-Ham project.

Stefano Badessi replies to the questions I asked in the earlystage of my involvement with the Envi-Ham project. From
my perspective the question were quite innocent I justwanted to learn about the project.
The background and the future of the Envi-Ham project.
The following is the text of a email I received from Stefano
Badessi - Chief Investigator of the Envi-Ham project. He
has very kindly responded to all the questions I asked him.

Francis Bell - Envi-Ham Licensee No. 43
Dear Francis,
I have extracted some notes from an ERSIN Overview, theEnvi-Ham Project Abstract and the answers to the questions
I asked Stefano Badessi in an email soon after I became
involved in the Envi-Ham project. The notes should put into
context the exciting Envi-Ham project run by ESA / ESRIN
from Frascati.

For a general introduction on Envi-Ham I suggest you lookat what we have published on our website:
http://dwlinkdvb.esrin.esa.it/DDS/docs/Public_Docs/EnviHam_abs
tract.pdf

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Envi-Ham project screenshots

The ATS_TOA data has world coverage day and night but has a very small swath widthThis MER_RR data screenshot shows (reduced resolution) has wider swath compared to ATS

16

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Below are answers to the particular questions you asked.
Who has used the data in the past?
The data distributed via the Envisat's Data Dissemination
System (DDS) are the ones originating from the Envisat
instruments. The system was implemented to respond a
mission requirement relating to the fast data disseminationand has been active since the very first data was generated. I
still remember with emotion in 2002 the night we received at
ESRIN Frascati the first SAR data acquired at Kiruna.
Initially data was only circulated among the institutions
involved in instrument Commissioning and CalibrationValidation (Cal-Val) activities.
http://www.esa.int/esaCP/ESA14LF18ZC_Italy_0.html Afterthat initial phase, we have opened DDS dissemination via analternative electronic
dissemination means for users, sending those systematic
data which would be required by a sufficient number of users
thus justifying the use of a satellite channel.
Why was the project Envi-Ham started?
The project started when I had the opportunity to talk with an
Italian enthusiast Alessandro IK5EHI during an AMSAT-I
meeting which was held at ESRIN in 2008. Up to that moment
we had only sporadic cases of non-professionals receiving
DDS data. Given the enthusiasm shown by Alessandro andthe support received by Francesco
Fontana, we have elaborated a sustainable approach tosupport a new category of non-professional users, which has
led to the Envi-Ham project.
What are the objectives of the project?
The major objective of the Envi-Ham project shall be to widen
the knowledge of ESA's 7Earth Observation missions among
non-professionals, to retrieve possible observations achievedby those users and to coordinate in a single non-commercial
project a whole groups of users which otherwise would beapplicant for individuals ESA-approved scientific (CAT-1)
projects.

GEO Quarterly No 25

about the quality of the service. I have to acknowledge the factthat we have been triggered by the early Envi-Ham users toinvestigate one subtle interference which was causing small
periodic signal degradations of about 1 dB.
This was eventually identified and resolved by Eutelsat. I
consider the Envi-Ham users as a kind of litmus test of the
DDS echo environment.
Judging the success of the Project
Today, 2nd December 2009, we have 48 registered users
which are mostly located in Italy, which is justified by theincidental entry points in the user community. I tend not torate this figure in term of success, but I am rather looking at
the quality and satisfaction of the user community comparedwith the sustainability of the project. I have to say that in fact
the project, although useful in the development of the DDS
system and supported by ESA, is carried out by me in the roleof Principal Investigator on a completely voluntary basis.
Consequently I have mixed feelings when I look at the targetof the 100 users, I would extremely glad as it means that the
project is well built and of interest, but I would be a bit
concerned about the extra resources that we would need toinvest in the project. However, I do not expect problems inextending the number of free licences beyond the current 100
limit.
How long will Envi-Ham project run?
I expect it will last as long as the DDS. DDS is today linked toEnvisat instrument data distribution and the Envisat
mission has been extended till 2013, but we are alreadyplanning the DDS extension for the future Sentinel satellites(DDS - Second Generation or DDS-SG). Also the system isinherently multi-mission capable, and I can not exclude thepossibility that we may decide in the future to introduce inthe stream other missions' instrument data.
(screenshots courtsey Arne van Belle continue on page 29
North Sea colour image page 32)
Envi-Ham Additional notes
Arne van BelleI have read the draft of Francis Bell's article about Envi-Ham
reception. I think this additional contribution may help
beginners who wish to engage in this Envi-Ham project.

Dissemination via Eutelsat W2A
We started the dissemination on Eutelsat W1 located at 10 E
which has been now replaced by Eutelsat W2A in the same
location. The selection of the satellite was based on acompromise between satellite coverage extension and satellite
power in order to use commercially available technology forthe anticipated receiving ground stations.
What feedback would you like to receive?
The EnviHam project is one of the registered the CAT-1
project (Nr. 6837) as it can be seen from the ESA Principal
Investigators web site http://eopi.esa.int/ and all projects are
due to prepare periodical reports on the activity. I am acting
myself as Principal Investigator, and all the other registeredusers are qualified as Co-Principal Investigators. At the timeof writing this note, users are about to receive a request to
provide feedbacks for the 2009 activities. Basically they will
be asked to put together some global indicators about theiractivity indicated by the number of images received, thenumber of receptions which failed and the number of images
successfully processed. Also we will be asking for the best
images that users have elaborated so far. However, from theservice point of view
I am constantly looking forward to receiving information

My recordings from passes over Europe show a delay between
actual satellite pass and reception of Envi-Ham files to beabout 1.5 to 2 hours minimum. So "may be just a few minutes
old just like we are used to with EUMETCast." is a bit too
optimistic. To prevent disappointments I think it should be
mentioned that we only receive a small selection of Envisat
data in the high 300m resolution also with the smaller swath
width of Envisat a certain location can only be captured once
every 3 days. This can be seen in screenshot BEAM-Visatworldmap-20091113+14+15.jpg
I have experimented a lot with the complex BEAM-Visat
software. Using a different approach I have been able to get
more insight in the location of received data by using
wildcards when opening data you can open all files received
that day. When activating the world map function, all opened
files are shown in a map and this takes away a lot of theguesswork! Using the number shown in the segment on the
map I create a view from this file (see ENVI-HAM screenshots)
At the time of writing, early February 2010, I have noticed
considerable variations in the Envi-Ham signal strength tothe point where I miss many segments of data. I believe
experiments and changes are being undertaken by ESA at thedata uplink stations in Frascati, Italy and Kiruna, Finland
which they are using for this project.

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Arne van Belle
This article is based on a Lecture that I gave at the GEO
symposium at Guildford July 18 2009.
Lightning provides one of nature's most spectacular displaysof energy. Though fascinating to observe, lightning can be
dangerous, deadly and damage our equipment.
Lightning is formed in Cumulonimbus clouds. The upper
portion of these clouds usually show the shape of a half anvil.
On average, an individual cumulonimbus cloud will take only
one hour to take shape, grow and dissipate. The averagethunderstorm is approximately 10 kilometres wide andtravels at approximately 40 km/h and can be seen on satellite
images. Using
David Taylor's MSG Animator and Ton
Lindemann's Colour table I have composed stunning
animations of heavy thunderstorms over the Netherlands
using Meteosat-9 HRIT data.
Not all cumulonimbus clouds bring thunderstorms; somebring heavy showers or hail.
The average thunderstorm has a very turbulent environment.
Strong updrafts and downdrafts occur with regularity, even
within small thunderstorms. The updrafts transport water
droplets up into the cloud, while ice particles descend fromthe frozen upper regions of the cloud. As they do, they bumpand collide with each other. Through this process, electrons
shear off of the ascending water droplets and collect on thedescending ice particles. This generates an electric fieldwithin the cloud, with the top having a positive charge, andthe bottom having a negative charge. A thundercloud acts likea huge charged capacitor !
An electric field is also generated between the bottom of thecloud and the surface of the earth, though not nearly as
strong as the field within the cloud. As a result, mostlightning occurs within the cloud itself.

There are several types of lightning:•
Intra Cloud lightning (IC)•Cloud to Cloud lightning (CC)•
Cloud to Ground lightning (CG, only accounts for 10
to 20% of all lightning)
From the CG strikes, 95% are of negative charge from thebottom of the cloud, less than 5% are positive charges fromthe top of the cloud, called "Bolt from the Blue".
A "Bolt from the Blue" is a cloud to ground lightning flash
which typically comes out of the back side of thethunderstorm cloud, travels a relatively large distance in clear
air away from the storm cloud, and then angles down andstrikes the ground. These lightning flashes have been
documented to travel up to 15 kilometres away from thethunderstorm cloud.
"Bolt from the Blue" lightning flashes are very dangerous, as
they "appear" to come out of the clear sky and are more
powerful than negative CG strikes.
This is why it is dangerous to be outside when thunderstorms
are in the region, the lightning can, and does, strike many
miles away from the thunderstorm cloud itself. It is a goodidea to wait 30 minutes or more after the rain ends before
resuming outdoor activities.
The lightning strikeIn the world of electricity, opposites attract and insulators
inhibit. In a developing storm cloud there is an electric
attraction (i.e. electric field) between its top and bottom. As
the charges separate within the cloud, the field strength
grows. The greater the magnitude of separation, the stronger
the field, and the stronger the attraction between thepositively charged top and the negatively charged bottom.
However, the atmosphere is a very good insulator, so a
tremendous amount of charge has to build up before
lightning can occur. When that threshold is reached, thestrength of the electric field overpowers the atmosphere's
insulating properties, and lightning results.

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While lightning occurs instantaneously, it consist of several steps:

STEP 1)
A CG lightning discharge typically initiates inside the thundercloud. When enoughelectrons collect in the bottom of the cloud, a very faint, negatively charged channel,
called the stepped leader, emerges from the base of the cloud.
Under the influences of the electric field established between the cloud and theground, the leader propagates towards the ground in a series of luminous steps about
50 meters in length and 1 microsecond (0.000001 seconds) in duration, in what canbe loosely described as an "avalanche of electrons".
Between steps there is a pause of about 50 microseconds, during which time thestepped leader "looks" around for an object to strike. If none is "seen", it takes anotherstep, and repeats the process until it "finds" a target. It takes the stepped leader in theorder of 50 milliseconds (0.050 seconds) to reach its full length, though this number
varies depending on the tortuosity of its path.
As the stepped leader's channel approaches the ground, it has a very strong electric
potential of about 100 million volts with respect to the ground (though this can be as
high as a billion volts)
STEP 1

STEP 2)
When the stepped leader approaches the ground, its strong, negative electric field
repels all negative charge in the surrounding ground, while attracting all positive
charge. This induces an upward moving positive charge from the ground and/or
objects on the ground.
When this positive charge collects into a high enough concentration, they form boltsof ground-to-air lightning known as streamers. When one of these positively charged
streamers contacts the tip of a negatively charged leader, (anywhere from 30 to 100
meters above the surface),
the following three steps occur:

STEP 2

STEP 4

STEP 3The leader channel's electric potential is connectedto the groundAll other branches of the leader channel cease further
propagation toward the ground, and all negative charge
within these branches starts flowing to the ground throughthe newly established ground/cloud connection.

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STEP 5)
An electric current wave then propagates up the channel as a bright pulse. This
discharge process takes less than 100 microseconds and is called the return stroke. It
produces almost all of the luminosity and charge transfer in most cloud-to-groundstrokes.
The lightning is actually travelling from the ground into the cloud, but because theprocess takes place so quickly, to the unaided eye it appears that the opposite is true.
Electric charge flows up the channel behind the wave front and produces a ground level
current. This current has a peak value of about 30,000 amperes, though it can be as
high as 300,000 amperes. It takes about 1 microsecond for the current to reach its peakvalue, and about 50 microseconds to decay to half that value.

STEP 5
STEP 6)After the current has ceased flowing up the leader channel, there is a pause of about
20 to 50 milliseconds. After that, if additional charge is still available in the cloud,another leader can propagate down the established channel.
This leader is called a dart leader because it is continuous instead of stepped. Dart
leaders are what give lightning its flickering appearance. Not every lightning flash willproduce a dart leader, as sufficient charge to produce one must be made available
within about 100 milliseconds of the initial stepped leader.
The negatively charged dart leader will induce a new, positively charged return stroke
from the ground. The peak amplitude of the current usually decreases as additional
dart leaders are produced. As a consequence, the induced field changes are also
smaller in amplitude and have a shorter duration than those of the first return stroke.
The combination of each leader (stepped and dart) and the subsequent return stroke is
known collectively as a stroke. All strokes that use the same cloud-to-ground channel
constitute a single cloud-to-ground flash.
A flash can be made up of a single stroke, or as many as tens of strokes. (The highest
number of strokes in a single cloud-to- ground flash ever recorded is 47.)
All these steps take place within half a second !
STEP 6

Communication towers are hit frequently:

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In the United Kingdom the average annual thunderfrequency is less than 5 days in western coastal
districts and over most of central and northern
Scotland, and 15 to 20 days over the east Midlands
and parts of southeast England. There is relatively
little seasonal variation on the western seaboard but
elsewhere summer is the most thundery season.
Last June a lightning strike killed 16 cows in a fieldin East Lothian.
That same week a man in Lincolnshire was struck bylightning as he was moving some sausages on abarbecue. He suffered burns to his arm but escapedwith his life after the freak accident.
According to the Met Office : The chances of being
struck by lightning are about one in three million,
higher than your chances of winning the jackpot in
the Lotto, which is one in 14 million!
All steps caught in one photo, a "lucky shot" !

Although statistical data does not show anincrease of the number of thunder days per
year, NASA scientists have developed a new
climatemodel
thatindicatesthat
thunderstorms may become more common
and more severe as Earth's climate warms.
Instead of counting the number of thunderdays per year, measuring the number oflightning discharges over a year will provethat thunderstorms are getting morecommon and severe.
By the way, it is a long-standing myth that
if something is hit by lightning, it will bespared a second hit. The Empire State
Building in New York has been struck bylightning as much as 48 times in one day
and 15 times within 15 minutes, but they
have lightning conductors to carry theelectricity harmlessly to the ground.

In the Netherlands we have 22 to 34
days of thunder per year.
But May 25th they counted over
68.000 lightning strikes in 24 hours
which is registered as only 2 thunderdays !

The internals of an APC SPD

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Indirect lightning:
Electromagnetic fields generated by the lightning flash cancause indirect lightning damage. Indirect lightning does notcarry the severe punch that direct lightning strikes do. But
the induced voltage and current can travel kilometers andcan enter buildings through telephone wires, mains wires,
metal pipes that are often buried. It is a myth that only
overhead lines can carry lightning surges into your home !
A nearby lightning strike can cause a ground potential rise(GPR) that can cause damage to all grounded equipment inyour home.

An SPD from APC
protecting Mains andphone line, fault andearth indicator lights

Even indirect lightning surges can cause serious damage tocomputers and other home electronics. People have been
injured by indirect lightning while using "wired" equipment !
Surges caused by indirect lightning can travel for tens ofkilometers along lines and can enter your home unnoticed.
These surges can shorten the lifespan of "wired" electricalequipment. Nowadays most equipment does not have an
isolating Off switch anymore. Instead it is always connectedto the mains and running in stand-by mode !
Without visible arc damage (as is seen after a direct lightning
strike), insurance companies are generally not convinced that
failure of your equipment was caused by lightning !

SPDs are best used as close to your equipment as possible.
They are available for power, telephone, network and coaxial
lines.

How to protect against lightning damage:
Disconnecting all cables connected to your equipment gives
best protection but this is not practical.
Although nothing can be completely protected from thedamage caused by a direct lightning strike, we can take steps
to prevent damage from the more occurring indirect lightning
surges.
To minimize chances of a direct lightning strike, do not mountyour antennas or dish higher than required. But even if you
mount them well below the surrounding buildings, there is no
guaranty it will never be hit ! Only an external Lightning
protection system can lead a lightning bolt safely to groundwithout it causing damage to your home.
External Lightning protection systems consists of lightning
collectors (lightning rods), multiple down conductors and agrounding system consisting of multiple earth electrodes .
These systems are expensive and must be professionallyinstalled an maintained, they will not prevent your building
from being struck. They actually increase it by making yourhouse taller. The purpose of the lightning rod is to direct thecurrent from the lightning to the ground along a preferredpath instead of into the house. However, this works only if therod is connected to the ground with heavy gauge wire.
Only in high risk scenarios you see these systems applied likehigh towers or buildings, public buildings, data centers orother sensitive equipment labs or factories handling volatile
products.
But additional measures are still required to prevent
induction in power lines inside the building.
Surge Protection Devices:
Regular fuses, circuit breakers and residual current circuit
breakers are much too slow to detect surges. Surge Protection
Devices act very fast and prevent surges from entering yourvaluable equipment.
In addition to the lightning threat, SPDs also protect against
surges created locally by switching large inductive loads orgas igniters.

22

A simple mains-only SPD withfault indicator

But be careful ! Older or badly designed Surge protectors canbe a fire hazard. Surge suppressors manufactured in the US
before January 1998 and cheap Chinese ones often lack athermal fuse. Without this fuse an SPD can start a fire when
hit by too many surges.
SPDs consist of multiple Metal Oxide Varistors blue or yellow
disc shaped devices ( in the APC they happen to be yellow),sometimes combined with Spark Gap Arrestors (gas filled
white ceramic tubes).
MOVs have a precise trigger voltage and can handle surges up
to 8000 amperes each.
Spark Gap Arrestors contain a gas filled spark gap that arcs
at a less precise set high voltage.
But MOVs wear out if they frequently have to act or when thecurrent is above rated or stays on too long. A worn out MOV
will heat up, even if there is no surge anymore, and finallyburn or explode.
That is why an additional 1 Euro thermal fuse should be
included in the design ! This fuse disconnects the MOVs andyour valuable equipment from the mains if they heat up toomuch

The internals of an APC SPD (see colour image above)
consisting of fast fuse, reset able fuse and thermal fuse(black cylindrical component with yellow bead placed in
between the yellow MOVs)
Underwriters Laboratories now requires that SPDs shouldwithstand a 2 fold over-voltage for at least 7 hours without
igniting a fire. Look for UL 1449, 3rd Edition listing.
Good SPDs have a control light that signals when one of the
MOVs is worn out. Some also warn when a proper ground is
missing.
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GEO Quarterly No 25

Group for Earth Observation(continued from page 22)SPDs are most effective if they have a proper groundconnection. But a surge can trigger your Residual Current
Circuit Breaker.
When your RCCB is triggered multiple times without lightning
nearby, make sure your SPDs are still functional.Althoughmost Uninterruptible Power Supplies already have an SPD
built-in, you won't find them built-in in your expensive PC orflat screen ! So add an SPD to your valuable equipment.
Multiple SPDs can be used spread over the home to protect
multiple zones

March 2010

There are mains SPDs available that can be mounted in yourswitch panel as a first barrier, but this requires a qualified
electrician. You can replace the MOV cartridges yourself ifthey wear out and the indicator shows up red.

Lightning safety guidelines:
If you are caught outside in a thunderstorm:•Always look for an appropriate shelter, building or car, avoid
taking shelter under trees, in or near water or simple sheds
that have no wiring or plumbing to lead away lightning• Stay away from fencing and overhead lines• Do not hold antennas, umbrellas, golf clubs or wear otherconducting materials like earphones/Ipods
There are also telecom line and coaxial line SPDs
available to protect all incoming lines to create a“bubble of protection”• If you cannot find a shelter, find an open spot away and put
your feet as close together as possible and crouch down withyour head as low as possible without touching the ground.
• Never lie flat on the ground, when lightning strikes theearth, it induces currents in the ground that can be fatal up
to 30 meters away from the strike centre.
• Flying a plane in a thunderstorm can be hazardous,
especially in modern planes that have many parts build from
non-conductive composites ! Metal bodied planes are safe as
they form a Faraday cage but damage to instruments orcontrol systems is likely.
If you are at home and a thunderstorm is approaching:• Unplug appliances not necessary for obtaining weather
information as soon as thunder is heard.
• Stay off the phone, about 4-5% of people struck by lightning
are struck while talking on a corded telephone ! If you must
call someone, use a cordless phone or cell phone.
• Stay away from the plumbing like bath tub, shower, kitchensink, washer.
• Stay away from electrical appliances that are connected bywiring.
Protect your equipment against surges, stay inside and enjoy
nature's most spectacular displays of energy !
(Links continued on page 25)

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EUMETCast
On-Line Registration
Guide
If you require to register as a first-time user for
any of the free EUMETCast data streams such as
MSG, NOAA AVHRR, Metop etc., or need torenew an existing subscription, this must be done
on-line.
GEO has produced a step-by-step guide to theentire process at
http://www.geo-web.org.uk/eumreg.html
This guide also contains a direct link to the official
EUMETCast on-line registration form, which canotherwise prove somewhat tricky to locate.

GEO Helplines
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: dsdeans@tiscali.co.uk
John Tellick
Surbiton, Surrey, ENGLAND
Meteosat-8 advice - registering for the various
MSG services, hardware and software installationand troubleshooting. John will also field generalqueries about any aspect of receiving weather
satellite transmissions.
• telephone: (0208) 390 3315
• e-mail: info@geo-web.org.uk
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 forsome time 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
Mike Stevens
Portland, Dorset, England.
Advice offered on EUMETCast (MSG and Metop)and APT.
• email: mikeg4cfz@mypostoffice.co.uk
Guy Martin G8NFU
Biggin Hill NW Kent, ENGLAND
Guy is prepared to advise anyone who wishing toreceive MSG/Metop using Windows 2000 or XP.
Can also help with networking and ADSL router
setup..
• gmartin@electroweb.co.uk
Hector Cintron
San Juan, Puerto Rico, USA
Hector is prepared to field enquiries on HRPT,
APT, EMWIN and NOAAPORT• Phone: 787-774-8657• e-mail: n1tkk@hwic.net
Email contact can of course be made at any time,
but we would ask you to respect privacy by
restritricting telephone contact to the period 7.009.00 pm in the evenings.

Group for Earth Observation

Internet
News/Discussion
GroupsThere are a numerous Internet-based discussion
groups available to weather satellite enthusiasts.
You can join any of these by sending an e-mail tothe appropriate address, with a request to
subscribe. Indeed, a blank e-mail containing theword ‘subscribe’ in its Subject line is all that isrequired. Some of the more useful groups andtheir contact addresses are listed below.
APT Decoder
This is a group where users of Patrik Tast’s
APTDecoder can share information and problems.
http://tech.groups.yahoo.com/
group/APTDecoder/
GEO-Subscribers
This is GEO’s own group, where members can
exchange information and post queries relating to
any aspect related to weather satellite reception(hardware, software, antennas etc), Earthobservation satellites and any GEO-related matter.
http://tech.groups.yahoo.com/
group/GEO-Subscribers/
Satsignal
An end-user self help group for users of David
Taylor's Satellite Software Tools (SatSignal,
WXtrack, GeoSatSignal, HRPT Reader,GroundMap, MSG Data Manager, AVHRRManager and the ATOVS Reader).
http://tech.groups.yahoo.com/group/SatSignal/
MSG-1
A forum dedicated to Meteosat Second Generation(MSG), where members share information about
the EUMETCast reception hardware and software.
http://tech.groups.yahoo.com/group/MSG-1/
METOP
A forum for users of high-resolution AHRPT datafrom the MetOp satellite, available via
EUMETCast.
http://tech.groups.yahoo.com/group/METOP/
AVHRR
A forum for users who download high-resolution
EARS-AVHRR data from the NOAA polar orbiting
weather satellites via EUMETCast.
http://tech.groups.yahoo.com/group/AVHRR/ATOVSA Group for discussions about using ATVOS data.
Data from the whole world is available from
CLASS (www.class.noaa.gov) and for an extended
Europe, via EUMETCast.
http://tech.groups.yahoo.com/group/ATOVS/
Weather Satellite Reports
This group provides weekly reports, updates andnews on operational aspects of weather satellites.
http://tech.groups.yahoo.com/
group/weather-satellite-reports/
WXtoImg
Users of the WXtoImg software package for
capturing and imaging NOAA APT can air theirproblems, discuss its features and ask questions
about it.
http://groups.yahoo.com/group/wxtoimg-l/

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GEO Quarterly No 25

The Copy Deadline for

GEO Quarterly No 26
is Saturday, May 1, 2010
The Editor is always delighted to receive
articles and images for inclusion in GEO
Quarterly. These can relate to any aspect ofEarth Imaging, especially• Technical articles concerning relevant
hardware and 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 toanswerContributions should of course be original and,
where possible, should be submitted to theeditor in electronic format (floppy disc, e-mailattachment, CD, DVD). But of course we will
also accept handwritten and typed copy
should the need arise.
Please note, however, that major articles
which contain large numbers of satellite
images, photographs or other illustrations
should be submitted as early as possible, sothat they can be prepared and made up into
pages in time for publication.
Images and Diagrams
Images can be accepted in any of the major
bitmap formats: JPG, BMP, GIF, TIFF etc.
Images in both monochrome and colour are
welcomed. Line drawings and diagrams are
preferred in Windows metafile and postscript
formats. We can also scan original
photographs, negatives and slides.
Gridding, Overlays and Captions
Please note that readers’ satellite images
should be provided without added grid lines,
country outlines or captions unless these areconsidered essential for illustrative purposes
within an article.
If your article submission contains embedded
images and diagrams, please note that you
must also submit the individual, original
images, in one of the formats describedabove: these are essential for page make-up
purposes.
Submission of Copy
All materials for publication should be sent to
the editor,
Peter Green‘Hollowtree’
Eggesford, Devon EX18 7QX, England.
Tel:01769 580 700
The most efficient way to do this is as email
attachments to the following address
geoeditor@geo-web.org.uk

And finally . . .
if you do have material ready for the next
issue of GEO Quarterly, please submit it assoon as it is ready—do not wait till thedeadline above: this will simply create an
editorial log-jam and delay publication.

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Robert Moore

This image from Metop-A received on November 17 gave avery fine view of the Great Lakes. The St Lawrence River andits main tributary, the Ottawa River, also show up veryclearly.
The St Lawrence is just over 3,000 kilometres long anddrains an area in excess of one million square kilometres.
The St Lawrence Seaway makes the Great Lakes accessible
to ocean-going shipping and thus, as well as being a major
Canadian highway, opens up mid-western US cities like
Detroit and Chicago to the Atlantic.
Whilst the St Lawrence is a major commercial andinternational waterway, a number of its tributaries, notably
the Ottawa River, are attractions for hardier adventureseekers (white water rafting etc) and no doubt ordinary
tourists seeking spectacular wilderness landscapes.

According to Wikipedia it also has thirteen hydro-electric
generation plants.
The location of the Niagara Falls between lake Eyrie andLake Ontario is plainly visible although the spray does notshow up in this satellite image! The higher reaches of theMississippi and Minnesota rivers can just be seen in the
more hazy western part of the image. I am sure there ismuch more of interest in this image to geographers,
geologists and mariners. Historians will already be aware of
how important the rivers were in the early exploration of
Canada. Four of Canada’s major cities can be seen here;
Toronto, Ottawa and Montreal are quite easily visible in thehighest resolution on screen and one does not need too
much imagination to pick out Quebec, although the latter isonly faintly visible.

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Francis Bell

Recent travel dispatched me to South America for almost
three weeks. In anticipation of this visit I was particularly
excited in expectation of visiting new places encompassing
tropical South America to Cape Horn and back.
Part of my decision making about taking my APT receiving
equipment with me when travelling relates to the countries
to be visited. There should be a cautionary word here.
Although most people would consider weather satellite
reception an innocent technical hobby, some lessenlightened political systems may be paranoid about
satellite surveillance of their country. For example I did nottake my APT system with me on a recent visit to Cuba and a
GEO member in the past warned me not to take APT
receiving equipment to Egypt. I also know we have amember in Sri Lanka who has had problems with local
customs when importing APT receiver into their country.
I judged my planned operations on a cruise ship aroundpart of South America sometimes in international waters
would not be provocative to anybody. I always knew when
the ship was in international waters because the onboard
casino would be open. I have been known to gamble a little
but this time I was satisfied to watch others lose theirmoney and use the casino as a measure of the ship's
position.
My Receiving Station was already well travelled. Although I
had previously promised myself to smarten up my turnstile
APT antenna the reality was that it was still the fold up wire
and plastic piping I had taken abroad before. Its attributes
are light weight and may be folded into a suitcase.

best location available and my activities did not attract too
much attention by fellow passengers. Because of thenecessity of establishing my receiving station and thendismantling everything and taking it back to the cabin I
only tried reception on four occasions. Each time I planned
afternoon reception of NOAA 19 neglecting all other passes.
The rationale was to receive high elevation visible images
when the ship's decks were relatively quiet and my activities
unobtrusive.
I received four good digital recordings of NOAA 19 passes
which I transferred to my lap top in the cabin with further
processing done at home when I had more time to devote tothis mini project.
Three of the images are shown alongside this text. I wasparticularly pleased to see the coastal outline of the
Falkland Islands on two of the images. The ship visited Port
Stanley for just one day but it so happened that in spite of
the moderate wind which was blowing the sky was relatively
clear, hence the images showing visible coastal outlines
which I think may be quite rare for this 'British Crown
Dependency' .
The ship's captain said this was not uncommon in this area
because the sea and air temperatures were almost the same.
We entered this area of mist about 12 hours after leaving
the Falkland Islands and this was not insignificant.

In my report about APT reception in Turkey I said that I had
used my digital audio recorded to store the live APT signals
but with the consequence that I could not instantly view thereceived image. For security and weight reasons on myTurkey visit I did not take my laptop computer with mehence having to wait until I returned home to view myrecordings.
Technically this worked well but I missed the charm andexcitement of having a live image immediately available on
my computer screen. Hence for my travel this time I planned
to take my lap top with me. Wow, how life can conspireagainst you! A few days before departure the battery on mylaptop died leaving me with no time to replace it.
Resourcefully I changed the plan: take the digital recorderand the laptop. It worked out well. I used the digitalrecorder on the ship's deck with the receiver and antenna,
then promptly took the recording to my cabin where I had
wired the laptop into the ship's 110v power supply. I said
wired it into the ship's power because none of the electricaladaptors I had with me fitted the ship's power sockets so I
stripped the ends of the computers power cable andinserted them, with care, into a power socket. It worked
beautifully and the cabin steward made no comment.
However, I do not recommend others take this approach; I
was careful and I did know what I was doing.
After reconnoitring the ships decks I chose the highest open
public deck for my satellite operations. The location was
windy most of the time but it gave a clear view of the sky
only partly shadowed in one direction. I think this was the24

NOAA 19 APT visible image 16th December 2009 showing
an extensive band of sea mist stretching NE from the
Falkland Islands

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It so happened that before we entered the sea mist there
was a medical emergency onboard. The ship changed courseback to the Falkland Islands and a Sea King helicopter was
dispatched from the Falkland Islands to rendezvous withthe ship which was still many miles from the islands. The
image below I recorded the day after we left the Falkland
Islands shows sea mist stretching for several hundred miles
north east of the islands.
The helicopter did hover over the ship for about 30 minutes
to take of the medical patient and apparently arrived safely
back in the Falkland Islands.
During this night time emergency everybody except the
emergency crew were exclude from any outer deck andlighting was restricted. The point of relating this event isthat just a few hours later the ship was enveloped in the sea
mist and any helicopter rescue mission would have been
impossible.
A further point is to express my admiration to the brave andcommitted individuals from a British base involved in sucha medical emergency.
I was pleased with the images I recorded because they
remind me of visiting the area. The location of Port Stanley,Montevideo and Buenos Aires can be identified on theimages - if you are good at geography. Montevideo andBuenos Aries are located on banks of the extensive River
Plate ( Rio de la Plata ) estuary.
I learned about the large river systems of South America
which drain into this estuary and yes I did see in
Montevideo bits of the German battleship 'Admiral Graff
Spee' which sank in the River Plate in 1939 just a few
kilometres off shore.
Just as a comparison between the resolution of my NOAAAPT and Envisat MERIS images of the same area I havechosen an Envisat view of the River Plate taken in 2008
which covers some of the area I recorded recently from theship. This images also closely relate to the article about
direct Envisat reception which is becoming available tolicensed users.

NOAA 19 visible image received while the ship was anchoredin the Falkland Islands
Lightening & Surge Protection Continued from page ii
General information:
http://fire.cfs.nrcan.gc.ca/lightning-eclair-eng.php
http://www.srh.noaa.gov/jetstream/lightning/lightning_max.
htm
http://www.srh.noaa.gov/mlb/?n=what_is_lightning
http://www.metoffice.gov.uk/corporate/library/factsheets/fa
ctsheet02.pdf
External Lightning protection:
http://www.obo-bettermann.com/downloads/
en/kataloge/tbs_grund_blitz_en.pdf
http://www.obo-bettermann.com/downloads/
en/prospekte/blitzsch_en.pdf
Indirect lightning and ground potential rise:
http://www.ipst.org/techpapers/2007/ipst_2007/papers_IPST2007/Session23/197.pdf
Firehazard SPDs:
http://www.rbs2.com/fire.htm
http://www.eeel.nist.gov/817/pubs/
spd-anthology/files/Black%20boxes%20ICLP.pdf
Dangers of wearing iPod:
http://community.wddty.com/blogs/adverse_reactions/archive/2007/07/13/The-unexpected-dangers-of-theiPod.aspx
Christophe Suarez's lightning images:
http://www.thunderstorm-chaser.com/thunderstormpictures.htm

NOAA 19 APT visible image 20th December 2009 centred on
the River Plate with its associated river systems

Dutch only links:
http://www.weerstationarnhem.nl/uitlegonw.htm
http://www.eenvandaag.nl/binnenland/32268/waar_slaat_de_bliksem_morgen_in_
http://www.knmi.nl/kenniscentrum/luchtelektriciteit_onweer.html
http://www.knmi.nl/klimatologie/daggegevens/onweer/
http://www.knmi.nl/cms/content/8307/onweer_en_bliksem

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March 2010

Marciano Righini, I4MY/Giampaolo Rossini, IW4CSG/Franco Tiozzo, IW4CQD

Francis Bell in The GEO Quarterly No 24 drew up a list of

12:45 and 13:00 UT. Meteosat-8 was located at 3:4°W

free publications related to weather satellites.

and the highest elevation of NOAA-18 over our horizon

One of these is MSG Meteosat Second Generation, In

was 62°W. Moreover, on October 10, 2009 a view from

Orbit -In Use, a book produced by EUMETSAT in 2005.

Meteosat-9 at 12:45 UT and a pass of NOAA-19 between

In the first chapter, on page 16, they say "Comparisons

13:11 and 13:26 UT. Meteosat-9 was located at 0° andare inevitable between HRV with its nominal 1 km

the highest elevation of NOAA-19 over our horizon was

resolution and the Advanced Very High Resolution

35°W.

Radiometer (AVHRR) instrument with similar resolution

Where

Of course the most meaningful comparisons are thoseon the polar orbiting NOAA satellites of the USA". On themade in areas not too far from the MSG subpoint, that issame page they publish two images of the Alps: one fromto say in Africa, but we have expanded our research also
the NOAA AVHRR channel 2 and the other from SEVIRI
to more northern countries.
HRV channel. The former taken from near-overhead at
In the Sahara desert three main types of surface andabout 800 km, the latter taken from a position over thescenery may be recognised: the hammada, the reg andequator at an altitude of 36,000 km. They conclude by
the erg. The hammada are rocky plateaus with bare rocksaying that "HRV cannot provide quite the same level ofoutcrops. The reg consists of windscoured plains strewn
detail".
with pebbles, boulders and gravel. The erg is the desert ofThis is true over central and especially northern Europe
shifting sand dunes. The undulations of the surface of
where the perspective from the equatorial plane is
the Great Eastern and Western Ergs are a proper testing
considerably oblique, but what level of imagery does MSG
bench for a picture from above. (Figure 1)
provide at or near the subsatellite point? In other words:

What

Can the images generated by AVHRR and SEVIRI be
compared? In order to answer this question let's see

Let's consider the instruments generating the images.

when, where, what and how to compare.

AVHRR (Advanced Very High Resolution Radiometer) is

When And Wherethe environmental sensor for the NOAA satellites. It is a6-channel scanning radiometer sensitive in the visible,

In our archive we have looked for passes of NOAA andnear infrared and infrared window regions.
HRV images of MSG taken the same day at the same
A scan motor continuously rotates the scan mirror at 360
time. We have found two showing a cloudless Sahara,
rpm to produce a cross-track scanning in orbit. The
clear skies over the Mediterranean, and a fleecy sky overmirror (21 by 29 cm) fills the field-of-view of a 20 cm
western England. On July 21, 2005 a view fromtelescope. The instantaneous field was chosen so that theMeteosat-8 at 12:30 UT and a pass of NOAA-18 between

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satellite motion along its orbit would cause successive
scan lines to be contiguous at the subpoint.
Data is read at the appropriate rate for the HRPT (HighResolution Picture Transmission) data format. All
spectral regions are transmitted at full resolution, i.e.
1.1 km on the Earth surface at the subpoint. For thecomparison we have used channel 2 (0.725-1.1 m).

our traditional METEO programme, the one supplied by
Giampaolo, with which we have always displayed andprocessed the images of Meteosat, NOAA, Meteor, etc. All
the views from each satellite were displayed at the
maximum level of resolution so that they can becompared.

SEVIRI (Spinning Enhanced Visible and Infrared Imager)
is the instrument which delivers images and data thus
performing the core mission of MSG (Meteosat Second
Generation). The images are generated through a
combination of an east to west scan obtained from thespinning of the entire satellite at 100 rpm, together withthe stepping of a 51-cm telescope mirror from south tonorth after each scan line.

A Draw

SEVIRI has the capability to observe the Earth in12
spectral channels at 15-minute intervals. We have usedchannel 12 which is the High Resolution Visible
channel (0.5-0.9 m)¸it provides a nominal resolution ofaround 1 km at the sub-satellite point.

Also the MSG pictures taken over the Mediterranean(Figures 5a/b, 6a/b) are more than acceptable even if the
AVHRR shows a certain superiority in portraying thesmaller structures.

How
After receiving the data of MSG with Tellicast, weconverted the image files into a sequence of pixels with
256 grey steps. Then we processed the new files withIn the three pairs of images taken over the Sahara(Figures 2a/b, 3a/b, 4a/b) it is practically impossible todistinguish between those taken from NOAA and thosefrom MSG in spite of the great distance from which MSG
sees the Earth surface. SEVIRI is a very efficient
instrument. Its capability is outstanding.

Figures 7a/b portray an unfair comparison. The view
from the equatorial plane is too oblique compared withthe vertical view of NOAA. However, these images
demonstrate that excellent use can be made of SEVIRI
imagery even in the northern countries of Europe.

Figure 1 - An HRI VIS image of Meteosat-7, ch. BIV, showing the areas used to compare AVHRR and SEVIRIGreat Eastern and Western Ergsa refers to NOAA images b refers to the images of MSG in all examples

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Figures 2a/2b - The Great Western Erg lies in the bottom of a great basin where the ancientrivers (wadis) piled up most alluvium. In these pictures some wadis, or dry rivers, flow downfrom the Atlas Mountains.

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GEO Quarterly No 25

Continued from page 17

This MER_FRS data (full resolution) only covers certain areas of interest. All MER data covers daylight passes only, in
mid-winter Edinburgh sadly falls outside the received data !

Hidden in the program is also a border overlay option, seen from this BEAM-Visat-bitmask-option.jpg

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Figures 3a/b - The Great Eastern Erg, a region of dunes lying between Algeria and Tunisia.
Today it is dotted with black spots that are oil and gas wells from which plumes of smoke rise.

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Figures 4a/b - The Edeyen Erg lies to the south of the Great Eastern Erg. It consists of strip ofland covered with dunes surrounded by the Hammada.

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North Sea Image
This is an Envisat MER-FRS image of the North Sea.This picture illustrates the quaility of the images which can begenerated from the raw Envi-Ham project data.
Image courtsey ESA

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Figure 5a/b - The three great islands of the Tyrrhenian Sea, Sicily, Sardinia
and Corsica, are well represented in the HRV channel.

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Figure 6a/b - A view of the western Mediterranean where the Balearic Islands, Gibraltar and thestrip of land near Melilla are clearly represented in both images.

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Figure 7a/b - The views of Brittany and south-western England were taken on a day of light cloud cover. The
HRV image cannot be compared with that of NOAA, but it shows the MSG capability of producing valid imagery
far from the sub-satellite point.

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March 2010

Dale Hardy

The warm tropical waters surrounding northern Australia are
the home and breeding grounds to a vast array of exotic
marine creatures and corals. However when these ocean
waters warm to at least 26.5°C through a relatively deep layer(~50 m) of the ocean, something more menacing can breed:
the Tropical Cyclone. This 26.5°C value is tied to theinstability of the atmosphere in the tropical and subtropicallatitudes. Above this temperature deep convection can occur,
but below this value the atmosphere is too stable and little tono thunderstorm activity can be found.
A tropical low formed in the Arafura Sea (Fig 2 & 3) on
December 8 and was given the designation ‘92P’. The low
moved southwest, passing over Darwin on December 12,
causing heavy rain in excess of 100 mm and squalls causing
tree damage. As it passed back over open waters it intensified
and when west of Darwin was named Laurence, the first
tropical cyclone of the Australian 2009/10 season. Quickly
gaining strength, Laurence attained category-3 on December
15 when close to the north Kimberly coast with recorded wind
gusts to 187 kph.
Still small but intense, Laurence was now feasting on the
30°C tropical waters as it skirted the Kimberly coast, where
it rapidly matured into a category-5 severe cyclone (> 250kph) for a brief period on December 16 before crossing thecoast east of Koolan Island, south of Kuri Bay that evening asa category 4 cyclone with -estimated gusts to 260 kph near its
centre.

Figure 1 - Tropical Cyclone Laurence on December 15

By the afternoon of December 20, Laurence had reduced tocategory-3 and turned south south-east, taking aim at the
Pilbara coast. As it made the final dash on the course todevastation Laurence grew to a mighty category-5 again andcrossed the coast near Wallal, 230km NE of Port Hedland,with estimated wind gusts of 285 kph near its centre.
As it moved inland considerable damage to property andlivestock occurred with the estimated loss of 1500 cattle
reported. It still had a pressure of 929 hPa.
Finally Laurence, starved of energy, gradually weakened,
dumping heavy rain as it moved southeast, some areas
reporting of 245 mm in the 24 hours to 9 am on December 22.
Although dying, Laurence was not going to give in easily andsought to join an approaching front from the southwest
coming across Perth and wreak more havoc. By now,
Laurence was 6 days old and had travelled some 3500
kilometres.
By December 24 it had travelled another 1200 km acrosscentral Australia to the borders of NSW, Queensland andNorthern Territory, and had joined the up with the front(figures 9, 10). A stationary High over the Tasman Sea
hindered Laurence’s progress and the system formed a troughwith the remnants of the cyclone feeding moisture from theCoral Sea into the front causing severe flooding in northern
NSW. In Coonabarabran it was described as ‘biblical’.

36Windspeeds in Tropical Cyclones
Roads were submerged in floodwater, ghostly rivers rose fromthe dead, paddocks became seas of green and mosquitoes
were breeding as if it were the tropics. ‘Welcome to thedrought, NSW style’ quoted one newspaper.
By January 4, 2010 the cyclone system finally cleared, having
starting 27 days earlier.

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Group for Earth Observation

Fig 2 Afafura Sea

Figure 4 - Laurence on December 12

GEO Quarterly No 25

Figure 3 - Tropical Cyclone Laurence on December 8th

Figure 5 - Laurence on December 15

Figure 6 - Laurence on December 18

Figure 7 - Laurence on December 20

Figure 8 - Laurence Thermal Signature

Figure 9 - Laurence on December 21-Cat 5

Figure 10 - Laurence on December 24

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Potomac Falls Blizzard
Steve Ross

March 2010

Steve sent these images in when here in the UK everything
was at a stand still with just a few inches of snow.
He used a R2FX receiver with a homebrew QFH he made from
8mm copper tubing.
The decoding software is WxToimg running on a MacPro 8
core. The total snow accumulation in his area was 25 inches.
He was snowed in for 3 days until he was ploughed out. The
last time a storm this big hit his area was back in 2003.
Visit Steve at:www.weatherscience.net

Yes, this is inches!

Fig 1 NOAA19 1758 on 19 December 2009
Potomac Falls VA

Post-Blizzard noaa-19 hvc composite

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GEO Quarterly No 25

Faeroe Islands
DisturbanceAnders Höök

On the APT images of 2010-01-20 (I only have APT), I saw a"disturbance" in the cloud flow around the Faeroe Islands. I
attach an image (NOAA 19, 2010-01-20, 12:35 UT, maxelevation 38 deg., decoded and processed with Patrik Tast's
APT Decoder).
In order to see a little more of what was happening, I turned
to Modis, where I found the "disturbance" in an image fromthe Aqua satellite (Modis Aqua 2010-01-20, 13:10 UT).
I processed it with Les Hamilton's "Smooth Modis" andDavid Taylor's "CorrectGeometry" (I attach this image too).
Looking thoroughly at the resulting image, it is possible tosee the sort of "ship waves" described by Les in GEO Q 11,
p10. The waves are not as clear as in Les' article, but areclearly there. I don't know if it is of importance, but thehighest mountain on the Faeroe Islands that I could find on
a map is 882 m.
It may be also be of interest that my equipment is a DC
antenna of Jerry Martes design and a R2FX receiver (wedon't have problems with pagers in Sweden).

Modis Aqua 20-01-2010 13:10 UT Faeroe Islands

One interesting thing is that the last month I have had amuch weaker antenna signal than usual. I guess that thishas to do with some deterioration of the down-lead coaxial
cable or some contact due to the very cold weather we have
had, occasionally down to minus 25C degrees. And I will notclimb the roof until it becomes a bit over zero. My QTH isVallentuna, some 25 kilometres North of Stockholm.

Peter Green
Like me you may well have heard all the chat about twitterand thought, “well do I really want to know what Stephen Fry
is doing every minute of the day” and probabley came to thesay answer.
Well having just bought a new mobile phone with internet
access I spotted that the MET Office were doing alerts byregion via twitter and so signed up.This was just before
Christmas so I was kept up to date with all the snow and ice
warnings.The nice thing about twitte is that its free. You canaccess it from any internet enabled device, so you can use iton your laptop or desktop.
There is an amazing array of “tweets” that interest me. Space
related, you get info and photo’s from the ISS as theastronaughts tweet from the ISS. Just have a look around I
think you may be pleasantly surprised.
Below are a some example tweets.
www.twitter.com

NOAA 19, 20 January, showing area of interest

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A NASA Earth
Observatory Report

Shortly before the southernhemisphere’s spring,
Antarctica’s Inexpressible
Island and the Northern
Foothills Mountains were
illuminated by a glimmer ofsunlight from a low angle
when the Advanced Land
Imager (ALI) on NASA’s
Earth Observing-1 (EO-1)
satellite captured thisimage on September 16,
2009.
The seaward slopes of themountains are gleaming
white and cast longshadows inland over the
Nansen Ice Sheet.
The scene provides two
indications of the bay’s
persistent and fierce
katabatic winds—downslope
winds that blow from theinterior of the ice sheet
toward the coast .
One is the windswept groundin the mountainous terrain. In
many places, there is apattern of bare rock andsnow drifts that suggests thewinds have scoured snow
from upwind slopes anddeposited it on the lee sides.
The second sign appears in
the open waters of Terra
Nova Bay (upper right), in theparallel white streamers of
newly formed sea ice. The
ice is continually pushed out
to sea by the strong offshore
winds, leaving a pocket ofopen water, a polynya.
The winds are responsible formaking this location an ideal
spot for Adélie penguins,which have a colony on
Inexpressible Island and atother sites around Terra Nova
Bay. Unlike Emperor
penguins, which breed onsea ice, Adélie penguins nest
on ice-free land, which mustbe accessible to them via
open water and close to theirmarine food supply.
NASA Earth Observatory image
created by Jesse Allen and RobertSimmon, using EO-1 ALI data
provided courtesy of the NASA EO-1
team and the United States

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March 2010

Douglas Deans - dsdeans@tiscali.co.uk
Well I wonder how many of themembership are now using someedition of Windows 7 and whether you
upgraded or undertook a fresh install?
As I mentioned in my last column I was
facing a decision as to whether to installthe 32 or 64 bit option. Both DVDs areprovided with all editions of Windows 7.
In the end I played safe and decided on
the 32 bit system.
I could haveupgraded as I was already running
Vista (upgrade is not possible from XP)
but decided that a fresh install would be
the best choice, providing a new clean
installation after several years of
running Vista. The speed after a fresh
install makes the additional effort all
worthwhile. Of course it is essential
under those circumstances to ensurethat you have back-ups of all your data
files and can readily put your hands on
programs which will need to be reinstalled. It is also worthwhile to checkdrivers for your new Operating Systemand have them ready if necessary. In
other words a little fore-thought andeffort can save a lot of headaches later.
Nevertheless there will always besomething you will forget. To beabsolutely sure I took an image of myVista system using Norton Ghost so all
my data was readily accessible forloading back. Better safe than sorry.
By the way it is worth noting at thisstage that all editions of Windows 7 now
provide an option to take an image ofyour hard drive in addition to the usual
back-up provision. It is not as good assome of the commercial offerings withless options, but it is still a very usefuland potentially cost saving tool ….. welldone Microsoft.
I should also mention that my brothershowed more courage than me andinstalled the 64 bit Windows 7.
He reports very good performance allround and it is reassuring to hear that
his Eumetcast results are excellent(probably better than mine) even with asingle computer system. Indeed his
opinion is that the 64 bit system isgiving a better performance from
Eumetcast than the 32 bit, hepreviously used. Perhaps I should havebeen more courageous !

42

Followingmyprevious
criticalcomments regarding the interference by
the European Commission to stop
Microsoftoffering only Internet
Explorer with their operating system, I
am pleased to report that the disputehas been settled and a compromisereached.
This nonsense has been on-going foryears, with the EC imposing fines on
the basis of Microsoft’s anti-competitive
behaviour. Microsoft will now provide a
range of browsers (choice screen) tomake the installation of your choicestraightforward to achieve. It will be
added to new computers and theexisting Windows XP, Windows Vistaand Windows 7 computers in Europe,
where Internet Explorer is set as thedefault browser, for the next five years.
Goodness me have the EC nothing
better to do.
Google Earth has been around for avery long time now but I wonder how
many are aware of the interesting
options it can offer our hobby. I willtake a brief look at those as well as theusual program updates.

Google Earth
Eumetsat and David Taylor provide
options to view their products via the
Google Earth framework. Obviously you
will first need to have Google Earthinstalled on your computer. For thosethat do not yet have it, simply go to :-the system. Download the kml file fromthe following site.
http://www.eumetsat.int/Home/Main/News/F
eatures/713983?l=en

Double click on the file from its
download location and the Eumetsat
options will be loaded into yourTemporary Places. When you decide toclose Google Earth you will then be
given an option to put the Eumetsat
links into your my Places for future use.
As simple as that. To view the products
simply select the ones required from the
expanded My Places. I have shown an
example of this in the adjacent image.
David Taylor’s WXtrack (registeredusers only) can also be used inconjunction with Google Earth. It cansend the sub-satellite location of thecurrently selected satellite to Google
Earth and drive the map display on aregularly updated basis. As David says
in his own notes this is a fun mode ofoperation. The speed of the update canbe adjusted by simply selecting Options> Google Earth and setting as required.
In addition there is an option to control
the camera height. Well worth a try.
An example of what is currently
possible can be found on the inside
cover.

Software Updates

http://earth.google.com/downloadearth.html

POVIM
There have been a number of updates toFred van den Bosch’s POVIM program.

There is a multitude of interesting
things to do and enjoy with Google
Earth so it is a fascinating program touse even without the hobby related
options.
Let us first look at the Eumetsat
package which at the time of writing islimited to their 0 degree (Meteosat 9)
and IODC imagery. For the moment the
package only uses their Multi-sensor
Precipitation Estimate data (MPE) for
the 0 degree and IODC data. Do not
expect too much from this but
Eumetsat have stated that further
products will be made available in due
course so this data provides anintroduction to the uses of overlays on

Let me remind readers that POVIM
stands for Product Orientated Video,
Images and Maps. Fred developed theprogram many years ago for theweather satellite fraternity recognisingthat our hobby often comprises a wide
selection of different quite separate
programs and a wide array of files andfile locations. The idea behind it was toprovide a structured and integrated
environment to help draw everything
together. There has been a couple ofinteresting articles by Fred in two of ourprevious journals and I strongly
recommend those interested to have a
read.
The first was in GEO Quarterly 8,

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December 2005 and the second in GEO Quarterly 21, April
2009.
POVIM Presentation Manager which integrates the suite ofprograms under the umbrella of POVIM, has two constituent
parts.
Those are Product Manager and Presentation
Manager.
Very briefly Product Manager allows you to create your own
products and select where you want them stored. A wizard isprovided to ease defining the products. You can put similartypes of products into your own defined groups.
With the Presentation Manager there is a vast array of
options, and I have tabled some of the more interesting ones
below.
selecting up to 20 products from a list of products.
present them in thumbnails: 2, 6, 12 or 20 on the screen.
synchronized scrolling in steps of 15 or 60 minutes.
synchronize the time with a button or automatically.
setting the time with a slider.
call your favorite photo viewer to see the images on full screen.
use all the options of your photo viewer like zoom, scroll andprint.
make a slideshow of all images in one folder (only with
IrfanView: hardcoded functionality).
display generated images or generate the image “on the flow”.
always display the latest received image depending on theselected time.
display images (jpg, bmp,gif) video (avi, mpeg) and maps(jpg,bmp,gif) from e.g. Digital Atmosphere (due to limitations ofDelphi png and tiff are not possible).
start satellite- or weather program or go to a specific internetsite.
To learn more about Fred’s suite of programs and to download
the latest updates please go to :http://www.fredvandenbosch.nl

David Taylor’s programs (latest releases).
Just a reminder that the list below is for full tested releases
and does not include the latest beta (or alpha) versions
currently on test. Those can also be downloaded from David’s
site.
To learn more about those programs and to download thelatest updates please go to :http://www.satsignal.eu

ATOVS Reader
AVHRR Manager
BUFR Viewer
CMA Viewer
DWDSAT HRPT Viewer
GeoSatSignal
GRIB Viewer
GroundMap
HDF Viewer
HRPT Reader
Kepler Manager
MapToGeo
Metop Manager
MSG Animator
MSG Data Manager
PassControl
SatSignal
Sea-Ice & Viewer
Wxtrack

v 1.2.0v 1.6.6
v 1.1.4
v 1.2.0
v 1.1.2
v 7.1.2
v 2.3.4
v 2.1.2
v 1.4.2v 2.9.2
v 1.3.2
v 1.1.6
v 1.4.2v 2.5.32
v 2.5.36
v 3.2.4
v 5.1.4
v 1.4.2
v 3.8.2

GEO Quarterly No 25

Storm Dunlop, Sky,
Guild of Master
Craftsman
Publication, 2009.
ISBN 978– 1–
86108–660–0, pp. 160,
£14.99.
Robert Moore
Storm Dunlop’s work will be well-known to many GEOQ
readers. While we mainly look down on the sky andclouds from Earth orbits, he looks upwards and, more
importantly points his camera upwards also.
This handsome volume contains photographs fromphotographers across the world. Every shot is a work ofart and the images include a number of rarities, seldom
seen and much less photographed (a circumhorizontal
arc, a combined parhelion and subparhelion and a‘bishop’s ring’ for example).
The pictures will not disappoint the reader – they are
magnificent. The brief captions accompanying each
image may however disappoint GEOQ readers. Most of
us know something about climate and weather, many
may be keen amateur photographers.
The text is too sparse to tell us anything of scientificinterest and there is no information about how thepictures were taken or processed.
There is, of course, a problem for authors which effects
both academic writers and serious popular authors like
Dunlop: if you write for a scientific readership you lose
your popular readers, if you write a book that isaccessible to all, the more specialist readers will befrustrated by the lack of technical detail. In thesematters the publishers usually hold the whip hand.
So Sky will not become a reference book although it will
be one source of images of some rarer types of cloud andoptical phenomena.
Readers with an interest in climate and weather will turnto Dunlop and Wilson’s Weather and Forecasting(Chancellor Press, 1982) and anyone wanting information
on clouds, as such, will probably pick up Pretor-Pinney’s
The Cloudspotter’s Guide (Sceptre, 2006).
Aspiring weather photographers will read Dunlop’s
Photographing Weather (Photographers Institute Press,
2007).
Whilst Sky would enhance any coffee table it is muchbetter than a ‘coffee table book’. It would, for example,
be of great value in a school library where it might
encourage young people to look upwards and to ask
questions about clouds and the sky. Furthermore kept
on a shelf in the Art class it would stimulate debates
about colour and form and perhaps lead to the
production of some very adventurous art works.
There is a big ‘Wow!’ factor in this book and given theextraordinarily low price for such books it can beenjoyed and admired by the more technically minded
reader as well as enchanting the casual reader. Anybook that challenges us to look, and to look intelligently,
at our environment is to be welcomed.

www.geo-web.org.uk

43

GEO Quarterly No 25

Group for Earth Observation

May I through GEO quarterly, express my thanks
to Les Hamilton for his sterling service and help
he has given me in writing articles for GEO over
the years. (Even though his answers are
sometimes not what I wanted to hear, he is always
honest and to the point)
I wish you luck in your new ventures Les andthanks for being a friend.I have decided tocontinue with the hobby when I find another place
to live, (Ed Murashie was right, I have a passion
for the hobby) and it would be a shame to give up
all I have learned and accquired over the years. I
look forward to helping our new editor Peter Green
who I have met and is a great guy, Thanks to you
both.

44

March 2010

Greeting card from Argentina
I would like to express my thanks and acknowledgement onbehalf of GEO to all those individuals and organisations who
posted and emailed Christmas and New Year greetings to ourgroup. I received greetings from within the UK and from fourother countries. It is rewarding to think our active
membership is spread so widely.
I found the above email greeting from Carlos Cotlier of special
interest because on my recent travels I came so close to hishome town of Rosario, Argentina. I have met Carlos at two
NOAA conferences in 2004 and 2008. I hope we will keep in
regular touch in the future.

Rob Denton G4YRZ

Note that this greeting card and the Envisat image of the River
Plate estuary shown elsewhere, form the basis of this issue's
Quarterly Question.

www.wxsat.org

Francis Bellwww.geo-web.org.uk