Group for Earth Observation

The Independent Amateur Quarterly Publication for

Number 28

Earth Observation and Weather Satellite Enthusiasts

December 2010

Inside this issue . . .
GEO Symposium 2011
GEO Return Visit to
EUMETSAT in 2011
The Thanet Offshore
Windfarm from Space
Colouring APT Images in
WxSat
BUFR Files with Francis
BreameEUMETCast keeps Gliders& UltraLights Flying
Les Hamilton gives us a
Major Article on Aurora
The PADAT 137 Again
with Ruud Jansen
EUMeTrain, Free Online
Training & Briefings
A View from North Cyprus
with Nigel Heasman
Terence Smith Updates his
2008 Article Using
InfanView Remotely for
Animations
GEO Attends the ENVIHAM conference in
Frascati
Douglas Deans Explores
Channel 3 in his Series in
Computer Corner
Updates on GEO attending
Rallies, Third Generation
Meteosat Announcements,
Full Page Images
Plus much more ...

ENVISAT images of Gibraltar

Clorophyll concentration

Peter Burden made the above image available to us, he explains
briefly how this was achieved.
The MERIS MER_FRS_1P level 1b product , 630 640,00 KB, wasdownloaded from the ENVISAT satellite in September 2010 with the
ESA DDS receiver software and processed with the BEAM VISAT
software which is programmed in pure JAVA and runs on Windowsor other operating systems.
VISAT extracts all the data from the product and the RGB image caneasily displayed with View>Open RGB image view.

September 2010

left of the screen, the Meris2r / Bands a BW image is displayed. The
false colours can be added from within 'Colour Manipulation"section at the bottom left of the screen. Using 'Manage view layer
visibility and transparency' from the toolbar, the image is overlaid
and produced from View>“Open RGB image view.
The colour concentration legend is obtained from File>Export>Export
colour legend.
There is a BEAM tutorial here:
http://www.brockmann-consult.de/cms/web/beam/tutorials

To show the chlorophyll concentration in the ocean the 'MERIS
Case-2 Waters Processors' in the VISAT Tools folder is used, thisprocesses the data and displays a black and white image.
This takes 10 minutes with my ASUS P7p55D-E + Intel Quad 2.6 .
Selecting chl_conc from the 'Product View' that is displayed on the

BEAM is an open-source toolbox and development platform forviewing, analysing and processing of remote sensing raster data.
The software is free to download and is available forWindows,Mac,Linux and UNIXhttp://www.brockmann-consult.de/cms/web/beam/

The GEO Quarterly

GEO MANAGEMENT TEAM
Public Relations
Francis Bell,
Coturnix House, Rake Lane,
Milford, Godalming, Surrey GU8 5AB
England.
Tel:
01483 416 897
email: francis@geo-web.org.uk
General Information
John Tellick
email: info@geo-web.org.uk
GEO Quarterly EditorPeter Green‘Hollowtree’
Eggesford, Devon EX18 7QX, England.
email: geoeditor@geo-web.org.uk
Assistant GEO Quarterly Editor
Les Hamilton
email: les.hamilton@tiscali.co.uk
Membership and Subscriptions
David Anderson,
35 Sycamore Road,
East Leake, Loughborough LE12 6PP
England, UK.
email: members@geo-web.org.uk
Tel:01509 820 067
Fax:
01509 559 015
Technical Consultant (hardware)David Simmons
email: tech@geo-web.org.uk
Webmaster and Website Matters
Ray Godden
e-mail: ray-geo@lescharriols.eu
Education Coordinator
David Painteremail: education@geo-web.org.uk
GEO Shop Manager
Clive Finnis (Assistant: David Simmons)
email: tech@geo-web.org.uk
International Liaison
Rob Denton
email: international@geo-web.org.uk
Nigel Evansemail: nigel@geo-web.org.uk

December 2010
Editorial: Peter GreenR

eaders may be surprised to see an image from the Sun on the front cover of thisissue, associated with an article on the Aurora Borealis. After all, GEO is theGroup for Earth Observation! What may come as a surprise to you is the fact that
Earth observing satellites, including the familiar NOAAs and Metop, are continuously
observing Earth’s polar atmosphere to determine the current state of the Aurora. The
Aurora is an indicator of strong solar radiation reaching us, and has important
implications for world-wide communications.
ven the astronauts on the ISS are fascinated by this phenomenon. On the backcover is a picture taken by one of them from the new viewing platform recently
attached to the ISS. This picture was 'tweeted' live from the ISS. Everyday numerous
images that are unique and personal to the astronauts are available via twitter if you
are following them and these picture may not be available elsewhere. If you have nottried twitter yet, why not give it a go, sign up via www.twitter.com, where you canalso follow GEO @GEOWEBUK. Best of all it's free and a free program to view tweets
try Tweetdeck, www.tweetdeck.com.
he following is a request for any member to donate an unused / spare laptop to thegroup. The computer does not have to be high specification and a dead battery or
missing power supply can be dealt with. It would be very useful to have these laptops
which could be loaded up with slide shows for any rally or exhibition stand. I don't
think the processor speed or memory will matter for this simple dedicated use. A 14
or 15 inch screen would be useful because passing public may struggle when viewing
anything smaller. This appeal is the result of Francis having his personal laptop
stolen from the Kempton rally which he attended for GEO recently.
ou will see in this issue that GEO is announcing it's intention to hold our 2011
symposium at the National Space Centre, Leicester on May 7th. We would likeyou suggestions and ideas for speakers and workshops, see page 17. GEO also wants
this year to return to EUMETSAT in Darmstadt, we had such an enjoyable visit in2007 that we would like new and older members to join us for what looks to be apacked and enjoyable few days with friends from across Europe.
lease keep sending in your articles and images for the Quarterly, I want to reflect
the wide spectrum of interest our members have, I can't do it without you.
f you have an iPad, Kindle or similar device please let me know as I would like toinvestigate delivering the Q via the ePUB format.

E

T

Y

P
I

Contents
Publisher
Published by The Group for Earth
Observation Limited, a company inEngland and Wales, limited by guarantee
and not having share capital. The
Company number is 4975597.
The registered office is Coturnix House,
Rake Lane, Milford, Godalming, Surrey
GU8-5AB England.

GEO Report

Francis Bell2

Thanet Offshore Wind FarmJohn Tellick

3

Colouring APT Images in WXSATLes Hamilton

4

BUFR Files What are they & what can you do with them Francis Breame

7

EUMETCast keeps Gliders and Ultra Lights flying

Esko Petäjä

11

The Aurora

Les Hamilton

Printing
Hedgerow Print
16 Marsh Lane
Crediton
Devon EX17 1ES

GEO Symposium 20111217

Observations

Robert Moore

18

ESA Announce Third Generation Meteosat

ESA

20

Attenuation by glass

Robert Denton

20

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

GEO at the National Hamfest

Francis Bell21

The PADAT137 Again

Ruud Jansen

23

Copyright GEO © 2010
The contents of this Quarterly remain theintellectual property of the Group for Earth
Observation Ltd. and its contributors.
Copying of text or images, either from theprinted Quarterly or from any electronicallystored source, is forbidden without
permission from the Editor.

The Quarterly Question

Francis Bell28

Jarno Schipper

30

A View from North Cyprus

Nigel Heasman

33

Using InfanView for remote Animations

Terence Smith

35

GEO Attends the ENVI-Ham ConferenceFrancis Bell38

Douglas Deans

41

GEO Shopi

NOAA Satellite Predictions for the UK and Western Europeii

Helplines and Internet Discussion Groupsiii

Copy Deadline for the next issue of GEO Quarterlyiii

GEO Membership Renewal Form

iv

GEO Returns to EUMETSAT in 2011
EUMeTRAIN

28

Feedback
Computer Corner40

GEO Quarterly No 28

Group for Earth Observation

December 2010

Francis BellThe past few months have been particularly busy for me
progressing the interests of GEO. In late July there was the
AMSAT-UK colloquium in Guildford where David Simmonsand I made a presentation to the delegates relating to the
new Envi-Ham project. Encouragingly, the feedback fromthis presentation has been very positive. I believe three
AMSAT-UK members successfully applied for an Envi-Ham
license to join the project. There were also the National
Hamfest held at Newark, the RMetS conference at Reading
which I attended fleetingly on one day, and my three-day
visit to Italy representing GEO at the joint AMSAT-Italia /Envi-Ham conference at Frascati. As I write there is still theSouth London Computer and Radio Fair to be held at
Kempton Park in November to come. Some reports of these
event appear elsewhere in this Quarterly.
The European Space Agency (ESA) ‘Bulletin’
I have just received my copy of the latest edition of the ESA
Bulletin (No 143). I have previously reported to GEO
members about this publication. I enjoy reading the paper
copy which is sent to me; however, out of curiosity for thisedition, I also looked at ESA’s website for the same
publication. The web version was identical, even to theelectronic method of turning pages. To access ‘Bulletin No.
143’ visit www.esa.int/publications. I found this particular
Bulletin interesting because it covers topics such as
satellite observations of earthquake damage, oil spills in
the Caribbean and atmospheric shedding of vortices southof the Canary Islands, a phenomenon which has beenfeatured from time to time in GEO Quarterly. I was alsointerested in page 15 which analyses the water recycling
within the International Space Station. I have anotherinterest relating to water in the ISS because they are
currently flying one of my experiments relating to the
behaviour of water in zero gravity. More on this topic in a
future Quarterly.

unless you are serious! Examples of images I have received
using my home system are published in this and previous
Quarterlies, and can be stunning in detail. If you live
within the Ku band footprint of the geostationary satellite
Eutelsat W2A, located at 10°E, which covers Europe thenyou should be able to receive Envi-Ham data for yourself.
A very serious point here. If potential users of satellite data,such as amateur, educational and non-commercialorganisations express little interest in receiving satellite
images and other data then there will be little incentive forsatellite operators such as ESA to provide a dissemination
infrastructure them. I know ESA’s plans are well in handfor future generations of Earth observation satellites suchas ‘Sentinal’, and I hope a system will be in place allowing
users like myself access to these data.
Banking changes
The decision has been taken to close our Barclaycard
account, effective from the end of 2010. In the past the
Barclaycard account has been very useful, but today ittransacts very little business and, because of its fixedmonthly charge it is judged no longer worthwhile. Payments
via PayPal, cheque or direct bank transfer are the preferredmeans of money transactions.
Membership issues.
Here is my usual and constant reminder for you to renew
your membership when it becomes due. It can be adestructive process: you forget to renew your membershiphence the consequences that you receive no more
Quarterlies to remind you that you are a member of GEO.
The reason I am writing this now is that I am just about topost some 100 reminder letters to lapsed members, aworthwhile exercise, because there will be positive responses
from many, but it’s just so costly and time consuming.

Envi-Ham
Elsewhere in this Quarterly is an account of my recent visit
to Frascati, Italy. It is quite straightforward, almost like adiary, but in the background there is information andencouragement for those GEO members who may beinterested in participating in the Envi-Ham project. When I
joined the project about a year ago my only direct cost was
the purchase of a one-metre dish from the local satellite TV
shop, which cost me £80. I already owned a DVB Worldsatellite receiver. If you don’t have one, it costs £60 fromthe GEO shop. The receiving and display software is freefrom ESA. Of course you need a computer!

Coming Events
The United Kingdom Space Agency (UKSA) are expected tohave a conference in Godalming Surrey in late March 2011.
GEO will attend if invited.

Both a note of encouragement and caution here. ESA, via
the Envi-Ham project, have agreed to issue without charge
100 licenses for this project (70 having already been
issued). I know nothing of their policy beyond these 100.
My usual proviso applies here: don’t apply for a license
unless you are really serious about Envi-Ham reception
because it will just clog up the system for others; however,
if you wish to participate then contact ESA-ESRINusing attheir email address (tta@esa.int), stating that you want toparticipate in the Envi-Ham project. Again, don’t do thisAMSAT-UK are holding their annual colloquium from July
29-31, 2011 at the Holiday Inn Guildford. It is hoped that
GEO will be represented in some way, if invited.

2

NOAA are holding a Direct Readout conference In Miami
Florida April 2011. GEO will be represented either by anindividual member or, if necessary, by a poster presentation.
EUMETSAT are holding their annual conference in Norwayfrom September 5-9, 2011. Again GEO will try to be
represented by literature and a poster presentation.

GEO Symposium. The date and venue for this event still
have to be fixed.
There are other plans for GEO events in 2011 and details,
which still have to be finalised, will be published both on
our website and in the March 2011 Quarterly.

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December 2010

Group for Earth Observation

GEO Quarterly No 28

Thanet Offshore Wind Farm, Kent, England
John Tellick

Credit: ESA, Siemens and Vattenfall UK

The world’s largest offshore wind farm, off the UK’s Kent coastin the North Sea, is seen in this Envisat radar image. The
Thanet Offshore Wind Farm opened last week on 23 September,boosting
UK
windenergycapacityby
30%.

The wind farm is made up of 100 turbines that generate 300
megawatts (MW) of renewable electricity – enough to power
more than 200 000 homes.
Continued on page 6

3

GEO Quarterly No 28

Group for Earth Observation

December 2010

Les Hamilton

After describing how to set up an APT Ground Station in GEO
Quarterly 27, and recommending WxSat as the recording software,
this article takes newcomers a stage further by explaining how to
obtain attractive colour composite images from WxSat. But first, anapology is in order and I'm grateful to Laurence Holderness forpointing this error out to me. The previous article incorrectly listed
the available NOAA satellites. The current satellites are of course
NOAAs 15, 18 and 19. With a number of pages still to be filled ascopy deadline approached, we decided to reprint this article fromour Launch issue for the benefit of newcomers to APT; and as so
often is the case, a rushed job creates mistakes. I hope no-one wasseriously inconvenienced spending hours searching for a nonexistent NOAA-12.
These days, most APT enthusiasts use more modern software suchas SatSignal[1] and WxToImg[2] to produce APT images, as they
offer a much wider range of features, are easier to configure, andhave been frequently updated over the years following user
feedback. WxSat was the first program of its type, has not been
updated for over a decade now, and is consequently harder to workwith. Nevertheless, WxSat does offer a challenge, and is capable ofproducing excellent coloured APT images. Just one word of
warning: during the winter months, coloured images are notfeasible, due to the low intensity of winter sunlight which renders
the visible images sadly lacking in detail. The NOAA-19 pass used
for figure 1 was acquired on October 2 this year and the colour
composite version (figure 6) is decidedly lacking in contrast.
Installing WxSat
The most recent version of the software is WxSat 2.59, released in
1999, available as the self-installing file inst257e.exe [3]. Just run
this file to install the program, complete with subfolders for BMP
images and WAV files, and a desktop shortcut. Connect the audio
output from your weather satellite receiver to the left channel of thesound-card, and you’re ready to start. (In practice, any stereo audio
lead with a 3.5 mm jack-plug at each end should do the needful).

Figure 1 - NOAA 19 at 13:10 UT on October 2, 2010

figure 1, which shows the two NOAA images side by side (infraredon left, visible on right). Although you will probably obtain an imageof sorts on your first attempt, it may well be too dark or overly light,
and lack a full range of tones. To produce an optimum result, youmust make adjustments to WxSat’s Parameter Window and apply
them to a saved WAV file.
Setting the Luminance Range
Immediately after decoding an image from a saved WAV file, click<calibrate / Histogram> on the WxSat menu bar. A histogram
overlay will pop up over the image (figure 3). To ensure the widest
range of tones in the image, the upper curve (Amplitude
distribution) must stretch along the baseline to as nearly as possible
1.00. If it only stretches to 0.50, the image will be very dark; if it
overflows beyond 1.00 the image will be pale with washed-out
cloud highlights.
To adjust the amplitude distribution in the image, click the

Decoding NOAA Signals with WxSat
WxSat permits the user to produce images in real-time during
actual reception of a NOAA satellite signal. This image is saved in
BMP bitmap format while the raw data can be archived as a wave
(WAV) file. The program can also allow unattended capture ofimages and wave files, the latter being specially useful for future
decoding and manipulation purposes. There are facilities to decode
either NOAA channel (visible or infrared) individually, to decodeboth images side-by-side, and even to combine the two channels tocreate a colour composite image (though principally during thesummer half-year, when daylight levels are high).

<Parameters> option on the menu bar to reveal the ParameterSoundcard Capture
Load WxSat, open the <Parameters> menu and select item No 0.
By default, this is configured to produce a visible and an IR
greyscale image, side by side, as shown in figure 1.

Saving the New Parameters
After making the above changes to the default parameter set theymust be saved in order to be used automatically with future NOAA
data. Do not click the ‘OK’ button at the foot of the Parameter
Window yet or your changes will be lost when you load the next file.
Instead, click the <File> option on the Parameter Window’s own
menu bar and click <Save Current Parameter Set> followed by ‘OK’
in the subsequent ‘Save Parameter Set’ confirmation window. When
you are asked to confirm ‘Overwrite existing parameter set’ in the‘Store Parameters’ popup window—click ‘OK’ to confirm. Now you
can safely click ‘OK’ at the foot of the Parameter Window tocomplete the process. All subsequent images from this satellite
should now decode with a full range of tones. You may wish to finetune the 'BasicAmp' value occasionally as solar illumination waxes
and wanes over the year.

From the <Recording> menu, select ‘Start at Subcarrier’ then ‘Save
Bitmap & Wave’. This means that you will be able to see the image
building on screen as the satellite passes overhead but also store
the data as a WAV file for future manipulation. As soon as a NOAAAPT signal is detected, WxSat will start decoding it and the image
will build up on the screen, one line at a time. Files are saved withnames derived from the PC clock, e.g. the file 07231341.wav, which
was recorded starting at 13.41 UT on July 23.
The Initial NOAA image
If all goes well, you should receive an image similar to the one in4

Window (figure 2), then select the topmost option ‘Decoding’. The
key item is the value in the <BasicAmp> field. Keep adjusting thisvalue and decoding the WAV file until its histogram stretches fully
across the graph.
Next, the luminance histogram (figure 3) must also be adjusted tofit along its horizontal axis, in identical fashion. You can do this bymaking adjustments to the <Ampl.1> value on the Parameter
Window. Processed images should now display a full range ofgreyscale tones.

www.geo-web.org.uk

December 2010

Group for Earth Observation

Figure 2 - The WxSat Parameter Window

GEO Quarterly No 28

Figure 3 - The WxSat Histogram Display

Processing Wave Files
Every WAV file you save on your hard drive contains all the datarequired to reproduce visible light, infrared andcolour composite images. The file can be
decoded time and again while you experimentwith the variables in WxSat’s Parameter
Window. So, after selecting a WAV file, you candecide which image to decode from the<Parameter> option (figure 4). Select the NOAA_VIS button to decode just a channel-2 visible
light image, NOAA_IR for the channel-4 infrared
image or NOAA_mIR for the channel-3 overnight
IR image. All these modes produce fullresolution 1040 pixel-wide images. (Note thatmIR is only transmitted during the hours ofdarkness, has poor contrast and does notprovide very satisfying images). To create animage, move to the <File> menu and select'Start processing'. Decoding may be terminatedat any time through the <File/Stop Processing>
Figure 4
option (or just pressing ‘S’ on the keyboard).
Images processed from WAV files are not saved automatically so
you must save them manually using the <Bitmap/Save> option.
Note
You will also have to adjust the specific 'BasicAmp' and 'Amp.1'
values and save these for each of option on this menu to obtain
optimum results.
Automatic Image Acquisition
For those who have to be at work for most of the day, automatic,
unattended reception of satellite images is highly desirable, and
WxSat is well able to meet this need through the <Recording>menu. There are several possibilities—you can choose to savebitmap images, wave files, or both.

(though generally this gives good results only between March andOctober, when daylight is strongest). This simple process can
produce surprisingly attractive results once you have optimised theparameters, in particular, detailing layering in cloud structure by
subtle changes in hue. Only the middle luminance values are
modified by this process, as WxSat retains black and dark neutral
shades for the lowest intensities (sea) and white and light greys forthe highest intensities (cloud).
First, select the ‘NO_VIS+IR’ parameter set from the Decoding
Parameters page. Note that the ‘DualCh’ box is already selected,
an essential prerequisite for producing coloured images. Follow theprocedure already described above for histogram optimisation of
monochrome images. Note however, that the upper histogram now
shows two curves (figure 5), a black one containing the channel-2,
visible light data, plus a red one with the channel-4, infrared data.
This time, the entire histogram, from the start of the black curve tothe conclusion of the red curve, must sit squarely between zero and1.00 on the horizontal axis.
Colour Adjustment using the Lower Histogram
The lower histogram consists of two overlapping curves, the black
channel-2 trace and a multicoloured trace representing channel-4.
First, adjust the <Ampl.1> value so that the black curve of the'Luminance/Chrominance' histogram lies exactly between zero and1.00 on the horizontal axis (exactly as previously), then adjust the<Ampl.2> field to ensure that the coloured curve straddles the samerange. As usual, decode a file following each adjustment till you
achieve a balanced histogram.
You will certainly be obtaining coloured images now, but you may
find that the land colouring is too 'blue' or 'cold' for your taste. Thisis easily rectified by gradually decreasing the value in the<Offset 2> field; this slides the coloured histogram to the left (itdoesn't matter if it no longer stretches fully to 1.00). As this value
increases, more and more brown tones start appearing in the land
areas.

Use the menu to select a recording mode, say NOAA_VIS, makecertain that your receiver is active on the correct channel, thenmake your selection from the <Recording/Start at Subcarrier>options. Each time the satellite passes over your location, WxSat
will become active on detecting the satellite signal, and save data
continuously until the signal fades again. The process is elegant
and works perfectly for all the NOAA satellites.

I find that the default value of -0.12 has to be decreased to between-0.20 and -0.30 to produce land showing a pleasing mix of green
and brownish tones. Experiment till you find the value that seems
most realistic and save it using the <File> option in the Parameter
Window. Provided output from your receiver into the soundcard isconstant, these settings should not require changing again.

How to Make Colour Composite Images
WxSat can produce attractive coloured images by using the IR
channel data to impose a colour palette on the visible image

Summary
Even though it is now somewhat dated, WxSat is still one of thebest entry-level software packages available for decoding weather

www.geo-web.org.uk

5

GEO Quarterly No 28

Group for Earth Observation

December 2010

Figure 5 - Histograms for Colouring Images

satellite signals, particularly as it is completely free of charge foramateur use. In addition to producing high quality monochrome
APT images showing striking detail, the program includes a few
features for optimising image quality.
For the enthusiast who enjoys experimenting, WxSat is a dreamcome true. However, as can be seen from the colour composite
image in figure 6, cloud structures do tend to have a distinct colour
cast that cannot easily be corrected. Even after all these years, I
still consider WxSat to be the best software for recording WAV files
from NOAA satellite transmissions while at the same time providing
an immediate rough idea of the scene depicted. But I have longsince moved on to use other software (see references) to create
coloured images that suit my taste.
Thanet Offshore Wind Farm continued from page 3.
Some 12 km off the most eastern part of Kent, the farmcovers an area of 35 sq km. The distance between turbines,
each 115 m tall, is approximately 500 m along rows and 800
m between rows.
There are about 250 wind farms operating in the UK, with afurther 12 offshore farms, and plans are under way to installanother 10 000 turbines. The farms are part of a plan to cut
greenhouse gas emissions from coal, oil and gas-fired power
stations and help Europe meet its climate change targets.
Offshore wind farms have started to contribute important
supplies of renewable energy. However, to be viable they
have to generate at least 200 MW, and building on that scalecosts at least €300 million.
Quantifying the amount of energy that can be expected froma prospective offshore wind farm site is vitally important forincreasing the cost-effectiveness of planning wind farms.
The traditional approach to obtain this information is tomeasure coastal wind with an offshore meteorological mast
for at least a year. Gathering in-situ data from a single mastcan cost a million euros a year, and provides data for only asmall area.
Using data from Earth observation satellites enables a shift
from a local to a global view and provides a cost-effective
approach to determining potential energy fields. The

6

Figure 6 - NOAA 19 colour composite - 13:10 UT on October 2, 2010

References
1 http://www.satsignal.eu/software/satsignal.htm
2 http://www.wxtoimg.com
3 http://www.hffax.de/inst257e.exe

sophisticated radar sensors on ESA’s ERS-2 and Envisat
satellites can provide high-resolution 100-m data on thewind field, and a 15-year-long data archive is available.
Optical sensors such as Envisat’s Medium Resolution
Imaging Spectrometer can be used to carry out environmental
impact assessments. Satellite images can also be used formarine traffic management during initial construction andlater maintenance work, as well as for forecasting dailyenergy production.
The Gunfleet Sands Offshore Wind Farm is visible off theEssex coast (centre top), and the port town of Dover is seenin the bottom as a white circular feature on the coastline.
Envisat’s Advanced Synthetic Aperture Radar acquired
this image on 14 September.
Siemens connection map
As part of the grid connection for the Thanet offshore wind
farm, Siemens is constructing an offshore substation
platform which will be the world’s largest to date and thefirst with more than one power Transformer. A 33/132-kV
substation with two 180-MVA power transformers will be
installed on this platform. Prysmian will supply two threephase 132-kV high-voltage subsea cables to transport theelectrical power to the grid connection point, a new highvoltage switching station, which will be built by Siemensin Richborough, Kent.

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December 2010

Group for Earth Observation

GEO Quarterly No 28

Francis Breame - vf0123@btinternet.com
Introduction
A lot of data files broadcast by EUMETCast are in the BUFR
format (see my Internet site [1] for a partial list). These
somewhat enigmatic files have generally been viewed asdifficult to use, mainly because of the lack of amateurfriendly interpretation software [4]. A notable exception isDavid Taylor’s BUFR Viewer [2], another in his definitive lineof meteorological display software, which displays
scatterometer and polar winds data.
So what exactly is BUFR? Standing for Binary Universal
Form for the Representation of meteorological data, it ismore properly known as the World MeteorologicalOrganization (WMO) binary code FM 94 [3,5]. It was first
approved by the MWO in 1988 and is widely used within themeteorological community. It apparently had the following
design aims:
         a point).
                 
end, extensive use is made of external tables which are
use to expand 'data definitions' within the file (which is
why it is not completely self-defining). New data
definitions can be added by updating the tables, rather
than by changing the BUFR decoder itself. The data
itself is encoded to use minimum space, as well as
using built-in data compression. A consequence is thatthe file is just a string of binary 1s and 0s and not text
which could be human-read.

there is nothing in BUFR which mandates this. A message ismade up of a number of headers which provide general
information about the message, and data descriptors which
define the data format. Each descriptor is a number of theform n-nn-nnn, e.g. 0-01-007, which is used to access a
BUFR table, which in turn defines how the data is encoded
and what units it is in. Some descriptors perform operations
on the data, rather than simply describing data values.
A message also contains subsets, which hold the data as
defined by the data descriptors. There are one or more datasubsets, each having the same format. Usually there arequite a few, e.g. a number of observations.
I have introduced further terminology, data fields and data
elements, which are not part of the BUFR specification.
Each subset consists of a number of data fields, each fieldholding one data element per subset.
A data field corresponds to a data descriptor which iscapable of holding data (not all are). A data element is thedata contained within a data field, per subset. Thus eachsubset holds a row of data elements, one for each field.
So, conceptually, wheres = total number of subsets
n = total number of fields
we have

Whilst there are probably better and more general-purpose
ways of doing all this now, BUFR, it seems, is here to stay.
Unfortunately, BUFR seems to have been, and continues tobe, modified over the years, with a considerable number ofextensions as particular facilities were found to be needed.
This doesn’t make the task of writing a decoder easy, as
there are many special cases and exceptions to be taken into
account if a complete job is to be done.
Data elements can be empty if the data is not available.
A couple of years ago, I decided to write some software to
analyse the data definition part of the EUMETCast BUFR
files to find out just what was in each one. The answer wasquite surprising—there is often a lot more that one would
expect. I emphasise that I am not a meteorologist, so a lot of
the data is over my head. Things like temperature, pressure,and wind speed I can understand: however, 'parcel lifted
index' is beyond me.
Once I learned something about the file structure, I extended
my program to decode the data into numbers suitable forprocessing by other software, and then added display
facilities so that geographical data could be plotted on amap. Thus BUFRdisplay came into being.
BUFR File Basics
How is a BUFR file structured? I appreciate that this is notof general interest, but it shows where some of theterminology such as 'message' and 'subset' fits in.
Each BUFR file consists of one or more messages. Normallyeach message contains data in the same format, although

Values are usually simple numbers (e.g. degrees, m/s), but
can also refer to code values which require lookup in yet
another BUFR table to discover the meaning of the number.
For example, descriptor 0-01-007 is 'Satellite Identifier'. A
value of 209, say, if looked up in the table for 0-01-007, willtranslate to 'NOAA 18'. Flags are similar, but the number is
encoded differently so that several meanings can beincorporated within a single number.
Finally, each message is terminated by an end marker.
The BUFRdisplay Program
If you want to try this software, the latest version of myprogram, BUFRdisplay, can be downloaded from my Internet
site [1]. I’ll just give a brief outline of it here, as it has quite afew options. A fuller user guide is included with the program.
BUFRdisplay is written in Perl and Perl/Tk, and is
distributed as a self-contained .exe file which includes all thenecessary Perl runtime files. You do not therefore need towww.geo-web.org.uk

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have Perl installed. It runs under most versions of Windows.
Being written in Perl, it should also run under Linux but I
haven’t tested this yet.
BUFRdisplay isn’t installed as such: just unzip thedownloaded file 'BUFRdisplay.zip' to a convenient folder thenclick on 'BUFRdisplay.exe' to run it (or setup a shortcut on
your desktop). The first time you run the program it will
cache some files which will make it take longer to start.
Thereafter it will start normally.
Using BUFRdisplay
When run, you should see the main program window(figure 1). Assuming that you have used David Taylor’s MSG
Data Manager, MetOp Manager, or AVHRR Manager to savesome EUMETCast files, use the <Files/Open> menu to selectone from the folder where it is stored. I’ll use Global
Instability Index data in this example, which is saved by
MSG Data Manager under the MSG/MPEF folder structure.
A typical filename is 201009200000-gii.bfr+.
BUFRdisplay will scan the first message in the file andproduce, in the DATA SELECTION pane, a list of the data
fields contained therein. This example in the table below
doesn’t contain many fields; some files contain hundreds.
Some field numbers may be missing (2 and 22 in this case).
This is either because they are used internally by BUFR itself
or because they contain data which is not relevant.
Check that 'Data field' is selected in the DATA SELECTION
pane. Browse through the fields, choose one which looks
interesting—say 'K index'—and click on it. This isfield No 17, which
Data Field
Unit
will appear in the
1 Satellite identifier
Code table'Data field' box
underneath.
3 Satellite classification
Code table
4 Segment size (nadir) Xm

5 Segment size (nadir) Ym

6 Yearyear

7 Month

month

8 Day

day

9 Hourhour

10 Minute

minute11 Secondsecond12 Row number

numeric

13 Column number

numeric

14 Latitude (high accuracy)

degree15 Longitude (high accuracy)

degree16 Satellite zenith angle

degree17 K index

K

18 KO index

K

19 Parcel lifted index

K

20 Maximum buoyancy

K

21 Precipitable waterkg m-223 Pressure

Pa

24 Pressure

Pa

25 Precipitable waterkg m-226 Pressure

Pa

27 Pressure

Pa

28 Precipitable waterkg m-229 Pressure

Pa

30 PressurePa

31 Precipitable waterkg m-28'Latitude field' (No14) and 'Longitude
field' (No 15) will be
automaticallyselected (if there areno latitude/
longitude fields,
then the data is
non-geographicaland cannot be
displayed). Now
press 'Input/decode
data' at the bottomof the screen to
decode the file (thisis not done
automatically when
the file is opened
since some files cancontain vast
amounts of data).
Finally, press'Generate map' andyou should see
something likefigure 2, the value
ranges being colour
coded. Once you’ve
input the data, you
can make different
data selections andgenerate new maps.
Map Projections
Data can bedisplayed in avariety of map

Figure 1 - The main BUFRdisplay window

projections, probably far more than are actually useful, but I
like playing with them. The two which are handiest are
Mercator (the default) and orthographic, the latter producing
a view of the Earth as seen from infinity, which isparticularly useful for polar views. By default, the BUFR data
is used to select automatically the latitude and longitude
limits of the map for Mercator projection, or the central
latitude and longitude for orthographic. However, you canchoose the map parameters yourself. A zoom facility allows
you to draw a map larger than the screen, which can then be
scrolled. This is mostly useful for the orthographic
projection.
An example of orthographic projection is shown in figure 3,
which shows Total Ozone data.
Templates
Because some BUFR files have a very large number of data
fields, many of which are of little interest, certain files have atemplate facility to make data selection easier (for technicalreasons, not all files can at the moment use templates).
Select 'Use templates' in the DATA SELECTION pane, andyou will be given a shorter list of interesting data items
rather than the full set. I have selected those items which I
think are interesting, but let me know if you would likechanges.
Vector Display
Some data, notably winds, can be displayed as a vector
quantity, consisting of two data fields providing both a value
and a direction. To display these, if not using templates, tick
'Plot vector mode' in the OPTIONS pane at the top of
figure 1. Then choose 'Data field' from the DATASELECTION pane and select the data (value) field as before.
Then choose 'Vector direction field' and make your selection
from the associated direction data field. If using templates,
this is all done automatically.
Two displays are possible—a simple arrow pointing towards
the direction value and standard winds symbols selected

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Figure 2 - A map of K index generated by BUFRdisplay

Figure 3 - An orthographic map of Total Ozone concentration

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Figure 4 - An example of Polar Winds databy ticking 'Vectors use wind symbols' under OPTIONS. I
believe that I have the latter right but I’m open tocorrection. The direction of either symbol will be corrected
for the map projection so that it is shown relative to northon the map. An example of Polar Winds data is shown infigure 4.
Multiple Files
A lot of data is distributed across several files, eachcontributing to a world view. When opening a file, it istherefore possible to select several files (by holding down
the control key while clicking on them), and process themas if they were one. Beware though that this can produce a
lot of data, which may therefore take some time to decode.
The files must obviously all be of the same type.
List BUFRThis button is used to generate a text file containing adescription of the contents of the opened BUFR file(s). A
separate window is opened which allows the degree of
detail to be specified.
BUFR–>CSVThis button is used to generate a comma-separated
variable (CSV) file containing decoded data from the opened
BUFR file(s), which will be useful if you want to process thedata with another program. The format of this file is givenin the user guide. Again, a separate window is opened
which allows the data to be filtered if there is a large
quantity.
I also have available a separate program, called
BUFRextract, which uses the same decoding engine andproduces the same CSV file. It doesn’t have a Windows
user interface and so is useful if you want to call it as a
decoder from another program of your own. In fact, David
Taylor’s BUFR Viewer uses this for decoding some of its
data.

10

Caveats
Bear in mind that BUFRdisplay is based on my personalunderstanding of the BUFR format, which is incomplete andpossibly incorrect in some areas. In particular.
     "#  $&*&<  
may well handle other BUFR files, but BUFR includes a
lot of cases which are rarely used and which it may nothandle properly.
 * "#          
quality of the data, which is important to professionals
but less so to this community. BUFRdisplay ignores it.
   >$   @  $ X  
limited beta testing, so there are certainly bugs (thanks
Douglas/Ian).
 "#      $  X 
things are apt to change without notice!
Conclusion
There is a lot of data available in BUFR format. Admittedly
it’s not as easy to use or appreciate as simple images, but try
having a look at it and see what you can do with it. Pleasecontact me (vf0123@btinternet.com) with any problems orsuggestions concerning my program.
Links and References
1 My Internet site
http://www.vf0123.btinternet.co.uk/
2 David Taylor’s BUFR Viewer program
http://www.satsignal.eu/software/bufr-viewer.html
3 WMO Documentation, especially 306 Manual On Codes, vol 1.2
http://www.wmo.int/pages/themes/wmoprod/manuals.html
4 European Centre for Medium-Range Weather Forecasts (ECMWF) Unix BUFR decoding software
http://www.ecmwf.int/products/data/software/bufr.html
5 A Guide To The WMO Code Form FM 94 BUFR - very useful if you
want to write a decoder
dss.ucar.edu/docs/formats/bufr/bufr.pdf

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GEO Quarterly No 28

EUMETCast & Satsignal software keeps Gliders and Ultra lights flying
Esko Petäjä & Hannu Korhonen
This article describes how EUMETCast and SatSignal
software can be used to assist in flying gliders and otherlight planes such as ultralights. The history of gliding started
with Sir George Cayley around 1849 and later, Otto
Lilienthal, who started to build (barely) controllable gliders
around 1880.

Glider having Aero tow

Otto Lilienthal first hop with glider

How Gliders are Built
Gliders—or sailplanes—have a cockpit between the plane’swings, where the pilot sits. Materials used in these aircraft
are carbon-fibre, fibre-glass and kevlar. There are two
methods of launching sailplanes: towing behind either a lightaeroplane or a ground-based winch. In the former case, theglider is towed behind a powered plane using a rope about
60 metres long; the glider pilot then releases the rope after
reaching the desired altitude. For a winch launching, apowerful stationary engine located on the ground at the far
end of the launch area is attached to the glider by an 800–
1200 metre length of cable, which the winch rapidly winds
in.

Flying by Glider
Once launched, gliders must gain height using thermals,
rising currents of warmed air. After finding a thermal, aplane can stay aloft for several hours and fly hundreds ofkilometres. To able to do this, glider pilots must have good
information as to where they can expect to find thermals,
and also how the weather is forecast to develop during a longday. Without this information, the pilot could find himself
sitting, in his cockpit, in a harvest field.

Hannu Korhonen in his cockpit

Esko with Dynamic WT-9 ultra light plane
Cockpit of glider

Continued on page 44

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December 2010

Les Hamilton
David Taylor’s article in GEO Quarterly 27, relating his
experiences ‘aurora hunting’ north of Norway, reminded methat the fast approaching winter could be one of the best
opportunities in a long while for most GEO readers to
observe the phenomenon. Aurorae occur all the time in
Earth’s far polar regions but are a much rarer occurrencein the planet’s temperate zones. The frequency andstrength of aurorae mirror solar activity; they are observed
to best advantage within a couple of years of the peak of
the eleven-year sunspot cycle. NASA currently forecaststhat the next solar maximum will occur during May 2013.
If you haven’t seen the aurora before, readers may havetheir best chance to remedy the situation during the clear,dark nights of the next few winters. August 2010 has
already produced numerous aurorae world-wide, such asthat photographed by Colin Chatfield below on August 3,
this year.
The Active Sun
Although, to the casual observer, the sun is simply a large
uniformly white disc in the sky, closer study reveals that
this is not the case. As early as the 4th century BC, Greek
observers had recorded what we now call sunspots on thesurface of the sun. These mysterious dark patches appear
and fade: some last only a few hours while others survive
for several complete revolutions around the sun, the actual
numbers of sunspots varying over an approximately 11-year
period. During this cycle, the sun gradually changes from astate of low activity (solar minimum, few sunspots) to highactivity (solar maximum, many sunspots) then back to low
activity once more.
The variability of our sun is often taken on board by
misguided opponents of man-made climate change. In
denial over the role elevated atmospheric carbon dioxide
concentration plays, they claim the effects we areobserving stem from variable solar output. Given that the
average solar output received over the surface of ourplanet is 1366 Wm-2 (watt/square metre), and thevariance between solar maximum and minimum is aminuscule ±0.65 Wm-2 this idea just does not hold water.
While the average temperature of the sun’s surface is close
to 6000°C, that of sunspots can be as much as 1500°
cooler, and hence they appear darker. These sunspots are
regions of intense magnetic activity, which can heat the

Figure 1 - A fine display of the Northern Lights above Saskatoon, Saskatchewan, Canada on August 3, 2010.
Photographed by Colin Chatfield using a Canon 40D with Tokina 10-17mm fisheye lens - ISO: 1600, Exposure: 20s, f/3.5, Focal Length: 10mm.

12

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overlying solar corona to temperatures as high as two
million°C; they also generate immense turbulence in thecorona, which may lead to the production of a Coronal Mass
Ejection (CME)—the sun’s equivalent of a volcanic eruption—
which hurls vast quantities of material out into space atenormous speed. As noted above, the sun is now well on theway towards its next sunspot maximum.
Figure 2, acquired by the Solar Terrestrial Relations
Observations (STEREO) spacecraft last May, shows a CME
leaving the solar corona. Though directed predominately
sideways and not directly towards the Earth, its effect stillcreated coloured auroras across polar skies. The Sun ejected
this CME on May 23 this year, when a bright mass ofcharged particles looped from its atmosphere and was
catapulted out into space. The image shows only the corona,
the outermost layer of the solar atmosphere. A dark disk inthe detector obscures the glare of the Sun and the whitecircle represents the Sun’s surface. When the charged
particles from this CME reached Earth, they caused nodamage, but did generate sheets of coloured light dancing
across polar skies.

Figure 3 - Interaction of the Solar Wind with Earth’s Magnetic Field

At a distance of some 70 000 km from Earth, the solar windencounters the planet’s magnetosphere: this is the volume ofspace within which moving charged particles interact with
Earth’s magnetic field (figure 3). The electromagnetic
interaction between Earth’s magnetic field and the solar
wind causes charged particles to be deflected along themagnetic field lines. Though some of these particles simply
travel around the Earth and back into space, the electronsin particular (because of their relatively tiny mass) become
funnelled towards the north and south poles. There, theycollide with molecules of atmospheric gases, chiefly oxygenand nitrogen, at an altitude of some 80 to 120 kilometres.
This has several effects
 @         Z2 and N2) can be split
into single atoms by the energy of collision        $     electrons stripped away to create an ion
             displaced into excited energy levels within their parent
particle
All these processes absorb kinetic energy from the solar
wind particles and produce excited, unstable intermediates;when these return to their original states, this extra
excitation energy is emitted in the form of coloured light.

Figure 2 - A CME is ejected from the Sun’s corona on May 23, 2010

The Auroral Oval
Although the aurora is not visible to the naked eye regularly
on a nightly basis, it is almost always present. The solar
wind is continuous and the stream of particles bombarding
Earth’s atmosphere never ceases. The same NOAA satellites
that provide us with APT and AVHRR imagery of the Earthand its weather monitor the aurora every time they orbit
above the poles. Figure 4 shows a typical auroral oval chart

NASA image courtesy the Solar Terrestrial Relations Observatory Team.

The front cover image, obtained from NASA’s new Solar
Dynamics Observatory satellite (SDO) on August 1, 2010,shows the first major Earth-directed coronal mass ejection
for some considerable time being launched towards us.
Almost the entire Earth-facing side of the sun displays atumult of activity and this multi-wavelength extreme
ultraviolet image shows the sun's northern hemisphere
during mid-eruption. A few days later there were reports ofsplendid aurorae over Denmark, Norway, Greenland,
Germany the northern United States and Canada as
material from the CME encountered the atmosphere: see
Colin Chatfield’s fisheye photograph of the ensuing aurora
over Canada, above.
What Causes the Aurora?
Earth’s aurorae originate 150 million kilometres away, in the
sun’s corona, that normally invisible outermost layer of its
atmosphere. In addition to radiation in the form of light andheat, the sun is continuously emitting into space a highly
rarefied stream of electrically charged particles, mainly
electrons and protons. Popularly termed the solar wind, thisstream of particles travels at about 400 kilometres per
second as it moves out from the sun and takes around fourdays to reach Earth.

www.geo-web.org.uk

Figure 4 - The auroral oval surrounding the North Pole
Image: NOAA

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December 2010

Figure 5 - This is another photograph of the Northern Lights from Colin Chatsfield, Again from Canada on November 9, 2004 using a Canon Powershot A80.
ISO: 400, Exposure: 15s, f/3.2, Focal Length: 9.6 mm.

generated from NOAA-19 data on August 12, 2010. You canalways view the extent of the current auroral oval atwww.swpc.noaa.gov/pmap/

It is clear that, over Europe, the aurora only extends as far
south as Northern Norway on this date. Because themagnetic north pole is currently off the west coast ofEllesmere Island, at 83°N, the auroral oval tilts several
degrees towards North America where, in consequence, theaurora is more frequently visible than in Europe. In general,
the oval is centred some 5° to nightward of the magnetic
pole and has a typical radius of 17° of latitude, around 2400
kilometres. Observers farther away or nearer to the magnetic
pole, will observe the phenomenon less frequently.
The NOAA POES Instruments
Ever since the polar orbiting TIROS-N satellites—forerunnersof the current NOAA series—started orbiting Earth in thelate 1970s, NOAA has furnished the majority of them with aSpace Environment Monitor (SEM). This package contains
instruments to measure the flux of energetic charged
particles encountered by the satellite. The current version of
the monitor, SEM-2, has been flying aboard all satellites
since NOAA-15, as well as Metop-02. The SEM-2 contains
two instruments, the Total Energy Detector (TED) and the
The Medium Energy Proton and Electron Detector (MEPED).
The TED measures the energy flux carried by auroral
particles (principally protons and electrons) into the polar
atmosphere. The magnitude and extent of this flux provide
measures of the level of auroral activity. Data from TED is
used to produce Auroral Oval charts like figure 4.
The MEPED includes a set of solid-state particle detectorsthat monitor the intensities of energetic species from all

14

sources, including solar particle events and lower energy
galactic cosmic rays. Enhanced fluxes of these particles
entering the atmosphere can produce significant andwidespread degradation in short-wave radio propagation
and, in extreme cases, even radio blackouts.
The Aurora from Space
Spectacular though the Aurora can be when viewed from
Earth, it it even more splendid when viewed from orbit,
where it can create a halo of light girding each of Earth ’spoles. The Aurora Australis was observed by NASA’s IMAGE
satellite on September 11, 2005, four days following arecord-setting solar flare (figure 6). The glowing halo of the
Aurora appears green, superimposed on a Blue Marble imageof the Antarctic. If viewed from below, this display would
have appeared as a curtain of light shimmering across thenight sky.
Although scientists had long understood that aurorae
occurred when charged solar wind particles interacted with
the Earth’s magnetic field, they were unable to actually
measure the interaction until NASA launched the IMAGE(Imager for Magnetopause-to-Aurora Global Exploration)satellite in 2000. This satellite’s mission was to collect datathat would allow scientists to study the structure anddynamics of Earth’s magnetic field for the first time.
Designed to operate for two years, IMAGE sent its last data
to Earth in December 2005 after a highly successful fiveyear mission.
Aurorae have also been observed from both the Space
Shuttle and the International Space Station (ISS). Figure 7
shows a particularly striking green Aurora image acquired
over the southern Indian Ocean following the May 23 CME
shown in figure 2.

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Figure 7 - A striking aurora image taken from the ISS on May 29, 2010

Figure 6 - The Aurora is seen encircling Antarctica by NASA’s
IMAGE satellite during September 2005.

Image: NASA/Johnson Space Center

Image: NASA

Figure 8 - An Aurora viewed from Space Shuttle
during the 1991 solar maximum

Figure 9 - An image of the Aurora taken from the ISS on February 2, 2003
Image: NASA/Johnson Space Center

Image: NASA/Johnson Space Center

Figure 8 shows an Aurora Australis photographed during aSpace Shuttle mission at the time of the 1991 solar
maximum. Red and green colours predominate in thisview. The red aurora displays from as high as 500 km
altitude and reaches down to around 200 km. The green
aurora occurs between about 250 km to 100 km altitude.
Figure 9, acquired from the ISS some 400 km above theEarth, provides a splendid edge-on view of the upper
atmosphere, where its ‘visible edge’ at around 50 km lends
scale to the Aurora. The green emissions extend from theever present thin shell of airglow at about 100 km altitude
to perhaps 300 km. The red emissions are again at higher
altitudes. They lie atop the green and extend beyond thatlayer by a further 200 km.
Frequency of Aurorae
Aurorae occur most frequently in the years near solar
maximum, and are particularly strong after a CME is
directed straight towards the Earth. The CME increases
the density of the solar wind which in turn expands theauroral oval over the Temperate Zones, spreading theaurora closer to the equator. During the 1958 solar

maximum, the Northern Lights were observed as far south
as Rome (40°N).
It has been estimated that, given clear skies, the aurora
can be observed on well over 100 nights a year in theregions where it is most frequent. However, imaging
cameras aboard satellites—much more sensitive than thehuman eye—observe a diffuse aurora around the polar cap
almost all the time. How often the aurora can be seen
depends on several factors, not least light pollution at theobserver's location.
Over the years I have, on rare occasions, been fortunate tosee a number of auroral displays from my home innortheast Scotland. One of the most spectacular was on
April 12, 2001, when we were treated to a stunning displayof red and green Lights in the sky. This followed theeruption of a CME from one of the largest sunspots
recorded during a decade. However, a friend of mine who
used to live on a farm up country, 40 km from Aberdeen,
where light pollution was negligible, told me that sightingsof the Northern Lights were commonplace at that time,
particularly over his northern horizon.

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Polar latitudes, of course, experience the most frequentAurorae. In the northern hemisphere, there is a 50% or
greater chance of seeing an Aurora between the latitudesof 55° and 80° north, where, in theory, it could be inevidence on at least half of the nights throughout the year.
Auroral displays usually increase during the periods ofsolar maximum and are also usually more frequent during
the winter months, where the nights are longer and theskies less hazy. Occasionally, the Northern Lights havebeen observed south of latitude 35°N, usually when a large
solar CME has created a huge geomagnetic storm inEarth's outer atmosphere. This occurred during the nightof November 5 and 6, 2001, when amazing Auroral
displays were seen as far south as Texas and Arizona.
Another significant event was on the night of April 7-8,
2000 when a strong aurora was visible, not only
throughout Scotland, but right down to the south coast of
England. The effect was strong in Aberdeen, even withnearby street lighting, and took the form of a ‘vaulted
temple’, consisting of streamers, mainly green with just atinge of red, angling down on all sides from a point close to
the zenith, like fluted pillars .
Types of Auroral Display
The aurora manifests itself in numerous guises which
often change dynamically while we observe them. The
strongest and brightest aurorae tend to display as discretearcs and bands of light, often characterised by ‘folds’,
leading to a curtain-like appearance. A weak aurora may
simply produce a diffuse band of light across the northernhorizon, not dissimilar to the reflection of city lights on
cloud when seen from a distance. If you are far from any
such source of light pollution you can be sure you areobserving an aurora.
The the most common form of Aurora is the arc, whichtakes the form of a simple, slightly curving band of light
across the night sky. Arcs often extend from horizon tohorizon, a distance of several thousand kilometers or moreand can stretch more than 100 km upward, following thenear vertical magnetic field—and yet they may be less thana hundred meters thick.
Another term is the band, which refers to an Aurora which
has an irregular shape with kinks or folds. There is also
the patch aurora, in which case it resembles transient
patches of pulsating, luminous cloud. The term veil
describes an Aurora which covers a large area withuniform light, often covering most of the heavens while a
Ray aurora is made up from straight vertical shafts of lightaligned in the direction of Earth’s magnetic field lines.
Most typically, the aurora appears as either a diffuse glow
or as ‘curtains’ that generally extend east-west. Auroral
curtains consist of numerous parallel rays, all lined up
with the local direction of Earth’s magnetic field.
A superb auroral ‘curtain’ photographed in Alaska appears
at the top of the inside back cover of this issue. And below
it is a photograph obtained on August 13, 2010, from theISS, by NASA astronaut Doug Wheelock. Although there
weren’t widespread auroral displays on Earth at the time,the view from orbit was sublime. Although the planet
directly below is partially sunlit, the aurorae remain visible
against the black, starry backdrop beyond Earth’s limb.
Auroral Events of Historical SignificanceAn aurora which occurred as a result of the ‘great
geomagnetic storm’ on September 2, 1859 has been
considered the most spectacular ever witnessed. It followed
an exceptionally intense solar flare on September 1 andproduced Aurorae so extraordinarily brilliant that they
were reported in ship's logs and newspapers throughout
the United States, Europe, Japan and Australia.

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December 2010

Photographing the Aurora
Colin Chatfield
Now that you have seen the splendid aurora images
accompanying this article, some of you may now be
encouraged to try this for yourselves. So what exactly isrequired?
First, particularly if you live near street lighting, you will
have to relocate out of town to a location with minimum
light pollution, on a clear night when the moon is below thehorizon. Also, because exposure times are likely to be
10-20 seconds, a tripod is essential to prevent camera
shake. But what about the camera?
Colin Chatfield's 'green curtain' aurora (figure 5) was madeusing a relatively simple Canon PowerShot A80. This is afairly simple camera with a 3x zoom and several shooting
modes. The image was obtained using 'Auto' mode, giving a
15 second exposure. In order to prevent camera shake witha point-and-shoot camera like this, try using the timer. For
example, set the timer for a 10 second delay and let it snap
the picture, with your hands off the camera.
For more ambitious photographs like figure 1, whichdisplays the entire northern sky, a Tokina 10-17mm fisheye lens was used, and with it a digital SLR camera. Colinacquired this superb image using a Canon EOS 40D SLR, amore advanced camera which allowed him to choose
manual operating mode, setting exposure as 20 seconds
and aperture to f/3.5. While a fish-eye lens is not required,a wide or super-wide angle lens with a range from
8mm-18mm is. The other factor when choosing a lens is its‘speed’. The lower the f number the better. For example, an
f/4.5 lens is considered slow. Most kit lenses (those thatare sold in camera packages) generally range from f/3.5 to
f/5.6, so they are not so suitable for long exposureshooting. When using exposure times above 10 seconds
with a lens like that, star trails usually start to appear.
With an f/3.5 lens, up to 20-25 second exposures can betaken and with an even faster lens, such as an f/2.8 or
f/1.8, up to 60 second exposures can be taken before startrails appear.
A further advantage of this camera is that the sensitivity(ISO number) could be increased to a maximum of 3200
(the PowerShot has a maximum ISO of just 400). One
consideration however, is that the higher the ISO number,the more noise that is introduced into the photograph. Inorder to prevent camera shake in a DSLR, the best way is
to use either a wireless remote or wired shutter releasecable. That way, your fingers are not touching the shutter
release button, thus preventing shake. If you do not have aremote or a cable release, again try setting the timer. Most
DSLRs have a 10 second (or longer) delay setting that will
wait for 10 seconds after the shutter button is pressed totake the picture.
There are two more important aspects when talking about
camera shake. The first is this: if a lens with image
stabilisation is being used with a camera mounted on a
tripod, turn off the image stabilisation. The second is touse exposure delay mode, if your camera is so properly
equipped (usually just DSLRs are). This delays taking thepicture for a second or so. The specific purpose of exposure
delay is to eliminate the vibration caused by the mirror
flipping up. It's mostly useful on short duration exposures
on a tripod, where the slight and short-lived vibration isenough to cause blur. Of course, it's useful even for a longexposure if there's something bright in your image (such as
Aurora) that you are capturing.

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December 2010

Group for Earth Observation

The New York Times claimed that ‘ordinary print could beread by the light of the aurora’. This Auroral storm was also
notable as the first occasion where an Aurora became
unambiguously linked with electricity, after many thousandsof kilometres of telegraph lines were significantly disrupted
for many hours throughout the storm. Indeed, that night,
after disconnecting their normal power supply (batteries),
two operators of the American Telegraph Line between
Boston and Portland conversed with each other for some twohours, powered solely through current induced by thisAurora. Claimed to have ‘smothered two-thirds of the Earth’sskies in a blood-red aurora’, the so-called ‘Carrington flare’(named after its discoverer) that gave rise to the event also
burned out telegraph wires across Europe and the USA andcrippled all global communications, such as they were atthat time, as phantom electricity surged through telegraphwires. Navigation also became impossible as compasses
needles spun and danced in the gyrating magnetic field,
rendering them useless.
More recently, in 1989, a smaller but still enormous storm
caused the power grids in Quebec to go down for nine hours,
resulting in hundreds of millions of dollars of lost revenue.
The Colours of the Aurora
The light emitted from excited ions, atoms and molecules in
the ionosphere creates the Aurorae that we see. The actual
colour produced depends on the identity of each particularparticle that interacts with the solar wind and how strongly
its electrons become excited. Following a collision involving ahighly energetic solar wind electron, the quantity of energy
released when excited gas molecule electrons return to their
original states is likely to be large also—which would givethe Aurora a bluish tinge. On the other hand, a lessenergetic electron exciting a gas molecule would result in therelease of a smaller quantity of energy when the excited state
returns to normal: this time, the Aurora would take on areddish shade.

GEO Quarterly No 28

excited. Oxygen at about 100 kilometres altitude gives off thefamiliar yellow-green colour, whereas oxygen at higher
altitudes produces the all-red aurora. Nitrogen ions produce
the blue light while neutral nitrogen atoms give off redpurple hues. Altitude is all-important, as this governs how
closely atmospheric particles are to each on average, andhence how easily they can interact (i.e. collide) to release
their ‘excited’ energy.
As a general rule you can judge the altitude of the Aurora
from its colourRed- oxygen, above 250 km altitude
Green- oxygen, up to 250 km altitude
Purple/violet - nitrogen, above 100 km altitudeBlue- nitrogen, up to 100 km altitude
The most commonly observed colour of aurora is green,caused by light emitted from excited oxygen atoms at
wavelengths centred at 0.558 μm. Red aurorae are generated
by light emitted at a longer wavelength (0.630 μm), and othercolours such as blue and purple are also occasionallyobserved.
Acknowledgements
Thanks are due to Colin Chatfield for providing some of his
superb contemporary photographs of the Northern Lights toillustrate this article, and also for his help in producing theguide: ‘Photographing the Aurora’.
I am also indebted to sources on the Internet, too numerous
to mention, for further illustrations and backgroundinformation.
Further Reading
http://www.geo.mtu.edu/weather/aurora/
http://en.wikipedia.org/wiki/Aurora_(astronomy)
http://www-spof.gsfc.nasa.gov/Education/aurora.htm
http://www.crystalinks.com/aurora.html

Different species emit specific colours when they become

GEO Symposium 2011
Our annual symposium has been booked for 7th May 2011 at
the National Space Centre, Leicester. In the past we haveused this venue for our symposium and feed back from themembership suggests this is a favoured venue.
On the day we hope to have presentations bringing us up todate with EUMETCast, Envi-Ham, other relevant satellite
schedules together with speakers on topical issues which
relate to GEO's interest areas. GEO members are invited andencouraged to make their own presentation or run workshops
and time will be allocated within the programme for thispurpose. Contact Fancis Bell francis@geo-web.org.uk
It is anticipated that May 7th 2011 will be a busy day but time
will be allowed for personal demonstrations and importantly
for interaction with other members.
Further details will be published in our March Quarterly but
in the meantime please record the 7th May 2011 as animportant date in your diary. There are several modestly
priced hotels in Leicester for anyone staying overnight. Rob
Denton a member of GEO's management team will be taking
registrations for the symposium at the NSC Leicester. He iscurrently preparing a location map and a list of hotels the finedetail of this will be published in our next Quarterly. Please
register with Rob via email international@geo-web.org.uk

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17

GEO Quarterly No 28

Group for Earth Observation

December 2010

Observations
Robert Moore

Striking cumulonimbus cloud was visible from Robert Moore's window at 1800 (BST) on the 7th September.

freezes in winter. In the summer the prevailing winds bring ice
flows to the east coast of Sakhalin, the climate of which may
be described as ‘cold and cloudy’. The image (full page right
METOP-A 12-09-10 ) is therefore an unusually clear view of
Sakhalin.
Ownership of the island has long been disputed between
Russia and Japan. In the 19th century the majority of the
33,000 population were Russian convicts. The Korean
population, forcible moved there during the second world war
largely remains. Much of the native Ainu population moved to
Hokkaido (at bottom of picture) after the war when theJapanese were expelled.
Full Page image
With the huge amount of worldwide high resolution imagery
now available from weather satellites from a wide range ofsources including direct reception, Internet and DVB sources,
it is now very easy to find an image of a particularly interesting
meteorological condition.

A very striking cumulonimbus cloud was visible from Robert
Moore's window at 1800 (BST) on the 7th September. The
photograph shows the classic anvil formation as vigorous
convection hits the boundary of the troposphere and spreads
outwards. The overshooting tops of the cumulonimbus cloudshowed up clearly on the current Meteosat 9 imagery (above).
Sakhalin Island is Russia’s largest island. The island is veryrich in natural resources with a great diversity of wild-life andgeology. Sakhalin is in ‘the ring of fire’ and therefore
earthquake-prone.The Amur river can be seen in the left of theimage. The sea between the island and the mainland regularly

18

Often the temptation is to look at the worldwide HRPT dataand select the satellite pass that best coincides with thegeographic area of interest.
However sometimes much more can be seen when the imaging
satellite is not directly overhead and when the sun is low on
the area of interest.
This often highlights interesting
topography not seen with an overhead pass.
The image (page 22) is such an example. It shows Hurricane
Igor on the 13th September 2010, north east of the Leeward
Islands. Amazingly this was imaged by Meteosat 9 at 0
degrees and demonstrates the points made above.

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GEO Quarterly No 28

Group for Earth Observation

December 2010

ESA - Observing the EarthDevelopment of Meteosat Third Generation to startMarking a significant milestone forEurope's next fleet of meteorologicalsatellites, ESA has given the go-ahead toThales Alenia Space in France to start
work on developing the Meteosat Third
Generation.

Generation,
theMeteosat
Third
Generation (MTG) is being createdthrough cooperation between Eumetsat
and ESA to ensure continuity of highresolution meteorological data to beyond
2037.

The 'Preliminary Authorisation To
Proceed' was signed today after a kickoff meeting between ESA and Thales
Alenia Space. This approval follows
several months of negotiations that has
resulted in a final industrial team ofThales Alenia Space (FR) and the initialconsortium members, OHB (DE) and
Kayser Threde (DE), together with, in arange of complementary functions,Astrium (DE/FR).

This next series of geostationary weather
satellites will be a step change by
providing significant improvements overthe capabilities of the current Meteosat
generation.

Formal introduction of Astrium into theconsortium will take place over the next
six months.

The sounding element, which also
carries the Sentinel-4 payload for the
Global Monitoring for Environment andSecurity programme as a guest payload,
is a key innovation. For the first time,

Following on from Meteosat Second

The series will comprise six satellites:
four MTG-I imaging and two MTG-S
sounding satellites. The two types will
be positioned over the same longitude in
their geostationary orbits.

Meteosat satellites will not only image
weather systems, but also analyse theatmosphere layer by layer and provide
deeper insight into the complexities of
its chemical composition.
The first MTG-I satellite is expected inlate 2017, with the first MTG-S following
in early 2019.
With the go-ahead now in place, theresulting consortium sees Thales Alenia
Space as prime contractor andresponsible for the MTG-I imaging
satellite, including the primary Flexible
Combined Imager. OHB is prime for the
MTG-S satellite, supported by Astrium(DE) as the System Architect. The
Infrared Sounding Instrument will be
developed by Kayser Threde.
Information courtesy
ESA www.esa.int

Attenuation by GlassRob Denton g4yrz@wxsat.org

I remember some time back Francis
Bell was enquiring in GEO Quarterly
about the effect of satellite signals
onto dishes when received throughglass .My story relates to Atomic Time
Signals and GPS reception throughglass.
Having recently moved into a newhome I was very excited to find that I
would be getting new double glazed
windows. I am all for energy
conservation and cost cutting but it
was only recently I learned thedrawbacks.
On a positive note I immediately
noticedanincreaseinroom
temperature of 2 degrees and it was somuch quieter as previously my house
was single glazed.
On a drawback I noticed my DCF77
atomic time signals were being
attenuated and to make things worst,
my GPS signals for the weather satellite
programs were also being affected.
It was not an immediate reaction at
first but then I noticed the clocks were
not receiving time signals, this however
only seems to apply to my DCF signals
on 77Khz and NOT to the MSF 60Khz
signals from Anthorn, Cumbria UK. I
know Anthorn
transmitter outputs
15Kw (15,000 watts) and DCF at
Frankfurt Germany outputs a massive

20

50Kw ( more than 3 times the power of
Anthorn) but further from UK. I guess
the DCF signals are not strong enoughto penetrate the glass. But find it very
strange that the MSF signals do as
they are on similar frequencies.
As for the GPS signals, I first noticed aproblem when running my APT
software. It would state no signals havebeen received from my GPS receiver. I
never realised it was the window glassattenuating the signal but decided toexperiment. The GPS antennas (I have3) that normally sit on my inside front
window ledge but to test them I placed
one just outside the window on theledge whilst observing the satellite
reception. The signals immediately
came to life and normality was restored.
I now have to find a route through my
new windows or wall to place theantennas so they have a clear line ofsite of the open sky (South Facing).
The thing is, here in UK it's very likely
someone will take a liking to them
being outside and maybe I could wakeup one morning to find they are gone. I
guess I will have to disguise them orplace them high up out of reach ofprying eyes. .The flashing LED's don't
help the disguise.
I would just like to point out that when
my house was single glazed, I had noreception problems,www.geo-web.org.uk

So, there is a lesson to be learned, I
know I will find a solution but bearthat in mind before having new
windows installed. I would love to hearfrom readers where they mount theirantennas and how, you can email me
privately or write to GEO so that all theworld can hear about it.
Related Article: GPS in Weather Satellite
stations GEO Q18 2008
Courtesy Wikipedia
LF transmitter: National
Laboratory time signal

PhysicalThe National Physical Laboratory (NPL)
has installed three atomic clocks at
Anthorn and on 27 February 2007
Britain’s
national
time
signaltransmissions, retaining their original
call sign of MSF, were transferred there
on a trial basis, moving formally on 1
April 2007. Monitoring and logging of
the clocks and control of thetransmissions is by internet link fromthe NPL offices at Teddington, using
comparison with GPS signals at both
locations. Signal monitoring is by radio.
To
ensureaccuracy,
dynamic
adjustment of the aerial according tolocal conditions (such as wind distortion)is controlled from computers on site. The
signals, transmitted at 60 kHz, also
provide a national frequency standard.
The effective radiated power is 15 kW

December 2010

Group for Earth Observation

GEO Quarterly No 28

National Hamfest
Francis Bellavailable literature from EUMETSAT plus
our own general guide to home weather
satellite reception. I had written a one page
summary relating to APT, EUMETCast andEnvi-Ham reception which was printed on
the back of our blue GEO flier. Those
visitors to our stand who expressed
particular interest in personal live satellite
reception were given one of these guides.
In addition to literature we had on display
computer pre-recorded ENVISAT images,
NOAA APT images and almost live
EUMETCast
images with appropriate
animations.
The displayed ENVISAT images generated
several quite specific questions from anumber of visitor to our stand relating to
the ground resolution possible with thissystem. My response was to give an almost
standard answer: ‘The MERIS instrument
will give a 300m ground resolution ‘. I’m notsure whether this was convincing or
accurate but I believed what I was saying.
Francis talking with a member of the Worthing Amateur Radio ClubI thought this year’s National Hamfest based in Newark,
Nottinghamshire was an outstanding success. This was thesecond year of this two day event which was held on the
Newark showground, it seems to have taken over from thepervious Leicester radio rally at Donnington which GEO
attended for several years. The National Hamfest was organisedby the Lincoln Short Wave Radio Club in association with theRadio Society of Great Britain ( RSGB )I think everybody who attended last year’s eventwasimpressed with the organisation, the number of trade andspecial interest groups who had stands, not to mention thenumber of the general public who attended.
This year was even better. I judged there to be more stands
inside the exhibition hall plus other traders and sales stands
just outside the exhibition hall. There were marquees for
information and a meeting point for administration. There
were mobile exhibition trailers, for example the RSGB’s
GB4FUN mobile station. The whole event was well locatedwith easy car parking. It was only on the second day that I
realised that in addition to cars with individual groups of the
public attending there were organised coach visits to theevent, presumably organised by their own radio clubs.
GEO was allocated a stand in the special interests area within
the main exhibition hall. We were very happy with this as it
was close to where we had been last year. The only
complication was the cable run from the outside where we
had our EUMETCast receiving dish linking our stand which
was well within the exhibition area: ‘Health and Safety’
dictated a safe route for the cable. Accordingly we had brought
a 3m steel pole which we clamped to our stand and ran thecable from the pole tip to the outer wall of the exhibition hall,thence to the dish. We had some problems with aligning thedish but these were later resolved.
The photographs show our GEO stand in the exhibition area.
The display boards were intended to give a general perspectiveof GEO’s activities and interest areas. Additionally there was

GEO stand with David Anderson

Other particular enquiries came separately from representatives/ staff from Salford and Nottingham universities, each wanted
satellite reception for research and student based projects. In
both cases they left our stand saturated with information andan invitation to join GEO.
Because the two days at the Hamfest were so busy I find it alittle difficult to quote the numbers who visited our stand,perhaps a thousand visitors, of whom a few hundred stopped
and took an interest. An encouraging number of visitors
joined GEO on the spot and we also took renewals frommembers who had joined last year.
My congratulations to the organisers of the Hamfest andparticular thanks to David Anderson our GEO Membership
Secretary who was supportively there on both days.

www.geo-web.org.uk

21

December 2010

Group for Earth Observation

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GEO Quarterly No 28i

GEO Quarterly No 28

ii

Group for Earth Observation

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December 2010

December 2010

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.
   <=?Z\^`{^||^|^  } < ~$ 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.
   <=?|?^{?Z  } < ~}$ 
Geoff Morris GW3ATZ
Shotton, Flintshire, NE WALES
Geoff has lots of experience with aerial,
co-ax,connectors, mounting hardware etc. and has
also done a lot of work with the orbiting satellites.
Geoff has been a EUMETCast Meteosat-8 user forsome time and is familiar with David Taylor’s MSG
software; he should be able to share his
experiences with newcomers to this branch of thehobby.
   <=?Z| {^Z^||  } < Z|~$    Mike Stevens
Portland, Dorset, England.
Advice offered on EUMETCast (MSG and Metop)and APT.
 <  ~  
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..
   ~  $
Hector Cintron
San Juan, Puerto Rico, USA
Hector is prepared to field enquiries on HRPT,
APT, EMWIN and NOAAPORT  #<\^\}\\ }^`\  } <Z ~ 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 Groups

GEO Quarterly No 28

The Copy Deadline for

GEO Quarterly No 28
is Saturday, Oct 30, 2010

There 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,
AVHRR Manager 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.

The Editor is always delighted to receive
articles and images for inclusion in
GEO Quarterly. These can relate to any
aspect of Earth Imaging, especially           
hardware and software                           
stations              ! 
 # $  %   *  
answerContributions 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.

http://groups.yahoo.com/group/wxtoimg-l/

www.geo-web.org.uk

iii

GEO Quarterly No 28

Group for Earth Observation

December 2010

Current Subscription Rates
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You can make your annual GEO Membership payment by any of the following methods:
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iv

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December 2010

Group for Earth Observation

GEO Quarterly No 28

The PADAT137 Again
Ruud Jansen PA0ROJ – translation by Chris van Lint
I received many enquiries regarding the availability of the hardto get parts for this aerial, following my articles in “De
Kunstmaan” and GEO Quarterly no. 9 and 10.
Since the various sizes and materials used are critical for thecorrect functioning of the aerial, there are few alternatives
which use other materials or sizes. By way of example I wouldrefer you to our aerial measurement comparisons in Zoetermeer(GEO Quarterly no.16).
Due to transport difficulties, I had removed the head and strip
elements from my aerial mast.
Once I arrived at themeasurement site, the aerial was quickly re-assembled,
positioned, followed by waiting on the arrival of a satellite.
Fully confident in the performance of my aerial, I awaited
further developments. However during the pass it became
obvious that my aerial performed poorly, compared to theother aerials to be measured. In fact, I had to conclude thatmy aerial was completely useless for receiving weather
satellite signals. After accepting that fact, I removed the aerial
from its mount and checked all cables and connections.
Everything appeared to be fine! The only possibility left, were
problems of a mechanical nature. When I checked saidmechanical components I discovered that in my hurry I had
made a mistake during the re-assembly of the head and thevertical strips to the mast. This meant that the large loop was
1cm shorter and the small loop was 1 cm longer, i.e. a
difference of only plus/minus 10mm. Once the head was
re-assembled correctly, my PADAT 137 functioned as expected.
Back to the aerial itself
In order to facilitate home construction, I have developed a
new head. Instead of a piece of solid POM material, I now use
a piece of thick walled POM pipe. Whilst the catalogue claims
this material has an inside diameter of 40mm and an outside
diameter of 60mm, the actual measurements of the pipe asdelivered are 38mm and 62mm. Although the external
diameter is now 60mm instead of 70mm, the head issufficiently sturdy to permit mounting of the horizontal rod
pieces. There is no change to the length of the rods. Only the
position of the holes in the rod pieces to allow fixing to thehead and the solder lugs require change (fig. 1 and 2).
The mounting of the head to the mast also requires modification.
If the 32mm (diameter) PVC tube is used an adapter toaccommodate the 38mm inside head diameter has to beconstructed. I solved this problem by machining the bottomof the head with a lathe to 40mm, which permits the use ofreadily available PVC adapters from your local DIY hardware
store (Wickes etc). The piece of printed circuit board is also
no longer required. In this design the coaxial cable is soldereddirectly to the solder lugs (fig. 3). A profile of this aerial isshown in fig. 4 and 5.
Some practical tips
The drilling of the holes in the top of the mast must be carriedout with great accuracy. If the horizontal rod pieces or not
square in relation to one another, the shape of the cylinder
will change, resulting in a direct and very negative effect on
the radiation pattern. In this article I will explain a method
which will facilitate the drilling of holes at right angles.
The mast
Before drilling the 4 x 12mm holes in the mast, we measure
the exact location of the where the holes are to be positionedon the mast. (fig. 5) . A handy aid to do this can be easily
constructed at home. Take a 32mm socket and saw off justless than half, which leaves a ring which can be slid over the

tube. Now position the non-sawn end exactly on the firstmarked drilling position. Using a blunt pencil, draw a line
around the circumference of the pipe (fig. 6). Slide the ringexactly 40mm on to the pipe and draw a second line.
Next we place a so-called V-block on the drill platform and asmall long drill (3-5 mm or better a small centre bit) bit isplaced in the drill chuck. The block is shifted in such a waythat when the drill bit is lowered, it is positioned exactly inthe centre of the V-block (fig. 7).
We now fix the V-block onto the drill platform with a G-clamp
and after placing the mast in the V-block a hole is drilled
through the pipe in the previously marked spot. The small
bit is now replaced with a 12 mm bit and is slowly drilled
through the pipe. The pipe is now shifted 40 mm for thesecond hole. This hole must be drilled at right angles(90°angle) relative to the first hole. The 90° rotation isachieved as follows: The piece of rod which will later bemounted in this hole is placed in the already drilled 12 mm
hole. If we now ensure that by rotating this piece of rod it isin a horizontal position, we only need to ensure that whendrilling is commenced (first small, followed by large), the drill
is positioned on the second ring we have drawn on the pipe.
We can now also drill the two 4 mm holes on both rings,
which are required to fix the pieces of 12 mm rod in the pipe.
The choice as to whether or not to use the two reinforcement
sleeves to pass the rod through is left up to you. Using thesleeves results in added strength, but is a little difficult toaccomplish mechanically. If sleeves are used, a 12 mm holehas to be drilled first into the sleeve, following the completionof the mast holes, however only on one side. The sleeve is
now slid over the mast and the hole which has already been
drilled in the sleeve is positioned exactly over the hole in themast. This can be checked, by sliding a piece of scrap rod
through the sleeve into the mast. The rod is now removed
and a 12 mm hole is drilled through the sleeve and mast.
Repeat this step for the other sleeve (fig. 8).
V-block?
I am aware, that not everybody necessarily has a V-block
lying around on the shelf, but there is a good and cheap
alternative available, which you can construct yourself. Go
to your local hardware store or metal shop and buy a pieceof scrap aluminium U profile. Mark the middle of the profileon the back and drill a 3 mm hole in this spot. When weturn this piece of U profile around we will see a gutter witha hole in the bottom exactly in the middle. Since the U
profiles available generally have almost the same wall
thickness, both left and right, we now have made a cheap
construction aid. The procedure as above with the V-blockis described in fig. 9 and 10. The result of a practical exercise
can be in fig. 11.
The head
The drilling of the 12 mm holes proceeds as described above.
We do however have the disadvantage that when the 12 mm
holes are drilled in the head, the pipe will be slightly
squeezed. This means that the rod pieces are not horizontally
positioned. Therefore use only a small amount of pressure
when drilling. Actually (if possible) a special drill bit should
really be used, which has been ground in such a way tomake it suitable for plastic. (different cutting edge angle
compared to a normal steel bit). In response to requests by
a number of members of our group I found a shop prepared
to produce a complete head, which satisfies the moststringent requirements. (fig. 12).

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GEO Quarterly No 28

Group for Earth Observation

December 2010

Fig 3

Fig 1

Fig 4 Aerial profile

Fig 2

Fig 3 In this design the coaxial cable is soldered directly tothe solder lugs

Fig 5 Aerial profile

Note: The 12 mm holes on the side, as well as all other holes
are produced on a special computer guided CNC millingmachine. The required thread is also included.
Points to watch- About the seal between head and lid. Rings which are
perfectly suited for use as a seal are available at the local DIY
store. A self produced packing of non hardening kit may also
be used.

24- Protection of the coaxial cable connections, as well as solder
connection between the pieces of coax against the elements.
- Protection against corrosion of the mechanical joints – referto the previous PADAT 137 article.
Tip
When marking the hole position on the mast, maintain adistance of about 840 mm to 880 mm, measured from the topof the mast (exactly 40 mm between both holes). When the

www.geo-web.org.uk

December 2010

Group for Earth Observation

GEO Quarterly No 28

Fig 9

Fig 6 You must measure the exact location of the holes

Fig 10

Fig 7

Fig 8

Fig 11www.geo-web.org.uk

25

GEO Quarterly No 28

Group for Earth Observation

December 2010

holes in the mast have been drilled, the mast
can be pushed into the head and the distanceis measured as shown in fig. 5. This should be
845 mm between both holes (middle point tomiddle point) for the topmost hole in the mast.
Trim the mast, to ensure that the dimensions
in fig. 5 are achieved. It is better to have totrim the mast a bit, rather than having to workwith sleeves.
Conclusion
Providing one has access to the requiredmaterials and tools and construction is carriedout with the necessary accuracy one is quite
capable of producing this aerial, which
compares favourably with other very expensive
professional aerials, but is much cheaper.
Impedance matching with inductor andcapacitor
By way of (for the time being) addition to myarticles relating to the PADAT 137, I would liketo refer to the impedance matching. We knowthat this aerial exhibits a low impedance when
the dimensions and materials I have used are
adhered to, which needs to be shifted to 50
Ohm. Although matching with pieces of coax
cable of differing impedance or throughFig 12 The completed headFig 13

Fig 14

soldering in a series capacitor is a suitable solution, I havelooked for a method which will avoid having to mess about
with soldered coax cable joints. Experiments with the
PASAN programme suggest that a circuit consisting of aseries inductor and a parallel capacitor, providing we use
lossless components would perform at least as good.
Refer to fig.13 for the LC solution. When using the LC
approach, I assumed that both components are lossless.
By using SMD inductors and capacitors it was possible tofit the whole circuit on a small single sided pc board strip
measuring 25X4 mm (fig. 14).

26

By removing a thin strip of copper in two places on the pc
board, using a very small file or a hack saw or coping saw,
three copper islands are formed. Both ends of the pc board
strip are soldered to the solder lugs in the aerial head, using
as little wire as possible. The inner conductor of the coaxial
cable to the receiver is soldered to the middle island and thecable shield of the cable is soldered to the one strip end (fig.
15 and 16).
To facilitate attaching, it will be necessary to drill 3 holes ofapproximately 0.8 – 1 mm in the strip, through which thewire ends are fed. This methodology ensures at the samewww.geo-web.org.uk

December 2010

Group for Earth Observation

GEO Quarterly No 28

Fig 16

Fig 15

In conclusion
After having completed a number ofaerials ( more then 20) using this method,
I have often wondered why I did not thinkof this before. I guess it was due to thefact that I only recently came to haveaccess to SMD inductors suitable for thisapplication. The only disadvantage ofusing this matching method is the size ofboth SMD components. A steady hand, afine tipped soldering iron and a decent
magnifying glass (I use a Leitz stereo
microscope for watch makers) is essential
for this method.
Luckily the SMD
components are usually bought in lots of
10. It is my experience that I generally
need two or three inductors and capacitors
for one pc board strip – one to solder into
the circuit and two to allow for the ones
which are ejected by my tweezers into theworkshop.
You will never find theseescapees again. It is also helpful to fix thepc strip onto the bench with some double
sided adhesive tape on the back. At least
it will not move.
Note I must order a minimum order of 10
heads.
Please note that the above article waspublished earlier in the group journal of
the “Werkgroep Kunstmanen”, titled “De Kunstmaan”.

Fig 17

Also now on my website in Dutch
time that the coaxial cable is provided with good strain relief.
When everything been mounted and/or soldered into theaerial head (fig. 17) and in order to prevent corrosion, theprint, the coaxial cable end and the solder joints can besprayed with a plastic spray suitable to protect HF circuitry
against weathering (Plastik 70, Kontakt Chemie).

http://www.jendela.nl/Padat137kop_LC_compleet.html.

For other relevant articles relating to weather satellites,
please refer to:

www.geo-web.org.uk

www.kunstmanen.net

27

GEO Quarterly No 28

Group for Earth Observation

December 2010

The Quarterly Question
The Quarterly Question in GEO Q 27 related to an image I had
received from the Earth Observation satellite ENVISAT. Thissatellite carries many sophisticated instruments, the image
was created using the Medium Resolution Infrared
Spectrometer (MERIS). At best the MERIS instrument will givea ground resolution of about 300m in many spectral bands. A
subset of the complete imaging program is disseminated via
the Envi-Ham project which is how I received that particular
image. When I recorded this image I was on a sharp learning
curve about ENVISAT reception and image processing.

showing the middle east. This image was published and isshown on page 37 of GEO 26. The boundaries between Egypt,Israel and Palestine can be seen. Citrus groves in Israel withadjacent desert in Egypt can be seen as a boundary and thelack of vegetation in Palestine shows up compared with Israel.
I know some part of the boundary between the USA and
Canada can be distinguished as a result ofdifferent
agricultural practices but I do not have a personal image.
Please can somebody submit an image to the editor showing
this boundary?

The image in question shows the Cape Verde Islands. It justhappened to catch my eye as one of a number of images I
received one day. Although the published image is in black
and white I did subsequently practice colour processing andusing other facilities offered by the ‘ESA Beam’ software toenhance the image. For example with some processing I wasable to reveal some interesting patterns in the sea which were
presumably created by local currents and marine life.

A river as a political boundary can cause disputes becauserivers can change their course and the political claims causedby changing or new islands generated by meanders can be
dynamic. In the 1960s Russia and China were almost at war
over such a territorial dispute in some remote desolate part ofcentral Asia.

I thought the question was quite straightforward as there are
only a few island groups in the Atlantic: such as The
Bahamas, The Azores, Canary Islands, Madeira but theanswer I was looking for was Cape Verde Islands.
Much of the history and background to the Cape VerdeIslands can be found on the Internet. However, it wasinteresting to note that the islands were newsworthy in early
October 2010 because a local thunder storm close to theislands which developed into a hurricane and then, as is often
the case, it swept westward across the Atlantic.
I received the follow competition entries, all correct:Nick Tebneff VK5NT Willunga South Australia
Mike Bragg Timaru New Zealand
Herman ten Grotenhuis Neterlands
David Rennolds G0BXS UK
Peter Shulver Portsmouth UK
Chris Warrington UK
Jack Willford G0TGP UK
Elmar Bogels Peterborough UK
Dave Lane G3VOM also AMSAT-UK
Adrian Chamberlain G4ROA Coventry UK

Answers to Francis Bell by email francis@geo-web.org.uk or
by letter -see page one for contact details, copy deadline for
GEO Quarterly 29. And yes the winner picked at random will
receive some marine related goodie from the Comoros Islands.
We depart just after Christmas 2010.

GEO Returns to EUMETSATHQ Darmstadt in 2011
GEO's first visit to the EUMETSAT HQ in Damstadt was in
2007.

The fact that the Cape Verde Islands also featured in the same
Quarterly on page 16 was a coincidence, but well spotted byseveral members who included this item of information in
their answer. I have not yet picked a winner for the completion
but I will do this shortly. The prize to be something marine
from the Comoros Islands.
The Quarterly Question for this issue:Again this question stems from an ENVISAT image I received.
The question is:- Name the river shown in the images
opposite?
One of the reasons for my own curiosity in this case was thedetail of the river which could be seen in the image I received
at home using the Envi-Ham project. Another reason was thefact that the river in question is a political boundary between
two countries. Political boundaries do not often show up on
satellite images unless they are coastal features. An interesting
exception to this was an image I received from ENVISAT

28

There are two clues to help with an answer to this Quarterly
Question.
One clue is that one of the two countries bounded by theriver in question is Mozambique. The second clue is present
in the Meteosat 7 image showing a part of the Indian Oceanand some adjacent countries. The line of the river is justshown, if you can spot it! It is also interesting to note thedifference in resolution between the Meteosat 7 image andthe one from ENVISAT.

To be supportive of new members, those who missed the first
visit and those members who wish to be brought up to datewith EUMETSAT's services, another two day visit is plannedfor 7th and 8th July 2011. It should be noted that this date
has to be confirmed by EUMETSAT but verbally they areencouragingly supportive and consider our visit very
worthwhile.
The outline plan is to visit EUMETSAT's HQ on the 7th July.
Then on the morning of 8th July visit their satellite
communication centre at Usingen.In the afternoon of that day
there is a planned visits to the European Space Operation
Centre (ESOC) which is also located in Damstadt.
There will be no charge for these two days visits except a small
payment to cover shared costs of local coach hire and the costof a guide for the ESOC visit.
Confirmed details will be published in our next Quarterly but
in the meantime put the dates of 7th and 8th July 2011 in you
diary.

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December 2010

Group for Earth Observation

GEO Quarterly No 28

Quarterly Question,can you name this river? © ENVISAT

www.geo-web.org.uk

29

Meteosat 7 image showing a part of the Indian Ocean and some adjacent countries. The line of the river is just shown, name the river. © EUMETSATGEO Quarterly No 28

Group for Earth Observation

December 2010

EUMeTrain
Jarno Schipper (ZAMG)

EUMeTrain is the biggest training project of EUMETSAT . It
started in 2005 and for the past 5 years has been dedicated tothe development of training resources and methods in satellite
meteorology. By this it responds to training requirements
expressed by European National Meteorological Services(NMS) over the recent years and gathered from a direct contact
with NMS trainers and operational forecasters.
The principle goal of EUMeTrain is to provide users of
EUMETSAT satellite data and products with training resourcesthat will assist them to make more effective use of this satellitedata, either as stand-alone material or in combination withother meteorological data sources. The project team of
EUMeTrain consists of the national meteorological services ofAustria (ZAMG), Croatia (DHMZ), Finland (FMI), Germany(DWD) and Portugal (IM).
Training Activities of EUMeTrain
The EUMeTrain training resources that were built in thecourse of years comprises training modules (sometimes
referred to as CAL Module, where CAL stands for Computer
Aided Learning), case studies and recorded lectures. Many ofthese resources come with interactive exercises designed for
self-testing. The resources are freely available and a student
can access them wherever and whenever he/she has the time.
A more interactive approach with the trainee is achieved by
the weather briefings, that are organised every month (Satrep
Online), the event weeks and the blended satellite course.

Case Studies
Some scientists blame it on the global warming and thechange of our climate, but the fact is that we are faced withmore hazardous weather such as convection with tornadoes
and large hail, extreme rainfall causing flooding andabundance of snow during winter months. All of these affectour public life with different severity. Especially whereconvection is concerned, a more precise warning for a more
precise area is required by the public. With the spin-up of themodels, that usually takes several hours, the use of remotesensing tools such as satellite and radar proves to bebeneficial for nowcasting. In the case studies such hazardous
or extreme weather situations are described revealing thebenefit of a good interpretation of satellite data. One example
is a case study of a severe storm over the island of Mallorca in
October 2007. With no radar data being available over theisland and a wrong forecast by the model the forecasters had
to rely on Meteosat Second Generation (MSG) satellite imagery
to monitor the progress of a large supercell which was
suddenly setting course to the island. A warning was issued
just in time and probably prevented casualties that could
have occurred when an F2 tornado swept over the island.
Training Modules
These comprise of more comprehensive topics and include alarge variety of interactive exercises for self testing. One such
example is the module “Operational use of RGB”, which
explains the different channels of the MSG satellite and theneed for combining the informationof some of these channels in to RGB
images, where the R, G and B referto the colours red, green and blue,
respectively. The introduction ofsuch composed images in theoperational forecast has been a very
slow process, despite the fact thatthey provide the forecasters withmuch more information than before
the MSG era. Therefore a training
module, teaching the benefits anduse of these was an absolutenecessity.
Weather Briefings
Organised by the Satrep Online
platform which was developed in
2007, weather briefings are aimed atteaching the meteorologist torecognise cloud patterns in satellite
images by using the technique ofconceptual models.

The EUMeTrain homepage at www.eumetrain.org

30

www.geo-web.org.uk

Cloud tops and cloud patterns seenby the satellites, are the fingerprintsof physical processes in the
troposphere. Conceptual models
describe the physical processes
through cloud phenomena, physicalparameters, life cycles and weather
events. Analysing a satellite image interms of conceptual models is theinitial step in retrieving a 3D- or evena 4D-mental picture of the weather.
Discrepancies between the NWP
model output and the satellite image
can also act as an indication of themodel error.

December 2010

Group for Earth Observation

GEO Quarterly No 28

MODIS image used for a case study of a severe storm over the island of Mallorca in October 2007 ©NASA

The analysis of a satellite image bymeans of conceptual models has provennot only to be useful to weather
forecasts but also serving as a great
training tool. In SatRep Online thistraining aspect is addressed.
The Satrep online consists of a web
based
platform(http://www.
satreponline.org)
inwhich
operationally four times day, the 00,
06, 12 and 18UTC Meteosat satellite
images are presented in a combination
with a corresponding set of ECMWF
model parameters and derived products
such as GII and products from NWC
SAF. It thereby offers the student thechallenge to operationally analyse asatellite image using the SatRep
method. This concept is also the basis
for a monthly weather briefing.
Coordinated by either ZAMG (Austria),
DHMZ (Croatia), IM (Portugal) or FMI(Finland) a discussion of the actual
SatRep is lead once a month providing
a more in-depth training on theinterpretation of the different satellite
images of MSG.
This form of training, performed online,
uses a software called Elluminate andno costs are charged for the participation
to a weather briefing. Depending on thetime of the year the analysis is doneusing different satellite imagery andderived products. The use of NWCSAF
and related products, such as the
Global Instability Index (GII), have beenvery beneficial to the forecaster when it
was trained during the weather
briefings during the past summer.
During the winter season the weight
will shift from convection to fog andsnow. More weight is now also being
given to the warnings issued by
METEOALARM and their relation to theconceptual models.
Over the past three years Satrep Online
has trained dozens of forecasters fromall over Europe. The website itself getsseveral hundreds of visitors per day.
The whole production chain of theimages is changing to present new
products which are fitted depending on
the season of the year. Future
developments, including the monthly
training sessions, are already planned
and are found in the calendar at the
SatRep Online website.
Event Week
The event weeks are probably the mostpopular part of training organised by
EUMeTrain. In one week there areusually twelve online presentations
dealing with topics like convection, fog,snow etc. Half of the presentations aredone by researchers, explaining thenew products that are being developed

www.geo-web.org.uk

and the way they can be used
operationally. After such an expert talkof 30 minutes a forecaster from one of
the European meteorological institutes
takes over to explain how he deals withthe topic in the forecasting room. Up to
500 people worldwide follow thesepresentations and have shown theirinterest for future event weeks.
Blended Satellite Course
The word blended implies a mixture of
online and face-to-face training. Thesesatellite courses last for about threemonths and comprise mostly of online
lectures by experts on the different
topics related to meteorologicalsatellites. The lectures always conclude
with exercises that the students need toperform. A full assessment on how thestudent has performed over the entire
course is done in the classroom part,usually conducted at the training site of
the Deutscher Wetterdienst in Langen,Germany. The student is then given awide variety of exercises and he/she
also needs to present some of the work(usually a case study) that they haveproduced. The WMO has issued theguidelines on what a Meteorologist
shouldknow
aboutsatellite
meteorology. These requirements arefound in the WMO-258 document. The
blendedcoursesorganisedby
EUMeTrain meet these requirements.

31

GEO Quarterly No 28

Group for Earth Observation

December 2010

The launch of Meteosat Second
Generation (MSG) in 2002 provided
forecasters with satellite images ofhigher spatial and temporal
resolution. The Earth could beobserved in 12 different spectral
channels. These channels can be
combined to produce so called RGB
images. Such images were the main
ingredient of the training material
in the first 5 years of EUMeTrain.
Several case studies dealing withhigh impact weather were produced,
showing the benefit of these images
when correctly interpreted. Also an
extensive training module on theoperational use of RGB images wasproduced. In the meanwhile thedevelopment of derived satellite
products continued.
The Nowcasting Satellite Application
Facility (NWC SAF) has played amajor role in these developments.
By exploring the 12 channels andknowing about their physicalproperties, new products have beendeveloped that can, for example,
help to discriminate between
different cloud types, identify theheight of the clouds but also derive
the information on which clouds
produce drizzle, rain or hail. In thelast few years a trend to identify the
pre-convective environment (GII)and to recognise very small
convective
cells(Convective
Initiation) has taken a major step
forward. These developments willcontinue to improve and in the
coming years the training should
address these new derived products.
This inevitably also implies that thetarget audience for the training
material, which until now used tobe the forecasters in Europe, will be
widened to other interest groups
suchashydrologists
andclimatologists.

Satrep online consists of a web based platform (http://www.satreponline.org) in which operationally four times
day, the 00, 06, 12 and 18UTC Meteosat satellite

New Training Resources
The best way is to visit our website(www.eumetrain.org). There you
will find a calendar informing you
about the scheduled weather
briefings, event weeks and the startof a new satellite course. It also
contains the latest news item
updating you on the new resources
being developed. If you are more
into that, you may also sign up at
our Facebook or Twitter to be
informed on any new updates being
done in the project.
www.eumetrain.org
www.satreponline.org
www.eumetrain.org
Jarno Schipper (ZAMG)
Natasa Strelec-Mahovic (DHMZ)

The EUMeTrain Satrep archive page

Vesa Nietosvaara (FMI)32

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December 2010

Group for Earth Observation

GEO Quarterly No 28

A view from North Cyprus
Nigel Heasman
A week ago we awoke to an overcast sky and after weeks and However, as often is the case out here, "promises, promises"
weeks of clear blue sky and scorching sun, this was a very and we haven't yet had the pleasure of standing out in awelcome relief. The local forecast is saying that we could soon refreshing downpour. The ground is bone dry and even thesee the start of the long awaited rains and, indeed, the MSG weeds have stopped growing. Luckily, the piped drinking water
images for today seem to show that as a possibility.
supply has held up throughout the summer and, apart fromtheoccasional
pump
breakdown, we have hadwater for at least an hour
every day to top up thestorage tanks that every
house is equipped with.
The Carob (http://en.
wikipedia.org/wiki/Carob_tree) harvest has been andgone with, apparently, agood crop being gathered by
the local folk.
Very soon now the local olives
will be ready for picking andit looks as if there will be abumper crop - most trees arevery heavily laden and just
waiting to be shaken loose.
No “health and safety”
regulations out here!! Local
folk lore has it that we get agood harvest every 7 years
and this looks to be the one.
The recent harvest moon waspretty spectacular last week
(below) and made eating
outside in the evenings very
pleasant,
withthe
MSG image 29th September 2010 ©EUMETSAT

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GEO Quarterly No 28

Group for Earth Observation

December 2010

Spectacular thunderstorm on 8th October ( – sorry about the raindrops on thelens!)

temperature hovering around 30C.8th October 2010
Wonderful news - the rains arrived this morning, accompanied
by a very spectacular thunderstorm and in the last 4 hours
we have had nearly an inch of the lovely stuff! The highest
rainfall rate recorded so far is 4.7” per hour and the thunderis rolling around the surrounding hills in a very dramatic
fashion. The temperature has dropped by 7C in the last few
hours (see plot on the right) and, of course the humidy has
shot up. The smell of the rain falling on bone dry ground isquite wonderful.
The advancing rain can be seen very clearly in an animation
available
atwww.nigelheasman.com/animations/easternmed.avi which was made from Eumetcast RSS
images, using MsgDatamanager and MSGAnimator fromDavid Taylor. www.satsignal.eu
I find it fascinating to see the clouds “well up” as they
approach land but what causes them to do it over the open
sea remains a mystery, to me!
The olive harvest started on Monday, (by government decree)and yesterday the olive grove just down from my house wasalive with villagers climbing up the trees to fill their sacks.
They will then carry them to the local mill where each
persons “take” will be separately processed and the oil takenback home for use in those special meals.
A long awaited project, to bring water to the island fromTurkey, has now started apparently. It is being paid for by
Turkey and will deliver around 70 million cubic metres ofwater each year, through 80 Km of plastic pipe suspended

34

Temperature plot from Nigel's home on Cyprus

250 metres below the surface of the Mediterranean. (http://
www.articlesbase.com/news-and-society-articles/turkeyto-northern-cyprus-water-pipeline-by-2012-537589.html)
This project will be of very great benefit to both farmers andthe general population in Cyprus and will, hopefully, mean theend of the near drought conditions experienced almost every
year. Whether the Greek, south side, of the island will takeadvantage of it remains to be seen, however, due to politicaldifferences between Turkey and Greece.
More news from North Cyprus soon!

www.geo-web.org.uk

December 2010

Group for Earth Observation

GEO Quarterly No 28

Using ‘IrfanView’ for remote viewing of animation files
Terence Smith
I accept that those for whom this modus operandi would be
useful may be few in number, but I hope it is worth relating
nonetheless.
In March 2008, the Geo Quarterly Journal No.17 carried anarticle of mine (but not forgetting the very significant input of

the then editor, Les Hamilton, to layout) describing theoverlaying of isobaric charts onto various animations produced
by David Taylor’s GeoSatSignal software. At that time I
mentioned the employment of Irfanview (or indeed any
suitable equivalent image viewing programme) to conveniently
screen one’s animations – particularly in full screen mode.

An example of a Bracknell isobaric chart overlaid on a EUMETCast image received using David Taylor's GeoSatSignal software and subsequently made into an
animation

The article also illustrated how such animations can be
automatically updated using command-line files, so I will
not repeat that here; but the method will be helpful withwhat follows below, and the article is available as a PDF
online at http://www.rifleman.org.uk/mslp_article.
htm

satellite dish.

If you are comparatively new to EUMETCast reception,and have yet to delve into the preparation of suchanimations, several examples are available to view at
http://www.rifleman.org.uk/mslp.htm.

In order to have my several animations readily available towatch on my remote PC, I ensure that those generated byboth GSS and MSG Animator are saved to the same
directory on my processing PC. This enables each of them
to be viewed using Irfanview from anywhere on my
network, and obviates any need for further instances of
either of David’s programmes to be installed on a remote
PC. Whilst not directly connected with the subject of thisarticle, it is perhaps worth mentioning that the same
technique can be employed to remotely view individual
images such as Metop and NOAA AVHRR files.

This follow-on development of my use of Irfanview wascalled for when I moved my desk and day-to-day computer
to a room in the house remote from that which housed thetwo-PC EUMETCast receiving and processing system. The
latter PCs remain in their original room, which isnecessarily situated within a short cable-run from theI have no experience of remote networking, but suspectthat what I am about to describe may also be a practical
proposition over a VPN system, were one to be remote fromone’s home network.

www.geo-web.org.uk

35

GEO Quarterly No 28

Group for Earth Observation

I hope David will not mind me advertising the fact that
he generously elected not to key-code his superb
HRPT Reader software, thus permitting installation of
the programme on any computer and allowing anyone
in receipt of the image files to view them – fromanywhere networked to the receive PC.
If you do not have the freeware Irfanview progam
already up-and-running, but would like to give it atry, simply download and install both the latest
version of the programme file, and the plug-ins/addons file, from http://www.irfanview.com/ andinstall each in turn. The latest version at the time ofwriting is v4.23.
Open the programme and, using ‘File > Open’,navigate to the network directory holding your (*.AVI)
animation files. Select the topmost file and open it.
The animation should open and run once. Either byrolling your mouse wheel, or perhaps more controllably
using the page-up/down keys (down first), eachanimation in the directory may be viewed in turn. In
the programme’s default configuration, if you attempt
to move down to the next animation when the last fileis being viewed, then a window will appear asking if
you wish to remain in that directory or change toanother. Hitting Enter will close the box and re-open
the first animation file. The same situation applies if
you work back to the first file and try to go ‘page-up’
from there. This setting can be amended, in the

programme’s set-up, to roll over to the first file fromthe last, and vice-versa. Go to “Options > Properties/
Settings > Misc.1” and check “If the end/begin of
the folder is reached, loop current folder (duringbrowsing)”
It is just possible that you are not aware where theanimation files produced by MSG Animator are saved;
so this would need to be ascertained. The top of thedefault directory tree has hitherto usually been the
MSG-1 directory under which lies the Images directory
to which one is advised to set the path for MSG
Animator’s source files. However you have chosen to
save your Meteosat image files, the Animations
directory, under that Images directory, is most likely
to be the one to which the MSG animations areautomatically saved. Because there is an option
provided within GeoSatSignal to save its animations
anywhere you wish, I find it simplest to save GSS .AVI
files straight to the C:\MSG-1\Images\Animations
directory, where they accompany the MSG Animator
files. Any or all of these files may then be accessedfrom that same source by Irfanview.
To re-open any file, and thereby load the latest buildof an animation, it is only necessary to press ‘Shift andR’. This effectively re-opens the updated files for ALL
your animations in that directory. If, as I, you prefer
this to be done automatically, say every fifteen
minutes to bring up the latest HRIT animations as

A frame from the false colour animation using Irfanview with GeoSatSignal software

36

December 2010www.geo-web.org.uk

December 2010

Group for Earth Observation

they are received and processed, then this can beachieved using Command Line operation via the
Windows Task Scheduler*.

GEO Quarterly No 28” and checking “ Stretch all images/movies toscreen”. The slider is particularly useful, offering
the ability to wind back and forth through theanimation to any point, and at varying speeds. You
can transit as slowly or quickly as you and yourmouse care to move the slider, and stop at any
frame.

It is only necessary to make one command (.cmd) file todo this, since, as soon as one animation file is openedin Irfanview, the others in the same directory are eachavailable at a key-press. If you are unfamiliar with how
to do this, please download the PDF file at the URL
given above. Remember that the command file ( e.g.
animations.cmd ) must lie within the Irfanview
programme directory and be called up from there by aWindows scheduled task. There is also a description of
how to do this in the old article on page 4; but do bearin mind that the method shown relates to Windows XP,
and subsequent Operating Systems may entail different
means to achieve the same end.

If you like to see your animation in a ‘clean’ window
but not necessarily in full-screen, then you can hide
one or all of the caption, status, menu and tool bars
using the “View” menu. If using full-screen withyour Windows Taskbar hidden, it will be necessary
to press Alt+Tab to change between programmes. If
viewing in Normal mode, a single press of the Enter
key will take you to full-screen, and one press of Esc
will revert to Normal.

Irfanview can be set up to show your animations inseveral ways. By default the programme opens awindow of a size less than your full screen, and thismay well best suit your needs. If you wish theanimations to be opened full-screen, then add “ /fs “ tothe end of your command line. In this mode the filename of each animation is shown above the imaged
section.

There is a plethora of viewing options available in
the programme, and there are a great many commandline options too. Irfanview is an excellent tool for
handling images of almost any type. It has one of thebest screen-shot or screen-capture facilities that I
have come across. The Help for the programme ismost comprehensive, and the command line options
are all listed there.

A typical command line, saved as a .cmd file in
Windows Notepad, could be

To afford some idea of the practicality of thismedium, I regularly run animations of MSG-1 RSS- IR ch.09, as illustrated here, UK and otherlocations of Ch.12 Visible data; plus MSG-2
animations of various FSD and Fire products, aswell as two GSS isobaric chart overlain animations– perhaps eight or nine animations in total. In either
MSG Animator or GSS it is a multi-mouse-click task
to change from one animation to another; not tomention that with frequent updating of lengthy
animations in Animator there are long periods when
the animations are not available to view. Using
Irfanview makes animation-switching incredibly
easy and convenient. With this in mind, it should beapparent that the use of an image-viewing programmesuch as IrfanView can be helpful not only for remote
viewing, but even on the processing PC itself. I am
well aware that MSG Animator has the useful option
to cycle through the animations at varying timed
intervals, but, with more than just a couple ofanimations in progress, this can result in either aconsiderable wait before the one you most wish tosee comes into view, or such short viewing periods
that you can barely assimilate the imagery before itchanges. Switching animations in GSS is also time
consuming, as each file requires loading separately.

i_view32.exe \\local or remote PC\c\msg-1\images\animations\
north_atlantic_ir_rss.avi /hide=15 /one /fs

In this example, Irfanview opens the file “North_Atlantic_IR_RSS.avi, hides the Toolbar, Status bar,Menu bar and Caption(/hide=15), closes the previous
instance of Irfanview (/one) (or you will end up withmultiple instances open), and opens in full-screen mode(/fs). Note the spaces before each oblique (‘slash’ to ouryounger or North American readers).
The hiding of Caption and bars can be applied to eachor all. The numbered values can be combined as shownin the example above, but the values must be added
together for the required configuration; i.e. “/hide=15”
amounts to ‘hide=1+2+4+8’ for all four. The separate
values are

Toolbar1
Status bar 2
Menu bar 4
Caption 8
There are many options for display of video, but it is by
far preferable to use the original GSS or MSG Animator
programmes to determine basic display speed (frames
per second) and any smoothing required, leaving
Irfanview to do nothing but show the animation.
However, there are useful exceptions, and there is aplaying speed option available by right-clicking on therunning animation. If the animation is stopped at any
point, the frame can also be copied to the clipboard
from the options box opened by the same right-click of
the mouse – very handy.
To loop the animations, go to “ View > Full Screen
Options > Video/Sound ” and check the Loop box.
There are a number of “full-screen” options too; anotable one permitting sight of only the images and theslider at the bottom of the screen. Set this by again
going to “ View > Full Screen Options > Video/Sound* The one thing that does require careful handling is
the timing of any auto-scheduling of Irfanview tobring up the latest animation update. The Task
Scheduler should be set to re-open Irfanview outside
the MSG Animator or GSS update times; a goodreason not to attempt to update every 5 minutes ifanimating Rapid Scan imagery from MSG-1 (RSS). If
you are shown an error message “Unknown format
or file not found” when manually opening a file, itis probable that an animation build is underway.
Just wait a few moments for that to finish on theprocessing PC before trying again.
As I wrote at the beginning, this manner of remoteanimation-display may be of limited interest to themajority of readers, but if it proves useful to only one
or two then it will be worth having put pen to paper.
Good world and weather-watching.

www.geo-web.org.uk

37

GEO Quarterly No 28

Group for Earth Observation

December 2010

GEO attends AMSAT-I and Envi-Ham conference, Frascati
Francis BellFor the second time, I was delighted to be telephoned by
Stefano Badessi in Frasacti. The European Space Agency(ESA) have located their European Space Research Institute(ESRIN) at Frascati, which is located about 20 km SE of Rome,and Stefano is a senior member of their staff. The first call I
received from Stefano was about a year ago when I was invited
to take part in the ‘Envi-Ham’ project. The outcome of that callresulted in my joining the project and some of the images I
have received have been published in GEO Quarterly.
This recent call related to a joint AMSAT-I and Envi-Ham
conference to be held in Frascati. I was instantly attracted by
the invitation and, with the help of the ESRIN travel office in
Frascati, took about two hours to check accommodation andtravel details before accepting the invitation to attend. My
contribution was to be a guest and to give a 30 minutepresentation relating to GEO and our members’ experienceswith Envi-Ham.
I did check the language to be used at the conference and wastold that it would be English. This was reassuring because theonly word I know of Italian in Pizza. In fact the common
language of ESA, ESRIN and EUMETSAT is English . The
reality was that some of the AMSAT-I conference presentations
were given in Italian, as you would expect, but otherwise
almost everybody on site spoke English.
My outward travel to Italy was straightforward and after
checking into my accommodation I arrived at the ERSIN
centre on the outskirts of Frascati by mid afternoon on the day
before the conference. I was a little flattered by the VIPtreatment which I received. I was shown around the technicalareas by Stefano and allowed to walk around the rest of thesite on my own with camera in hand.

surprised by the ESRIN centre. Not only were there offices andtechnical areas bristling with electronics, but also on site were
the satellite communication dishes. Without comment toanyone I contrasted this with our GEO visit to EUMETSAT
Headquarters in Darmstadt. The EUMETSAT offices
accommodate their administration and many of their technicalfacilities, but their main satellite communication dishes arelocated at Usingen about 50 km north of Damstadt. I’m surethere are commercial, geological and RF reasons for locating
EUMETCast’s main satellites dishes away from the centre ofDarmstadt.
I did consider the local geology around Frascati which islocated on a rocky hill. The ESRIN site, formally an olive grove,is in an almost earthquake free zone, which is not the case formost of Italy which suffers from many earthquakes, somedevastating. The site also benefited from a clear view of thesky thus providing communication links with satellites. I’msure it’s beneficial to have the satellite communication dishes
and the computing and radio all on the same site.
It was quite by coincidence that my visit to ESRIN overlappedwith a number of ‘European Science Evenings’. ESRIN was
hosting one of these events, and immediately after the
AMSAT-I / Envi-Ham conference, some of the facilities wereopen to other visitors. I benefited from this because I used any
spare time to look round the exhibition areas and displays
which were being prepared. Some of these were in the samehall as our conference, so visiting them was easy, with noformalities. I had managed to take a laptop computer with me
to the conference, together with a small quantity of GEO
literature, and was grateful to be allocated a shared table inthis exhibition area. I was pleased to note that, during theconference day, this table proved to be attractive to visitors
and the conference delegates.

Although I had no particular expectation, I was slightly
I have been a member of AMSATUK for about 20 years. There are
AMSAT groups in a number ofother countries and I know thegroups in America, Italy,
Germany and elsewhere areparticularly active in promoting
the
use
of
satellite
communication, all of which is in
the very best tradition of amateur
radio. On a number of occasions
I have given presentations at theannual AMSAT-UK conference
and reports and photographs ofpast events have often been
published in GEO Quarterly.
This year, David Simmons and I
gave a presentation at the
AMSAT-UK
conferencein
Guildford. The feedback fromthis was very positive andapparently a number of the
AMSAT
members
later
successfully applied for an EnviHam license. This may have beenpart of the rationale for inviting
me to Frascati for the AMSAT-I /Envi-Ham conference. I neverasked.

ESRIN satellite communication dishes

38

www.geo-web.org.uk

What I did ask Stefano about
were the origins and backgroundDecember 2010

Group for Earth Observation

GEO Quarterly No 28

Stefano Badessi and Francis Bell at the Frascati conference

Conference sponsors

to the Envi-Ham project. It became clear as a result of ourconversations that the vision of Envi-Ham was principally
Stefano’s, perhaps triggered by enthusiasm within the
AMSAT-I membership. I quite specifically congratulated him
for his vision, technical skills and administration for bringing
the Envi-Ham project to so many people. I repeat these
congratulations now in writing!

the soft option with dedicated computers for each application,
one for EUMETCast with a dish, one for Envi-Ham with a dish,and one for APT with turnstile antenna. Living on the edge ofa village with plenty of garden, I am fortunate in being able torun as many dishes as I like without upsetting anybody. The
conference was televised and shown live on the Internet: it
may still be available for viewing. From some feedback I havereceived, I know that some of our GEO members did follow
events via a TV Internet link.

The programme of conference presentations related to bothamateur radio in space—that is the AMSAT-I perspective—
plus other contributions relating to the Envi-Ham project. My
30 minute presentation was split between the background of
GEO, our members interests and then more specifically about
experiences I and other GEO members have experienced with
Envi-Ham reception: all illustrated with example images I had
received at home. I know that Arne van Belle had been invited
to the conference but was unable to attend in person becauseof other commitments. Instead, Arne submitted a computerpresentation illustrating his reception of EUMETCast andEnvi-Ham using the same dish and computer and Stefano
read the text relating to Arne’s presentation. I admire thetechnical skills of Arne and other members of Werkgroep
Kunstmanen, who seem to work at the leading edge of satellite
reception and subsequent computer processing . I tend to takeI have already mentioned the European Science Evenings
which coincided with my visit to Frascati. Not only did I
benefit from the exhibitions that ESRIN were preparing on
their site but, additionally, there were other events in the town
centre on the Friday and Saturday evenings. The town centre
was sprinkled with lines of marquees containing exhibitions
and hands-on experiences. Topics covering physics, chemistry
and biology were on display. I was particularly interested in

the space science displays. The sponsors of the event were
impressive and to be congratulated. On the Friday evening I
was in the town centre which was full of children and adults
visiting the science marquees but unfortunately I had left mycamera behind so my photographs taken next day record thevenue but without the activity.
My thanks to AMSAT-I and to Stefano Badessi on behalf of
ESA / ESRIN for inviting me to their conference. I had adelightful two and a half days there. On behalf of the GEO
membership I will continue to promote the Envi-Ham project
and the stunning Earth images which it provides. For more
information relating to ESA and ESRIN visit their web sitewww.esa.int

Giving my presentation

www.geo-web.org.uk

39

GEO Quarterly No 28

Group for Earth Observation

In response to the query by David Taylor (Geo 27, p38)
concerning the feature 'Comma Cloud or Cyclone?' from July
1st 2010. David asks if the cloud formation is a comma cloud,though I think the question is posed just to open thediscussion, as he answers the query himself in the quotations
he gives on the same page. The answer is that it is mostcertainly not. It is in fact a mature cyclone or depression, quite
a deep one for a summer month too, central pressure 967
mbar. Attached is the ASXX analysis for 1200z on the 1st
July.
A comma cloud has a much smaller scale than this gigantic
cyclonic feature. Generally a comma cloud has a scale of a few
hundred or so kilometres. Most comma clouds consist of
conglomerations of convective clouds, although some of thelarger ones may be associated with a developing depression
with multilayered cloud, probably with some convection
embedded. Comma clouds in one of their most common forms
are a visible manifestation of what is known as a PVA or
Positive Vorticity Advection feature. Regions of PVA are
typically found on the forward (upwind side) of a short-wave
upper trough. They are often identified on a surface chart asa trough, and can be associated with quite large but shortlived pressure falls and rises as the comma crosses aparticular location. The dynamic ascent produced in a PVA
region can lead to the comma shaped convective cloud when
the troposphere is unstable to moist convection, and is mostoften seen in situation where the large-scale flow is bringing

40

December 2010

air of cold origin over a relatively warm sea.
The image at the location below shows a comma cloud just to
the west of Ireland, and readers can see from the scale of thisfeature that it is far smaller than the synoptic scale cyclone
shown in David Taylor's image.
Image from NOAA19 at 1424z on the 10th September 2010.
Received at Wokingham and processed using David Taylor's
HRPT Reader and AVHRR Manager software, it is a combinationof spectral channels 1, 2 and 4, with channel 4 alone near thepole, which is in near darkness.
http://www.woksat.info/etcsi10/si10-1424-a-apt-w.html

Weather satellite images at:www.woksat.info/wwp.html

Dover Ham Radio Rally 2011
January 16th 2011 see return of the Dover rally which was
revived having missed out a few years. This year we are hiring
additional space to accommodate more traders. Tables are amodest £10 pre booked. Last year several traders had bits andbobs relating to Wx sats.

www.geo-web.org.uk

www.doverradiorally.com

December 2010

Group for Earth Observation

GEO Quarterly No 28

Douglas Deans - dsdeans@btinternet.com
Since my last column I have invested ina new computer specifically to help withrunning EUMETCast more efficiently.
It is something I had been considering
for a long time but having taken theplunge, the results have been excellent.
Perhaps a brief background to this may
be of interest to those also running a
EUMETCast system and for those not,my experience using a very small
computer may still prove interesting.
EUMETCast now provides hugeamounts of data although there aremany ways which allow you to be
selective in data choice. Neverthelesseven just taking the various sources ofhigh resolution imagery can constitutea few Gigabytes of data coming in every
hour. Recommendations are to run a
two computer system so that thereceiving computer is solely employedfor EUMETCast. Some people do wellwith a one computer system but
undoubtedly two is preferable. I had
tried both and whilst the two system
was the best, being loss free, theinconvenience of 2 desktop computers,
their associated noise and runningcosts was off putting.
In particular,
depending on your house layout, anoisy computer can be a real nuisancewhen running overnight.
So when the option of a mini-computer,small in size, not too expensive, low inrunning cost and relatively quiet (onlythe power supply has a fan) came about
it seemed a perfect solution.
Bothmyself and my brother had used acompany before called Pcspecialist
where you can specify how yourcomputer is to be built. A visit to theirwebsite confirmed that in addition to all
their other products they now offeredmini-computers and so I went on totheir site to try combinations ofhardware for price and specificationcomparisons. Let me say from theoffset that other than a very satisfied
customer I have no association withthis Company. For more information
about what this company offers please
go to :http://www.pcspecialist.co.uk/

Themini–computerissmall,
approximately 225mmW, 193mmD and
76mmH. It can stand flat or on its edge.
My model uses the very low power andefficient Intel dual core Atom processor

on an Intel D510MO motherboard andhas 2GB of RAM fitted. I could easily
increase this to 4GB but there seems
little point given its use and since it is a
32 bit system.
As this computer issolely for EUMETCast I chose to havevery few additions. I did select thefaster 2.5 inch 7200rpm, 16MB cache
hard drive (250GB) and also chose tohave a small RW DVD recorder. I
already had a copy of Windows Vista
which was no longer in use and as it
was not an OEM it could be activated inanother computer so there was a big
saving in not having to purchase a new
operating system. I probably would
have preferred to use either XP or
Windows 7 as Vista still gets the nameof being a bit bloated but beggars (orrather pensioners) cannot be choosers
and the set up is working perfectly.
Suffice to say that the whole package
was just a little over £200.
I did some power checks whilst it wasreceiving EUMETCast data for about 12
hours and found that the entire set up
is rated about 30W. For a computerwith the specification it has that isquite an incredible figure andconstitutes a running cost of less than
10p for a full 24 hour operation.
I did have a few concerns about the lackof a fan other than a small one
incorporated in the power supply unit.
The processor uses quite a large
heatsink so cooling is purely passive.
This, of course, keeps the noise down
and provides one of the real attractionsof this unit. However the box is wellventilated and despite having run so far
in summer conditions there have beenno problems. I am hoping to do sometests on temperatures at a later datebut my concentration has been on tests
on its performance for my EUMETCast
system.
It does mean that I can now runovernight without any noise and withlow running costs although as yet I
have not done this on a regular basis.
As I write this column a number of GEO
members including myself have been
testing a new EUMETCast Client
Software for Windows. Readers will
have read Arne’s excellent preview of
the new client testing in the previous
journal (GEO Q 27) and I expect further

www.geo-web.org.uk

information will be provided when this
Journal goes to press. So I will makeno further comment other than to say I
loaded the new Client into my new
mini-computer and it worked perfectly
without issue. I am no longer using a
RAMdisk mainly as it is not needed by
the new Client particularly when used
on a dedicated EUMETCast computer.
This quarter I will briefly explain what
Aero Snap shortcuts are in Windows 7
and will also be continuing with mynew section on EUMETCast
data
channels.
As a reminder to readers I have alreadydealt with Channels 1, 2 and 5. This
quarter I am tackling the rather complex
Channel 3. Again I hope readers willconsider building up a comprehensive
package of the EUMETCast Channel filetypes as the project continues. Those
who do will have something not available
elsewhere.
Aero Snap Shortcuts.
Aero Snap is a new feature in Windows
7 management, which allows you toeasily position (Snap) windows on theedges of your computer screen. It isfast and effortless and for that reason isparticularly useful. How often do you
need to have two windows open to editor copy a file name or even drag anddrop. The ideal scenario for that is tohave the two windows on your monitor
side by side. That can be a fiddly
process but Aero snap allows you to do
it with 2 simple mouse operations.
Simply drag the first window to theright side of the screen and it will alignitself to the edge and fill half the screen.
Repeat this with the other window on
the left side. Job done ! In addition
this option allows you to maximise awindow in the vertical direction only,
something that may be appealing for
widescreen users. I often do not findWindows shortcuts of much use but
this is one I use regularly. Of course
there are other options as well. To
maximise a window vertically andhorizontally to fill the screen simply
drag it to the top of the screen. There
are also a number of aero snap shortcut
keys but personally I hate shortcut keys
as they are anything but shortcuts if
you cannot remember them so I will
leave you to check them out yourselves.

41

GEO Quarterly No 28

Group for Earth Observation

EUMETSAT Data Channel 3.
Channel 3 has a heady mix of data types and file types making
it a complicated channel to detail. Because of that it isdifficult to know just what data it contains so all the morereason for this to now be tackled.
The first group of data on this channel is the Primary Low
Rate SEVIRI data (LRIT) from the geostationary satellite
located at 0°. For the moment the primary satellite is Meteosat
9, also known as MSG 2 being the second of the Meteosat
Second Generation of satellites. You will recall that in GEO
27 we identified and listed Channel 2 for the equivalent High
Rate SEVIRI data from Meteosat 9. Unlike the lossless HRIT
data, the LRIT data is in lossy jpeg compression with data in
30 minute repeat cycles instead of the 15 minute repeat cyclesof the HRIT data. In addition there are only 5 channels of data
sent as opposed to the 12 HRIT channels. In other words the
LRIT channel only contains sub-sets of data compressed byhigher factors but the lower bandwidth may be appealing tosecondary data users. So in summary features of the Low
Rate SEVIRI are :-December 2010

(FSD) but in keeping with this awkward channel even thisdata is not straightforward.
The data consists of 3 hourly GOES E (GOES 13), 3 hourly
GOES W (GOES 11), 3 hourly MTSAT-2, and half-hourly
Meteosat 7 for the IODC project. GOES E, GOES W and
MTSAT-2’s data is provided in 4 wavelengths whilst Meteosat
7 is in 3 wavelengths.
Just as a reminder, and to be dealt with in another column,that the additional GOES E and W data to provide the hourly
service, the additional MTSAT-2 data to provide an hourly
service comes in Data Channel 4. Feng Yun geostationary
data (CMA) is provided on Data Channel 11 and will be dealt
with separately.
Here is a description of the file types provided for the FSD
service on Channel 3.
L-000-MSG2_-GOES13______-00_7_075W-PRO___-201008092100-_
L-000-MSG2_-GOES13______-00_7_075W-000001___-201008092100-C_

Data in 30-min repeat cycles.
Lossy JPEG compression.

Repeated for segments 000002 – 000007 inclusive and foreach of the other 3 wavelengths.

Full spatial resolution in 5 spectral channels:

L-000-MSG2_-GOES11______-00_7_135W-PRO___-201008092100-_

Channel 1 (VIS 0.6)

L-000-MSG2_-GOES11______-00_7_135W-000001___-201008092100-C_

Channel 3 (IR 1.6)

Repeated for segments 000002 – 000007 inclusive and foreach of the other 3 wavelengths.

Channel 4 (IR 3.9)
L-000-MSG2_-MTSAT2_____-00_7_145E-PRO___-201008092100-_

Channel 5 (WV 6.2)
L-000-MSG2_-MTSAT2_____-00_7_145E_000001___-201008092100-C_

Channel 9 (IR 10.8)
Each repeat cycle nominally consists of 8 segments of image
data. A repeat cycle prologue file precedes the delivery of theimage segments and a repeat cycle epilogue file follows after
the delivery of the segments. The image segments arenumbered and a fixed relationship between the image segment
number and the line offset is established. The image segment
numbering direction follows the radiometer scan direction.
Now let us look at the typical file names and types you will see
on Channel 3 for the LRIT data.

Repeated for segments 000002 – 000006 inclusive and foreach of the other 3 wavelengths.
L-000-MTP__-MET7_____-00_7_057E_PRO___-201008092100-_
L-000-MTP__-MET7_____-00_7_057E_000001___-201008092100-C_

Repeated for segments 000002 – 000010 inclusive and foreach of the other 2 wavelengths.
In addition there is an administration file provided in thefollowing format.

L-000-MSG2_-MSG2____-IR_016__-000008__-201008100615-C_
L-000-MSG__-SERVICE____-ADMIN___-03840_001-201008092100-_

Some features to note.
The ‘L’ refers to the Low rate previously explained.
MSG-2 confirms the satellite of origin.
The IR_016 is the channel reference where 016 represents the$   |}~
The 000008 refers to the 8th segment of the cycle.
201008100615 refers to the 06.15 segments on the 10th
August 2010.
So with 8 segments per channel and 5 channels there will bea total of 40 segments per cycle plus a further 2 for the
prologue and epilogue files.

And the final group of products provided in Channel 3 is the
MPEF meteorological products. There are too many of thoseto give a detailed description so I will limit each to a brief
description with file types and leave the reader to get more
information from the EUMETSAT Product Navigator withwhich all EUMETCast users should now be familiar.
CLM (Cloud Mask)
The Cloud Mask product describes the scene type (either‘clear’ or ‘cloudy’) on a pixel level. Each pixel is classified as
one of the following four types: clear sky over water, clear sky
over land, cloud, or not processed (off Earth disc). The productis provided every 15 minutes.
L-000-MSG2_-MPEF______-CLM____-PRO____-201006191815-_

The prologue and epilogue files take the form :L-000-MSG2_-MSG2____-____-PRO___-201008100615

L-000-MSG2_-MPEF______-CLM____-000001____-201006191815
etc to 000006

L-000-MSG2_-MSG2____-____-EPI___-201008100615

FIRA (ASCII format)
The active fire monitoring product is a fire detection productindicating the presence of fire within a pixel. The underlying

Channel 3 also carries some of the Foreign Satellite Data

42

www.geo-web.org.uk

December 2010

Group for Earth Observation

GEO Quarterly No 28

concept of the algorithm takes advantage of the fact that
SEVIRI channel IR3.9 is very sensitive to hot spots. The
product is provided every 15 minutes.

The product is provided every 3 hours.

L-000-MSG2_-MPEF______-FIRA____-PRO____-201006191815-_

L-000-MSG2_-MPEF______-CLA____-000001____-201008092345
etc. to 000003

L-000-MSG2_-MPEF______-FIRA____-000001____-201006191815-_

FIRG (Grib format)
The active fire monitoring product is a fire detection productindicating the presence of fire within a pixel. The underlying
concept of the algorithm takes advantage of the fact that
SEVIRI channel IR3.9 is very sensitive to hot spots.

L-000-MSG2_-MPEF______-CLA____-PRO____-201008092145-_

CLAI (Cloud Analysis Image)
Identification of scenes type for each image segment. This is
an image product derived along with CLA.
The product is provided every 3 hours.
L-000-MSG2_-MPEF______-CLAI____-PRO____-201008092345-_

The product is provided every 15 minutes.
L-000-MSG2_-MPEF______-FIRG____-PRO____-201006191815-_
L-000-MSG2_-MPEF______-FIRG____-000001____-201006191815-_

GII(Global Instability Index)
Atmospheric air mass instability in cloud free areas. The
original statistical algorithm was developed by the SAF insupport of Nowcasting and Very Short Range Forecasting but
the GII is produced at EUMETSAT.

L-000-MSG2_-MPEF______-CLAI____-000001____-201008092345
etc to 000003

CSR(Clear Sky Radiances)
This product contains information on mean brightness
temperatures and radiances from all thermal (e.g. infrared
and water vapour) channels, for those regions containing noor only low-level clouds.
The product is provided every hour.

The product is provided every 15 minutes.

L-000-MSG2_-MPEF______-CSR____-PRO____-201008092345-_

L-000-MSG2_-MPEF______-GII____-PRO____-201006191815-_

L-000-MSG2_-MPEF______-CSR____-000001____-201008092345
etc to 000003

L-000-MSG2_-MPEF______-GII____-000001____-201006191815-_

MPEG(Multi-Sensor Precipitation Index GRIB)
The Multi-Sensor Precipitation Estimate (MPE) productconsists of the near-real-time rain rates in mm/hr for each
Meteosat image in original pixel resolution.

CTH(Cloud Top Heights)
The product indicates the height of highest cloud. Based ona subset of the information derived during Scenes and Cloud
Analysis, but also makes use of other external meteorologicaldata.

The product is provided every 15 minutes.

The product is provided every hour.

L-000-MSG2_-MPEF______-MPEG____-PRO____-201006191815-_

L-000-MSG2_-MPEF______-CTH____-PRO____-201008092345-_

L-000-MSG2_-MPEF______MPEG____-000001____-201006191815 etc to 000004

L-000-MSG2_-MPEF______-CTH____-000001____-201008092345
etc to 000002

AMV(Atmospheric Motion Vectors)
Atmospheric Motion Vectors at all heights below thetropopause, derived from 5 channels (Visual 0.8, Water
Vapour 6.2, Water Vapour 7.3, Infrared 10.8 and the High
Resolution Visual channel), all combined into one product.

DIV(Divergence)
The Divergence is calculated directly from the field of the
MSG channel 6.2 Atmospheric Motion Vectors. Only highlevel (above 400 hPa) vectors are considered, and the output
variables are Horizontal Divergence and Relative Vorticity on
a 32 x 32 pixel grid.

The product is provided every hour.
The product is provided every hour.
L-000-MSG2_-MPEF______-AMV____-PRO____-201008092145-_
L-000-MSG2_-MPEF______-DIV____-PRO____-201008092345-_
L-000-MSG2_-MPEF______AMV____-000001____-201008092145-_

L-000-MSG2_-MPEF______-DIV____-000001____-201008092345-_

ASR(All Sky Radiances)
This product contains information on mean brightness
temperatures and radiances from all thermal (e.g. infrared
and water vapour) channels. It includes both clear andcloudy sky radiances and brightness temperatures.
The product is provided every hour.

TH(Tropospheric Humidity)
Relative humidity in both mid and upper layers of thetroposphere, using a 16 x 16 pixel segment grid. The upper
level is derived from the mean layer relative humidity between
about 600 hPa and 300 hPa using the WV6.2 micron channel,
while mid-tropospheric humidity represents the mean value
between 850 hPa and 600 hPa using the WV7.3 micron
channel.

L-000-MSG2_-MPEF______-ASR____-PRO____-201008092145-_

The product is provided every 3 hours.
L-000-MSG2_-MPEF______ASR____-000001____-201008092145-_

L-000-MSG2_-MPEF______-TH____-PRO____-201006192345-_

CLA(Cloud Analysis)
Identification of cloud layers with cloud type and coverage,height and temperature.

L-000-MSG2_-MPEF______-TH____-000001____-201006192345-_

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43

GEO Quarterly No 28

Group for Earth Observation

TOZ(Total Ozone)
Total density of ozone in atmospheric column for each image
segment, based on the SEVIRI 9.7 micron Ozone channel andother IR and WV channels.
The product is provided every 3 hours.
L-000-MSG2_-MPEF______-TOZ____-PRO____-201006192345-_
L-000-MSG2_-MPEF______-TOZ____-000001____-201006192345-_

Not everyone will find the meteorological data of great interest
but for those, like myself whose weather satellite interests aremeteorologically based, there is a wealth of interesting data
included. As an example I have provided an image from an
AMV file showing wind speeds and directions at differentpressure levels. I have included the corresponding surface
weather analysis chart to show where wind directions would
be expected. Out of interest the lower pressure level winds (0– 350hPa) are shown in the lighter shade of purple. The imageis shown on the page opposite.
Next quarter I hope to look at Channel 4 which is a little
simpler than Channel 3.
Updates.
BUFRdisplay V0.1.2 101004 by Francis Breame.
You will find a detailed review of this program by the author
elsewhere in this journal. The program examines the contentsof BUFR encoded files to ascertain what data is included in
the file and also provides a detailed list of the file structure.
The program also decodes files and displays the data on aselection of map projections, assuming, of course, there isdata within the file that can be represented geographically.
This is a free program and so far I have not found a BUFR file
it will not open although do remember that some files only
include numerical data and not image data. To download thefile and get further information please go to :http://www.vf0123.btinternet.co.uk/

David Taylor’s programs (latest releases)
Just a reminder that the list below is for fully tested releases
and does not include the latest beta (or alpha) versions
currently on test. Those can also be downloaded from David’s
site.

December 2010
Continued from page 11

How EUMETCast aids Gliding
Hannu has used Meteosat satellite information since 1985,
first receiving the WEFAX data through an Italian VHF
receiver and video converter and displaying the images on a
monochrome TV screen. The same system was used toreceive polar satellite images but needed too much manual
work. The next significant step was the Dutch Digisat PC
software in 1995, which made it possible to show theMeteosat data automatically in a continuous coloured strip.
The Meteosat WEFAX data service stopped operation insummer 2006 so Hannu had to start using EUMETCast data
and the whole bundle of David Taylor's software that same
summer. First, LRIT data was downloaded through theInternet but, after a very short time, a parabolic antenna
and Technisat card, to receive HRIT data straight from thesatellite, were added to his system.
All the time the most interesting data have been the sixhourly visual images of views over northern Europe. From
those images one can see how the fronts and overcast areas
are moving, and on this base the start time and flight plan.
This is very important during gliding competitions on tricky
days. You can also even see single cumulus clouds andwhen and where they are starting to develop with the new
HRIT data false colour images. Originally, it was not possible
to have images from GeoSatSignal, but an update has now
made this possible.
With this new system, it is also possible to make use of theprevious 12 hours of infrared images to view front
movements. During the evenings you may try to visualize
what will happen during the night for the following day's
weather, but modern weather forecasts are much better
now.
Ultralight Application
Ultralight planes are only used in good weather conditions(VFR-flights). Before flying, it is necessary to check thecurrent weather and also forecast for the planned flying
route. Aviation authorities offer meteorological services for
current weather (METAR) and weather forecast (TAF). Each
forecast is given by codes, which include data on winds,
cloud cover and also probabilities as to how the weather isforecast to develop.

To learn more about those programs and to download thelatest updates please go to :-EFVA 111730Z 1118/1218 VRB03KT 9999 SCT012 BKN020
TEMPO 1119/1124 OVC012 TEMPO 1200/1207 4000 BR BKN004
TEMPO 1208/1218 6000 RA BKN013

http://www.satsignal.eu

TAF forecast for Vaasa airport

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
MODIS L1 & Fire Viewer

44

v 1.2.2
v 2.0.6
v 1.1.4
v 1.2.0
v 1.2.4
v 7.1.6
v 2.3.10
v 2.1.6
v 1.4.4
v 2.9.6
v 1.3.2
v 1.1.8
v 1.4.8
v 2.5.40
v 2.5.42
v 3.2.4
v 5.2.2
v 1.4.2
v 3.8.10
v 1.0.4

Weather codes are clear but it is quite hard to make a visual
understanding how weather could develop. Using Meteosat
12-channel information it becomes quite easy to get anexact picture of the current weather and forecast.

The writer is using MSG Data Manager, MSG Animator and
GeoSatSignal for data visualisation.
About the Authors
Hannu Korhonen is a senior glider pilot with over 5000
hours of flying experience. He has a master’s degree inaviation engineering and has designed several types ofgliders (PIK 20 series). He has also won a gold medal in his
national gliding championships. Today he is the happy
owner of an ASG29 glider plane and works in his own
company, HKAvionics, selling equipment needed in gliding.
Esko Petäjä is a junior glider and ultralight pilot, with as yet
only a few hundred flying hours. He is also a Ham radio
operator: call sign OH6MQM.

www.geo-web.org.uk© NASA