Group for Earth Observation

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

54
June 2017
Inside this issue . .
GEO recently attended theLondon Amateur Radio andComputer Rally held at
Kempton Park, and you canread Francis Bell’s illustrated
report on page 13.
Meteosat-7, one of the longest
serving meteorologicalsatellites, ended a 19-year
operational life-span when it
was decommissioned last
March. David Taylor
reminisces over this oldfriend.
Data from the Copernicus
Sentinel-3A satellite is now
available for download fromthe internet, a boon formembers who do not use the
EUMETCast service. Les
Hamilton details how to
obtain this data, and also
explains how to use Hugo
Van Ruyskensvelde’s
EUMETCastView software in‘passive’ mode to create
stunning images of ourplanet.
We also feature a fascinating
article from NASA illustrating
the ‘Night Light’ maps ofEarth that are now being
created using data from theSuomi-NPP satellite.
And of course there is theusual eclectic mix of shortfeatures from NASA’s Earth
Observatory.

GEO MANAGEMENT TEAMLes Hamilton

Director and 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: information@geo-web.org.uk
GEO Quarterly Editor
Les Hamilton,
8 Deeside Place,
Aberdeen AB15 7PW, Scotland UK.
email: geoeditor@geo-web.org.uk
GEO Quarterly Despatch
Peter Green
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
Technical Consultant (Hardware)David Simmons
email: tech@geo-web.org.uk
Webmaster and Website Matters
Alan Banks,e-mail: webmaster@geo-web.org.uk
GEO Shop Manager
Nigel Evans (Assistant: David Simmons),
email: shop@geo-web.org.uk
International Liaison
Rob Denton,
email: liaison@geo-web.org.uk
Management Committee Members
Clive Finnis
Carol Finnis

Publisher
Published by The Group for Earth
Observation Limited, a company in Englandand Wales, limited by guarantee and nothaving share capital.
The Company Number is 4975597.
The registered office is Coturnix House,
Rake Lane, Milford, Godalming,
Surrey GU8 5AB, England.
Printing (December Issue)
Hedgerow Print,
16 Marsh Lane,
Crediton, Devon EX17 1ES.
Tel: 01363 777 595
Responsibility
Every effort is made to ensure that thetechnical and constructional articles
published in this Quarterly are correct.
However, the ultimate responsibility iswith the reader to ensure the safety of
constructions and for any interfacing withother equipment. GEO cannot accept liability
for shortcomings in any published design or
any constructions carried out by members orother third parties.
Copyright GEO © 2017
The contents of this Quarterly remain theintellectual property of the Group for Earth
Observation Limited and its contributors.
Copying of text or images, either from theprinted Quarterly or from any electronicallystored source, is forbidden without
permission from the Editor.

geoeditor@geo-web.org.uk

Ihave been editing and compiling GEO Quarterly since the start of2004, making this year my 14th at the helm, and it is time to ask aserious question: “Is there any point in continuing with this magazine”.

In earlier years it was a joy to work with members who were keen
to share their experiences and ideas concerning satellite imaging,making up their submissions and collaborating to create attractive
articles. But this is long gone. EUMETCast has made everything tooeasy. There is no longer any innovation, and almost no-one can bebothered researching ideas to share with the membership.

A

ll too often I find myself working for weeks on end on a projectin which I have no personal interest, just to keep the magazine‘afloat’ and provide content (such as the piece on the EUMETCastView
software, which occupied much of my spare time for at least five
weeks). Many GEO members use this software, but none was preparedto help create an article on using it, despite prompting from myself.

A

glance at the Contents list shows that this Quarterly, like many
before it, exists only through reprinting web-based content fromNASA and ESA—material that anyone can consult freely on theinternet.

T

he outcome is that I plan to retire from post following theDecember 2017 issue of GEO Quarterly. Also, I plan to be far too
busy with my own interests over summer to create original content for
the September issue. If members do not rally round and help, thenthere may not be a September Quarterly.

Iwill of course make up any material received for Quarterly 55, but if
past experience is anything to go by, I will wait in vain.

C

opy deadline for the June issue of GEO
Quarterly is Sunday, August 27, 2017.

Contents
GEO Report
Cover Image Details
Quarterly Question
Phytoplankton Blooms in the Black Sea
Lake Mackay
Farewell Old Friend: Decommissioning of Meteosat-7
Cloud Streets in the Norwegian and Barents SeasLong Island: an island carved by water
Rare Glimpse of Cloud-Free Patagonia
GEO Outreach at Kempton Park
Glaciers Ebb in South Georgia
Improving Meteor M2 Reception
Copernicus Online Data Access for Sentinel-3
Processing Sentinel 3A files with EUMETCastView
Blooming Gibraltar
Arctic Meltdown
Russia’s Bay of Whales
Suomi NPP Night Light Maps
Satellite Status
GEO Helplines and Internet Discussion Groups
GEO Membership Application FormGEO Shop Catalogue and Price List

Francis Bell2
2
Francis Bell
3
MODIS Web
4
ESA: Space in Images
6
David Taylor
8
MODIS Web
9
NASA Earth Observatory
10
MODIS Web
12
Francis Bell
13
NASA Earth Observatory
14
Norbert Puetz
17
Les Hamilton
19
Les Hamilton
21
NASA Earth Observatory
31
NASA Earth Observatory/NSIDC 33
NASA Earth Observatory
35
NASA Earth Observatory
36
40
41
42
43

GEO Quarterly No 54

The Group for Earth Observation

June 2017

Francis BellI have found the last three months unusually quiet inrelation to my usual GEO activities, possibly for two
reasons.
Travel has taken me away from home for some of thetime which nowadays means no direct weather satellite
reception for me. This has not always been the casebecause, on many occasions in the past, I have taken
an APT receiving station with me on holiday and I havereceived images as far afield as India, Falkland Islands,
Ecuador and California. However, for security reasons I
am now a little more circumspect about taking satellite
receiving equipment abroad.
A second reason for my relative inactivity relates to thelack of arrangements for a GEO annual meeting this year.
Although rewarding with a successful event, organisingsuch a meeting can take up a lot of my time, but thisyear, disappointingly, there seems to have been a lack ofdemand for such a meeting. I was disappointed with the
response to the request in our previous Quarterly for ideas
and support for an annual meeting: only three members
contacted me and I judged this was far too small a
response to justify setting up a meeting. It’s not too late fora meeting this year but we need ideas and prompt action if
this is to happen.
Perhaps a compromise idea for an annual meeting may
be attractive, that is, to share such an event with anotherorganisation. I note this year that AMSAT-UK is hoping toshare its annual meeting with the RSGB’s annual meeting.
Something similar could be a way forward for GEO. Please
let me have your comments.
I continue to promote GEO as best I can at local events
such as radio rallies, club meetings and other events
if requested, and have several such events lined up forthe coming months. If any GEO member needs supportin presenting GEO’s activities to their local radio clubs
or similar events, please get in touch with me. Help andsupport can be arranged.

This image, from NASA’s Aqua satellite, shows the dreadful storm that
hit the UK on June 6, 2017. Worst hit was northeast Scotland, where
over a month’s rain fell over the ensuing three day period.
Image: LANCE Rapid Respones / NASA / GSFC

Front CoverThis splendid image in which the entire British Isles basks insunshine was captured from the Sentinel 3A satellite on March
25, 2017 by Mike Stevens.
Image © EUMETSAT 2017

Inside Front CoverOn the brink of summer, this was the scene captured byMeteor-M2 at 10.03 UT on the final day of May this year.
LRPT image captured by Les Hamilton

Inside Back CoverUnder a cloudless sky on May 25, 2017, the Sentinel 3A satellite
captured this image of the AWPR (Aberdeen Western Peripheral
Route), a new highway being built to divert through traffic past
the heavily congested NE Scotland cith of Aberdeen. Stretchingnearly 50 kilometres from Stonehaven in the south, the newdual carriageway is estimated to cost £745 million, and will becompleted early in 2018.
Image: Modified Copernicus data © ESA / Sentinel (2017)

Back Cover
Alaska was imaged by the MODIS instrument aboard NASA’s
Terra satellite on June 1, 2017—the first day of meteorologicalsummer—emerging from its winter mantle of snow and ice. This
image is remarkable in being almost cloud-free: it’s rare to see somuch of Alaska in this detail.
Image: LANCE Rapid Respones/NASA/GSFC

2www.geo-web.org.uk

June 2017

The Group for Earth Observation

GEO Quarterly No 54

Francis Bell
Quarterly Question 53
My thanks to those members who contacted
me with regard to the last Quarterly Question,
which related to two HDTV images recorded
from the ISS. One of these images was ofLake Michigan, USA which I thought was
rather difficult to quickly identify becausesome of the northern costal outline wasmasked by snow and ice as the image wastaken in late winter. However, given thescale of this enormous lake, with most of thecoastal outline clearly visible, it should havemade identification straightforward.
The other image in question was of the Gulf
of California, which separates Baja California
from the rest of mainland Mexico. This gulf
is about 700 miles long and almost certainly
created by the activities of the San Andreas
geological fault line.
It is often the case that I take an interest in
Earth images because I have visited theareas in question; in this case I had visitedseveral of the ports along the Pacific coastlineof Baja California. This personal connection
applies to this issue’s Quarterly Question,
asking for the names of three capital cities.

Figure 1 - This irecent Sentinel 1A radar image shows part of mainland Europe together withislands which belong to the country shown. The capital city is close to the centre of this image.

Quarterly Question 54
Quarterly Question 52 asked for the namesof two capital cities, which turned out
to be Lisbon the capital of Portugal and
St Petersburg the ancient capital of Russia,
although Helsinki, capital of Finland andTallinn the capital of Estonia were also clearlyvisible. The question for this issue again
relates to capital cities which can be seen on
two satellite images. And yes! I once more
have a personal interest because, during mytravels, I have visited all three of these cities.
The question is straightforward: name thethree capital cities seen in these two images.
When considering the images, note thedifferences in scale. Figure 1, showing a littleof mainland Europe and some islands, has awidth of about 50 miles (80 km) while figure 2
showing part of mainland South America
has a width of about 320 miles (510 km). A
little consideration should enable the threecapital cities to be named. A glance aroundthe European coastline should give just one
candidate, while inspection of the coastlineof South America should reveal the names of
the additional two cities.
Answers, please, by email to:
francis@geo-web.org.uk
by Sunday, August 27, 2017.

Figure 2 - This EnviSat visible image from April 2004 shows part of the coast of SouthAmerica with a large river estuary. One capital city is located on the north of the estuary close
to the open sea;.the other is located closer to the start of the estuary on its southern side.

www.geo-web.org.uk

3

GEO Quarterly No 54

The Group for Earth Observation

June 2017

MODIS WebOh May 29, 2017, the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite acquired astunning true-color image of phytoplankton blooms in the Black Sea. The blue, green, and turquoise swirls represent
huge colonies of single-celled, microscopic organisms called phytoplankton. These plant-like organisms live in the waters
year-round in small numbers but when they have the right combination of nutrients, water temperature and sunlight,
they can reproduce explosively, creating blooms that can easily be seen from space.
Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC

4

www.geo-web.org.uk

André T’Kindt from Ronse in Belgium sent in this evening APT image from NOAA 15, acquired from the 17:54 UT pass on May 10, 2017.

www.geo-web.org.uk

5

GEO Quarterly No 54

The Group for Earth Observation

June 2017

ESA: Space in Images

Copyright contains modified Copernicus Sentinel data (2017), processed by ESA , CC BY-SA 3.0 IGO

Brown hills speckle the eastern part of Australia’s Lake
MacKay in this satellite image. Located on the border
between the states of Western Australia and Northern
Territory, this salt lake only contains water following
seasonal rainfall—if at all. It is classified as an ephemerallake, meaning thet it exists only after precipitation. This
is not the same as a seasonal lake, which sees water for
longer periods. About half of Australia’s rivers drain inlandand often end in ephemeral salt lakes.
The greens and blues in this image show desert vegetationor algae, soil moisture and minerals—mainly salt. On

6some of the brown ‘islands’, and on the shore at lower
right, you can see the east–west sand ridges forming lines
in the landscape.
The lake lies at the edge of the Great Sandy Desert, which
covers nearly 285 000 sqare kilometres. Roads are scarcein the area, and often frequented by four-wheel drive
adventurers. Roads include the Canning Stock Routeabout 300 kilometres to the west of the image, and Tanami
Track, which connects Australia’s Stuart Highway to theGreat Northern Highway around 300 kilometres to theeast.

www.geo-web.org.uk

Mike Stevens captured this fascinating Sentinel 3A image of the Aral Sea region on April 16, 2017. It looks as though large quantities of water havebeen released from the North Aral Sea as the channels to its south, completely dry in recent times, are now filled with water.
Image © EUMETSAT 2017www.geo-web.org.uk

7

GEO Quarterly No 54

The Group for Earth Observation

June 2017

David Taylor
Although scheduled to stop at 09:00 UT on Friday,
March 31 2017, images carried on being disseminatedfrom Meteosat-7 until 12:30 UT when this final
transmission was made. The image looks as thoughsomeone pulled the plug just before it was complete.
Meteosat-7, the last of its line, was a ‘Meteosat First
Generation’ bird, and started its life covering Europe andAfrica following a September 1997 launch. It replaced
Meteosat-5.

As the newer MSG (Meteosat Second Generation) satellites
were launched, providing greater spatial resolution, morebands and a greater repeat frequency, Meteosat-7 was
relocated from zero degrees to 57 degrees East in 2007
where it provided coverage of the Indian Ocean (IODC)
until 2017. The IODC service is now provided by the
first of the MSG satellites—Meteosat-8. Zero degree
coverage is currently provided by Meteosat-10 (full-scan)and Meteosat-9 (rapid-scan), with MSG-4 (Meteosat-11)
currently being stored in orbit.

The last ever IODC image transmitted from Meteosat-7, prior to the satellite’s decommissioning at 12.30 UT on March 31, 2017.

8www.geo-web.org.uk

June 2017

The Group for Earth Observation

GEO Quarterly No 54

MODIS Web

Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC

On March 28, 2017, the Moderate
Resolution Imaging Spectroradiometer(MODIS) aboard NASA’s Terra satellite
captured a stunning true-color imageof cloud streets over the Greenland,
Norwegian, and Barents Seas.
Greenland sits in the northwesternsection of the image and Norway,
Sweden, and Finland sit in the south.
The Greenland Sea lies off the coastof Greenland and blends with theNorwegian Sea, which lies north andwest of Norway. The Barents Sea lies
to the northeast of Norway and northof Russia. Cloud streets, which are
long, parallel bands of cumulus clouds,
stretch from roughly north to south
over each of these bodies of water.
Cloud streets are formed when cold air
blows over relatively warmer waters.
To transport the heat away from thesea surface, columns of warmed air
www.geo-web.org.uk

called thermals naturally rise throughthe atmosphere. These air masses
rise until they encounter a warmer air
layer (temperature inversion), whichacts like a lid. The rising thermals rollover when they hit this ‘lid’, and loop
back on themselves, creating parallel
cylinders of rotating air. On the upperedge of these cylinders of rising air,clouds form while along the downward
regions (descending air), skies areclear.

9

GEO Quarterly No 54

The Group for Earth Observation

June 2017

NASA Earth Observatory
The story of Long Island beganwith ice. As glaciers advanced
and retreated over this patchof land at the end of the mostrecent Ice Age, the sediment
they deposited piled up as
hills. When the ice melted andseas rose, those piles of glacial
debris became surrounded by
the sea. Stretching out into the
Atlantic like a giant fish, Long
Island continues to change:
thousands of years later, water
still resculpts the island’s
shoreline.
On October 17, 2016, theOperational Land Imager (OLI)
on the Landsat 8 satellite
captured this image of Long
Island’s East End. While theNorth Shore is characterized bycraggy inlets and peninsulas,
the South Shore is linedwith smooth, protective sandbars—the result of constantly
pounding waves.
Between the branching tailsof the East End lies Gardiners
Island, which spans more than
five square miles and is closed
to the public—a source of
curiosity given its proximity topopulation-dense Long Island.
In the 1600s, Gardiners was
believed to possess a cacheof pirate gold, but modern
scientists appreciate it foranother form of booty: its richcoastal geology.
On the northern end of
Gardiners Island (figure 2), afang-like feature juts into thewater. This cuspate foreland at
Bostwick Point owes its shape
to the waves. As they hit theshore, waves agitate sedimentalong the coast. When they
break at an angle to the coast,this creates a current parallel tothe coastline called a ‘longshore
current’. Combined, theseprocesses can rake sand andsediment into this triangularfeature.

10

Figure 1 - Long Island, highlighting its northern and southern regions (white rectangles)

The opposite end of the island(figure 3) includes a long, fingershaped sand bank called a spit.
These sand features frequently
form at the mouths of inlets andin places where water must movearound coastal barriers and otherfeatures. The spit projecting fromthe island’s southern end has
grown by 1.6 kilometres over the
past few decades. In the process,the ocean has breached its length
at several points, creating smaller
islets like Cartwright Island.
Coastline breaches mostoften form during hurricanes,
nor’easters, and other potent
storms. However, over time, theconstant pounding of waves tends
to smooth out spits, refilling
the gaps between them. Strong
currents tend to develop aroundsuch features, and in this image,the faint, light-coloured streams
of sediment in the water trace
this movement. The spit acts likea funnel, forcing water to movethrough a narrower channel
and resulting in more powerfulcurrents.

Figure 2 - Bostwick Point foreland on Gardiners Island

Figure 3 - Spit at the south of Gardiners Island

NASA Earth www.geo-web.org.uk
Observatory image by Jesse Allen
using Landsat data from the US Geological Survey
Story by Pola Lem

During the early days of May this year Great Britain enjoyed an extended period of high pressure. Long hours of sunshine warmed theland by day, but clear skies during the evening resulted in temperatures rapidly falling to near freexing. This Meteor M2 infrared image
acquired by Les Hamilton at 20:29 UT, paints a vivid picture of the anticyclone on the evening of May 9, 2017.

www.geo-web.org.uk

11

GEO Quarterly No 54

The Group for Earth Observation

June 2017

MODIS Web

When clouds parted over southern Patagonia during early
April 2017, NASA’s Terra satellite was flying overhead.
The Moderate Resolution Imaging Spectroradiometer(MODIS) aboard that satellite captured this stunning truecolour image of the nearly cloud-free landscape on April 7.
Southern Patagonia is a remote, sparsely populated,roughly triangular region at the tip of South America. The
country of Chile lies along the Pacific coast while Argentina
sits along the Atlantic Ocean. The borderline between thetwo countries lies in the Andes Mountains throughout

1212

most of southern Patagonia, although it does cut acrossthe large island of Tierra del Fuego. Tierra del Fuego lies
south of the continent and is separated from it by the
Magellan Strait.
The ice fields in the Andes are the most spectacularfeature of this image, along with the turquoise glacial lakes
in the north. Glacial sediment suspended in the watersof these lakes gives them a turquoise colour when viewed
from space.
Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC

www.geo-web.org.uk

June 2017

The Group for Earth Observation

GEO Quarterly No 54

Francis Bell
Since 2004, GEO has regularly
attended the twice-yearly London
Amateur Radio and Computer Rally
held at Kempton Park, London. This
spring the rally was well attended,with stands covering interests inamateur radio (including the RSGB)
and computing plus related hightec. activities with visitor numbers
contributing to a busy day.
In the past the GEO stand had
run a display of live EUMETCast
reception but nowadays, withthe requirement for a larger dishand its very accurate alignment,
we have dropped live reception
and instead display recorded
images from the previous day.
To be honest, I think a displayof well prepared images is better
than risking marginal receptionof live signals on the day with
unpredictable image reception.
I think visitors to our standwere attracted by the recorded
EUMETCast and NOAA images
being displayed, and the fact thatthey can be received at homewith guidance and the supportof our GEO Group was an added
attraction. As a result, we took four
new memberships on the day withother visitors saying they may join
via our website. We also sold eightSDR dongles with their potential
for APT and low rate digital image
reception, while also recognising
the potential of these dongles
for other modes of radio signal
reception.

David Simmons making adjustments to one of the four computerson our GEO stand just prior to opening for visitors.

Again my thanks to David Simmons
G1MAL for his support on the day,manning the GEO stand with me.
I feel sure that other radio
rallies around the country would
welcome a stand representing
GEO so, if you have a local rally(or just a club event) which you
could attend and represent GEO,
that would be great both foryour local groups and for GEO by
publicising our skills and support
for satellite image reception.

A quiet moment during an otherwise busy day with just one
visitor remaining at the GEO stand.
www.geo-web.org.uk

13

GEO Quarterly No 54

The Group for Earth Observation

June 2017

NASA Earth Observatory
Frequent cloud cover in the southern
Atlantic Ocean often obscuressatellite images of South Georgia andthe South Sandwich Islands. But
occasionally the clouds give way. On
September 14, 2016, the Operational
Land Imager (OLI) on NASA’s
Landsat 8 satellite captured naturalcolour images of South Georgia
Island, where several glaciers are in
retreat. The rectangles overlain on
figure 1 pinpoint the locations of twoof these glaciers.
Figure 2, a closer crop of the Landsat
scene, shows Neumayer Glacier. A
blue line indicates the position of
its terminus, or leading edge, on
September 10, 2000. In the 16 years
since, Neumayer has retreated morethan four kilometres. Like other large
glaciers on the island, Neumayer isa tidewater glacier—that is, it flows
down into the ocean.
“The glacier is on the verge ofseparation into two main tributaries,”

Figure 1 - Locations of the two receding glaciers on South Georgia island

Figure 2 - Neumayer glacier imaged on September 14, 201614

NASA Earth Observatory images by Joshua
Stevens, using Landsat data from the U.S. Geological Survey
www.geo-web.org.uk

June 2017

The Group for Earth Observation

wrote glaciologist Mauri Pelto in his blog. “This will
enhance calving from the glacier and promote additional
mass loss and retreat. This retreat will impact Konig Glacierto the north, which is connected to the Neumayer Glacier.”
Roughly 30 kilometres to the southeast of Neumayer, on
the same side of the island, Hindle Glacier has also retreatedmarkedly since 2000—more than three kilometres(figure 3). Like Neumayer, Hindle used to merge withanother glacier (Ross), and as recently 2002, the two werestill connected, according to Pelto.

GEO Quarterly No 54

The retreating ice on South Georgia Island could have asignificant impact on the island’s animals. Glaciers act
like barriers, preventing the spread of certain animals
such as the non-native rats that have become a threat toother species in the area. Rat populations have boomedon the north side of the island as the ice has ebbed,
while colonies of seabirds like pipits and small burrowing
petrels have declined in number in that area—likely due topredation of eggs and chicks. As the glaciers in the centreof the island shrink, rat populations could spread to thesouth and decimate bird populations.

Figure 3 - Hindle glacier imaged on September 14, 2016www.geo-web.org.uk

15

This beautiful image from the Meteor M2 satellite was acquired by Enrico Gobbetti on February 28, 2017.
Particularly striking is Iceland, virtually cloud-free and covered by snow and ice.

16

www.geo-web.org.uk

June 2017

The Group for Earth Observation

GEO Quarterly No 54

Norbert Pütz
In GEO Quarterly 46, I explained that I was being plagued byinterference from unknown sources which was disturbing my
Meteor M2 satellite reception. As a result, I could not decodesignals from south of the Alps. I am happy to report that the
disturbances of my neighbourhood have since reduced and I no
longer need to use the Würth 829 999 USB-filter stick.

Attached are some nice pictures, and as you can see, I am now
often able to obtain excellent imagery from far south of the Alpsand well into North Africa. Of course this is not true every time:
the picture below is one of my best ones.

It turned out that my problem was not related to disturbances in
my immediate neighbourhood, but to a Pluto Over-the-Horizon
radar installation. Fortunately—the station recently changed
its signal modulation. This new modulation is less critical andproduces fewer harmonics, which no longer cause strong
disturbances in the shortwave bands and less intermodulation
products in preamplifiers.
I have now bought a galvanic separation device with built
in separated power source which brings two benefits: 2 kVprotection of my FUNcube Pro dongle and laptop (in caseof voltage surges) and perfect decoupling of my FUNcube
from my laptop. The coupling capacity between both sides isapproximately 2 pF (note that this galvanic separation does notwork with the RTL-SDR DVB dongle).

Meteor M2 imaged Iceland on March 4, 2017

But this nice box isn´t, however, able to power my DVBT stick,because it needs more power then my FUNcube dongle. But
it’s not a big problem as there is still the possibility to use a split
USB-cable.

Improved reception is achieved using a USB isolator
which contains an IC for galvanic separation

The reverse side of the isolator housing
showing the type and manufacturer.

This fine Meteor M2 image was acquired on February 6, 2017www.geo-web.org.uk

17

18

Using his recently upgraded hardware, Norbert Pütz captured this Meteor M2 image, stretching all
the way from Greenland to Morocco, from his location in Germany, on March 10, 2017.

June 2017

The Group for Earth Observation

GEO Quarterly No 54

Les Hamilton
I’m sure that like me, many readersof our March issue would havebeen impressed by the Copernicus
Sentinel-3A images displayed throughout
its pages. Of course, a fair number ofyou will have been receiving these on
your home systems via EUMETCast: but
again like myself, not all GEO Quarterly
readers have access to this distribution
channel.
So it was with great interest that
I learned a few months ago that
EUMETSAT now offers precisely thesame Sentinel-3A data in the form ofinternet downloads from their new web
portal athttps://coda.eumetsat.int/
Figure 1 illustrates the startup screenthat is displayed when you first visit thissite.
Signing Up
Use of this EUMETSAT service is free,
but you do have to sign up for it before
being afforded access to the data. Clickthe ‘SIGN UP’ button at top right on thescreen then, at lower left on the following
screen, select ‘NEW USER - CREATE NEWACCOUNT’. This reveals the EUMETSATEO Portal Account Creation screen where
you input your details: Username,
Password, Email Address, Organisation
etc.

Figure 1 - The Coda start screen

This does not, however, bring immediate
access, and the password you enter
seems quite irrelevant. About 24 hours
later you will receive an email confirming
your registration, but providing you
with a new password (of EUMETSAT’s
choosing). From this point, you will beable to access Sentinel-3 data by hitting
the ‘LOGIN’ button and entering yourchosen Username and the EUMETSATsupplied password. Be aware thoughthat this password is case sensitive:
enter it exactly as supplied.
Using the Portal

Figure 2 - Selecting and data sets for the UK on March 3, 2017

Open the Insert search criteria panel at top
left on the screen (figure 2) by clicking
highlighted, both by boxes overlain
the icon. Here you select the date/on the map and in a menu at thetime of the image(s) you are seeking,left of the screen, as illustrated in
the Product Type and Instrument. Next,
figure 3. Select your tile and press its
select the area of interest on the map,
‘Download’ button in the menu list.
then finally click theicon to search
for the available data. Provided data are That’s the gist of it. Now let’s take itavailable, all relevant image tiles will be more slowly, one step at a time.
www.geo-web.org.uk

Navigating the Map
The map can be dragged to reveal any
part of the Earth’s surface you wish.
By default, dragging the cursor overthe map selects an area of interest.
But if you click on theicon atupper right, you toggle the cursor into

19

GEO Quarterly No 54

The Group for Earth Observation

June 2017‘Drag Mode’, whereby the map can be
dragged around to reveal the region
you require. Once you have positioned
the map, click theicon again to
return it to ‘Select Mode’.
Searching for Sentinel-3 Images
Figure 2 shows the Search Panel,with the map moved somewhat tothe east so that, in this instance, theBritish Isles is clearly seen. This panel
includes options to set a specificwindow of time—spanning either a few
hours on a particular date or a periodof many days duration—within which
to search for images. There are two
options: Sensing Period (the actual
time when the satellite acquired its
images) or Ingestion Period (the time
when images were placed in thearchive). I tend to select both to cover
all bases, as it were.
Sentinel-3 Instruments
There are two optical instruments
aboard Sentinel-3 that produce
300 metre/pixel images. These are:
• OLCI, the Ocean and Land Colour
Instrument, described as a mediumresolution imaging spectrometer
which uses five cameras to provide awide field of view.
• SLSTR, the Sea and Land Surface
Temperature Radiometer, whichmeasured in eleven spectral
channels to determine global seasurface temperatures to an accuracyof better than 0.3 K.

Figure 3 - Available segments revealed by the search (March 26, 2017)

Instrument and Product TypeIt is also advisable to selectappropriate Product Type and Instrument
options from the Search Panel,otherwise you will obtain a list of allavailable Sentinel-3 products, most ofwhich are of no meaning to the casual
enthusiast. The two meaningful
selections are• Product Type: OL_1_EFR___
Instrument: OLCI
• Product Type: SL_1_RBT___
Instrument: SLSTR

Figure 4 - A file is selected for download

Of the two, the former usuallyprovides the most realistic colour
composite images.
Selecting an Area
This can be done either before orafter setting the search parameters.
Make sure that the search area isclearly accessible on the screen anddrag a rectangle over the map tosuit your requirements (figure 3),
in this example, over the British
Isles. Because every available tilethat overlaps even the tiniest cornerof this rectangle will be listed anddisplayed on the map, it’s a good idea
to make the search area quite small.

20

Figure 5 - An image is selected from the panel

Of course, you can select as large
an area as you like, but this often
produces a confusing clutter of many
overlapping tiles.

additional tiles to the east of Britain
are displayed because the searchrectangle partly overlapped them.

You are now all set to go, so click
the Search Icon ( ) and await theappearance of the list of tiles. In
figure 3, you will observe that

Every tile outlined on the map will
have an accompanying entry in the
Display Panel at the left hand side of
the screen. As you hover the cursor

www.geo-web.org.uk

Selecting a Tile

June 2017

The Group for Earth Observation

GEO Quarterly No 54

Probably the most useful of the five icons is the middle
one, which displays an information window (figure 6). Hereyou can quickly verify that you have selected the intended
tile (left hand image), and can check a coloured ‘quicklook’
image of the included scene.
When the tile you wish to download is highlighted, hoverover its menu entry and click its download icon, .
The Downloads
The files that are downloaded are large, generally between
600-650 MB, and in my experience can take up to ten
minutes to download—but this will very much depend on
the speed of your internet connection.
The downloaded files are not themselves images. The
OLCI downloads are zipped archives containing datafor 21 bands in the 400 - 1020 nanometre range, tuned
to specific ocean colour, vegetation and atmosphericcorrection measurement requirements. The spatial
resolution is 300 m/pixel in all cases, similar to thehighest resolution of NASA MODIS imagery.

Figure 6 - A Tile Information Screenover the entries on this panel, each tile shown on themap becomes highlighted in turn (figure 4). Figure 5 is anenlarged image of the list entry for the tile that is shown
covering Scotland and much of England. At left is a (very)small thumbnail image covered by the selected tile, and on
the right are five small clickable icons. From left to right,
these are:• Select Product• Zoom to product (on map)
• View Product Details• Add Product to Cart
• Download Product

The SLSTR downloads are also zipped archives, in thisinstance comprising 11 channels, three in the visible
spectrum and the remainder in the infrared.
Resolving Sentinel-3A zip Archives into Images
Probably the most straightforward way to create images
from this data is to use Hugo Van Ruyskensvelde’s
EUMETCastView software.
David Taylor introduced this versatile software in theprevious Quarterly for processing images downloaded fromEUMETSAT. Using it to process the files downloaded fromthe internet is explained in the following article.

Les Hamilton
Many GEO readers will already be familiar with Hugo Van
Ruyskensvelde’s EUMETCastView software as a means ofprocessing the satellite files they acquire via EUMETcast.
Fortunately, the same software package can be used to process
Sentinel-3A files downloaded from the CODA internet site.
There is one minor difference however. Sentinel-3A files obtained
from EUMETCast are bundled together as .tar archives whereas
those from the internet are bundled in .zip archives. To create
imagery from the zip archives, you need to have installed v 1.2.3(or later) of EUMETCastView. Earlier versions only accept the.tar archives. EUMETCastView v 1.2.3 can be downloaded fromhttps://github.com/hvanruys/EUMETCastView/releases
Also, if you wish to investigate the SLSTR imagery, again, youwill have to install this version.
Installation of EUMETCastView
EUMETCastView is a ‘portable’ program, so can be installed
anywhere on your computer. The program comes as a zippedarchive, which, when extracted, places all its files in a folder
named ‘DeployEUMETCastViewer’. A word of advice here: do
not install into the Program Files—or Program Files(x86)—

folder, because the software needs to write files to its own folder,something that modern versions of Windows do not allow.
David Taylor recommends unzipping EUMETCastView into aworking folder called C:\Tools\. I prefer to unzip the program
directly to a different disc partition, D:\ DeployEUMETCastViewer.
If your hard drive is not partitioned, the program runs perfectly if
extracted to the main drive as C:\ DeployEUMETCastViewer.
The next step will almost
certainly differ from that used withEUMETCast.
Despite my exhortations, no-one
has seen fit to support GEO by
providing a comprehensive article
on the use of EUMETCastViewer:
so I have had to invent my own work
scheme. In order to accommodate
the files downloaded from the CODA
website, I created a new folder
named ‘Downloads’ inside the main
DeployEUMETCastViewer folder, as illustrated here.

www.geo-web.org.uk

21

GEO Quarterly No 54

The Group for Earth Observation

June 2017

Figure 1 - Three key areas on the Satellite Setup screen

The program file, found in the DeployEUMETCastView folder, is‘EUMETCastView.exe’. It is a good idea to right-click this file,drag on to the Desktop, and create a shortcut for future ease ofuse.
When you run EUMETCastView for the first time it opens todisplay the Satellite Setup Screen (figure 1). Although this appears
hugely complex, in fact very little of it is relevant to processing
Sentinel 3A files from the CODA site. The relevant areas aremarked by prominent red numerals, and are the Segment
Directories panel (1), the Selection Calendar (2) and the 3D Globe
button at upper left (3).
The Segment Directories Pane
By default, this pane is filled witha long list of folders relating to
EUMETCast reception. If, likeme, you are not receiving thisdata, click each entry in turn toselect it then click the ‘Delete
Directory’ button. When thepane is empty, click the ‘Add
Directory’ button, navigate to the‘Downloads’ folder, click on thefolder to select it then click the‘Select Folder’ button.
Finally, ensure that
EUMETCastView ‘knows’ where
Figure 2
to look for your downloaded files
The Initial Segment Directoryby ticking the checkbox against
its name in the Segment Directories Pane (which now contains
just one entry, your new Downloads folder.

22

The Calendar
Every file you downloadfrom the CODA site
includes the date ofacquisition in its filename.
I’m using files relating to
Cyclone Debbie which hit
northern Queensland inAustralia on March 27,
2017, which are safely
stored in my ‘Downloads’
folder. Each download
comes with a 94 character
filename like the example
at the foot of this page
(figure 3). The key
feature is the fact that
this contains the date ofacquisition—March 27,
2017.
To load this file into
EUMETCastView, moveto the Selection Calendar,
select the correct Year,
Month and Day, then press
the Reload Segments button
immediately below the calendar.

Figure 4
Loading Segments

In my case, I had collected four files relating to Cyclone Debbie:
two each from OLCI and SLSTR (because the storm was split
between two tiles) and these all now appear in the Directory list
beneath the calendar (figure 4).

Figure 3 - A typical, 94-character Sentinel‑3 tile filename
S3A_OL_1_EFR____20170327T234004_20170327T234304_20170328T013642_0180_016_030_3239_MAR_O_NR_002
www.geo-web.org.uk

June 2017

The Group for Earth Observation

GEO Quarterly No 54

Cyclone Debbie shown shortly after making landfall on Queensland, Australia on March 27, 2017 in this Sentinel 3A image, realised in
EUMETCastView using data from CODA, with additional processing in Photoshop.
Image: Modified Copernicus data © ESA / Sentinel (2017)www.geo-web.org.uk

23

GEO Quarterly No 54

The Group for Earth Observation

June 2017

Figure 5 - The 3D-Globe Image Processing Screen, showing the positions of two tiles, one selected (red) and the other yet to be selected (green).

The 3D Globe Button
The final step is to analyse the file(s) that have been loaded.
Click the 3D Globe button to reveal the Image Processing screen(figure 5). The centre pane is now a map of Earth which can be
dragged around by the mouse to bring any desired area intoview. You can also zoom in and out using the mouse-wheel.
Although there are zoom-in/zoom-out buttons at the top of thescreen, I have found these to be totally ineffective.
Creating High Resolution OLCI-EFR Sentinel 3A Images
To produce images from ‘EFR’ high-resolution OLCI tiles, you mustselect the OLCI EFR # 2/2 button from the right-hand pane, shownin green in figure 5. The areas covered by the two OLCI tiles that
I had selected relating to Storm Debbie were outlined in green
over Queensland. To create an image, it is necessary to rightclick on each tile to select it, when its outline turns to red. If you
right-click on just a single tile, only that tile will be processed. By
selecting both tiles, EUMETCastView will not only process eachtile, but seamlessly join them together to create the full scene.
To create an image, click the Make Image button at the foot of theright-hand pane. The image produced will be in accordance withthe default settings in the left-hand panel (figure 5). A progress
bar at the foot of the panel reaches 100% when the image is

24complete, and a thumbnail of the result is generated within thetile outlines on the World Map, as shown in figure 7. You canzoom in to view the scene in greater detail by means of themouse wheel. The image can now be saved as either a PNG or
JPG using the second-left button at the top of the screen.
OLCI Image Processing Options
The left hand panel (figure 5) is the Toolbox, where you cancontrol how the Sentinel 3A tiles are processed. The Toolbox may
be toggled on/off using the ‘spanner’ icon. The top section of the
Toolbox lists all the OLCI channels, and immediately below are anumber of image processing controls.
The ‘Configuration’ dropdown list, contains three
options (figure 6a), which are:• User defined• Natural Colors• True Colors‘Natural Colors’ and ‘True Colour’ select default (fixed) channel
combinations, either of which is capable of rendering attractive
colour composite visible light images. The ‘User defined’ option
allows you to experiment using your own choice of channel
combinations.

www.geo-web.org.uk

June 2017

The Group for Earth Observation

Figure 6a - Colour and normalisation options

GEO Quarterly No 54

Figure 6a - Image equalisation option

Figure 7 - Processing two Sentinel 3A tiles for Cyclone Debbie. The progress counter shows 80% at lower left (blue strip)

Below this is the ‘Histogram Matching’ dropdown list, shown infigure 6b, which also contains three options:• None 95%• None 100%
• Equalise
What precisely the ‘None 95%’ and ‘None 100%’ entries mean
is beyond me: clearly these are presets that apply a degree of
histogram stretching. These options do have a definitive effect on
the Sentinel 3A images, which is best appreciated by referring to
the comparison images of Cyclone Debbie on page 26.
Each time new tiles are selected in EUMETCastViewer, you mustclick the Make Image Button to initiate the processing operation,using your selected parameters. However, to subsequently
investigate the effects of the different Histogram options, this canbe achieved by simply making a new selection from the dropdown list. Note though, that a change to the Configuration dropdown list does not take place automatically: you must click theUpdate OLCI Image button in the Toolbox to effect this change.
Processing SLSTR Tiles
Creating images from the Sentinel 3A SLSTR data follows avery similar course to what has already been described above.
The one essential difference is that the SLSTR #1/2 button, justbeneath the OLCI EFR #2/2 button, must be clicked, whereupon itturns green. This brings with it a change in the appearance of the
Toolbox, which now displays the eleven SLSTR channels in placewww.geo-web.org.uk

continued on page 28

25

GEO Quarterly No 54

26
26

The Group for Earth Observation

June 2017

OLCI / Natural Colour / None 100%

OLCI / Natural Colour / None 95%

OLCI / Natural Colour/ Equalised

OLCI / True Colour / None 100%

OLCI / True Colour / None 95%

OLCI / True Colour / Equalised

SLSTR / Natural Colour / None 100%

SLSTRNatural Colour / None 95%

SLSTR / Natural Colour / Equalised

SLSTR / False Colour / None 100%

SLSTR / False Colour / None 95%

SLSTR / False Colour / Equalised

Credit (all images): Modified
Copernicus Data © ESA / Sentinel (2017)www.geo-web.org.uk

26

June 2017

The Group for Earth Observation

GEO Quarterly No 54

OLCI / Natural Colour / None 95%

OLCI / True Colour / Equalised

SLSTR / Natural Colour / None 95%

SLSTR / False Colour / None 95%

Credit (all images): Modified
Copernicus Data © ESA / Sentinel (2017)www.geo-web.org.uk

27

GEO Quarterly No 54

The Group for Earth Observationof the 21 OCLI channels. Again there are two ‘Configuration’presets: ‘Natural Colors’ and ‘False Colors’, and the same three‘Histogram matching’ possibilities. Comparison SLSTR images of
Cyclone Debbie are shown on the lower half of page 26.
Of course, the colours rendered in the SLSTR images are
frequently quite weird, but can be useful for highlighting
certain features. The four images featuring western Europe
on page 27 show Sentinel 3A products from April 30, 2017. In
general, for well illuminated scenes like this, I find that setting
Histogram Matching to ‘None 95%’ results in the most pleasing
results in the vast majority of cases. The one exception seems
to be when using a Configuration of ‘True Color’, which typically
produces very dark land features: in this particular case, the mostpleasing results come by setting Histogram Matching to ‘Equalise’.
48-bit OLCI PNG Files
Readers familiar with David Taylor’s Sentinel 2 to JPEG software,
reviewed in GEO Quarterly 53, may be interested to learn thatit can also process 48-bit OLCI PNG files of Sentinel 3A data.,
providing more sophisticated adjustment of both gamma andhistogram equalisation.

EUMETCastView includes the Save 48‑bit PNG button on its OLCI
version of the Toolbox. For both the ‘Natural’ and ‘True’ colour
options, following image processing, this button will save theraw data for the three selected channels to a 48‑bit PNG file (nohistogram matching included). The resulting PNG file can be
rapidly processed many times over within Sentinel 2 to JPEG
to investigate the effects of altering both gamma and histogram
stretching.
The two images from April 30 presented below illustrate the True
Colour version from EUMETCastView, with Histogram Matching
set at ‘None 95%’ (left) and the 48‑bit PNG file after processing
with ‘Sentinel 2 to JPEG’ where the minimum histogram level has
been raised to 48 (right) to improve land rendition.
Feedback
I have only considered the default features of EUMETCastView,
and there is clearly a great deal of scope for further
experimentation, particularly with the ‘User’ option for selection of
OLCI and SLSTR channels. Any feedback that can advance ourcollective enjoyment of Sentinel 3A data from the CODA site will
be most welcome.

Sentinel 3A image acquired on April 30, 2017and processed in EUMETCastView

Image: Modified Copernicus Data © ESA / Sentinel (2017)28

June 2017www.geo-web.org.uk

Sentinel 3A image acquired on April 30, 2017and processed in Sentinel 2 to JPEG

Image: Modified Copernicus Data © ESA / Sentinel (2017)

This is a small segment taken from the March 3, 2017 Sentinel‑3A image, when the only area of the British Isles not underheavy cloud was Scotland. Snow lying on the tops of the Scottish mountains shows up clearly.
Image: Modified Copernicus data © ESA / Sentinel (2017)www.geo-web.org.uk

29

Mike Stevens submitted this April 17 Sentinel-3A image showing his home location of Portland (the small peninsula at the east of Lyme Bay on the
Dorset coast). The image shows remarkable cloud detail over the Atlantic Ocean, including a large cluster of aeroplane contrails west of Land’s End.
Image © EUMETSAT 201730www.geo-web.org.uk

June 2017

The Group for Earth Observation

GEO Quarterly No 54

NASA Earth Observatory

NASA image by Norman Kuring, NASA’s Ocean Color web. Story by Kathryn Hansen.

From space, the Strait of Gibraltar
appears tiny compared with thecontinents it separates. At the strait’s
narrowest point, Africa stands just 14
kilometres from Europe. But the narrow
waterway is a complex environmentthat gives rise to striking phytoplankton
blooms when conditions are right.
Water conditions and circulation near
the strait produced the bloom withcolourful tendrils visible in this image,acquired on March 8, 2017. The image
is composed from data acquired with
the Visible Infrared Imaging Radiometer

Suite (VIIRS) on Suomi NPP, andthe Moderate Resolution Imaging
Spectroradiometer (MODIS) on NASA’s
Aqua satellite. A series of processing
steps were applied to highlight colour
differences and bring out the bloom’s
subtler features.
The intricate swirls of phytoplankton trace
the patterns of water flow, which in thisregion can become quite turbulent. For
example, water moving east from theNorth Atlantic into the Mediterranean Sea
has created turbulence in the form ofinternal waves. These waves—sometimes
www.geo-web.org.uk

with heights up to 100 metres—occur
primarily deep within the ocean, with justa mere crest poking through the surface.
At the same time, water flowing west
helps stir up water in the North Atlantic,
including the Golfo de Cádiz.
While most of the swirls of colour are
phytoplankton, some of the colour nearcoastal areas could be due to sedimentsuspended in the water, particularly near
the mouths of rivers. Some of the yellowgreen plume near the Guadalquivir River,for example, could be due to coloured
dissolved organic matter.

31

It was a particularly wet day over much of Britain on Saturday March 4. Aberdeen in northeast Scotland suffered over 20 hours of continuous rain
and local flooding. Andre T’Kindt captured the 18.41 UT NOAA 18 pass and applied an MCIR+Precipitation overlay to illustrate the rainfall.

32

www.geo-web.org.uk

June 2017

The Group for Earth Observation

GEO Quarterly No 54

NASA Earth Observatory / NSIDCIn March 2017, Arctic sea ice reached a record-low maximum
extent, according to scientists at NASA and the National Snowand Ice Data Center (NSIDC). In the same month, sea ice on the
opposite side of the planet, around Antarctica, hit its lowest extent
ever recorded at the end of an austral summer—a surprising turnof events after years of moderate sea ice expansion.
On February 13, 2017, the combined Arctic and Antarctic sea
ice numbers were at their lowest point since satellites began
to continuously measure sea ice in 1979. Total polar sea ice
covered 16.21 million square kilometers (Mkm2), which is 2 Mkm2
less than the average global minimum extent for 1981–2010.
That’s the equivalent to losing a chunk of sea ice larger than
Mexico.

Figure 1 - A NASA visualisation of Arctic Ice cover on March 7, 2017.
Credits: NASA’s Goddard Space Flight Center

The line graphs below plot the monthly deviations and overall
trends in polar sea ice from 1979 to 2017 as measured bysatellites. The top line shows the Arctic; the middle shows
Antarctica; and the third shows the global, combined total. The
graphs depict how much the sea ice concentration changed
above or below the long-term average (not total sea ice
concentration.)

Figure 2 - Arctic Sea Ice Extent on March 7, 2017

Changes in sea ice concentration / Mkm2

Arctic and global sea ice totals have decreased consistently over
38 years. Antarctic trends are more muddled, but they do not
offset the great losses in the Arctic. The maps opposite provide
a closer look at the record lows that occurred at each pole thisyear.
The ice floating on the Arctic Ocean and its surrounding seas
decreases from mid-March until mid-September. As the Arctic
temperatures drop in the autumn and winter, the ice cover
increases again until it reaches its yearly maximum extent,
typically in March. This winter, a combination of warmer-thanaverage temperatures, unfavorable winds, and a series of storms
stunted sea ice growth in the Arctic.

Antarctic Sea Ice Extent on March 3, 2017

Figure 2 shows the concentration of Arctic sea ice on March 7,
2017, when it reached its maximum extent for the year. Opaque
white areas indicate the greatest concentration, and dark blue
areas are open water. All icy areas pictured here have an ice
concentration of at least 15 percent (the minimum at whichwww.geo-web.org.uk

33

GEO Quarterly No 54

The Group for Earth Observation

June 2017

space-based measurements give a reliable measurement), andcover a total area that scientists refer to as the “ice extent.”

several monthly record-high extents in Antarctica and decades ofmoderate sea ice growth.

The maximum extent on March 7 was a record low, measuring
14.42 Mkm2. That’s 97 000 m2 below the previous record low that
occurred in 2015.

‘There’s a lot of year-to-year variability in both Arctic andAntarctic sea ice, but overall, until last year, the trends in
the Antarctic for every single month were toward more sea
ice,’ said Claire Parkinson, a senior sea ice researcher at
NASA Goddard. ‘Last year was stunningly different, withprominent sea ice decreases in the Antarctic. To think that
now the Antarctic sea ice extent is actually reaching arecord minimum, that’s definitely of interest.’‘We started from a low September minimum extent,’ said
Walt Meier, a sea ice scientist at NASA’s Goddard Space
Flight Center. ‘There was a lot of open ocean water, andwe saw periods of very slow ice growth in late October andinto November because the water had a lot of accumulated
heat that had to be dissipated before ice could grow.
The ice formation got a late start and everything lagged
behind—it was hard for the sea ice cover to catch up’.
‘This year’s record-low maximum will not necessarily leadto a new record-low minimum extent in summertime, since
weather has a great impact on the melt season’s outcome,’stated Meier, ‘but it’s guaranteed to be below normal.’
Sea ice around Antarctica behaves in a similar manner, butwith the calendar flipped—it usually reaches its maximum in
September and its minimum in February. This year, Antarctic sea
ice reached a record-low minimum on March 3. Figure 3 shows
the concentration of sea ice on that day.
The extent on March 3 measured 2.11 Mkm2, 184 000 km2
below the previous record low in the satellite record, which
occurred in 1997. This year’s low happened just two years after

Meier said it is too early to tell if this year marks a shift in the
behavior of Antarctic sea ice.
‘It is tempting to say that the record low we are seeing thisyear is global warming finally catching up with Antarctica,’
Meier said. ‘However, this might just be an extreme caseof pushing the envelope of year-to-year variability. We’ll
need to have several more years of data to be able to say
there has been a significant change in the trend.’
You can view movie animations showing the changes in sea ice
cover at both Earth’s poles athttps://svs.gsfc.nasa.gov/12537
Credit: NASA Earth Observatory images by Joshua Stevens, using data from theAdvanced Microwave Scanning Radiometer 2 (AMSR2) sensor on the Global
Change Observation Mission 1st-Water (GCOM-W1) satellite and the Scanning
Multichannel Microwave Radiometer (SMMR) on the Nimbus-7 satellite.
Caption by Maria-José Viñas, adapted for Earth Observatory by Kathryn Hansen.

This photograph, taken inside Paul Geissmann’s satellite receiving station in Säntis in northern
Switzerland, shows off his recently acquired model of the Meteosat-7 geostationary satellite.

34

www.geo-web.org.uk

June 2017

The Group for Earth Observation

GEO Quarterly No 54

NASA Earth Observatory

NASA Earth Observatory image by Joshua Stevens, using U.S. Geological Survey. Story by Pola Lem.

If you were in the market for a moulting whale epidermis,
Russia’s Ulbanskiy Bay might be a good place to searchfor one. The area is mostly uninhabited by humans, but
it does support sizable numbers of whales, whose castoff skins have been spotted in these Siberian waters by
scientists.

when predatory orcas approach, belugas swim close to
the shore for protection. With the arrival of autumn, newice forms in the bay, and the whales head out to open
waters.

In summertime, this bay becomes a feeding ground forbowhead whales, as well as belugas and orcas.

Despite this abundant underwater activity, the bay’s
waters appear serene from space. The image above was
acquired on September 30, 2014, by the Operational Land
Imager (OLI) on the Landsat 8 satellite.

Beluga whales come to Ulbanskiy for the seafood buffet.
They hunt by driving fish like herring and smelt toward
the coast and into freshwater inlets. Some whales begin toenter Ulbanskiy Bay as early as May, when the winter fast
ice begins to break up. Their numbers swell in late July,and aerial surveys have observed upwards of 1,200 ofthem here in August, when food is plentiful. Occasionally,

Freshwater streams meander into marshlands and gently
sloped mud flats. Ground photography shows that further
inland, the incline becomes steeper, with darker green,pine-covered slopes. A lighter green band on the left sideof the image indicates deciduous trees that have begun toturn color. The marshes around the bay are dotted withsmall bodies of water—likely thermokarst lakes.

www.geo-web.org.uk

35

GEO Quarterly No 54

The Group for Earth Observation

June 2017

NASA Earth Observatory

A Suomi-NPP Night-Time image of Europe for 2016

NASA scientists have released new global maps of Earth atnight, providing the clearest-yet views of the patterns of humansettlements across our planet. Satellite images of Earth atnight—often referred to as ‘night lights’—have been a curiosity
for the public and a tool of fundamental research for at least
25 years. They have provided a broad, beautiful picture, showing
how humans have shaped the planet and lit up the darkness.
Produced every decade or so, such maps have spawned
hundreds of pop-culture uses and dozens of economic, social
science, and environmental research projects.
But what would happen if scientists removed the moonlight, fires,and other natural sources of light and updated such night-time
images yearly, monthly, or even daily? A research team led byNASA Earth scientist Miguel Román plans to find out this year.
Since the 2011 launch of the NASA-NOAA Suomi National Polarorbiting Partnership (Suomi-NPP) satellite, and the 2012 release of
Earth-at-night maps, Román and colleagues at NASA’s Goddard
Space Flight Center have been analysing night lights data anddeveloping new software and algorithms to make them clearer,
more accurate and more readily available. A research teamin the Earth Observing Satellite Data and Information System(EOSDIS) has also been working to integrate night-time data into
NASA’s Global Imagery Browse Services (GIBS) and Worldview
mapping tools. Freely available to the science community andpublic via the Web, GIBS and Worldview allow users to see
natural- and false-colour images of Earth within hours of satelliteacquisition.
The images below show Earth’s night lights as observed in 2016:
they are drawn from a new global composite map (below) thatwas recently added to Worldview and GIBS. The compositing

36
36

technique selected the best cloud-free nights in each month overeach land mass. (Note that clouds and sunlight have been added
to some of the images for aesthetic effect: those data are drawn
from our Blue Marble products.) The team has also reprocessed2012 data with the new techniques so that researchers cancompare and contrast light sources over the years. By late 2017,
Román and colleagues hope to provide daily high-definition
views of Earth at night.
To make the new maps, Román and colleagues examined thedifferent ways in which light is radiated, scattered, and reflectedby land, atmospheric, and ocean surfaces. The principal
challenge in night-time satellite imaging is accounting for thephases of the Moon, which constantly vary the intensity of lightshining on Earth, though in predictable ways. Likewise, seasonal
vegetation, clouds, aerosols, snow and ice cover, and even faintatmospheric emissions (such as airglow and auroras) change theway that light appears in different parts of the world.
Román and colleagues have been building remote sensing
techniques to filter out these sources of extraneous light,
gathering a better and more consistent signal of how humandriven patterns and processes are changing. The improved
processing moves Suomi NPP closer to its full potential ofobserving dim light down to the scale of an isolated highway
lamp or a fishing boat.
Suomi NPP observes nearly every location on Earth at roughly
1.30 UT and 13.30 UT (local time) each day, as it images theplanet in vertical 3000-kilometre strips from pole to pole. The
satellite’s workhorse instrument is the Visible Infrared Imaging
Radiometer Suite (VIIRS), which detects photons of lightreflected from Earth’s surface and atmosphere in 22 different

www.geo-web.org.uk
www.geo-web.org.uk

June 2017

The Group for Earth Observation

GEO Quarterly No 54

A Suomi-NPP Night-Time image of Asia for 2016

A Suomi-NPP Night-Time image of Earth for 2016www.geo-web.org.uk

37

GEO Quarterly No 54

The Group for Earth Observation

June 2017

A Suomi-NPP Night-Time image showing Italy in high resolution

wavelengths. Because Suomi NPP is a civilian science satellite,
those data are freely available to scientists within minutes tohours of acquisition.
VIIRS includes a special ‘day/night band,’ a low-light sensor thatcan distinguish night lights with six times better spatial resolution
and 250 times better resolution of lighting levels (dynamic range)
than the older Operational Line Scan (OLS) imaging systems on
Defense Meteorological Satellite Program (DMSP) spacecraft.
VIIRS makes quantitative measurements of light emissions andreflections, which allows researchers to distinguish the intensity,
types, and the sources of night lights, and observe how theychange over several years.
Armed with more accurate night‑time environmental products,
the NASA team is now automating the processing so that users
will be able to view night‑time imagery within hours of acquisition.
This has the potential to aid disaster response. For instance,
VIIRS detected power outages in the wake of Hurricane
Matthew, a major storm that struck the northeastern Caribbean
and the southeastern United States in September 2016. NASA’s
Disasters Response team provided those data to colleagues
at the Federal Emergency Management Agency; in the future,
NASA, FEMA, and the Department of Energy hope to regularly
produce power outage maps and integrate the information into
recovery efforts by first responders.
The NASA team envisions many other potential uses by
research, meteorological, and civic groups. For instance, dailynight‑time imagery could be used to help monitor unregulatedor unreported fishing. It could also contribute to efforts to track38
38

sea ice movements and concentrations. Researchers in Puerto
Rico are working with night‑time data to reduce light pollution
and help protect tropical forests and coastal areas with fragile
ecosystems. And a team at the United Nations has already usedpreliminary versions of Román’s night lights data to monitor theeffects of war on electric power, and the movement of displaced
populations in war-torn Syria.
In a separate, long-term project, Román is working withcolleagues from around the world to improve global and regional
estimates of carbon dioxide emissions. The team at NASA’s
Global Modelling and Assimilation Office is combining night
lights, urban land use data, and statistical and model projectionsof anthropogenic emissions, in ways that should make estimatesof sources much more precise.
‘Thanks to VIIRS, we can now monitor short-term changes
caused by disturbances in power delivery, such as conflict,storms, earthquakes, and brownouts,’ said Román. ‘We canmonitor cyclical changes driven by reoccurring human activities
such as holiday lighting and seasonal migrations. We can also
monitor gradual changes driven by urbanization, out-migration,
economic changes, and electrification. The fact that we can track
all these different aspects at the heart of what defines a city issimply mind-boggling.’
To view and download the new images, and to read stories ofnight light science, visit our Earth at Night page athttps://earthobservatory.nasa.gov/Features/NightLights/

NASA Earth Observatory images by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA GSFC
Storyby Michael Carlowicz
www.geo-web.org.uk
www.geo-web.org.uk

On May 10, 2017, Russia’s Meteor M2 satellite underwent one of its infrequent decontamination periods when the infrared sensors are inactive. In
place of the channel-5 infrared, the LRPT stream includes Channel‑3 briefly allowing the user to create RGB123 images as shown here.
Image captured by Enrico Gobbetti at 08.42 UT

www.geo-web.org.uk

39

GEO Quarterly No 54

40

The Group for Earth Observation

www.geo-web.org.uk

June 2017

June 2017

The Group for Earth Observation

www.geo-web.org.uk

GEO Quarterly No 54

41

GEO Quarterly No 54

42

The Group for Earth Observation

www.geo-web.org.uk

June 2017

June 2017

The Group for Earth Observation

www.geo-web.org.uk

GEO Quarterly No 54

43