Group for Earth Observation

No 63 - September 2019

Pictured a few seconds after leaving its launchpad, Russia’s new Meteor M2-2
Earth observing satellite heads for orbit aboard its Soyuz-2-1b/Fregat-M launcher.
Image: Roscosmos

Useful User Groups

GEO MANAGEMENT TEAM
Director and Public Relations

Weather Satellite Reports

Coturnix House, Rake Lane,

This group provided weekly reports, updates and news
on the operational aspects of weather satellites.
https://groups.io/g/weather-satellite-reports

Milford, Godalming, Surrey GU8 5AB,

SatSignal

Francis Bell,

England.
Tel:

01483 416 897

email: francis@geo-web.org.uk

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

This end-user self help group is for users of David
Taylor’s Satellite Software Tools, including the orbit
predictor WXtrack, the file decoders GeoSatSignal and
SatSignal, the HRPT Reader program, the remapper
GroundMap, and the manager programs - MSG DataManager, GOES-ABI Manager, AVHRR Manager etc.
https://groups.io/g/SatSignal
MSG-1
This forum provides a dedicated area for sharing
information about hardware and software for receiving
and processing EUMETCast data.
https://groups.io/g/MSG-1

GEO Newsletter Editor
Les Hamilton,
email: geoeditor@geo-web.org.uk

Technical Consultant (Hardware)David Simmons

GEO-Subscribers
This is the official group is for subscribers of the Groupfor Earth Observation (GEO), aimed at enthusiasts
wishing to exchange information relating to either GEO
or Earth Observation satellites.
https://groups.yahoo.com/neo/groups/
GEO-Subscribers/info

email: tech@geo-web.org.uk

Webmaster and Website Matters
Alan Banks,e-mail: webmaster@geo-web.org.uk

Management TeamDavid Anderson
Rob Denton
Nigel Evans
Clive Finnis
Carol FinnisPeter GreenDavid SimmonsDavid Taylor

2

www.geo-web.org.uk

Les HamiltonM

any readers will by now have been receiving LRPT images from Russia’s Meteor M2-2 satellite,
which was successfully launched on July 5. Following four weeks or so transmitting the threevisible channels, the satellite’s commissioning phase switched to displaying the three infrared
channels in early August before reverting back to the visible channels on August 19. A frustrating
factor has been the numerous changes in frequency between 137.9 MHz and 137.1 MHz andSymbol Rates of 72,000 and 80,000 baud. This behaviour also occurred during the commissioning
phase of Meteor M2 in 2014, so it is probable that by the end of the year, if not before, the ﬁnal
values for both frequency and symbol rate for Meteor M2-2 will have been ﬁnalised.

There are also ongoing developments in both the Meteor Plugin for SDRsharp and the LRPT
Decoder software, perhaps the most signiﬁcant being the ability to automatically detect the
Symbol Rate of the transmission. Details are regularly updated in Alex’s excellent tutorial to befound athttp://happysat.nl/Setup_Meteor/Setup.html
Alex also regularly updates a status page showing the current frequency, Symbol Rate andChannels in use by both the Meteor satellites, at
http://happysat.nl/Meteor/html/Meteor_Status.html
Another excellent resource for keeping up with developments—providing you are a Facebook
subscriber—is the APT Group (which covers both APT and LRPT satellite transmission modes. Thisis an open group, which means that anyone can read their posts: if you wish to contribute, though,you must register as a member. Their website ishttps://www.facebook.com/groups/Satellite.apt.group/IP

f you haven’t started receiving this new satellite yet, there are a number of ﬁne images in thisissue, sent in by readers, to whet your appetite.
lease remember that contributions from readers detailing their activities are always welcome, by
email, to the editor at
geoeditor@geo-web.org.uk

Contents
GEO Report and Quarterly Question
Francis Bell
Successful Meteor M2-2 Launch
Les Hamilton
Combatting severe ‘pager’ interferenceJohn Cooper
NOAA 15 on the brink
Atmospheric River swells Terrestrial Rivers NASA Earth Observatory
Northern Italy at Night
European Space Agency
Apollo 13 Launchpad
European Space Agency
Raikoke Erupts
NASA Earth Observatory
Deciphering the Maude Rise Polynya
NASA Earth Observatory
Okjökull RememberedNASA Earth Observatory
Satellite Status

www.geo-web.org.uk

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Francis BellI would like to start this brief report by offering
my congratulations to those members I know of
who are receiving the latest Russian polar orbiting
satellite Meteor M2-2. I have been reading thecorrespondence published via our GEO Subscribers
YAHOO group and admire the way individuals haveshared their experiences and advice relating to thereception of this new satellite. Sometimes, whenpossible, I have downloaded some of the images
which have been referred to in correspondence, andthese have included excellent images of Australia
and North America. I believe I have at home theequipment necessary to receive this new satellite. I
just need to overcome the personal inertia of getting
started with it.
Often in my reports I include comments about
rallies and shows which GEO has recently attended.
Unfortunately my attendance at the two events
which I had hoped to support on GEO’s behalf thissummer both had to be abandoned.

My thanks to those readers who responded to
Quarterly Question 62, which related to an isolatedisland in the mid Pacific Ocean. In addition to thesatellite image shown there were clues to the island’s
identity in the text. The name of the island and otherdetails can been read, below, in a correct answer I
received from David Rennolds (G0BXS).
Answers as follows:
Name:
EASTER ISLAND
Lat/Long:
109º WEST 27º SOUTH
Country claiming sovereignty: CHILE
Question 63
The question this quarter has been prompted by thenews in August 2919 relating to the many wildfiresin Brazil. In addition to Brazil there have been
wildfires on one of the islands in the Canary Island
Group. I was particularly distressed to learn of thefires in the Canary Islands because the particular4

The school ‘Space-Link’ one day event, which GEO
has attended for a number of years, was frustratingly
cancelled at the last minute and I’m not sure aboutfurther contacts with this group.
GEO did book a stand at the large Newbury radio
rally but unfortunately I was unable to attend
because a few days before this event I had to
go to hospital and have my leg put in plaster.
Unfortunately I had sustained an injury to my foot—medically known as Charcot-Foot—which needed
immobilising for immediate rest, hence the plastercast. The demand for rest and my lack of mobility
ruled out my attendance at the Newbury rally hence
there was no GEO stand there even though it had
been booked. At the time of writing my foot is muchbetter and I am walking almost normally again.
I am still in touch with Dundee University and theirprogramme of satellite reception and I hope to givean up-to-date report about GEO’s support for themin the next Quarterly Report.

island in question has been a holiday destination for
my wife and myself on a number of occasions andit’s unfortunate to think of the natural landscapebeing damaged by fire. However, it must berecognised that in this case it is a volcanic island somany devastating events must have happened there
in the past.
The question this quarter is quite straightforward:“Name the individual island shown in the satellite
image on page 5”.
A secondary question—perhaps more difficult—is why we call this group of islands the ‘CanaryIslands’. This is a more difficult question than asking
about the origin of the name for ‘Easter Island’
which, I understand, was discovered by European
explorers on 5th April 1722 which happened to be
Easter Sunday.

www.geo-web.org.uk

Copyright contains modified Copernicus Sentinel data (2019), processed by ESA

The recent satellite image of the island inquestion is shown above and notes which were
published with the image follow. I have edited
these notes a little to remove the name of theisland in question.
Satellite Image Information
An unprecedented wildfire has ripped through oneof Spain’s Canary Islands off the northwest coastof Africa. The wildfire, which started on Saturday
August 17, 2019, has now started to subside after
engulfing around 10 000 hectares of land, leading
to the evacuation of over 9000 people.
This false colour image, captured on August 19,
was created using the shortwave infrared
bands from instruments aboard the Copernicus
Sentinel-2 satellite, and allows us to clearly see
the fires on the ground in bright orange. Burnscars are visible in dark brown. These bands also
allow us to see through smoke—but not clouds.

The Copernicus Emergency Mapping Service wasactivated to help respond to the fire. The service
uses satellite observations to help civil protection
authorities and, in cases of disaster, theinternational humanitarian community, respondto emergencies.
The fire started near the town of Tejeda andspread to Tamadaba Natural Park, driven by a
combination of high temperatures, strong winds
and low humidity. According to authorities, over
700 firefighters on the ground and 16 aircraft
helped tackle the blaze, with some flamesreaching over 50 metres in height.
Answers, please, to Francis Bell via email at
francis@francisbell.com
orfrancis@geo-web.org.uk
by November 30, 2019.

www.geo-web.org.uk

5

Successful Meteor M2-2 Launch
Les Hamilton

Following a wait of almost eighteen months following
the unfortunate demise of the Meteor M2-1 weather andclimate-monitoring satellite, its twin, Meteor M2-2 was
successfully launched atop a Soyuz-2-1b/Fregat-M rocket
along with a cluster of 32 secondary payloads. The launch
was from Russia’s far eastern Vostochny Cosmodrome at
05:41 UT on July 5.
As readers may recall, Meteor M2-1 did launch as
expected but, due to a programming error—the rocket’s
take-off coordinates were mistakenly entered for the
Baikonur Cosmodrome in Kazakhstan, over 4000
kilometres to the west—the rocket’s upper stage fired
facing the wrong orientation, and as a result the launcher
and its payloads plunged into the North Atlantic ocean.

Personnel look on as the Meteor M2-2 payload is
integrated with the Fregat‑M upper stage of the launcher.
Image: Roscosmos

Moments before the second stage completed its firing 4
minutes and 47 seconds into the flight, the third stageengine started firing through the inter-stage lattice
structure, which itself separated along with the second
stage a second or so later.

Meteor M2-2 satellite
Image: Roscosmos

Following lift-off, the Soyuz flew under power from bothits first and second stages for a total of 118 seconds,
after which the exhausted strap-on first stage boosters
were jettisoned. The second stage then continued to burnfor another 170 seconds, with separation of the rocket’s
payload fairing taking place about a minute before the endof this burn.

The third stage then burned for four and a half minutes
before shutting down, releasing the Fregat upper stage
and its passengers into a ballistic trajectory just short oforbital velocity. This set the third stage into free fall backto Earth on a path designed to bring its debris crashingsafely into the Atlantic Ocean. Almost immediately, theFregat fired its engines for just over a minute to enter its
initial parking orbit, and about three-quarters of an hourlater fired again to establish the near circular 98.6° orbit of790 by 830 km from where it released Meteor-M No.2-2(Meteor M2-2 for short).
Following the successful release of its primary payload, theFregat’s task continued with a complex preprogrammedsequence, including multiple firings of its main engine,
designed to deliver its secondary payloads into two
different orbits. Payloads in the micro-sat range werereleased at an altitude of 580 km and inclination of 97.7°,
while the cubesats were to be released at around 530 km
and 97.5°. The total release programme was completed injust 4½ hours following lift-off.
Its task completed, the Fregat was placed in a suicidetrajectory through the atmosphere and disintegrated overthe equatorial east Pacific Ocean.

The Meteor M2-2 satellite undergoing final checks prior to its
integration with the Fregat‑M launcher upper stage.
Image: Roscosmos

6
6Meteor-M2-2 is identical with its lost predecessor,
and several more spacecraft of this configuration areplanned to fly in the next few years. Built by the VNIIEM
Corporation, the 2,750 kilogram satellite is designed for atleast five years of service.

www.geo-web.org.uk

Instrumentation
Meteor-M2-2 is equippedwith two imaging payloads.
MSU-MR is a low-resolution
instrument operating invisible-light and near-infrared
wavelengths which will takewide-swath images of Earthto help monitor cloud coverand the icecaps. The second
imager, KMSS-2, provides
complimentary high-resolution
visible-light images of more
specific areas.
The satellite also carries
two sounding instruments:
the MTVZA-GYa microwave
radiometer and IKFS2 infrared spectrometer,
which will build profiles oftemperatures, humidity andwind conditions within theatmosphere.

The Soyuz-2-1b/Fregat-M rocket being transported to its launchpad at the Vostochny Cosmodrome.
Image: Roscosmos

The Soyuz-2-1b/Fregat-M rocket on its launchpad the day before lift-off
Image: Roscosmos

The Soyuz-2-1b fires its motors at the instant of lift-off
Image: Roscosmos

www.geo-web.org.uk

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Enrico Gobbetti received his first Meteor M2-2 image (above) acquired from the 12.27 UT pass on July 18, 20198www.geo-web.org.uk

Combatting severe ‘pager’ interference
to Receive Meteor M2-2 Imagery
John Cooper G8GKUThe Meteor M2-2 Image above was captured by G8GKU at 15:25 UT on July 31 2019, and processed to give RGB123 false colour.
Orbit No 375, at 137.9 MHz OQPSK with 72000 symbol rate.
Read article on following page ...

www.geo-web.org.uk

9

Along with the new Meteor M2-2 satellite came thechallenge of OQPSK in place of the QPSK utilised byMeteor M2. The immediate situation was to leave mewith no working demodulation or decoding system
for OQPSK.
Discussion with Les Hamilton revealed the option ofusing tools as found in Les’s pre-packaged archive
tool sets. Please see
http://leshamilton.co.uk/MeteorLRPTSuite.htm
A ‘thank you’ has to go to Les for assembling thevarious sets of tools.
As always, things were not so simple as might havebeen thought. The tools chain as above is centredaround using the LRPT Demodulation within SDR#
as to be found in the archive.
The Pager Situation
Due to the quantity and strength of 137.x MHz dataand ‘pager’ signals in Oxford, it is not workable
to use the well tried and tested SDR‑RTL Dongle
receiver. As I am located close to Oxford, a hybrid
system had to be devised to facilitate the reception
and decoding of M2-2 images.
Beating the Pagers
The three key components which allow me to receive(mostly) unbroken images from Meteor M2-2 are as
follows. Other methods of course exist, and the useof the following products is merely descriptive as
opposed to an endorsement to purchase.
First, after the crossed dipole RHCP aerial, isthe use of a specific signal preamplifier, theMini‑Circuits PGA‑103+ device. A data sheet may befound on the Mini‑Circuits web pages. There areother devices by other manufacturers but thePGA‑103+ is excellent for the task. It has a very low
noise figure and an impressive degree of strong
signal handling, resulting in low (if any) crossmodulation of the weak M2-2 signal by the local
heavyweight data transmitters.

The device has to be embedded in circuit to be
actually used: the device is not ‘plug and play’,unless one has the evaluation module version. Thereis a useful article detailing the building of a amplifier
with the PGA-103+ at the following URL,
http://www.g4ddk.com/PGA103+2.pdf
To ensure maximum signal is obtained, the aerial isreal-time tracked in azimuth and elevation with dataobtained from Alex’s DDEtoSerial driver, to be foundat the following URL,
http://tripsintech.com/
orbitron-dde-azimuth-elevation-to-serial/
Secondly is the use of twin screened 50 Ohm coax
between the preamplifier and the receiver position.
Silver plated coax screen is highly recommended.
Thirdly is the use of the SDR-Play Duo receiver.
This receiver has a front end design which allows
repetition of weak signals in the presence of strongclose in-band signals at an offset of only a few
kilohertz. This is exactly the situation when I am
receiving 137.x MHz images.
The complete signal chain for Meteor M2-2 uses theabove for reception of the satellite signal and thereceived data is stored as a 16 bit I.Q. WAV file.
At this stage the tools within Les’s archive comeinto play. The SDR# application is fired up and therecorded dot.wav file selected as the signal source.
The LRPT demodulator plug-in within SDR# is used
to demodulate the OQPSK, resulting in an ‘s’ file,which is then decoded by the LRPT decoder within
the tools set archive. There are options to be set in
SDR#, the demodulator and the decoder, all of which
are self descriptive.
By using this hybrid system, the break-up andloss of many images due to strong local close
in-band interference has been very much reduced.
Acknowledgement is made of all software names andsuch items.

NOAA 15 on the Brink
Enthusiasts monitoring NOAA 15, a
weather satellite sent into orbit over 21
years ago (in May, 1998), experienced
problems receiving images from
July 23 this year. The problem
manifested itself in distorted images,
and sometimes no images at all, andwas attributed to instability of the scan
motor.

Several days later, the problem
appeared to have been overcome only
for it to reappear a few days thereafter.
By August, NOAA 15 was once againtransmitting good imagery, but the endof life for this satellite can surely not
now be long delayed, considering its
age.

www.geo-web.org.uk

10

Atmospheric River Swells Terrestrial Rivers
NASA Earth Observatory

In late June 2019, a potent
atmospheric river event carriedsoaking rain into southern
Chile, dropping nearly amonth’s worth of precipitationin just 48 hours. According
to atmospheric scientist René
Garreaud of Universidad deChile, between 100 to 200
millimetres of rain fell over awide area near Concepcion,leading to landslides and severe
flooding in the Biobio andAraucania regions.
The images above capturesome of the signs of thatdeluge. The top natural-colour
pair was acquired by NASA’s
Moderate Resolution Imaging
Spectroradiometer (MODIS)
instruments on May 18 by the
Aqua satellite and on July 1 by
Terra a few days after the storm.

The Pacific Ocean near Conception in Chile before and after the atmospheric river event.
MODIS images © NASA

The third image was acquiredon July 1 by the Enhanced
Thematic Imager+ on Landsat 7.
The discoloured water offshore,
which extends more than
50 kilometres in some areas,
is sediment that ran off thehillsides and downriver.
Atmospheric rivers can stretchtens to hundreds of kilometresin width, and can carry anamount of water vapour
equivalent to 7.5 to 15 times
the flow at the mouth of theMississippi River.
These weather systems are
essentially jet streams ofmoist air. They often occur
off the west coast of North
America, sending soaking rain
into California, Oregon, andWashington. In subtropical
Chile, atmospheric rivers
contribute 45 to 60 percent of
the annual precipitation, mostof it in the winter rainy season(June to September), according
to a 2018 research paper.

Sediment flowing from the Rio Itata as imaged by Landsat 7 on July 1.
Image: USGS / NASA

According to Garreaud, the early
winter rainfall increased discharge
on some rivers by ten-fold, carrying
nutrient-rich sediments into
the coastal zone. Garreaud andcolleagues study how such outflowsof nutrients promote and sustain
phytoplankton blooms in thesouthern winter.

NASA Earth Observatory images by Lauren Dauphin and Joshua Stevens, using Landsat data fromthe U.S. Geological Survey and MODIS data from NASA EOSDIS/LANCE and GIBS/Worldview.
Story by Mike Carlowicz.

www.geo-web.org.uk

11Northern Italy at Night
European Space Agency

Everyone is used to living with smarter
devices. But imagine living in a smart
city where everything from public
transport to city lamps is efficient andsustainable. This night time image ofnorthern Italy from Earth orbit is oneof the ways space is paving the way
for cities to get smarter.
Doorbells, refrigerators andtoothbrushes are everyday
devices that are now controllable,
customisable and designed to makeyour life run more efficiently bycollecting and relaying data using
telecommunications satellites.
Other space technology is helping
to collect valuable data that can
result in larger scale changes forcities. Take one of humankind’s
greatest achievement in space sofar, the International Space Station.
Astronauts routinely snap photos ofEarth from this orbital outpost, like thisone of northern Italy, taken by ESA
astronaut Luca Parmitano during his
2013 mission, provide vital data aboutcity efficiency and sustainability.

12

Researchers have devised a method
to assess the environmental impactof artificial light on humans, animals,
and the surrounding environment
using one of the few sources ofpublicly-accessible night images ofEarth in colour: pictures taken by the
astronauts aboard the International
Space Station.
City lights are disruptive not only
for the lives of nocturnal animals,
who suffer from disorientation
and behavioural and physiologicalchanges, but also for people. An
excess of artificial light before bedtime
reduces melatonin production,a hormone linked to sleep. This
suppression can lead to negative
effects on our health, including breastand prostate cancer.
In addition, street lights account fora large chunk of a country’s energy
consumption. As the world grapples
with climate change and cleaner
sources of energy, how that energy is
put to use is a bright topic.

Cities at Night
http://citiesatnight.org/
is an online platform that invites
citizens to flip through the half amillion photographs of Earth at nighttaken so far by astronauts from theSpace Station to identify cities. The
end result of Cities at Night will bea map of Earth that is accessible toanyone.
Researchers want to use the map tolocate energy inefficiencies in urban
cities to urge dimming of the lights. A
case in point is the city of Milan, which
replaced its orange sodium lamps withwhite LEDs. Comparisons of Milanfrom night as seen from space before
and after this change has shown thatthe white light is worse for the local
environment.
The data retrieved from these images
is vital for the drawing up of risk maps
for artificial lighting that can help to
guide city officials in these types ofdecisions. And that’s just smart.
Copyright ESA/NASA

www.geo-web.org.uk

Apollo 11 Launchpad
European Space Agency

Copyright: contains modified Copernicus Sentinel data (2019), processed by ESA, CC BY-SA 3.0 IGO

Celebrating 50 years since Apollo 11 blasted off
with the first humans that would walk on the Moon,
Copernicus Sentinel-2 captures the historic launchsite at Kennedy Space Center, Cape Canaveral,
Florida, US.
On 16 July 1969, the Saturn‑V rocket carrying
Apollo 11 began its momentous voyage to the Moon.
It lifted off from launch pad 39A—which can be seenin this image acquired on January 29, 2019. Launch
pad 39A is the second pad down from the top (thelaunch pad at the far top is 39B).
The crew—Neil Armstrong, mission commander,
Michael Collins, command module pilot and Edwin‘Buzz’ Aldrin, lunar module pilot—were embarking
on a milestone in human history.
Just four days later, the lunar module, Eagle,
touched down. Watched on television by millions
around the world, Neil Armstrong was the first to set
foot on the Moon, famously saying, ‘That’s one small
step for man, one giant leap for mankind.’

A few minutes later he was joined by Buzz Aldrin.
They took photographs, planted the US flag, spoke
to President Richard Nixon via radio transmission
and spent a couple of hours walking and collecting
dust and rocks. The two men returned to the lunar
module, slept that night on the surface of the moon:then Eagle began its ascent back to rejoin thecommand module, which had been orbiting the Moon
with Michael Collins. Apollo splashed back downsafely in the Pacific Ocean on July 24.
The Moon has again captured the attention of
space agencies. ESA and international partners
are now looking forward to the next era of human
exploration, and to understand better the resources
available on the Moon to support human missions
longer-term. While Apollo 1 touched down for the
first time on the near side of the Moon 50 years ago,
it is time to explore the far side, examine different
types of lunar rocks there, to probe deeper into
the Moon’s geological history and to find resources
like water-ice that are thought to be locked up inpermanently shadowed craters near the Moon’s
south pole.

www.geo-web.org.uk

13

Raikoke Erupts
NASA Earth Observatory
Story by Adam Voiland, with information from Erik Klemetti (Denison University),
Simon Carn (Michigan Tech), and Andrew Prata (Barcelona Supercomputing Center).

Unlike some of its perpetually active neighbours on
the Kamchatka Peninsula, Raikoke Volcano on the
Kuril Islands rarely erupts. The small, oval-shaped
island most recently exploded in 1924 and in 1778.
The dormant period ended around 4 am local timeon June 22, 2019, when a vast plume of ash andvolcanic gases shot up from its 700-metre-wide
crater. Several satellites—as well as astronauts on
the International Space Station—observed as a thickplume rose and then streamed east as it was pulled
into the circulation of a storm in the North Pacific.
On the morning of June 22, astronauts shot figure 1,
showing the volcanic plume rising in a narrowcolumn and then spreading out in an the umbrella
region; the area where the density of the plume andthe surrounding air equalise and the plume stops
rising. The ring of clouds at the base of the column
appears to be water vapour.
‘What a spectacular image. It reminds me of theclassic Sarychev Peak astronaut photograph of an
eruption in the Kuriles from about ten years ago,’stated Simon Carn, a volcanologist at Michigan Tech.
‘The ring of white puffy clouds at the base of thecolumn might be a sign of ambient air being drawn
into the column and the condensation of water vapour.
Or it could be a rising plume from interaction between
magma and seawater because Raikoke is a small
island and flows likely entered the water.’
The Moderate Resolution Imaging Spectroradiometer(MODIS) on NASA’s Terra satellite acquired the image
in figure 2 on the morning of June 22. At that time,the most concentrated ash was on the western edgeof the plume, above Raikoke. Figure 3, an oblique,composite view based on data from the Visible
Infrared Imaging Radiometer Suite (VIIRS) on Suomi
NPP, shows the plume a few hours later. After an
initial surge of activity that included several distinct
explosive pulses, activity subsided and strong winds
spread the ash across the Pacific. By the next day,just a faint remnant of the ash remained visible to
MODIS.
Since ash contains sharp fragments of rock andvolcanic glass, it poses a serious hazard to aircraft.
The Tokyo and Anchorage Volcanic Ash Advisory
Centers tracked the plume closely and issued several
notes to aviators indicating that ash had reached an
altitude of 13 kilometres. Meanwhile, data from the
CALIPSO satellite indicated that parts of the plumemight have reached as high as 17 kilometres.
In addition to tracking ash, satellite sensors can also
track the movements of volcanic gases. In this case,

14

Figure 1 - Raikoke erupts, viewed from the ISS
Astronaut photograph ISS059-E-119250 is provided by the ISS
Crew Earth Observations Facility and the Earth Science andRemote Sensing Unit, Johnson Space Center. The image wastaken by a member of the Expedition 59 crew.

Raikoke produced a concentrated plume of sulphur
dioxide (SO2) that separated from the ash andswirled throughout the North Pacific as the plumeinteracted with the storm.
‘Radiosonde data from the region indicate atropopause altitude of about 11 kilometres, so
altitudes of 13 to 17 kilometres suggest that theeruption cloud is mostly in the stratosphere,’ said
Carn. ‘The persistence of large SO2 amounts over thelast two days also indicates stratospheric injection.’
Volcanologists watch closely for plumes thatreach the stratosphere because they tend to stay
aloft for longer than those that remain within the
troposphere. That is why plumes that reach thestratosphere typically have the greatest effects onaviation and climate.

www.geo-web.org.uk

Figure 2
NASA Earth Observatory image by Joshua Stevens, using MODIS
data from NASA EOSDIS/LANCE and GIBS/Worldview

Figure 3
NASA Earth Observatory image by Joshua Stevens, using VIIRS
data from the Suomi National Polar-orbiting Partnership

Deciphering the Maud Rise Polynya
NASA Earth Observatory
Story by Kathryn Hansen

By the end of austral winter, the seas around
Antarctica are blanketed with up to 18 million
square kilometres of ice—an area about twice thesize of the continental United States. But that vastspan of ice is not always continuous. Cracks canopen up and expose the seawater below.

contrast, open-ocean polynyas like the one near
Maud Rise grow amid the ice far from shore. This
type of polynya is somewhat more complex, withcirculation in the atmosphere and ocean bothplaying a role in creating and sustaining them.
These openings can be large and long-lived.

Sometimes, state-sized areas of ice go missing
from the middle of the ice pack. This phenomenon
is known as a polynya, and scientists have been
investigating these features for decades. The
Moderate Resolution Imaging Spectroradiometer(MODIS) on NASA’s Terra satellite acquired theseimages of the Maud Rise polynya in the eastern
Weddell Sea on September 25, 2017. Figure 1 isnatural colour and Figure 2 is in false colour toafford better differentiation between areas of ice(blue) and clouds (white).

The Maud Rise polynya—named for thesubmerged mountain-like feature over which
it grows—routinely occurs in early spring andoccasionally in winter. According to Joey Comiso,
an emeritus scientist at NASA’s Goddard Space
Flight Center, the shape of the sea floor ‘causes
the ocean current driven by the Weddell Gyre to
bring warm water up to the upper layer of theocean and causes the sea ice to melt.’

Coastal polynyas form when strong offshore
winds move sea ice away from the continent. In

In winter 2017, the Maud Rise polynya wasespecially large, growing from 9,500 km2 in midSeptember to about 80,000 km2 by late October(nearly the same size as South Carolina). The
continued overleaf

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polynya was among largest in thisarea since the famous Weddell
polynyas that formed in 1974, 1975,
and 1976, which reached areas
larger than the size of California.
How polynyas can form, grow,and persist during Antarctica’s
cold winter has long been a
topic of investigation. Recent
research points toward strong
cyclonic winds—some as strong as
hurricanes—as the trigger for openocean polynyas. Diana Francis, ascientist at New York University
Abu Dhabi and leader of that study,
explained that cyclonic winds ‘dragthe floating sea ice in opposite
directions around the cyclone centre,
creating the opening.’
In some winters, atmosphericcirculation moves a significant
amount of heat and moisture frommid-latitudes to Antarctica, allowing
large cyclones to develop over thesea ice. For example, a cyclone
passed over the sea ice in winter2016 before a small, short-lived
polynya formed.

Figure 1 - The Maude Rise polynya, imaged on September 25, 2017 by NASA’s Terra satellite
NASA Earth Observatory images by Lauren Dauphin,using MODIS data from NASA EOSDIS/LANCE and GIBS/Worldview

Compared to 2016, the movementof heat was stronger and moreconsistent in 2017, according toFrancis. ‘The result was more
frequent and intense cyclones,
making the 2017 event bigger andkeeping the polynya open for alonger period.’
Comiso agrees that the atmosphereplays an important role, especiallyin initiating polynyas. ‘But theoceanographic contribution is just as
important in sustaining the polynya,’
he said.
Indeed, conditions in the ocean
and atmosphere most likely work
together. ‘I think the atmosphericconditions play the role of thetrigger for the initial opening,’ statedFrancis. ‘Once the area is free ofice, ocean dynamics bring warmer
water near the surface and preventthe formation of new ice and sustain
the polynya over longer period oftime. Satellite images are a powerfultool to help us understand such acomplex system where interactions
between atmosphere-ice-ocean takeon full meaning.’

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Figure 2 - The Maude Rise polynya, imaged on September 25, 2017 by NASA’s Terra satellite
NASA Earth Observatory images by Lauren Dauphin,using MODIS data from NASA EOSDIS/LANCE and GIBS/Worldview

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Norbert Pütz acquired this splendid Meteor M2-2 image of the Black Sea at 13.57 Ut on July 27, 2019www.geo-web.org.uk

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André T’Kindt captured this evening APT image from NOAA 18 at 21:59 UT on July 25, 2019. It graphically illustrates
the rash of powerful thunderstorms that erupted over Europe in the wake of record-breaking heatwave temperatures.

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This is another NOAA 18 APT image sent in by André T’Kindt. Acquired on August 16, 2019, it
depicts a weather front that brought intensive rainfall over most of the British Isles.

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Okjökull RememberedNASA Earth Observatory

The glacier atop Iceland’s Okjökull
volcano was declared dead in
2014. Satellite images show thelatter stages of its decline.
On August 18, 2019, scientists willbe among those who gather for amemorial atop Okjökull volcano inwest-central Iceland. The deceased
being remembered is Okjökull—aonce-iconic glacier that has melted
away throughout the 20th century andwas declared dead in 2014.
A geological map from 1901
estimated Okjökull spanned anarea of about 38 square kilometres(15 square miles). In 1978, aerial
photography showed the glacier was
3 square kilometres. Today, lessthan 1 square kilometre remains.
The satellite images above show
the glacier during the latter part ofits decline, on September 7, 1986,(top) and August 1, 2019 (bottom).
The images were acquired with theThematic Mapper (TM) on Landsat
5, and the Operational Land Imager(OLI) on Landsat 8, respectively.
The dome-shaped glacier appears
in the 1986 image as a solid-whitepatch, just north of the snow-filledcrater. Snow is also visible aroundthe glacier’s edges. In the August
2019 image, only a spattering of thin
ice patches remain. Notice the areasof blue meltwater, which are likely
associated with the mass of warm
air that hit Iceland as it moved frommainland Europe to Greenland in late
July.

Okjökull glacier, pictured during the latter part of its decline, on
September 14, 1986 by Landsat 5’s Thematic Mapper.

Okjökull glacier, pictured during the latter part of its decline, on
August 1, 2019 by Landsat 8’s Operational Land Imager

The glacier’s demise is not just a
matter of shrinking area. Glaciers
form from snow that becomescompacted into ice over time. The
ice then creeps downslope under
its own weight, helped along bygravity. Okjökull has thinned so much,
however, that it no longer has enoughmass to flow. According to somedefinitions, a stagnant glacier is adead glacier.

Langjökull group—one of Iceland’seight regional groupings of glaciers.
Ice covers about 10 percent of theisland, making it an integral part ofthe landscape. Loss of glacial ice
has wide-ranging effects, with thepotential to impact water resources,
infrastructure, and even the rising of
the land as it rebounds under a lighterload of ice.

Okjökull, also called Ok (jökull is
Icelandic for “glacier”), was part of the

Scientists have noted that glaciers
have disappeared from Iceland

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before, although perhaps none
as ceremoniously as Okjökull.
Anthropologists from Rice University
produced a film about the glacier’s
demise, and a plaque is set to beinstalled on the site of the former
glacier.

NASA Earth Observatory images by Joshua
Stevens, using Landsat data from the U.S.
Geological Survey.
Story by Kathryn Hansen.

This is another Meteor M2-2 image sent in by Norbert Pütz, one that he described as his best ever.
It was received on August 2 this year using a Russian style inverted V-antenna, pre amp and FUN Cube Pro+ dongle.

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André T’Kindt provided us with this almost surreal but beautiful WXtoImg HVC image—with precipitation overlay—that hecreated from the 17.59 UT pass of NOAA 19 on August 12, 2019. Glint from the setting sun is evident on the still waters of the
Bay of Biscay while a band of intense rainfall, with thunderstorms, crosses the British Isles.

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