Group for Earth Observation

No 70 - June 2021

Following a record-breaking dry month of April in the British Isles, conditions changed dramatically during May. This
Meteor M2 image from Bob Bale shows a deep depression arriving on May 3 threatening heavy rainfall.

Useful User Groups

GEO MANAGEMENT TEAM
General Information

Weather Satellite Reports
This group provided weekly reports, updates and news
on the operational aspects of weather satellites.

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

https://groups.io/g/weather-satellite-reports

GEO Newsletter Editor
Les Hamilton,

SatSignal
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.

email: geoeditor@geo-web.org.uk

Technical Consultant (Hardware)David Simmons
email: tech@geo-web.org.uk

https://groups.io/g/SatSignal

Webmaster and Website Matters
Vacancy

MSG-1
This forum provides a dedicated area for sharing
information about hardware and software for receiving
and processing EUMETCast data.

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

Management TeamDavid Anderson

https://groups.io/g/MSG-1

Rob Denton

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.

Nigel Evans: nigel.m0nde@gmail.com
Clive Finnis
Carol FinnisPeter Greenhttps://groups.io/g/GEO-Subscribers/

David SimmonsDavid Taylor

Rob Bale captured this Meteor M2 image on April 11,
2011, displaying Iceland, so often beset by cloud,completely cloud-free for once.

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2

Les HamiltonR

eaders will no doubt be pleased to learn that Russia’s Meteor M2-3 satellite
looks likely to launch in August and could well be transmitting imagery by
the time you receive the September edition of this Newsletter. News Agency Tass
reported on February 21 this year that a speaker during the 11th international
conference of the Association of Aviation and Space Insurers Aviation and Space
Insurance in Russia, had stated that “The Russian meteorological satellite
Meteor-M No. 2-3 is planned to be launched in August 2021”.

Those of you who take an interest in Meteor M2 may have noticed that thissatellite is now making its equator crossings more than two hours earlier
than when ﬁrst launched. This means that evening passes in the northernhemisphere are now much better illuminated, and throughout June and July,
could rival those acquired during
daytime.

S

ince our articles relating to iceberg
A68a in the previous issue, NASAhas posted a four minute video on
YouTube documenting the berg’s entire
journey. “The Voyage of One of thePlanet’s Largest Icebergs” can be viewed
at the url below
https://youtu.be/JxdcBNp0cTE?t=2

Contents
St Petersburg keeps the Sea at bay
Galapagos Islands
Great Salt Lake
Suez Canal Traffic Jam seen from Space
Sunny Summer Day in South Island, New ZealandEruption at Mount Etna
Fending Off the Wind on the Steppe
Preparing for Rising Seas in the Maldives
Lights in the North Sea
Colour off the Coast of Australia
Breakup at the Brunt Ice Shelf
Giant Iceberg breaks off Brunt Ice Shelf
Eruption at La Soufriere
Plankton Bloom off the eastern United States
Overwintering Fires on the Rise
Satellite Status

NASA Earth Observatory
European Space Agency
MODIS Image of the Day
European Space Agency
NASA Earth Observatory
Modis Image of the Day
NASA Earth Observatory
NASA Earth Observatory
NASA Earth Observatory
MODIS Image of the Day
NASA Earth Observatory
European Space Agency
NASA Earth Observatory
MODIS Image of the Day
NASA Earth Observatory

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Saint Petersburg Keeps the Sea at Bay
NASA Earth Observatory
Story by Adam Voiland

NASA Earth Observatory image by Joshua Stevens, using Landsat data from the U.S. Geological Survey.

Floods have long plagued Saint Petersburg, Russia’s
canal-filled ‘Venice of the North.’ Spread across 42 marshy
islands of the Neva River Delta, the historical core of thecity rises just one to two metres above sea level.
In 1703, construction had barely begun onSaint Petersburg’s first building—the star-shaped Peterand Paul Fortress—when floodwaters washed away
construction materials at the site. Since then, more than
300 floods have hit the city, including three catastrophic
events where water levels rose more than three metresand swamped thousands of buildings.
The largest floods are typically triggered when cyclones in
the Baltic Sea push water east into the Gulf of Finland andNeva Bay. The narrow, shallow gulf can set up powerfulseiche waves (standing waves) that are especially
dangerous if they coincide with high tides or seasonal
floods on the Neva River.

Russia’s answer to this flood-prone geography is theSaint Petersburg Flood Prevention Facility—a colossal
complex that includes 11 dams, 6 locks, 30 water
purification stations, and two navigation channels. As seenin this image from the Operational Land Imager (OLI)
on Landsat 8, the structure spans 25 kilometres acrossthe Gulf of Finland, from Lomonosov northward to Kotlin
Island, then east toward Gorskaya. A six-lane highway
runs across the structure’s wide top.
Work on the project began in 1979, but it was not until
2011 that officials declared it operational. The $3.85 billion
structure is designed to withstand storm surges of fivemetres. The floodgates are left open most of the time toallow water and marine life to pass. However, the flow
can be cut within 45 minutes if a flood is imminent, as has
been done more than a dozen times in the past decade.
Vulnerable areas in the historic core of the city—which isa UNESCO World Heritage Site—have not experienced
damaging flooding since the dam opened.

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Galápagos Islands
European Space Agency

Image contains modified Copernicus Sentinel data (2020), processed by ESA, CC BY-SA 3.0 IGO

The Copernicus Sentinel-2 mission takes us overthe Galápagos Islands—a volcanic archipelago
situated some 1000 kilometres west of Ecuador in
the Pacific Ocean. The archipelago consists of 13

major islands and a handful of smaller islands andislets scattered across approximately 60 000 square
kilometres of ocean. Repeated volcanic eruptions andongoing seismic activity have helped form the rugged
Continued overleaf ...

mountain landscape of the islands. In this image,
captured on 23 September 2020, several circularvolcanic cones can be seen atop the islands.
The largest island of the archipelago, Isabela(Albemarle), is visible in the centre. Around 132 km
in length, the island’s sea horse shape is the result of
the merging of multiple large volcanoes into a single
land mass. The five volcanoes seen on the island are(from north to south): Wolf Volcano, Darwin Volcano,
Alcedo Volcano, Sierra Negra Volcano and Cerro Azul
Volcano. Two of the island’s volcanoes, Ecuador and
Wolf, lie directly on the Equator.
At the southern end of the island, hills covered
with forests can be seen in bright green, separating
the Sierra Negra, the most active of the Galápagos
volcanoes, from the sandy coastline (partially visible
here owing to cloud cover). Tortuga Island, named
for its distinct shape, can be seen southeast from
Isabela. This tiny island is actually a collapsed

volcano and is a nesting location for a variety ofseabirds.
The second largest island of the archipelago, Santa
Cruz, can be seen to the right of Isabela. Its capital,
Puerto Ayora (not visible), is the most populated
urban centre in the islands.
The Galápagos Islands are best known for theirdiverse array of plant and animal species, manyof which are endemic. These include the giant
Galápagos tortoise, the marine iguana, the flightless
cormorant and the Galápagos penguin—the only
species of penguin that lives north of the equator.
These species were observed by Charles Darwin
during the voyage of the HMS Beagle in 1835 andinspired his theory of evolution by natural selection.
To preserve the unique wildlife on the islands, theEcuadorian government made the entire archipelagoa national park in 1959.

Great Salt Lake
MODIS Web Image of the Day

Credit@ MODIS Land Rapid Response Team, NASA GSFC

On April 4, 2021, the Moderate Resolution Imaging
Spectroradiometer (MODIS) on board NASA’s Terrasatellite acquired a stunning true-colour portrait of Utah’s
two-toned Great Salt Lake centred on a background oftans and white. The waters of the lake contrast not onlywith each other, but also stand out as a saline oasis in anotherwise arid basin housing scant vegetation and copious
salt flats. Tall mountains surround the basin and arecapped with snow—a truly precious commodity that holds
precipitation fast until warm weather, when it is released
as water. That water will be used by people for drinking,agriculture, and industry—and some will travel throughrivers and streams to add water to the Great Salt Lake.
It is effectively split into two by a man-made causeway,
which runs across the entire lake and stops the free-flow ofwater between the northern and southern arm. The plumcoloured northern arm, known as Gunnison Bay, contains
roughly thirty percent salt. More freshwater rivers run
into the southern portion (Gilbert Bay) so not only are thegreen waters less saline than the north, but the salinity canfluctuate between 6 and 27 percent.

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Suez Canal Traffic Jam seen from Space
European Space Agency

Image contains modified Copernicus Sentinel data (2021), processed by ESA, CC BY-SA 3.0 IGO

The enormous Ever Given container ship, wedgedin Egypt’s Suez Canal, is visible in this image
captured on March 25, by the Copernicus
Sentinel-1 mission. The giant, 400 metre longcontainer ship ran aground in the canal on
March 23, on its journey from China to theNetherlands.
The canal connects Port Said on the Mediterranean
Sea to the Indian Ocean via the Egyptian cityof Suez on the Red Sea. The blockage delayed
hundreds of tankers and vessels from reaching

their destinations, and these can be seen
accumulating in the Gulf of Suez.
The two identical Copernicus Sentinel-1 satellites
carry radar instruments to provide an all-weather,
day-and-night supply of imagery of Earth’s surface,making it ideal to monitor shipping traffic. The
sea surface reflects the radar signal away from thesatellite and makes water appear dark in the image.
This contrasts with metal objects, in this case theships in the bay, which appear as bright dots in thedark waters.

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Joachim Scharrer sent in this superb long Meteor M2 image of western Europe acquired on March 31, 2021, following the switch overto transmission of the three visible light channels three days earlier. A feature is the spectacular sunglint on the Mediterranean Sea.

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Sunny Summer Day in South Island, New ZealandNASA Earth Observatory

The stunning colours of New Zealand’s South Island
shone on March 18, 2021, when the Moderate
Resolution Imaging Spectroradiometer (MODIS) on
board NASA’s Aqua satellite acquired this truecolour image of a rare cloud-free late summer day.
The Southern Alps stretch down the length ofSouth Island, capped with snow and glaciers yearround. On this day, clouds also covered muchof the western slopes and the western coast, notunusual at any time of the year as the West Coastof South Island is the wettest region anywhere in
New Zealand. Thanks to the tall mountains andthe resultant rain shadow, the area just east of
the mountains is one of the driest areas in New
Zealand.

While most of South Island experiences copious
sunshine, capturing satellite images of the island
can be difficult due to frequent and shifting
cloud patterns brought by the island’s positionin the Roaring Forties. This is a wide belt of galeforce westerly winds that circle the Southern
Hemisphere, bringing storms and copious clouds.
Clouds are so frequent—and so appreciated—that
they are frequently used in common names. For
example, the highest peak in the Southern Alps(and in New Zealand) is Aoraki/Mount Cook at
3,754 metres. The native name is said to translate
to “The Cloud Piercer”, a nod to the dramatic clouds
that so frequently sit around the mountaintop.

NASA’s Aqua satellite captured this superb MODIS image of South Island, New Zealand on March 18, 2021
Image Credit: MODIS Land Rapid Response Team, NASA GSFC

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9Eruption at Mount Etna
MODIS Image of the Day

This MODIS image, captured by NASA’s Aqua satellite on March 12, shows an eruption plume from Mount Etna
Image Credit: MODIS Land Rapid Response Team, NASA GSFC

On March 12, 2021, Italy’s Mount Etna erupted
for the twelfth time in twenty-five days, sending alarge plume of ash about 10 kilometres into theatmosphere along with dramatic lava fountaining.
The Moderate Resolution Imaging Spectroradiometer(MODIS) on board NASA’s Aqua satellite acquired
this true-colour image on that same day, which
captured the large ash plume as it drifted eastward
over the Ionian Sea.
There is nothing particularly unusual about Mount
Etna flinging lava, volcanic ash, or molten rocks
into the air. The Italian volcano ranks as one themost active in Europe and has been in a state oferuption since 2011. This most recent paroxysm,
which started on February 16, has been particularly

violent. In February, lava fountains rose as highas 1.5 kilometres, about 3 times the height of One
World Trade Center, the tallest building in the UnitedStates. Columns of ash and small rock fragments(called lapilli) rose as high 11 kilometres in altitude.
Long lava flows poured down Etna’s eastern flankand lapilli (rock fragments) and ash landed in several
cities and villages near the volcano.
Despite the extreme strombolian activity, the risk
to people has been deemed as small. The Global
Disaster Alert and Coordination System (GDACS) gave
the eruption a ‘green’ (low risk) alert, stating that theevent is likely to have a low humanitarian impact.
About 2.75 million people live within 100 kilometresof the volcano and 940,000 within 30 kilometres.

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Fending Off the Wind on the Steppe
NASA Earth Observatory
Caption by Andi Hollier, Hx5, JETS Contract at NASA-JSC.

The dark, angular lines crossing this snowy
landscape attracted the attention of an astronautlooking down from the International Space Station.
This photograph shows the parallel lines of a major
shelterbelt—also known as a windbreak—crossing
the steppes of southern Russia near the Volga River(Volgograd Oblast). The image shows a 14-kilometre
section of an extensive system of shelter belts
planted to protect crops and reduce the erosion of
steppe soils by wind. The shelterbelt is broken where
it meets a local stream.
Each of the north-south trending lines is a dense
mass of trees about 60 metres wide. The trees throw
shadows to the east in this late afternoon view (northis to the right). Together the three lines span about
800 meters, and there is enough space between therows of trees for narrow fields to be tilled.

Shelterbelt construction began when open steppe
landscapes were first settled by Russian farmers in
the early 1700s. At present, more than two million
hectares of the steppes have been planted. The soils
within the main shelter belts in this region havebeen shown to be significantly improved, becomingricher in organic carbon than virgin soils that havenever been ploughed.
The photograph also shows narrower lines of trees
along farm boundaries; these protect individual fields
from winds and associated gully erosion. The trees
also protect water bodies from evaporation by thesteady winds, and they prevent ponds and streams
from filling with blown sand and silt. Lines of trees
at the crest of the creek bank protect the creek valley(top right).

Astronaut photograph ISS050-E-52312 © NASA

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Following a desperately cold winter and wet and chilly spring, summer suddenly arrived on May 30, 2021.
This Meteor M2 image includes sparkling sunglint on the Skaggerak, the Dutch waterways
and the Bay of Biscay, with a massive fog bank over much of the North Sea

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12Preparing for Rising Seas in the MaldivesNASA Earth Observatory
Story by Adam Voiland.

With more than 80 percent of its
1,190 coral islands standing lessthan one metre above sea level, theMaldives has the lowest terrain of
any country in the world. This makes
the archipelago in the Indian Ocean
particularly vulnerable to sea level
rise.
With global sea level rising 3 to 4
millimetres per year, and that rate
expected to rise in coming decades,
some analysts anticipate a grim
future for the Maldives and other lowlying islands. One study concluded
that low-lying islands could become
uninhabitable by 2050 as wave-driven
flooding becomes more commonand freshwater becomes limited. The
Intergovernmental Panel on Climate
Changes anticipates sea level could
rise by about half a metre by 2100
even if greenhouse gas emissions
are sharply reduced, or rise up to one
metre if greenhouse gas emissions
continue to increase strongly.

The artificial island of Hulhumalé, in the Maldives, imaged by Landsat in 1997
Image: NASA / USGS

While government of the Maldives has
explored plans to purchase land on
higher ground in other countries as aninsurance policy against sea level rise,planners are also working to enhance
the resilience of the country’s current
islands. One example is Hulhumalé,a newly constructed artificial island
northeast of the capital, Malé.
The two Landsat satellite images
opposite show just how much the area
has changed between 1997 and 2020.
Construction of Hulhumalé, designed
to relieve crowding in Malé, began
in 1997 in a lagoon near the airport.
Since then, the island has grown tocover 4 square kilometres, making
it the fourth largest island in theMaldives. Hulhumalé’s population has
swollen to more than 50,000 people,
and is expected to rise to 240,000 by
the mid 2020s.
The new island, built by pumping sandfrom the sea floor on to a submerged
coral platform, rises about two metresabove sea level, about twice theelevation of Malé. The extra height

The artificial island of Hulhumalé, in the Maldives, imaged by Landsat in 2020
Image: NASA / USGS

could make the island a refuge for
Maldivians who are eventually driven
off lower-lying islands due to risingseas. It could also prove to be an
option for evacuations during futuretyphoons and storm surges.
Hulhumalé is not the only island in theMaldives that has seen major changes
since the 1990s. Reclamation projects
have enlarged several other atolls

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in similar ways in recent decades.
Among them is Thilafushi, a lagoon
to the west that has became afast-growing landfill and a common
location for trash fires (note the smoke
plume blowing to the southwest in the2020 image). Gulhifalhuea is the siteof another land reclamation projectthat is opening up new manufacturing
and industrial space.

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There is one piece of positive news:
natural processes on coral reef atolls(like those in the Maldives) mightmake the islands more resistant tosea level rise than their low elevations
might initially suggest. Multiple
studies, many of which use Landsat
observations, show that most coral
atoll islands in the Maldives andelsewhere have remained stable oreven grown larger in recent decades.
Scientists are still studying why, butsome research indicates that storms
and floods that wash over islands
can move offshore sediment onto theisland surface, building the island up

in the process. Other research showsthat healthy coral reefs can growupward even when seas are rising byproducing abundant sediment.
“The key thing to understand isthat these islands aren’t static.
They don’t sit passively as if they
were in a bathtub and slowly
drowning,” said Murray Ford,a geologist at the University of
Auckland. “They are constantly
being reshaped by oceanographic
and sedimentary processes.”
These natural processes may offer
only limited protection to highly

developed islands, partly because
the construction of sea walls candisrupt the movement of sediment,
and human activity often degrades thehealth of coral reefs.
“Once an island is on anengineered pathway, it can’t easily
get off it. Islands that are being
built on reclaimed land must factor
in sea level rise and build higher
off the ground,” said Murray. “Forislands that are unpopulated, orsparsely populated, care should
be taken to not interfere with thenatural ability of islands to adjust
to changes in sea level.”

Image: Lights in the North Sea

NASA Earth Observatory images by Joshua Stevens, using VIIRS day-night band data from the Suomi National Polar-orbiting
Partnership and MODIS data from NASA EOSDIS LANCE and GIBS/Worldview.

This image, acquired by the day-night band (DNB) of the
Visible Infrared Imaging Radiometer Suite (VIIRS) carriedby the NOAA-NASA Suomi NPP satellite, shows lightsfrom oil rigs and the pathways of ships navigating between
the rigs in the North Sea on March 2, 2021.

The DNB detects light in a range of wavelengths fromgreen to near-infrared and uses filtering techniques toobserve signals such as city lights, auroras, and reflectedmoonlight.

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Colour off the Coast of Australia
MODIS Image of the Day
A swirling halo of blue surrounded the coastline ofnorthwestern and northern Australia in mid-May 2021. Thisgorgeous true-colour image was acquired by the Moderate
Resolution Imaging Spectroradiometer (MODIS) on board
NASA’s Aqua satellite on May 13.
The rugged landscape of the northern section of Australia’s
Northern Territory makes up roughly the eastern two-thirdsof this image, while the northern tip of Western Australiasits in the west. Both regions are coloured in bold rust
tones, tans, and washed with green. In contrast to therich Earth-tones found inland, stunning shades of blue,
turquoise, greens, and tan hug the shoreline. These jeweltoned colours were swept into the deep blue waters of the
Indian Ocean by strong currents found just offshore.
Some of the coastal colour comes from sediment, such as
the muddy-brown stain in the King Sound, which is foundalong the southwestern coastline of Western Australia
in this image. The dirt-coloured smudge in the water iscaused by mud stirred up by the strong tides in the shallow

Sound. It is also from sediment carried into the Sound by
the Fitzroy, one of Australia’s largest rivers.
When sediment is suspended near the surface, it appears
mud-coloured; however, as it sinks the reflective properties
change, so sunken sediment appears green or blue fromspace. This change in colour can be seen in King Sound,both at the edge of the sediment plume—where the colourchanges from tan to green—and further from shore, where
the water of the Sound takes on a turquoise tint.
While some of the colour surrounding the Australiancoast may come from sediment, most of the shining stain
probably comes from large blooms of phytoplankton.
These floating, microscopic, plant-like organisms carrypigment that, when massed together in large ‘blooms’,
can easily be seen from space. For the most part,
phytoplankton float near the surface of the ocean anddrift wherever currents take them. Because of this,
phytoplankton can sometimes be used to reveal the flow ofcurrents in the ocean.

Image Credit: MODIS Land Rapid Response Team, NASA GSFC

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Breakup at the the Brunt Ice Shelf
NASA Earth Observatory
Story by Kathryn Hansen with information from Christopher Shuman (NASA GSFC/UMBC JCET).

Antarctica’s Brunt Ice Shelf finally calved a large
iceberg in February 2021, two years after rifts
opened rapidly across the ice and raised concerns
about the shelf’s stability.
The break was first detected by GPS equipment
on February 26, 2021, and confirmed the next
day with radar images from the European Space
Agency’s Sentinel‑1A satellite. On March 1, clouds
were sparse enough for the Operational Land
Imager (OLI) on Landsat 8 to acquire the naturalcolour image of the new iceberg shown below.
Named A-74, the berg spans about 1270 square
kilometres, roughly twice the size of Chicago.
That’s a large piece of ice for the Brunt Ice Shelf,
but Antarctica is known for churning out someenormous bergs. For comparison, Iceberg A-68 wasalmost five times that size when it calved from theLarsen-C Ice Shelf in 2017.
A-74 broke from the ice shelf northeast of the
McDonald Ice Rumples—an area where the flow of
ice is impeded by an underwater bedrock formationthat causes pressure waves, crevasses, and rifts toform at the surface. The rift that spawned the new
berg appeared near the rumples in satellite images
in September 2019, and it advanced across theice shelf with remarkable speed during the australsummer of 2020-2021.

Map showing the location of the Brunt Ice Shelf
Image: Paleo nim / Wikipedia CC“I would not have thought that this rift could go
zipping across the northeast side of the Brunt
Ice Shelf and cause a significant calving—all ina tiny fraction of the time it has taken Chasm 1
to extend toward the ice rumples from thesouth,” said Christopher Shuman, a Universityof Maryland, Baltimore County, glaciologist
based at NASA’s Goddard Space Flight Center.
Chasm 1 is a separate rift located south of the ice
rumples and the Halloween Crack. After decadesof growth—and then a rapid acceleration in
2019—that rift appeared poised to spawn its own
iceberg, prompting safety concerns for researchers‘upstream’ at the British Antarctic Survey’s Halley
VI Research Station. This section of the shelf is still
holding on, but when it eventually breaks the berg
will likely measure about 1700 square kilometres.
Scientists are waiting to see how the complex
structure responds to the recent calving. “TheHalloween Crack may or may not be the firstto respond,” Shuman said. “We’ll be closely
watching that pinning point for changes to thelarger Brunt Ice Shelf remnant.”

NASA Earth Observatory image by Joshua Stevens, using Landsat
data from the US Geological Survey and data © OpenStreetMap
contributors via CC BY-SA 2.0.

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It also remains to be seen what will become of the
new iceberg. Most likely, it will eventually get caught
up in the Weddell Gyre—similar to the fate of A-68.
But first it needs to be pushed offshore, and to dateit does not appear to have moved very far.
The Brunt Ice Shelf lies adjacent to Coats Land, on
the eastern shore of the Weddel Sea, and was named
after Welsh meteorologist David Brunt. It was he who
initiated the Royal Society Expedition to this ice shelfin 1955 which set up Halley Bay Base, the precursorof the current British Antarctic Survey researchstation.
The Halley Research Station sits on the 130 metre
thick ice shelf which is slowly flowing towards theWeddell Sea. The first four Halley stations, theearliest of which were simply wooden huts, are now
long gone. They tended to become buried deep in thesnow, which caused access and ventilation problems.
The current state-of-the-art base station, operational
since 2013, is Halley VI, and comprises a numberof interconnected pods on hydraulic legs fitted withThe British Antarctic Survey’s Halley VI Base
Image: Hugh Broughton Architects / Wikipedia CC

retractable skis: this makes it possible to tow theentire facility across the ice. In 2015 a developing
crack in the ice shelf threatened the base, and in
March 2017, the Halley VI Station was successfully
relocated 23 kilometres farther inland to a moresecure location.

Giant Iceberg breaks off Brunt Ice Shelf in Antarctica
European Space Agency
A giant iceberg, approximately 1.5 times the size ofGreater Paris, broke off from the northern sectionof Antarctica’s Brunt Ice Shelf on Friday, February
26, 2021. Radar images, captured by the Copernicus
Sentinel-1 mission, show the 1270 square kilometre
iceberg breaking free and moving away rapidly fromthe floating ice shelf.
Glaciologists have been closely monitoring themany cracks and chasms that have formed in the
150 metre thick Brunt Ice Shelf over the past years.
In late 2019, a new crack was spotted in the portionof the ice shelf north of the McDonald Ice Rumples,
heading towards another large crack near the
Stancomb-Wills Glacier Tongue.
This latest rift was closely monitored by satellite
imagery, as it was seen quickly cutting across the ice
shelf. Recent ice surface velocity data derived from
Sentinel-1 data indicated the region north of the new
crack to be the most unstable—advancing at aroundfive metres per day. Then, in the early hours of
Friday 26th, the newer crack widened rapidly before
finally breaking free from the rest of the floating ice
shelf.
ESA’s Mark Drinkwater said, “Although thecalving of the new berg was expected, watchingsuch a remote event unfold is still captivating. Overthe following weeks and months, the iceberg could
be entrained in the swift south-westerly flowing
coastal current, run aground or cause further
Continued on page 18

The Brunt Ice Shelf on February 26, prior to breakup
Image contains modified Copernicus Sentinel data (2021)
processed by ESA, CC BY-SA 3.0 IGO

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The Brunt Ice Shelf, imaged by Sentinel-1 on February 28.
Image contains modified Copernicus Sentinel data (2021), processed by ESA, CC BY-SA 3.0 IGO

damage by bumping into the southern Brunt Ice Shelf. So we will be carefully monitoring the situation using
data provided by the Copernicus Sentinel-1 mission.”
Antarctic icebergs are named from the Antarctic quadrant in which they were originally sighted, plus asequential number: then, if the iceberg breaks, a sequential letter is added. This new iceberg was given thedesignation A‑74. The calving does not pose a threat to the presently unmanned British Antarctic Survey’s
Halley VI Research Station, which was re-positioned in 2017 to a more secure location after the ice shelf wasdeemed unsafe.
Routine monitoring by satellites offers unprecedented views of events happening in remote regions like
Antarctica, and how ice shelves manage to retain their structural integrity in response to changes in ice
dynamics, air and ocean temperatures. The Copernicus Sentinel-1 mission carries radar, which can return
images regardless of day or night (or cloud cover) and this allows us year-round viewing, which is especially
important through the long, dark, austral winter months.

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Eruption at La Soufrière
NASA Earth Observatory
Story by Kathryn Hansen

NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey
and MODIS data from NASA EOSDIS LANCE and GIBS/Worldview.

Eruptions at La Soufrière volcano
have propelled ash and gas high into
the air over the Caribbean islandsof Saint Vincent and Barbados. The
eruption—the volcano’s first explosive
event since 1979—prompted

thousands of people to evacuate. The
recent bout of explosive activity began
on April 9, 2021. At about 10:30 am
local time and the Operational Land
Imager (OLI) on Landsat 8 acquired
the above image of volcanic ash

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billowing from La Soufrière. The plume
obscures the 1178 metre volcano
beneath, which stands on the northernside of Saint Vincent. According toJean-Paul Vernier, an atmosphericscientist with NASA’s Earth Applied

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Sciences Disasters Program, activity
was apparent months before theexplosive eruptions. It started with
an effusive eruption in which magmathat reached the surface slowly built
up a lava dome. Then, in April, thedome finally turned out a massive
explosion without many precursor
signs. Explosive eruptions result fromthe rapid expansion of pressurised
gasses trapped in the rock or magma:
the pressure violently breaks rocks
apart and produces a plume of rock,ash, and gas.
Winds carried much of the ash
and gas east from Saint Vincent
and, on the afternoon of April 10

the Moderate Resolution Imaging
Spectroradiometer (MODIS) on
NASA’s Aqua satellite acquired theimage below, showing ash reaching
Barbados, 190 kilometres away.
Clouds (white) are also abundant inthis view.
These images show ash aloft in
the atmosphere, but some of it fellback to the ground. According tonews reports, ash fall blanketed
parts of Saint Vincent and Barbados.
It also has threatened food andwater supplies on Saint Vincent andreduced visibility, which complicatedevacuation efforts. People displaced
to the island’s southern side—away

from the volcano and generally
safer—still had to contend with fallingash and poor air quality.
Scientists are investigating the extent
and height reached by the ash andgas plume. They think some ash hadrisen all the way into the stratosphere,
where strong winds could potentiallycarry it great distances. Other satellite
instruments detected sulphur dioxide
reaching Cape Verde, an archipelago
in the central Atlantic Ocean. Sulphur
dioxide near ground level can irritate
the human nose and throat: higher in
the atmosphere it can make sulphuricacid aerosols which, in extreme
cases, may lead to a cooling effect.

NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey
and MODIS data from NASA EOSDIS LANCE and GIBS/Worldview.

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André T’Kindt submitted this NOAA 19 APT image dating from May 23, 2021, which illustrates one of
the succession of Atlantic depressions that soaked the British Isles that month.

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Phytoplankton Bloom off of the Eastern United States
MODIS Imge of the Day

Image Credit: MODIS Land Rapid Response Team, NASA GSFC

A spring bloom of phytoplankton coloured the shores
of Virginia, Maryland, Delaware, and New Jersey in
mid-May 2021. The Moderate Resolution Imaging
Spectroradiometer (MODIS) on board NASA’s Aqua
satellite acquired this image of the bloom in the Atlantic
Ocean on May 13. The jewel-toned swirls stretch along thecoast for about 320 km and measure about 55 km in width.
Phytoplankton are tiny, plant-like organisms that often
float near the ocean surface and utilise sunlight to convert
carbon dioxide into sugars and oxygen. In turn, they
become food for the grazing zooplankton, shellfish, andfinfish of the sea. They also play an important but not
fully understood role in the global carbon cycle, taking
carbon dioxide out of the atmosphere and sinking it to thebottom of the ocean. These microscopic organisms live inthese waters year-round, but usually their numbers are sosmall that they aren’t visible. It’s only when conditions areright—warming waters, lengthening sunlight, and adequate
nutrients—that they burst into the explosive reproduction
which creates massive blooms easily seen from space.
On April 24, only three weeks before this image was
acquired, a strong storm moved northeastward throughthe Mid-Atlantic states, carrying strong winds and torrential
rains. By April 26, when the skies cleared, MODIS imagery
revealed that the rivers as well as the waters of Delaware
Bay (north) and the Chesapeake Bay (south) were mudcoloured, indicating that a large quantity of sediment had
washed into the two bays and, most likely, continued into
the waters of the near-shore Atlantic. Although most of
the sediment rapidly cleared from satellite imagery, it islikely that this rush of soil-laden water provided a burst of
nutrients that spurred the phytoplankton growth.

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Overwintering Fires on the Rise
NASA Earth Observatory
Story by Kathryn Hansen.

Zombie fires, holdover fires, hibernating fires, oroverwintering fires: Whatever you choose to call them,
you’re probably going to hear a lot more about them inthe coming years. New research shows that this type of
wildfire—which can survive the snow and rain of winter tore-emerge in spring—is becoming more common in highnorthern latitudes as the climate warms.
“Smouldering fires are flaming fires that have entered‘energy-saver mode,’” said Rebecca Scholten of Vrije
Universiteit Amsterdam. “The fires start above ground,then continue to smolder in the soil or under tree roots
through winter. These fires are only just surviving
based on the resources they have—oxygen andfuel—and can transition back into flaming fires once
conditions are more favourable.”In their research, Scholten and colleagues show thatthe boreal forests of Alaska and Canada’s Northwest
Territories are especially prone to overwintering fires,
where fires can burn deep into the organic soil layer.
Combining ground-based fire data with fire detection
data from NASA’s Moderate Resolution Imaging
Spectroradiometer (MODIS) instruments on the Terra
and Aqua satellites, the scientists found a way to identify
overwintering fires based on their unique characteristics.
These fires tend to emerge close to the original fire, andthey flare up earlier in the year compared with fires caused
by lightning and people.

Figure 1 - September 24, 2015
A burn scar reveals the extent of
a seemingly extinguished fire.

The scientists found that between 2002 and 2018,
overwintering fires generally accounted for a small
amount of the total burned area in the region. But in
individual years, following hot and severe fire seasons,that number could escalate. In 2008 in Alaska for example,
overwintering fires accounted for 38% of the burned areas.
“For me, the sheer fact that these fires exist andhappen every other year now was probably the mostsurprising finding,” stated Scholten.
She also noted that early detection could help with fire
management and reduce the amount of carbon—stored
in large amounts in the region’s organic soils—that getsreleased to the atmosphere during fires.
The images in figures 1-4, acquired with the Operational
Land Imager (OLI) on Landsat 8, highlight the progressionof a particularly potent overwintering fire in Alaska during
2015-16. The images are false color (OLI bands 7-6-2),
which emphasise hot spots and actively burning fires while
distinguishing burned vegetation (brown) from unburned
vegetation (green).
Figure 1, acquired in September 2015, shows the burnscar from the Soda Creek Fire, which scorched nearly

Figure 2 - April 12, 2016
Unseen from above, the fire continues
to smoulder beneath the snow.

17,000 acres in southwest Alaska near the Kuskokwim
River. The fire was never completely extinguished before
winter set in. In April 2016 (figure 2), the fire continued tosmoulder in the soil under a layer of snow.

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Figure 3 - May 30, 2016
The fire reemerges and even begins to spread.

Figure 4 - June 5, 2016
The post-winter burned area increases by 57%.

Figure 5 May 30, 2016 - This is a natural colour version of figure 3.

When the snow finally melted in late May (figure 3), theadditional heat and oxygen caused flames to re-emerge
and quickly spread. (figure 5 shows a natural-colour
version of this image, overlaid with the shortwaveinfrared signature of active fire fronts). The June 2016
image (figure 4) outlines new burned area from theseoverwintered fires (compare with figure 1), which added
nearly 10,000 acres to the previously burned area.

“Although our satellite record of these fires in
itself is too short to look at long-term trends, wefound that the number of fires that overwinter isstrongly linked to summer temperatures and large
fire seasons,” Scholten said. “And for these we do
see a pronounced upward trend—hotter summers
and more burned area—with continued climate
warming.”

The incident was not an isolated case. The study points
to numerous fires that overwintered after Alaska’s large
fire years of 2009 and 2015, although they can happen
after other hot and active fire years, too.

NASA Earth Observatory images by Joshua Stevens,using Landsat data from the U.S. Geological Survey
and fire perimeter data from the Alaska Interagency
Coordination Center (AICC).

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