Group for Earth Observation

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

55
September 2017
Inside this issue . .
Not surprisingly, in view ofrecent events in the
Caribbean, imagery of boththe hurricanes and theislands themselves areprominent in this issue. In
particular, there is a revealing
report from NASA Earth
Observatory highlighting
difference in the appearanceof a number of islands before
and after the storm hit. The
image shown here is of
Hurricane Jose which
followed Irma.
We also have articles by John
Tellick on the subject of
sprites, those ephemeraldischarges that leap up
beyond the stratosphere fromthunderstorms.
We also cover Earth’s polar
regions with articles on the
Antarctic peninsula, ice
breakup in the Amundsen
Gulf and the south
Patagonian Icefield.
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

G

EO Management held a Skype meeting this past July to address
the future of our Quarterly Magazine. Despite numerous pleas tothe members for support regarding the provision of original content, it
has been clear for a long time that almost all information is nowadays
being propagated via on‑line media, particularly the GEO-Subscribers
YAHOO Group. Regrettably therefore, it has been decided that theprinted December issue, GEO Quarterly 56, will mark the end of its run.

T

he meeting accepted that this was an inevitable sign of the times.
The availability of information on the internet and an active GEO
Subscibers Yahoo Group meant that ideas, solutions and offers of help
were available in ‘real time’, rather than having to wait weeks for the
next edition of the magazine.

As is the case in this issue, most of the content has been gleaned
from public domain internet sites, such as those of NASA and ESA,a burden shouldered by John Tellick and myself. As I explained lastissue, I wish to rid myself of this huge demand on my time, and will
retire as editor at the end of this year to pursue my own interests.

H

owever, I am still prepared to make up any articles submitted by
GEO members, and have assured the Management Team that I
will be happy to create PDF copies of any such articles, which will thenbe made available for download on the GEO Website at
http://www.geo-web.org.uk
Also, I will continue to be available by email using
geoeditor@geo-web.org.uk

C

opy deadline for the December issue of GEO
Quarterly is Sunday, November 26, 2017.

Contents
GEO Report
Quarterly Question
Cover Image Details
A Menacing Line of Hurricanes
Oregon’s Crater Lake
Gigantic Jets over Hawaii
Hurricane Irma turns Caribbean Islands brown
Jellyfish Sprites over Europe
Mackenzie Meets Beaufort
Sweltering Southern Europe
The Volga Delta
Sunglit on the Aegean and Mediterranean
Direct Reception of Feng Yun 3C
Proba V Monitors the African Sahel
Where Tectonic Plates go for a Swim
New Island forms off Cape Hatteras
Severe Weather at EUMESAT Aﬂenz Uplink Station
Ice Breakup in Amundsen Gulf
Antarctica’s Most Studied PeninsulaSouth Patagonian Icefield
Sunglint Around Hawaii
Using Facebook Intelligently
Satellite Status
GEO Helplines and Internet Discussion Groups
GEO Shop Catalogue and Price List

Francis Bell
Francis Bell
NASA Earth Observatory
Les Hamilton
John Tellick
NASA Earth Observatory
Spaceweather.com
NASA Earth Observatory
European Space Agency
John Tellick
NASA Earth Observatory
Les Hamilton
European Space Agency
NASA Earth Observatory
NASA Earth Observatory
John Tellick
NASA Earth Observatory
NASA Earth Observatory
NASA Earth Observatory
NASA Earth Observatory
Les Hamilton

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GEO Quarterly No 55

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September 2017

Francis BellAt the time of writing these notes we seem to be at theheight of the hurricane season in the central Atlantic
and Caribbean. I have been following the progress of
Hurricanes Harvey and Irma for personal reasons.
Hurricane Harvey approached the coast of Texas while
I was staying in the USA, in the state of North Carolina(N.C), about 1,500 miles away from the hurricane.
There was no risk of its effects reaching N.C., but I wasperceptive of its effects and of the excessive rain depositedin Houston and adjacent areas of Texas. When I returnedto the UK after our visit the hurricane was still newsworthy
and I was able the see it on selected images transmitted
by EUMETCast which I regularly receive at home (image
below).
As I write, Irma is still classiﬁed as a maximum strengthcategory ﬁve hurricane and is just passing the Windward
Islands. I have visited these islands several times andcan imagine the damage such a violent storm can do tothese fragile environments. I can particularly remember
the island of St Martin, which I visited in the 1990s andswam around some of the beautiful coral reefs along thepalm lined coast. It so happened that I visited the sameisland about ﬁve years later, but in the interim it hadendured a force two hurricane. The damage that I saw
was considerable, with coral reefs all but destroyed andthe dead coral lying on the beaches as white pieces. Manyof the palm tress were missing and about half of thoseremaining were at an angle of about 45 degrees. I am
concerned about the damage that a force ﬁve hurricane

could do to these fragile small islands and then potentiallyto the larger territories of Hispaniola and Cuba—which I
have also visited in the past.
I continue to follow the latest hurricane season using
my EUMETCast system, which retransmits images fromthe GOES E American satellite as well as those from theEuropean Meteosat 10.
My August visit to the USA was timed not only for a visit
to my son and his family in N.C. but also to see the total
solar eclipse on the August 21, 2017, which was visible ina strip across the whole of the USA. From my son’s housein N.C. we had to travel about 150 miles south into South
Carolina to be within the total eclipse band. The travel was
worthwhile because, during our visit to S.C., we had nearlyclear sky and a near-perfect view of the eclipse. Totality
was a great experience which lasted only for about one anda half minutes but was a once in a lifetime experience.
Members’ Meeting
On matters more directly relating to GEO, I wish to
express a little concern that we have not held our usual
members annual meeting this year. Several times requests
have been made for members’ preferences for such ameeting but I have received so little feedback that noaction has been taken. I think the best course of action
is to arrange a meeting some time in 2018 and members
can attend or not according to their preference. I have anumber of ideas and I hope a decision can be published in
our next Quarterly.

This GOES-E image, acquired via EUMETCast on August 27, 2017, shows Hurricane Harvey battering Houston, Texas.

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Forthcoming Events
GEO will again be attending the South London Radio andComputer Rally at Kempton Park, where we will have astand displaying recorded satellite images and information
about GEO membership. The show is open between 10 am
and 3 pm on Sunday the November 5, 2017. For further
information consult
www.radiofairs.co.uk
The ‘Meteorological Technology World Expo’ is to be heldin Amsterdam between October 10‑12, 2017: previously
this Expo has been held in Brussels. Its move to
Amsterdam may be of interest to our GEO members in
the Netherlands. The Expo is free to attend as a visitor.
As well as many commercial display stands I expect that
EUMETSAT will be attending, so the event should be ofinterest to GEO members. For more information go to
www.MeteorologicalTechnologyWorldExpo.com.
The Radio Society of Great Britain (RSGB) is holding its
annual convention between October 13‑15, 2017 at Kents
Hill Park Conference Centre, Timbold Drive, Kents Hill,
Milton Keynes MK76BZ. For further details go to
www.rsgb.org/convention
I note from the draft lecture programme two items that
may be of special interest to GEO members. They are ‘How
Space Weather Affects Radio Signals’ and a presentation by
AMSAT-UK about satellites. I note that AMSAT-UK, insteadof having their own annual colloquium, are this year
sharing their event with this RSGB convention. Our own
GEO might find this potential sharing of a RSGB’s meetinga useful idea for the future.
The Royal Meteorological Society are holding a one day
event in London and the programme looks attractive. For
further information go to the Royal Met’s web site atwww.weatherlive.net
WeatherLive, the ultimate day out for weather enthusiasts,
with an opportunity to talk about the nation’s favourite
topic, takes place in Central Hall Westminster, London on
Saturday November 4, 2017.

This year the Royal Meteorological Society is working with
the Royal Horticultural Society and the Royal Photographic
Society to discuss ‘Gardening in a Changing Climate’, tofind the next Weather Photographer of the Year. The event
will also mark the anniversary of the 1987 storm. Further
information is available on the MetS website athttps://www.rmets.org/

This is an infrared image from the GOES‑E satellite, acquired by Francis Bell on September 8, 2017, showing the Atlantic hurricane season at its
peak. Hurricane Katya sits in the Caribbean, and Irma is shown just north of the Dominican Republic with Jose further to the east over the Atlantic.
Image © EUMETSAT 2017www.geo-web.org.uk

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Francis Bell
Quarterly Question 54
The last Quarterly question related to satellite photographsof Greece and the coastline of South America. My
background interest in these images related to the factthat I had visited the three capital cities shown on theimages. My thanks to those members who emailed me withthe correct answers which were:• Athens which could be clearly seen in the image ofGreece,• Montevideo on the north bank of the River Plateestuary shown in the images of South America and• Buenos Aires further inland on the south bank of theriver.
This Quarterly Question is a little different from previous
questions because this time without my own research I
don’t know the answer, but that does not stop me asking
the question!
Quarterly Question 55
Regular reports on radio and TV news programmes andother sources make statements stating that the world’s sea
level is rising steadily. The figure seems to be about two
centimetres in the last 20 to 30 years. Along with this sea
level change there is a steady rise in the temperature of
our atmosphere, oceans and Earth surfaces as indicatedby absolute measurement. I can understand melting
ice, warmer oceans and a more dynamic atmosphere,
as evidenced currently by hurricanes Irma and Jose. I
can understand the absolute measurements and theirconsequences, but what I can’t understand is how you
measure sea level changes in such fine detail, that is, tothe nearest centimetre or less against such a variablebackground.
Ocean levels are dynamic. There are about 20 celestial
factors which affect tidal levels and there are also
meteorological factors such as pressure, wind andtemperature which also affect sea level. Even some land
surfaces are bobbing up and down, so how can sea level bemeasured so accurately?
The Quarterly Question is this: “What is the reference
level for measuring sea level changes”.
Perhaps the answer is not a one line statement but please
don’t let this stop you submitting an answer even if itneeds a several page article—which it might!
Answers by email, please, tofrancis@geo.org.uk
before November 26, 2017.

Front Cover
On September 8, 2017, NASA’s Terra satellite acquired this true‑
colour image of category‑4 Hurricane Jose as it tracked towards
several Caribbean Islands that had already been devastated by
the massive Hurricane Irma. Venezuela sits in the far south of theimage, with the Leeward Islands on the eastern side of the storm.
Thick bands of thunderstorms circled Hurricane Jose’s very clear
and well-defined eye.
Image: LANCE Rapid Response / NASA / GSFC

Inside Front CoverThis lovely image from Russia’s Meteor-M2 satellite wascaptured at 10.07 UT on July 5, 2017 using an RTL dongle.
LRPT image captured by Les Hamilton

Inside Back CoverThis Meteor M2 LRPT image acquired on August 11, 2011 was
submitted by Enrico Gobbetti. It takes advantage of one of therare occasions when the satellite transmits channel 3 (visible)
in place of the more usual channel 5 (IR), to render an RGB123
image.
LRPT image captured by Enrico Gobbetti

Back CoverNASA’s Terra satellite observed this image of sun‑drenched Italy
on August 13, 2017, during perhaps the most severe heatwave
ever experienced in the region. Rome, Naples and Florence
had been baking in temperatures in excess of 40°C. Even in
the mountains the temperatures have been well above average,
forcing closure of summer skiing on the Stelvio Pass glacier(altitude 3,450 metres) for the first time in 90 years..
Image: LANCE Rapid Response / NASA / GSFC

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NASA Earth Observatory
Meteorologists struggled to find words todescribe the situation as a line of threehurricanes—two of them major andthreatening land—brewed in the Atlanticbasin during early September 2017 (figure 1).
Forecasters were most concerned about
Hurricane Irma, which was on track to makelandfall in densely populated South Florida
on September 10 as a large category‑4
storm. Meanwhile, category‑2 Hurricane
Katia was headed for Mexico, where it was
expected to make landfall on September
9. And just days after Irma devastatedthe Leeward Islands, the chain of small
Caribbean islands braced for another blow—
this time from category 4 Hurricane Jose.
The Visible Infrared Imaging Radiometer
Suite (VIIRS) aboard the Suomi NPP satellite
captured data to construct a mosaic of all
three hurricanes as they appeared in theearly hours of September 8, 2017. The
images were acquired by the VIIRS ‘day‑night band’, which detects light signals in arange of wavelengths from green to near‑infrared, and uses filtering techniques toobserve signals such as city lights, auroras,
wildfires, and reﬂected moonlight. In thiscase, the clouds were illuminated by anearly full Moon. The image is a composite,
showing cloud imagery combined with dataon city lights.

Figure 1 ‑ Three simultaneous hurricanes in the Atlantic Basin on September 8, 2017
NASA Earth Observatory images by Joshua Stevens and Jesse Allen,
using VIIRS day-night band data from the Suomi National Polar-orbiting Partnership

The Moderate Resolution Imaging
Spectroradiometer (MODIS) on NASA’s Terrasatellite acquired a natural‑colour image of
Irma (figure 2) at 16:00 UT on September 8,
2017.
The NASA Short-term Prediction Research
and Transition Center remarked on thestorm’s ‘buzz saw appearance’. The National
Weather Service field office in Miami
warned of ‘large airborne projectiles’ andcautioned that some locations might become‘uninhabitable for weeks or months’ after
the storm. Eric Blake, a meteorologist with
the National Hurricane Center tweeted that
he had ‘never seen anything like this in themodern record’.
In some respects, Irma is an unusual andrecord‑breaking storm. On September 8,
the storm had generated more accumulated
cyclone energy—a term meteorologists
use to describe the destructive potential ofa hurricane—than any other Atlantic storm
on record, according to meteorologist Philip
Klotzbach of Colorado State University. Irma
also broke a record for generating the mostaccumulated cyclone energy in a 24‑hour
period.
Story by Adam Voiland.

Figure 2 ‑ NASA’s Terra satellite images Hurricane Irma on September 8, 2017
Earth Observatory images by Joshua Stevens and Jesse Allen,

using Terra MODIS data from the Land Atmosphere Near real-time Capability for EOS (LANCE).

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September 2017

Les Hamilton

Crater Lake, Oregon, with Wizard Island prominent in the foreground
Image - Wikimedia Commons / Stuart Seeger, San Antonio Texas

Established in 1902, Crater Lake National Park in the
Cascade Mountains of southwest Oregon is the fiftholdest national park in the USA. It’s most notable featureis the caldera of Crater Lake, a remnant of a former
volcano, Mount Mazama, a probable 3,600 metre peakthat exploded and collapsed in a catastrophic eruption
approximately 6,000 to 8,000 years ago. The lake surface
stands 1,883 metres above sea level and is surrounded
by a caldera rim that rises between two hundred and five
hundred metres above it.
The caldera is endorheic, meaning that no streams
drain into it and therefore, water is lost from it only
by evaporation and seepage. The lake’s contents are
replenished solely from precipitation as snow and rain.
Crater Lake has a maximum depth of 594 metres, andis the deepest body of water in the United States. This
depth was first calculated by geologist Clarence Duttonand his team using measurements made with piano wire
and lead weights. Making comparisons based on average
depth, Crater Lake (350 m) is the deepest in the Western
Hemisphere and the third‑deepest on Earth.
On June 26, 2017, an astronaut aboard the International

6

Space Station shot the photograph of Crater Lake
reproduced on the following page. Snow still blankets mostof the slopes surrounding the crater, and clouds cast dark
shadows on the lake surface. Wizard Island, formed froma cinder cone that erupted after Crater Lake began to fillwith water, lies to the left of the image, almost hidden by
the clouds over the western part of the lake.
In 2016, more than 750,000 people visited the Crater
Lake National Park, which includes Crater Lake and thesurrounding 740 square kilometres. Part of the reason thelake is so popular is the fishing. In the late 1800s, several
species of fish were introduced to the lake, though only
rainbow trout and Kokanee salmon (the landlocked versionof sockeye salmon) remain today. Since none of these wasnative to the lake, fishermen are not required to obtain apermit.
The image was taken by a member of the Expedition 52
crew and has been cropped and enhanced to improve
contrast, and lens artifacts have been removed.
Sources
NASA Earth Observatory, Wikipedia

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Crater Lake, viewed from the International Space Station on June 26, 2017

Astronaut photograph ISS052-E-8744 was acquired on June 26, 2017, with a Nikon D4 digital camera using an 1150 millimetre lens, and is provided by the
ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center.

Crater Lake Panorama Spring 2016
Image: Wikimedia Commons / Achmathur

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September 2017

John Tellick
Every night, the Gemini Cloudcam atop Mauna Kea in Hawaii
monitors storms approaching some of the world's largest
telescopes, often capturing lightning bolts forking down to theground below. On July 24, however, something very different wasobserved: a gigantic jet, related to sprites but more powerful,and easier to see with the naked eye (figure 1). Cloudcam video
caught at least three of these jets springing from the tops of apowerful growing thunderstorm, the reaching all the way to theionosphere some 80 kilometres above.
Gigantic Jets are much rarer than sprites. While sprites werediscovered in 1989 and have since been photographed in theirthousands, it was not until 2001 that Gigantic Jets were firstrecorded from Puerto Rico and Taiwan. Even today, only a few
dozen Gigantic Jets have ever been seen, mostly over open
ocean.
Sometimes called ‘Space Lightning’, Gigantic Jets and their
cousins the sprites are true space weather phenomena. They
inhabit the upper atmosphere alongside auroras, meteors andnoctilucent clouds. Some researchers believe they are linked
to cosmic rays: subatomic particles from deep space that strike
Earth's upper atmosphere to produce secondary electrons that
could provide the spark for these upward bolts.

Figure 1 ‑ The Gigantic Jet observed by the Gemini Cloudcam
Photo credit: Gemini Observatory/AURA/NSF
Discovery and Image Processing by Steve Cullen

The link to cosmic rays is particularly interesting at this time
because, for the past two years, space weather balloons havebeen observing a steady increase in deep space radiation
penetrating the atmosphere. This increase is largely due to thedecline in the solar cycle as ﬂagging solar wind pressure andweakening sunspot magnetic fields allow more cosmic rays into
the inner solar system—a trend that is expected to continue foryears to come. These changes could result in more Gigantic Jet
sightings in the future.
You can view a time‑lapse video of the thunderstorm capturedby the Gemini Cloudcam on the night of July 24, 2017 at thefollowing URL
https://www.youtube.com/watch?v=ZMc0_k6CKd0
Upper-atmospheric lightning
Upper‑atmospheric lightning or ionospheric lightning are terms
sometimes used by researchers to refer to a family of short‑
lived electrical‑breakdown phenomena that occur well above
the altitudes of normal lightning and storm clouds. Upper‑
atmospheric lightning is believed to consist of electrically induced
forms of luminous plasma. The preferred usage is transient
luminous event (TLE), because the various types of electrical‑
discharge phenomena in the upper atmosphere lack several
characteristics of the more familiar tropospheric lightning.
There are several types of TLEs, the most common being
sprites, which are ﬂashes of bright red light that occur above
storm systems. C‑sprites (short for ‘columniform sprites’) is thename given to vertical columns of red light. C‑sprites exhibiting
tendrils are sometimes called ‘carrot sprites’. Other types of TLEs
include sprite halos, blue jets, gigantic jets, blue starters, and
ELVESs. The acronym ELVES (Emission of Light and Very Low
Frequency perturbations due to Electromagnetic Pulse Sources)

88

Figure 2 ‑ The first ever colour image of a Red Sprite
Image: Wikimedia / NASA/University of Alaska

refers to a singular event which is commonly thought of as
being plural. TLEs are secondary phenomena that occur in theupper atmosphere in association with underlying thunderstorm
lightning.
The first colour image of a sprite was obtained during a 1994
NASA/University of Alaska aircraft campaign to study thephenomenon. The event was captured using an intensified colour
TV camera. The red colour was subsequently determined to
be produced from nitrogen ﬂuorescent emissions, excited by alightning stroke in the underlying thunderstorm.

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NASA Earth Observatory

Figure 1 ‑ The British and U S Virgin Islands

Hurricane Irma churned across the Atlantic Ocean
during early September 2017, battering several
Caribbean islands before moving on to the Florida
Keys and the U.S. mainland. As the clouds cleared
over places like the Virgin Islands, the destruction
became obvious, even from space.
The natural-colour images in figure 1, captured by
the Operational Land Imager (OLI) on the Landsat 8
satellite, show some of Irma’s effect on the British
and U.S. Virgin Islands. The views were acquiredon August 25 and September 10, before and after
the storm passed. They are among the few relatively
cloud‑free satellite images of the area so far.
The most obvious change is the widespread browningof the landscape. There are a number of possible
reasons for this. Lush green tropical vegetation canbe ripped away by a storm’s strong winds, leaving
the satellite with a view of more bare ground. Also,
salt spray whipped up by the hurricane can coat anddesiccate leaves while they are still on the trees.
Irma passed the northernmost Virgin Islands on theafternoon of September 6. At the time, Irma was acategory‑5 storm with maximum sustained winds of
295 kilometres per hour. According to news reports,
the islands saw ‘significant devastation’.

A close-up of Virgin Gorda (figure 2, next page) gives
a better sense of the changes. Note how some of thevegetation on the south and west of the island is a bit
greener, probably because it was partly shielded fromwinds by the hills in the centre. Differences in ocean
colour most likely stem from differences in the ocean
surface: rougher surfaces scatter more light, andappear brighter and lighter.
The destruction is also clearly visible on Barbuda(figure 3). This small island in the eastern Caribbean
was directly hit by the category‑5 storm early on
September 6. These images were acquired by theModerate Resolution Imaging Spectroradiometer(MODIS) on NASA’s Terra and Aqua satellites. The left‑
hand image shows Barbuda on August 21; the rightimage shows the ravaged landscape on September 8.
In contrast, vegetation on Antigua appears relatively
healthy and intact. With the storm’s centre passing
to the north, the island sustained less damage.
Ground reports noted that by September 7, electricity
had been restored to most of the island, and theinternational airport reopened.
NASA Earth Observatory images by Joshua Stevens, using Landsat datafrom the U.S. Geological Survey.
Story by Kathryn Hansen.

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Figure 2 - Close-ip view of Virgin Gorda

Figure 3 - Antigua and Barbuda

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Spaceweather.com

So‑called ‘Jellyfish Sprites’, photographed over Austria during a thunderstorm
Photo: Martin Popek

On June 20, 2017, a thunderstorm over Austria unleashed a spectacular display of lightning. Observers
on the ground witnessed blinding flashes of crackling light. The most amazing aspect of this outburst,
however, was to be found high above the clouds at an altitude of some 80 kilometres—in the realm of the
sprites
Martin Popek photographed the display from his private observatory in Nýdek, Czechia (Czechia wasadopted as the official name for the Czech Republic on September 16, 2016), more than 500 kilometresaway from the storm. Such distances are ideal for seeing above the tops of towering thunderclouds.
‘Jellyfish sprite events like these are produced by very impulsive cloud-to-ground lightning flashes
draining positive charge from the stratiform rain region in large thunderstorms,’ explained lightningscientist Oscar van der Velde of the Technical University of Catalonia, Spain. ‘Somehow, in a processthat researchers only partially understand, the resulting electric fields draw jellyfish forms out of thecloud tops.’
The tops of the sprites were surrounded by a saucer‑like halo of red light, noted van der Velde. ‘The halois evidence of intense electric fields at 80-90 km shaking up the electrons (colliding with nitrogen to
produce light) for such a short time that sprite streamers cannot form. At lower altitudes the field exists
longer, allowing the jellyfish sprite streamers to grow from electron avalanches.’
Although sprites have been seen for at least a century, most scientists did not believe they existed until
after 1989 when sprites they were photographed by cameras onboard the space shuttle. Now ‘spritechasers’ routinely photograph sprites from their own homes.
Popek used a Watec 910HX security camera with UFOCapture software fromhttp://sonotaco.com/e_index.html
to catch his sprites, one such display being shown in the photograph above.
Source credit: Spaceweather.com / Martin Popek
Thanks to John Tellick for submitting this material.
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NASA Earth Observatory

The Mackenzie River delta feeding sediment into the Beaufort Sea

NASA Earth Observatory image by Jesse Allen, using Landsat data from the US Geological Survey.
Story by Mike Carlowicz.

The Mackenzie River is the leading source of freshwaterflowing into the Arctic Ocean. It’s also a leading sourceof sediment flowing into that basin. The Operational Land
Imager (OLI) on the Landsat 8 satellite acquired this imageof the Mackenzie Delta on July 19, 2017. At the time, theBeaufort Sea was coloured with milky tan brush strokesof sediment in various levels of dispersal after pouring outof the river.
The Mackenzie is the largest and longest northward‑
flowing river in North America, and the second largest
on the continent (after the Mississippi). The watersheddrains a huge but mostly unsettled portion of Canada:
population density along the 4,200 kilometre river is justone person per square kilometre.
About 7% of the fresh water that flows into the Arctic
Ocean each year comes out the Mackenzie and its delta,
and much of that comes in large pulses during June andJuly after the freshet—the spring thaw when inland ice
and snow melts and floods the river. This flood carries

12with it tremendous amounts of dissolved organic materialand sediment.
The freshet pushes out a lot of material, and most ofthat sediment is derived from erosion of the Rocky
Mountains through the Liard River, a major tributary to
the Mackenzie. The erosional debris comes mostly fromold sedimentary rocks (shales, sandstones, limestone)in the Rocky Mountains. This is fine-grained suspended
material that the river pushes out into the coastal ocean.
The fact that you see some dispersion in the Beaufort Sea
indicates that the delivery has been going on for sometime.
In a study published in 2014, a NASA‑led research teamdemonstrated that fresh water flowing from rivers into
the Arctic Ocean can have a significant effect on theannual extent of sea ice cover. Warm water discharges
can accelerate the melting of sea ice near the coast. It
also can have a wider impact on climate by creating more
open water, which absorbs more heat from sunlight.

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GEO Quarterly No 55

European Space Agency

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

During early August 2017, southern Europe
was in the grip of a relentless heat wave,
fuelling wildfires and water shortages.
Information from the Copernicus Sentinel-3A
satellite has been used to map the sweltering
heat across the region.
The map above shows that, on August 7,
2017, temperatures of the land surface rose
above 40°C—not an usual occurrence over theprevious few weeks. Much of Italy, including
Rome, Naples, Florence, Sardinia andSicily had been suffering these highs. With
numerous towns and cities on the ministry ofhealth’s maximum heat alert, the Italians have
aptly dubbed the heat wave ‘Lucifer’. Extreme

temperatures have also been recorded in
Spain and Portugal, the Balkans and Greece.
As well as wildfires and water shortages, theheat has also led to some tourist attractions
being closed, to ill health and even somefatalities, and the drought is also threatening
crops.
The map uses data from the satellite’s Sea
and Land Surface Temperature Radiometer,
which measures energy radiating from Earth’s
surface in nine spectral bands. The map
therefore represents temperatures of the land
surface, not air temperature which is normallyused in forecasts.

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13

On August 3, 2017, the MODIS instrument on NASA’s Aqua satellite acquired this image showing several phytoplankton blooms in the Caspian Sea.
Often harmless, these blooms are an important food source for marine life, but they can deplete the water’s oxygen and suffocate marine life, andproduce toxins that can be harmful to both aquatic creatures and humans.

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Image by Norman Kuring, NASA’s Ocean Color web - Caption by Adam Voiland.

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September 2017

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John Tellick
The Volga River delta is the largest in
Europe, and is situated where Europe’s
largest river system, the Volga, drains into
the Caspian Sea in Russia’s Astrakhan
Oblast. The delta is located in the Caspian
Depression—the far eastern part of the deltalying in Kazakhstan. The delta drains into
the Caspian approximately 60 kilometres
downstream from the city of Astrakhan.
The Volga Delta has grown significantly
during the past century because of changes
in the level of the Caspian Sea. In 1880,
the delta had an area of 3,222 km²; today
it covers an area of 27,224 km² and isapproximately 160 km across. It has aclassical ‘delta pattern’. The delta lies in thearid climate zone, characterised by very little
rainfall, in a region that receives less than 25
millimetres of rainfall in January and in Julyin normal years. Strong winds often sweep
across the delta and form linear dunes. Alongthe front of the delta are muddy sand shoals,
mud ﬂats, and banks.
The changing level of the Caspian Sea has
resulted in three distinct zones in the delta.
The higher areas of the first zone are knownas ‘Baer’s mounds,’ named after researcher
Karl Ernst von Baer who worked in thisregion. These mounds are linear ridges
of clayey sands, up to 22 metres in height(averaging about eight metres) and up to
10 kilometres long. Between these mounds
are depressions that fill with water andbecome either fresh or saline bays. These
depressions used to form part of the early,
very deep river delta, but have gradually
become separated from it. Because of theirisolation from the fresh waters of the Volga,
they are now becoming increasingly saline.
Together they form an extremely diverse area
which, because of the varying degrees of
wetness and salinisation, houses a wealth ofﬂora and fauna.
The second zone is the delta proper, which
generally has very little relief (usually lessthan one metre), and is the site of active andabandoned water channels, small dunes andalgal ﬂats. The third zone is composed of abroad platform extending up to 60 kilometres
offshore, and is the submarine part of thedelta.
The delta has been protected since the early
1900s, with one of the first Russian naturepreserves (Astrakhan Nature Reserve)having been set up there in 1919. Much of its
local fauna is considered endangered. The

This vegetation index Metop‑A segment from July 27, 2017 highlights the Volga delta, and also
cultivation north of the river as it flows east towards the delta through an arid region.
Image © EUMETSAT 2017

delta is a major staging area for many
species of water birds, raptors andpasserines. Although the delta is best
known for its sturgeon, catfish and carp
are also found in large numbers.
Industrial and agricultural modification
to the delta plain has resulted insignificant wetland loss. Between 1984
and 2001, the delta lost 277 km² ofwetlands—an average of approximately
16 km² per year—from natural andhuman‑induced causes. The Volga
discharges large amounts of industrial
waste and sediment into the relatively
shallow northern part of the CaspianSea, including fertilisers that nourish thealgal blooms that grow on the surface ofthe sea.
Algal Blooms
Given adequate sunlight and nutrients,
phytoplankton populations can swell
www.geo-web.org.uk

into blooms large enough to be visible
from space. On August 3, 2017,
the Moderate Resolution Imaging
Spectroradiometer (MODIS) on NASA’s
Aqua satellite acquired the image
opposite (page 10) showing several
such blooms in the Caspian Sea.
Phytoplankton blooms are often
harmless, and are an importantfood source for marine life. Other
times, blooms can be harmful; they
can deplete the water’s oxygen andsuffocate marine life, and produce
toxins that can be harmful to bothaquatic creatures and humans.
Lake Urmia is visible west of the
Caspian Sea, close to the bottom left
hand corner of the image. Microscopicorganisms periodically turn the lake’s
salty water striking shades of red andorange, as is the case here.

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September 2017

NASA Earth Observatory

On July 6, 2017, the Moderate Resolution Imaging
Spectroradiometer (MODIS) on NASA’s Terra satellite
captured this image of sunglint on the waters around Creteand the Aegean Islands. The phenomenon of sunglint is amatter of optics. Areas where the sea surface is smootherreflect more sunlight directly back to the satellite’s imager.
In contrast, areas of rougher water appear darker becauselight is scattered in many more directions.

windward side of the islands, those winds pile up the waterand disturb the surface. But as those air masses run into
the islands and their rocky peaks, a “wind shadow” withmuch calmer winds (and seas) form on the leeward side ofislands (in this case, the south sides). Darker areas amid
the bright streaks could be the result of wind or water
turbulence, or perhaps breaks in the wind‑blocking land
topography.

Dry, cool winds from the north, called the Etesian winds,
are common over the Aegean Sea during summer. On theNASA image by Jeff Schmaltz, LANCE/EOSDIS Rapid Response16

www.geo-web.org.uk

Caption by Kathryn Hansen

Landsat-8’s Operational Land Imager observed a volcanic plume streaming west from the Kamchatka’s Klyuchevskoy
volcano on August 19, 2017. The ash plume was at a height of roughly 6 kilometres on the day this image was collected.
Earth Observatory images by Joshua Stevens, using Landsat data from the US Geological Survey

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GEO Quarterly No 55

The Group for Earth Observation

September 2017

Les Hamilton
For more than a year now, Peter Kooistra from Gouda
in The Netherlands has been corresponding with me
about the home‑brew system he has been constructing
for the reception of high‑resolution satellite images.
Though the project is not yet complete, he is alreadyreceiving some superb imagery, exemplified by thisRGB composite from the Chinese Feng Yun 3C
polar orbiting satellite. The quality of the image isundeniable but at present, its length is limited bytrees and houses surrounding Peter’s location. Peterdoes not currently have a rotator, and the pass washand tracked from his garden.

Peter Kooistra received this Feng Yun 3C image on September 2, 2017

For the interest of readers, Peter has provided this description of his system
The hardware consists of a homemade, 1.1 metre mesh dish mounted on a camera tripod (F/D = +/‑ 0.3), a 2.5 turnhomemade helical feed tuned to around 1700 MHz, and an old Dartcom Meteosat LNC purchased on Ebay. Connections
are through good quality N‑connectors, 1.2 m of Ecoflex10 cable from feed to the LNC, and 5 m of Ecoflex10 cable from
LNC output to an Airpy‑mini receiver.
Software includes Orbitron for tracking the satellite, SDR# 1.450 for signal reception (including the baseband recorderplugin). Feng Yun’s output is processed in a demodulator running in Gnuradio For Windows, the .RAW output going intoa DOS‑based decoder from Trango (USA-Satcom). This decoder, though operational, is not yet finished, and still underdevelopment. Next, the .bin output from the decoder goes into Oleg’s MeTFY3x software, and finally, Oleg’s C10 output isprocessed by David Taylor’s HrptReader.

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GEO Quarterly No 55

European Space Agency

Proba‑V captured this image during February 2016
Image © ESA-Belspo 2017, produced by VITO

Proba‑V captured this image on September 2, 2016
Image © ESA-Belspo 2017, produced by VITO

ESA’s Proba-V minisatellite reveals the seasonal changes inAfrica’s sub‑Saharan Sahel, with the rainy season allowing
vegetation to blossom between February (figure 1) and
September (figure 2). The semi-arid Sahel stretches more than
5000 kilometres across Africa, from Senegal and Mauritania on
the Atlantic coast to the Sudan on the Red Sea. The few monthsof the rainy season in the Sahel are much needed in these hot
and sunny parts of Africa, and are critical for the food security
and livelihood of their inhabitants. The name Sahel can betranslated from Arabic as coast or shore, considered as the ever‑shifting landward ‘coastline’ of the arid Sahara Desert.

continent‑spanning 2250 kilometre swath width collects lightin the blue, red, near‑infrared and mid‑infrared wavebands at
300 metre resolution and down to 100 metre resolution in its
central field of view.

Smaller than a cubic metre, Proba-V nevertheless images theentire land surface of Earth every two days, allowing researchers
around the globe to trace gradual shifts in vegetation. Launchedon 7 May 2013, Proba‑V is a miniaturised ESA satellite tasked
with a full‑scale mission: to map land cover and vegetation
growth across the entire planet every two days. Its main camera’s

A gallery of still imagery from Proba‑V can be viewed to

VITO Remote Sensing in Belgium processes and then distributes
Proba-V data to users worldwide. An online gallery highlights someof the mission’s most striking time lapse sequences, including
views of storms, fires and deforestation. One of these videos
relates specifically to the Sahel region.
http://proba-v.vgt.vito.be/en/timelapses
http://proba-v.vgt.vito.be/en/proba-v-gallery
Thanks to John Tellick for sourcing this material
for GEO Quarterly.

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GEO Quarterly No 55

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September 2017

NASA Earth Observatory
There is an obvious difference between
the dark green coniferous forests that
dominate the western shore of Tomales
Bay and the lighter green grasslandson the east side. But the differences
between the two shores run much
deeper than the vegetation. Tomales
Bay lies about 50 kilometres northwestof San Francisco, along the edges of
two tectonic plates that are grinding pasteach other. The boundary between themis the San Andreas Fault, the famous riftthat partitions California for hundreds ofmiles.
The Operational Land Imager (OLI) on
Landsat 8 captured this natural‑colour
image of part of Tomales Bay on March
1, 2017. In figure 1 you can see thatthe direction of the fault follows theorientation of Tomales Bay, runningfrom the head of the Bay through Olema
Valley toward Bolinas Lagoon.
Lagunitas Creek, a northward-ﬂowing
stream that offers critical habitat for theendangered coho salmon, roughly traces
the fault and is shown in more detail in
figure 2.
To the west of the Bay is the Pacific plate;to the east is the North American plate.
The rock on the western shore of the Bay
is granite, an igneous rock that formed
underground when molten material slowly
cooled over time. On the opposite shore,
the land is a mix of several types ofmarine sedimentary rocks. In Assembling
California, John McPhee calls that side‘a boneyard of exotica’, a mixture of rockof ‘such widespread provenance that it isquite literally a collection from the entire
Paciﬁc basin, or even half of the surfaceof the planet.’

Figure 1 ‑ The San Andreas Fault follows the direction of Tomales Bay

As the plates shift, the ground west of
the San Andreas Fault moves northward.
On average, movement along the fault
averages about 3 to 5 centimetres peryear—about the speed that fingernails
grow. However, that movement isanything but steady. The two plates tend
to lock together until extreme amounts ofpressure build up; and when the pressure
reaches a breaking point, an earthquake
sends the plates lurching. During theGreat 1906 San Francisco Earthquake,a road at the head of Tomales Bay wasoffset by nearly 6 meters.
NASA Earth Observatory images by Jesse Allen,
using Landsat data from the US Geological Survey.
Story by Adam Voiland.

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20

Figure 2 ‑ Lagunitas Creek

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The Group for Earth Observation

GEO Quarterly No 55

NASA Earth Observatory

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

The waters off of North Carolina’s barrier islands
have been called a ‘Graveyard of the Atlantic’.
Countless ships have been wrecked there, due tothe area’s treacherous weather and currents, andits expansive shoals. These shoals are, by definition,
usually submerged. But occasionally parts of themcan rise above sea level.
These natural‑colour images, acquired by the
Operational Land Imager (OLI) on the Landsat 8
satellite, show the shoal area off of Cape Point at
Cape Hatteras National Seashore—the site of a
newly exposed shoal nicknamed Shelly Island. The
first image was captured in November 2016. Whenthe second image was acquired in January 2017,
waves were clearly breaking on the shallow region off
the cape’s tip. The site of those breakers is where theisland eventually formed, visible in the third image
captured in July 2017. The new island measuresabout a mile long, according to news reports.
‘What exactly causes a shallow region to become
exposed is a deep question, and one that is difficult
to speculate on without exact observations,’ said
Andrew Ashton, a geomorphologist at the Woods
Hole Oceanographic Institution. ‘A likely process
would be a high tide or storm‑driven water elevationthat piled up sediment to near the surface, andthen water levels went down exposing the shoal.
Waves then continue to build the feature while also
moving it about.’ While the exact mechanism forthe formation of Shelly Island is mostly unknown,
the phenomenon is not uncommon. Cape Lookout,
the next cape down the barrier islands (to thesouthwest, beyond this image) has had several
islands form on its shoal over the past decade ortwo.
The shoreline and cape tips along North Carolina’s
barrier islands are constantly in motion. Cape tips
are sculpted by waves and currents that hit fromall directions. Meanwhile, sediment is carried up
and down the coastline and often deposited near
the cape tips. Each cape has a so‑called ‘cape‑associated shoal’ lurking underwater. These shallow
submerged mounds of sand, which rise to anywherefrom 10 metres to a few meters below the surface,can extend for tens of kilometres.
‘Tidal flows moving up and down the coast are
diverted by the capes and result in a net offshore
current at cape tips and deposition at the shoals,’
Ashton explained. ‘Occasionally, a portion of the
shoal becomes exposed and forms an island.’www.geo-web.org.uk

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September 2017

John Tellick

The Aflenz Ground Station
Photo: Erich Voggengerger.

We are all used to rain‑fade on thesignal strength of our EUMETCast
reception at our own receiving
locations during periods of heavy
rain. But this can also happen due
to weather conditions at the uplinkground station, something that was
dramatically demonstrated on theevening of Sunday July 9, 2017.
It was a warm clear‑sky evening here
in southwest London, and while the
GEO management team were having
a Skype meeting I was simultaneously
watching EUMETCast imaging.
My SR1 SNR was at 13.1 dB at
18:00 UTC but I noticed that it slowly
began to deteriorate between 18:30
and 18:45. Strange, since it was stillclear sky outside.
The deterioration slowly but
relentlessly got worse, until at 19:39
UTC my SNR reading had fallen to
8.3 dB, still with clear sky conditions.
Looking at the Meteosat 10 IR
imaging and animation it was clearthat large storms had built up in
western Austria and were migrating
east, passing over the Aflenz ground22

station. These storms were severe,
producing very heavy rain and hail,and lasted a considerable time—seesequence of IR images for the area on
the following page.
I had never seen such a deep andprolonged reduction in received SNR
caused by rain‑fade at the uplinkstation since EUMETCast (Ku‑band)transmissions started. The severe
weather in Austria continued on
Monday, July 10 when a tornado
touched down near Vienna airportand some parts of eastern Austria had
hail stones the size of golf balls.
Aflenz is located on the southernflank of the Hochschwab massif,
the mountains in Europe with thelargest population of chamois. It issituated to the southwest of Vienna
in the Styria region. The Aflenz
Ground Station itself encompasses
more than 50 antennas. The largest
antenna weighs 275 tonnes and has adiameter of 32 metres, the equivalentof eight car lengths. Each antenna
is dedicated to a specific satellite,
which is responsible for transferring
www.geo-web.org.uk

data to a specific region of the globe.
All antennas send their data at
the speed of light to geostationary
satellites located 36,000 kilometresabove Earth’s equator, with data
racing across the universe at a speedof 300,000 km/sec. This allows forthe transmission of huge multimedia
data volumes across the globe within
fractions of a second; amongst others,
for the large Austrian customer, the
PCB manufacturer AT&S, whichneeds to communicate with its
business sites in China and India.
The Teleport Aflenz also enables thelive broadcasting of Austria’s world‑
renowned events such as the Vienna
New Year’s Concert, the Life Ball andthe Vienna Opera Ball to viewers
across the globe.
A photovoltaic park—A1 Earth
Station Aflenz—which was built in
2013, generates the electric power
for the satellite station at Aflenz.
This photovoltaic open-field plant
covers an area of 4,800 square
metres and encompasses a total of
790 photovoltaic modules. The park

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GEO Quarterly No 55

Meteosat 10 IR image at 18:00 UTC

Meteosat 10 IR image at 19:00 UTC

Meteosat 10 IR image at 20:00 UTC

Meteosat 10 IR image at 21:00 UTC

Meteosat 10 IR image at 22:00 UTC

Meteosat 10 IR image at 23:00 UTC

produces 190,000 kWh per year and the suppliedenergy is directly fed into the Aflenz Ground Station.
Thanks to this use of solar energy, it has been able
to reduce CO2 emissions by 90,000 kg per year. The
building, which was designed by the internationallyrenowned Vienna architect Gustav Peichl, is almost

invisibly integrated into the landscape and provides
space for state-of-the-art high-tech equipment
for ultra-fast data transmission over an area of
6,500 square metres. It is regarded as one of Austria’s
most successful architectonical achievements and hasreceived several architectural awards.

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September 2017

NASA Earth Observatory

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

On June 8, 2017, the Moderate Resolution
Imaging Spectroradiometer (MODIS) aboard
NASA’s Aqua satellite captured a stunning true‑
colour image of ice breakup in the Amundsen Gulf.
Sitting north of the Northwest Territory, Canada,
the Amundsen Gulf separates the mainland

24

from Banks Island (north) and Victoria Island(northeast). Frigid temperatures typically keep
the Gulf wearing a heavy coat of ice well into
July, with ice break‑up as late as August in someyears. Warm winter and spring temperatures havecontributed to substantial break up in early June
this year.

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GEO Quarterly No 55

NASA Earth Observatory
It is rare for satellites to get a clear view ofthe whole Antarctic Peninsula, one of thelargest contributors to sea level rise during
the past half‑century. In the winter, polar
darkness hides this rocky, ice‑covered
strip; in the summer, clouds usually block
the view. But every now and then, usuallyin January or February, the clouds break.
That is what happened on January 8,
2016, when the Moderate Resolution
Imaging Spectroradiometer (MODIS)on NASA’s Aqua satellite captured thisremarkably clear view of the peninsula.
The ice‑covered and mountainous
peninsula stretches 1,300 km into theSouthern Ocean. An arcing underwaterridge connects the tip of the peninsulawith several small islands (South Georgia,
South Sandwich, and South Orkney)then continues to Tierra del Fuego, thesouthernmost point of South America.
As with most of Antarctica, the feature that
dominates the peninsula and the ocean
surrounding it is ice: the glaciers and ice
sheets, the ice shelves, the icebergs andthe thin crust of sea ice that forms on theocean surface in cold weather. Just a few
percent of the peninsula’s land area is ice‑
free, and in some places the ice is as thickas 500 metres. The rare exposed areas(brown) are mainly isolated crags andmountain peaks—nunataks—that poke up
through the ice layer.
In recent decades, weather stations havemeasured ﬂuctuating temperatures on the
Antarctic Peninsula. Between 1951 and
2000, temperatures rose by 2.8°C, fasterthan anywhere else in the world. However,
air temperatures then began an equally
rapid swing in the opposite direction,
dropping by roughly 1°C between 2000
and 2014. Meanwhile, surrounding ocean
temperatures have been warming sincethe 1990s, particularly on the western sideof the peninsula opposite the Larsen C Ice
Shelf.

half‑century ago. Of these, 30 glaciers lost
more than ten square kilometres (km2)
of ice, 190 lost between one and ten
km2, and 558 glaciers lost 1 km2 or less.
Eighty‑two glaciers advanced, most byless than one kilometre.

While changing air temperatures may
have had some effects on the ice,scientists increasingly believe thatwarming waters have changed thepeninsula’s glaciers and ice shelves themost. Alison Cook and David Vaughanof the British Antarctic Survey analysedsatellite observations and aerial
photographs shot between the 1940s and2010 and found that, of the 860 glacierson the peninsula, 90 percent had retreatedsince they were first photographed a

A similar story has played out on the ice
shelves. Seven of the twelve ice shelves
along the coasts have become smaller
since 1960, with losses totalling more than
28,000 square kilometres in all. Larsen
A (3,736 km2 in the 1960s), Larsen B(11,958 km2 in the 1960s), and Wordie(1,917 km2 in the 1960s) have changed
the most, losing much of their ice. George
VI glacier has lost some ice, but it remains
about 92 percent of the size it was in1947. Larsen C has been relatively stable,
www.geo-web.org.uk

but is poised to calve an iceberg thesize of Delaware. Larsen D, which has
expanded by four percent, is the only ice
shelf that has grown larger over the past
50 years.
The Fleming, Hariot, and Prospectglaciers—which ﬂow off the peninsula
into Wordie Bay—retreated the most.
Hektoria, Crane, and Jorum—glaciers thatﬂow into the Larsen B embayment—havealso retreated significantly. All of these
glaciers saw rates of ice loss acceleratesignificantly when adjacent ice shelves,
which helped hold them in place, brokeup.
NASA Earth Observatory image by Jesse Allen,
using data from the Level 1 and Atmospheres Active
Distribution System (LAADS). Caption by Adam
Voiland25

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NASA Earth Observatory
Patagonia is one of the windiest and wettest
regions on Earth. Westerlies gain moisture andmomentum as they cross the Pacific Ocean,
and when they reach South America they rideover the Andes, through fjords, and across two
icefields. Having spent several field seasonson and around the South Patagonian Icefield,
glaciologist Michele Koppes of the Universityof British Columbia knows first-hand thechallenges posed by the elements.
‘The katabatic winds that drain down
the eastern slopes can pick you and yourheavy backpack right off your feet and turnyou over like a turtle,’ stated Koppes, aphenomenon she experienced a few times
while trying to reach glaciers in Torres delPaine and Los Glaciares National Park.
‘The winds can blow tents right off theirstakes and send them tumbling acrosslakes.’
And then there is the moisture to contend withtoo. Precipitation can be intense on the westside of the icefields, which receive up to four
metres of rain and snow per year; it is more
moderate in the east, which receives less than
one metre per year. Koppes has spent weeks at
a time waiting for weather clear enough for an
airplane to fly her to the glaciers to collect data.
She has met climbers huddled in tents for morethan a month on end waiting for a window of
weather favourable enough for ascending the
pinnacles on the icefield’s east side.

Figure 2 ‑ The Jorge Montt Glacier on April 29, 2016

Scientists endure these conditions in order togain better understanding of how and why thePatagonian icefields are shrinking.
‘The glaciers in this region are changing
rapidly,’ said Eric Rignot, a glaciologist atNASA’s Jet Propulsion Laboratory and the
University of California‑Irvine. ‘They are,in fact, melting away at some of the highest
rates on the planet. The reason is that they
are not only melting from the top becauseof warm air, but also from below, where
they come in contact with ocean and lakewaters.’Often shrouded in clouds and mist, the entiretyof the South Patagonian Icefield is rarely visible
from space. This mosaic shown in figure 1(previous page) combines cloud‑free images
acquired by the Operational Land Imager (OLI)
on the Landsat 8 satellite on April 29, May 1,
and May 24, 2016.
The North and South Patagonian icefields
are the remnants of a much more expansive
ice sheet that reached its maximum size

Figure 3 ‑ The Upsala Glacier on May 24, 2016www.geo-web.org.uk

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September 2017about 18,000 years ago. The
modern icefields are nowadays justa fraction of their original sizes,
though they remain the southernhemisphere’s largest expanses of ice
outside Antarctica. Today, the SouthPatagonian Icefield spans about
13,000 square kilometres, about fourtimes greater than the north icefield.
Its ice spreads across the border
between Chile and Argentina. (Thenorth icefield, in contrast, lies entirely
within Chile.)
The differences between the westernand eastern sides are clear to see in
figure 1 where the landscape west of
the icefield is much greener, driven by
the intense precipitation that drops
out of warm, wet Pacific air masses
as they ascend the mountains. Land
around the fjords support large trees
and lush forest cover.
‘The vegetation is so dense that
it is sometimes impossible topenetrate without a machete anda lot of patience,’ claims Koppes.
Many of the fjords are choked withicebergs, especially in front of Jorge
Montt. The presence of icebergs
indicates the rapid disintegration
and retreat of these glacier systems.
Ice becomes concentrated within
ten kilometres of the glacier fronts
due to shallow sills at the mouths ofthese fjords, which ground and trap
the larger bergs. Thick plumes in thefjords highlight the huge amount of
sediment that the glaciers erode as
they slide down toward the ocean.
In contrast, glaciers on the easternside of the icefield terminate in someof the largest proglacial lakes in
the world. The lakes are filled withso much fine sediment from theglaciers—known as glacial flour—that
their turquoise colour can be seenfrom space.
Detailed images provide a closer
look at some of the icefield’s largest,
most notable glaciers. Jorge Montt,
located on the north end of the SouthPatagonian Icefield, flows from south
to north, emptying into a fjord that
ultimately angles west toward thePacific Ocean. Since the mid 1980s,
the speed of ice flow has fluctuated,with particularly spectacular retreat
events documented in the 1990s. In
all, the glacier retreated 13 kilometres
between 1984 and 2014. Figure 2
shows the glacier’s former extent in
the 1980s, visible as the tan-grayarea devoid of vegetation around theice. This glacier has thinned andretreated so fast that vegetation has

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Figure 4 - Occidental and Greve glaciers on April 29, 2016

not yet had a chance to fill in. During
peak retreat, the glacier was thinning
vertically at a rate of 31 metres per
year.
‘When we flew over this glacierin 2014 to survey its thickness,’
Rignot recalled, ‘the airplane wasat an altitude that would have put
us inside the glacier in the 1980s.’
Upsala Glacier, on the eastern edge
if the icefield, and flowing into Lago
Argentino, is also among it’s largest
and longest glaciers (figure 3). Its
retreat has been ongoing since
the place was first documented in
1810. The light brown rock along
the glacier’s edge would have been
covered with ice in the 1980s.
Between 1985 and 2001, the glacier
doubled its speed, then slowed down,
and has since speeded up again.
Occidental, another of the larger
glaciers, has retreated less than its
neighbours—only about one kilometre
since the 1980s. It drains ice from abasin that spans almost the entire
icefield, the ice flowing via a deep
trough that extends below sea level(figure 4). Both Occidental, and Greve
Glacier to its southeast, flow along theflank of the active Lautaro volcano.
Bands of volcanic ash are visible atop
these glaciers at low elevation.
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Occidental sheds its icebergs into asmall, shallow proglacial lake where
they are trapped and then slowly melt
away. Greve also calves icebergs into ashallow lake, which is dammed to thesouth by Pío XI Glacier. According to
Rignot, there used to be a farm in thevalley in front of Greve, but he had tomove away when the valley became
blocked by the advance of Pío XI
which resulted in the formation of thelake. According to Koppes, the great
worry is that continuing addition ofwater to this ice-dammed lake willslowly cause the terminus of Pío XI tofloat, which may cause a catastrophic
outflow of water that would flood theneighbouring regions.
Meltwater from the Patagonian icefield
as a whole contributes to sea levelrise. The contribution is less thanthat which comes from Greenlandand Antarctica, but scientists plan
to keep studying the region fromspace, from the air, and on ground.
Understanding the evolution of these
glaciers helps to understand how
glaciers in Greenland and Antarctica
might look in a future, much warmer
climate.

NASA Earth Observatory images by Jesse Allen,
using Landsat data from the US Geological Survey.
Story by Kathryn Hansen.

This MODIS image of Hurricane Harvey making landfall near Houston, Texas was captured by NASA’s Aqua satellite on August 26, 2017.
Image: LANCE Rapid Response / NASA / GSFC

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NASA Earth Observatory

A combination of sunglint and cloud helped to create a stunning image of Hawaii in late July 2017. The Moderate Resolution Imaging
Spectroradiometer (MODIS) aboard NASA’s Aqua satellite acquired this true‑colour image on July 27.
Image Credit: Jeff Schmaltz, MODIS Land Rapid Response Team, NASA GSFC

The beautiful Hawaiian Islands are made up of eight majorislands stretching across almost 2,400 kilometres of the Pacific
Ocean. The rugged landscape of the islands was created byvolcanic activity over millions of years, with the oldest island,Oahu, estimated to have been created between 3.4 to 2.2
million years ago. The process continues to this day, with two
active volcanoes on Hawaii. Kilauea has been in continuous
eruption since 1983 while Maunaloa last erupted in 1984. Loihi,
an underwater volcano, has been intermittently pouring lava into
the ocean since 1996, a process that may ultimately result in thecreation of a new island.

tan or black rocky outcroppings, where rainfall is lower and lessvegetation grows.

From the lower right (southeast) to the upper left (northwest),
the islands visible in this image are the ‘Big Island’ (Hawaii),
Maui, Kahoolawe, Lanai, Molokai, Oahu, Kauai, and Niihau.
Clouds cover parts of each island, obscuring much of the green
vegetation from view. The visible landscape appears mostly dark

In this image, the water surfaces around the Hawaiian Islands
are roughened in varying patterns. Calmer waters on the leeward
sides of the islands, are indicated by brighter silver colour on thesouthwest side of most islands. In contrast, the cloud cover sits
primarily on the windward side of the islands.

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Sunglint occurs when light is reﬂected from waters of the surfaceof the ocean back towards the sensor, and it creates a silvery
appearance in true‑colour images. Sunglint reveals turbulencein the surface of the water. If the surface were perfectly smooth,
then—like a mirror—we would see the sun’s reﬂection as a large
circle. Because the surface water is rufﬂed and roughened due
to wave action, the reﬂection becomes scattered and softened,creating the silver‑coloured sunglint region.

www.geo-web.org.uk

Hurricane Irma was imaged by NASA’s Terra satellite as it approached Cuba on September 7, 2017
Image: LANCE Rapid Response / NASA / GSFC

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Hurricane Jose was imaged by NASA’s Terra satellite as it approached the Caribbean on September 7, 2017
Image: LANCE Rapid Response / NASA / GSFC

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The Group for Earth Observation

GEO Quarterly No 55

Enrico Gobbetti sent in this fascinating Meteor M2 image that he acquired at 09:43 UT
on September 10,2017, showing cloud vortices around the Canary Islands.

Using Facebook Intelligently
Les Hamilton
It’s well known that there is a vast quantity of ephemera, drivel
and downright trash peddled on Facebook. But the platform
does have its serious side, and many highly respectedorganisations now use Facebook to showcase theiractivities. The table below includes a list of sites that GEO
Members should find really interesting and informative.
I do not have a personal Facebook page myself, so to be able
to access sites of interest, I have created a ‘dummy’ Facebook
account, under an assumed name, and using a temporary email
address that I have since deactivated.
No-one can bombard me with trivia, nor try to ‘Friend’ me, as
my own name will not bring up a Facebook entry. Also, since I
have deactivated the email address, I do not get bombarded bymessages from Facebook.
Having accomplished this, I still need to use the email address
and username under which I created my ‘dummy’ account to sign
into Facebook before browsing the many interesting Facebook
Sites out there.
GEO Members are encouraged to post links to pages of interest
that fall under GEO’s umbrella of interest, on GEO’s own
Facebook page.

APT Grouphttps://www.facebook.com/groups/Satellite.apt.group/

EUMETSAT

https://www.facebook.com/eumetsat/

GEO

https://www.facebook.com/groupforearthobservation

ESA

https://www.facebook.com/EuropeanSpaceAgency

NASA

https://www.facebook.com/NASA/NASA Solar System

https://www.facebook.com/nasasolarsystem/

NOAA

https://www.facebook.com/NOAA/UK Space Agency

https://www.facebook.com/spacegovuk/

Werkgroep Kunstmanen

https://www.facebook.com/kunstmanen

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On July 16, 2017, NASA’s Terra satellite captured this image of a mid-latitude (extratropical) cyclone off the coast of Portugal. In the vicinity of
the Iberian Peninsula, these systems are relatively slow-moving and tend to be poorly developed in summer: they often form clouds without any
precipitation. In contrast, fast-moving systems dominate in winter when they are more developed and often linked to heavy rain and strong winds.
Image: LANCE Rapid Response/NASA/GSFC

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The Caribbean island of Barbuda was images by ESA’s Sentinel 2A satellite on August 30, 2017, prior to being struck by Hurricane Irma
Image: Modified Copernicus data © ESA / Sentinel (2017)www.geo-web.org.uk

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September 2017

The Group for Earth Observation

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September 2017