Close look at a crack on Larsen C

acquired November 10, 2016

From NASA 

In late August 2016, sunlight returned to the Antarctic Peninsula and unveiled a rift across the Larsen C Ice Shelf that had grown longer and deeper over the austral winter.
Satellites spotted it in natural-color imagery.

 Larsen Ice Shelf in the GeoGarage platform (NGA chart)

By November, the arrival of longer days and favorable weather made it possible for scientists to take a closer look.

 acquired November 10, 2016

These photographs show close and wide views of the rift from the vantage point of NASA’s DC-8 research aircraft.
NASA scientist John Sonntag snapped the photos on November 10, 2016, during an Operation IceBridge flight.
The mission, which makes airborne surveys of changes in polar ice, completed its eighth consecutive Antarctic deployment later that month.

 A NASA study says that Antarctica's Larsen Ice Shelf

is likely to disintegrate before the end of this decade.

The rift in Larsen C measures about 100 meters (300 feet) wide and cuts about half a kilometer (one-third of a mile) deep—completely through to the bottom of the ice shelf.
While the rift is long and growing longer, it does not yet reach across the entire shelf.
When that happens, Larsen C will shed an iceberg about the size of Delaware.

 Operation IceBridge, a NASA airborne survey of changes in polar ice, recently completed its eighth consecutive Antarctic deployment.

This page contains a wrapup video for the entire mission, as well as some footage over the Antarctic Peninsula's Larsen C Ice Shelf, and a few high definition still images.
One of this year’s missions flew over a massive rift in the Larsen C.

Ice shelves are the floating parts of ice streams and glaciers, and they buttress the grounded ice behind them; when ice shelves collapse, the ice behind accelerates toward the ocean, where it then adds to sea level rise.

Larsen C neighbors a smaller ice shelf that disintegrated in 2002 after developing a rift similar to the one now growing in Larsen C.
The IceBridge scientists measured the Larsen C fracture to be about 70 miles long, more than 300 feet wide and about a third of a mile deep.

The crack completely cuts through the ice shelf but it does not go all the way across it – once it does, it will produce an iceberg roughly the size of the state of Delaware.

Cracks and calving of ice from the front of an ice shelf are normal.
Shelves are fed by glaciers and ice streams coming from the interior of the continent.
They advance into the ocean until a calving event takes place.
The shelf front retreats and then advances again.
The whole cycle can occur over the span of a few decades.
But calving that happens faster than a shelf can re-advance can mean trouble for an ice shelf.
For example, large and frequent calving events at Larsen B preceded that shelf’s final period of rapid disintegration, which occurred in just six weeks in 2002.
Whether Larsen C will respond in a similar way remains to be seen, but that’s one reason why scientists plan to make observations before and after the next calving event.

Ice shelves float, so they do not directly contribute to sea level rise.
They are important, however, because they buttress land ice and keep it inland.
If a shelf disintegrates, glaciers that feed it can flow more quickly out to sea—a process that directly increases sea level.

Links :

• Washington Post : A widening 80 mile crack is threatening one of Antarctica’s biggest ice shelves
• Mashable : NASA photo reveals a startling 300-foot-wide rift in Antarctic Ice Shelf

Google unveils the most detailed view of Earth's changing oceans, seas, rivers and lakes

Over the past 32 years, 90,000 sq km of water have vanished. The drying up of the Aral Sea in Uzbekistan and Kazakhstan (pictured) accounts for the biggest loss
EC JRC/Google

From Wired by Victoria Woollaston

Google has partnered with the European Commission’s Joint Research Centre to produce the greatest views of water on the surface of Earth ever.

The images show changing water levels, and reveal some of the stories behind the changes from the past three decades to see how they "have shaped the world over time, in unprecedented detail."

Timelapse is a global, zoomable video that lets you see how the Earth has changed over the past 32 years. Explore the world through time at https://earthengine.google.com/timelapse.
Image credit: Landsat / Copernicus

The project took more than three years and involved thousands of computers downloading 1.8 petabytes of data from the USGS/NASA Landsat satellite program.
Each pixel in 3 million satellite images, going back to 1984, was analysed by an algorithm developed by the Joint Research Centre running on the Google Earth Engine platform.

Poyang Lake, Jiangxi China
EC JRC/Google 

More than 10 million hours of computing time was needed for this, roughly equivalent to a modern 2-core computer running day and night for 600 years.
From this, the researchers were able to establish that, over the past 32 years, 90,000 square kilometres of water - the equivalent of half of the lakes in Europe - have vanished, while 200,000 square kilometres of new, mostly man-made water bodies appeared.

The continuing drying up of the Aral Sea in Uzbekistan and Kazakhstan accounts for the biggest loss in the world.
Iran and Afghanistan lost over a half, Iraq over a third of its water area.

The research findings and the maps, published in the journal Nature, can be explored on the Global Surface Water Explorer site.
The data is also available in Google Earth Engine to help designers, engineers and other organisations research, use, and download.

The maps, statistics and stories, for example, can help global water security, agricultural planning, preparing for disasters, public health, climate research and so on.

The water research used the same engine recently involved in creating Google's fascinating Timelapse interactive map.

 

Timelapse was first released in 2013 and a recent update added four more years of satellite imagery, petabytes of new data and sharper photos than in any previous version.
Users can now explore Antartica’s shifting glaciers, Bangkok’s sprawling urban growth and the rapidly drying Aral Sea.

Links :

• The Guardian : Google's satellite timelapses show the inconvenient truth about our planet /  Google timelapse
• YouTube : videos
• Time : Google timelapse 2016 
• DailyMail : Watch Earth change eyes Google unveils stunning 3 decade timelapse planet

The climate-changing desert dust fertilising our oceans

Dust from western Africa in the centre of the picture, pushing across the Atlantic Ocean on easterly winds in June 2014.

NASA

From Leeds University

The way in which man-made acids in the atmosphere interact with the dust that nourishes our oceans has been quantified by scientists for the first time.

In an international study led by the University of Leeds, researchers have pinpointed how much phosphate “fertiliser” is released from dust depending on atmospheric acid levels.

 This portrait of global aerosols was produced by a Goddard Earth Observing System Model, Version 5 simulation at a 10-kilometer resolution.

Dust (red) is lifted from the surface, sea salt (blue) swirls inside cyclones, smoke (green) rises from fires, and sulfate particles (white) stream from volcanoes and fossil fuel emissions.

High-resolution global atmospheric modeling run on the Discover supercomputer at the NASA Center for Climate Simulation at Goddard Space Flight Center, Greenbelt, Maryland, provides a unique tool to study the role of weather in Earth's climate system.
Credit: William Putman, NASA/Goddard

Phosphorus is an essential nutrient for all life, and when it falls into the ocean, it acts as a fertiliser that stimulates the growth of phytoplankton and marine life.
The new study allows scientists to quantify exactly how much phosphate “fertiliser” is released from dust depending on atmospheric acid levels.

 Massive sandstorm blowing off the NW African desert (February 2000)

NASA

Dr Anthony Stockdale, from the School of Earth and Environment at Leeds, is lead author of the study.
He said: “The ability to quantify these processes will now allow models to predict how pollution on a global scale modulates the amount of fertiliser released in airborne dust before it falls into the oceans.
“Many regions of the globe are limited by the amount of phosphorous available, so pollution can have a very important impact on marine ecosystems.”

Fellow author Michael Krom, an Emeritus Professor from Leeds who is now at the University of Haifa, added: “If more carbon dioxide is taken up by marine plants due to fertilisation from acidified dust, it is possible that air pollution may have been inadvertently reducing the amount of greenhouse gases, while at the same time increasing the amount of plants and even fish in areas such as the Mediterranean Sea.”

Co-author Professor Athanasios Nenes, of Georgia Institute of Technology, said the implications went beyond the carbon cycle and climate.
“The Mediterranean is one of many locations of the globe where pollution and dust mix frequently,” he said.
“This study points to one more way this interaction can affect marine life and the 135 million inhabitants of its coastline.”

Professor Krom added: “The next step is to develop models which include this new pathway for increased plant growth in the ocean, in order to fully determine the effect on marine ecosystems and Earth’s climate, considering a full suite of chemical, physical and biochemical processes.”

 Satellite tracks Saharan dust to Amazon in 3-D

For the first time, a NASA satellite has quantified in three dimensions how much dust makes the trans-Atlantic journey from the Sahara Desert to the Amazon rainforest. Among this dust is phosphorus, an essential nutrient that acts like a fertilizer, which the Amazon depends on in order to flourish.
The new dust transport estimates were derived from data collected by a lidar instrument on NASA's Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation, or CALIPSO, satellite from 2007 though 2013.
An average of 27.7 million tons of dust per year – enough to fill 104,980 semi trucks – fall to the surface over the Amazon basin.

The phosphorus portion, an estimated 22,000 tons per year, is about the same amount as that lost from rain and flooding.

The finding is part of a bigger research effort to understand the role of dust and aerosols in the environment and on local and global climate.

NASA 

Apatite: the desert dust nourishing our seas 

Phosphorus is one of the essential elements for life and is a critical component of building blocks such as DNA.
Dusts, from deserts such as the Sahara, are an important source of phosphorus to Earth’s oceans.
The mineral-containing dust is generated in copious amounts during storms and is found throughout the atmosphere.
Most of the phosphorus in this dust is in an insoluble form that the microscopic plants of the oceans – phytoplankton and diatoms – cannot get at.
Known as apatite, the phosphorus in the dust is similar to the substance found in our teeth and bones.
Acids can be released naturally into the atmosphere from volcanic eruptions and from living organisms.

 Canary islands covered by dust (MODIS satellite image)

But the burning of fossil fuels is currently the most significant source of atmospheric acids.
In the same way that acid produced by the bacteria in our mouths can cause tooth decay, so can acids in the atmosphere dissolve apatite and turn it into a form of phosphorus that can be used by marine organisms, the study authors said.
As well as researchers from Leeds, Georgia and Haifa, experts from three institutions in Greece, one in Israel, one in Germany and two others in the UK worked on the findings, published today in Proceedings of the National Academy of Science of the USA. 

Links :

• PNAS : “Understanding the nature of atmospheric acid processing of mineral dusts in supplying bioavailable phosphorus to the oceans”
• NASA : Dust Over the Arabian Sea

Smyril

Smyril Line is a Faroese shipping company, linking the Faroe Islands with Denmark and Iceland; previously,
it also served Norway and the United Kingdom.

Smyril is the Faroese word for the merlin.

Invisible ocean: plankton & plastic

Invisible Ocean: Plankton & Plastic - Full Movie [HD] from BonSci Films

This movie, directed by Emily V. Driscoll, is an award-winning short documentary that follows NYC sci-artist Mara G. Haseltine as she creates a sculpture to reveal a microscopic threat beneath the surface of the ocean.

During a Tara Oceans expedition to study the health of the oceans, Haseltine finds an unsettling presence in samples of plankton she collected.

The discovery inspires her to create a sculpture that shows that the microscopic ocean world affects all life on Earth.

The film features Mara G. Haseltine, Christian Sardet (The Plankton Chronicles, TARA Oceans) and Mark Anthony Browne (Ecologist NCEAS).

Watch Mara G. Haseltine's art film featuring her sculpture and opera singer Joseph Bartning: La Boheme- A Portrait of Our Oceans in Peri