May 17, 2018, 07:29 PDT

Making a map of water and ice

By Ellen Gray,
NASA's Earth Science News Team

Hydrologist Matt Rodell at NASA's Goddard Spaceflight Center has been living with first-of-its-kind data from the Gravity Recovery and Climate Experiment (GRACE) for 16 years. That data shows big changes of mass in specific spots on Earth, primarily the result of the movement of water and ice, but it doesn’t tell them what causes those changes. That's where Matt and the GRACE team come in, painstakingly connecting these observed changes to the loss of ice sheets, depleting aquifers, and climate change. It's a problem they're still working on, getting closer every day. Matt explains the years-long process in his own words.

Matt Rodell
Matt Rodell is Chief of the Hydrological Sciences lab at NASA’s Goddard Space Flight Center in Greenbelt Maryland. Credit: Matt Rodell

Ominous beginning: Garbage data from a new satellite

Six months after GRACE launched in March 2002, we got our first look at the data fields. They had these big vertical, pole-to-pole stripes that obscured everything. We’re like, holy cow this is garbage. All this work and it’s going to be useless. But it didn’t take the science team long to realize that they could use some pretty common data filters to remove the noise, and after that they were able to clean up the fields and we could see quite a bit more of the signal. We definitely breathed a sigh of relief. Steadily over the course of the mission, the science team became better and better at processing the data, removing errors, and some of the features came into focus. Then it became clear that we could do useful things with it.

Steenstrup Glacier
In 2016, NASA’s Operation IceBridge took this picture of Greenland's Steenstrup Glacier. Credit: NASA/John Sonntag

And then trends emerged

It only took a couple of years. By 2004, 2005, the science team working on mass changes in the Arctic and Antarctic could see the ice sheet depletion of Greenland and Antarctica. We’d never been able before to get the total mass change of ice being lost. It was always the elevation changes – there’s this much ice, we guess – but this was like wow, this is the real number.

Not long after that we started to see, maybe, that there were some trends on the land, although it’s a little harder on the land because with terrestrial water storage — the groundwater, soil moisture, snow and everything – there’s inter-annual variability, so if you go from a drought one year to wet a couple years later, it will look like you’re gaining all this water, but really, it’s just natural variability.

But by around 2006, there was a pretty clear trend over Northern India. At the GRACE science team meeting, it turned out another group had noticed that as well. We were friendly with them, so we decided to work on it separately. Our research ended up being published in 2009, a couple years after the trends had started to become apparent. By the time we looked at India, we knew that there were other trends around the world. Slowly not just our team but all sorts of teams, all different scientists around the world, were looking at different apparent trends and diagnosing them and trying to decide if they were real and what was causing them.

Global freshwater map from 14 years of GRACE data
This map depicts a time series of data collected by NASA's Gravity Recovery and Climate Experiment (GRACE) mission from 2002 to 2016, showing where freshwater storage was higher (blue) or lower (red) than the average for the 14-year study period. Credit: NASA

A world of big blobs of red and blue

I think the map, the global trends map, is the key. By 2010 we were getting the broad-brush outline, and I wanted to tell a story about what is happening in that map. For me the easiest way was to just look at the data around the continents and talk about the major blobs of red or blue that you see and explain each one of them and not worry about what country it’s in or placing it in a climate region or whatever. We can just draw an outline around these big blobs. Water is being gained or lost. The possible explanations are not that difficult to understand. It’s just trying to figure out which one is right.

Not everywhere you see as red or blue on the map is a real trend. It could be natural variability in part of the cycle where freshwater is increasing or decreasing. But some of the blobs were real trends. If it’s lined up in a place where we know that there’s a lot of agriculture, that they’re using a lot of water for irrigation, there’s a good chance it’s a decreasing trend that’s caused by human-induced groundwater depletion.

And then, there's the question: are any of the changes related to climate change? There have been predictions of precipitation changes, that they’re going to get more precipitation in the high latitudes and more precipitation as rain as opposed to snow. Sometimes people say that the wet get wetter and the dry get dryer. That’s not always the case, but we’ve been looking for that sort of thing. These are large-scale features that are observed by a relatively new satellite system and we’re lucky enough to be some of the first to try and explain them.

Matt Rodell
Credit: NASA

What kept me up at night

The past couple years when I’d been working the most intensely on the map, the best parts of my time in the office were when I was working on it. Because I’m a lab chief, I spend about half my time on managerial and administrative things. But I love being able to do the science, and in particular this, looking at the GRACE data, trying to diagnose what’s happening, has been very enjoyable and fulfilling. We've been scrutinizing this map going on eight, nine years now, and I really do have a strong connection to it.

What kept me up at night was finding the right explanations and the evidence to support our hypotheses – or evidence to say that this hypothesis is wrong and we need to consider something else. In some cases, you have a strong feeling you know what’s happening but there’s no published paper or data that supports it. Or maybe there is anecdotal evidence or a map that corroborates what you think but is not enough to quantify it. So being able to come up with defendable explanations is what kept me up at night. I knew the reviewers, rightly, couldn’t let us just go and be completely speculative. We have to back up everything we say.

A view of California taken in 2014, showing impacts of drought season on the state.
A view of California taken in 2014, showing impacts of drought season on the state. Credit: NASA Earth Observatory

A tangled mix of answers

The world is a complicated place. I think it helped, in the end, that we categorized these changes as natural variability or as a direct human impact or a climate change related impact. But then there can be a mix of those – any of those three can be combined, and when they’re combined, that’s when it’s more difficult to disentangle them and say this one is dominant or whatever. It’s often not obvious. Because these are moving parts and particularly with the natural variability, you know it’s going to take another 15 years, probably the length of the GRACE Follow-On mission, before we become completely confident about some of these. So it’ll be interesting to return to this in 15 years and see which ones we got right and which ones we got wrong.

You can read about Matt’s research here: https://go.nasa.gov/2L7LXoP.

May 9, 2018, 17:38 PDT

Cloudy with a chance of chemistry

By Ellen Gray

The Atmospheric Tomography, or ATom, mission is investigating the atmosphere above the remote oceans. Above the Atlantic ocean near Ascension Island, the research team saw haze from African fires during ATom’s February, 2017, flight. Credit: NASA

The Atmospheric Tomography, or ATom, mission is investigating the atmosphere above the remote oceans. Above the Atlantic ocean near Ascension Island, the research team saw haze from African fires during ATom’s February, 2017, flight. Credit: NASA

The most important question at the daily briefing for NASA’s Atmospheric Tomography, or ATom, mission is: What are we flying through next?

For the 30 scientists plus aircraft crew loaded up on NASA’s DC-8 flying research laboratory on a 10-flight journey around the world to survey the gases and particles in the atmosphere, knowing what’s ahead isn’t just about avoiding turbulence. It’s also about collecting the best data they can as they travel from the Arctic to the tropics then to the Antarctic and back again.

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ATom’s flight path over the oceans. Credit: NASA

“ATom is all about the up and downs,” said Paul Newman, lead of the ATom science team and chief scientist for Earth Sciences at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The ups and downs he’s referring to are slow descents from 40,000 feet to 500 feet above the ocean so the researchers aboard can sample the atmosphere at all altitudes in between. That’s not a maneuver the pilots will do if they can’t see what’s below or ahead of them, but the measurements are why the team is out there.

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The DC-8 makes a series of dips to the surface during each leg of the flight to sample air at all altitudes. Credit: NASA

Which is why to find out what they might encounter and safely plan their flight path, it takes a team back home in their offices supporting them with freshly downloaded satellite data, updating forecasting models, an internet connection and phone. The pre-flight briefing takes place at 9 a.m. where the plane is, so for the forecasters calling in from Colorado, Virginia, and Maryland, it often means working late or early to brief the mission scientists and pilots at their hotel. And then when the flight takes off, one of them is in the plane’s private satellite chat room giving them live updates while the plane is in the air.

Weather is of course the big concern. The pilots of the DC-8, which in another life was a mid-sized passenger plane, need to know where the fair and foul weather is.

“Just cutting across the equator, what do you do?” Newman said. “You just fly through those thunderstorms? Or is it better to go west or east around a particular convective cell? You don’t want to get trapped. We don’t want to spend a lot of time flying through a thick cloud. It screws up your measurements, clogs up your air intakes. So with real-time meteorological support, it creates a level of comfort for the team and pilots to know that there won’t be any surprises.”

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View from the DC-8 above the Pacific Ocean, Feb. 2017. Credit: NASA/Róisín Commane

Weather isn’t the only forecast the team gets before and during the flight. They also get a forecast of the atmospheric chemistry. From supercomputers at Goddard, a computer simulation of Earth projects the paths of carbon monoxide plumes. Carbon monoxide is one of over 400 gases being measured aboard the DC-8, but since it’s the result of incomplete combustion, whether from cars, power plants, wild fires or agricultural fires, it’s one of the simplest for the computer to track. Like a weather forecast, the chemical forecast takes current satellite data of carbon monoxide and then uses winds and temperature to project where it will go into the future – and where the DC-8 aircraft might encounter it on flight day.

“It’s fun to see during the flight whether or not some of these forecasts are realized,” said Julie Nicely of the chemical forecast team. “The person who measures carbon monoxide, for instance, might get on the chat and say, ‘Oh, we just saw CO [carbon monoxide] rise right where you said it would!'” Where turns out to be the easier question to answer. How much of it there is and what other gases occur with and react with it to turn into other gases are much more difficult questions and are among the reasons ATom’s science team is flying through these plumes of pollution.

Carbon monoxide isn’t the only gas whose intermingling with other atmospheric chemistry is being studied. When Nicely’s not supporting ATom she’s researching the hydroxyl radical, a chemical that lasts for a fraction of a second before reacting with other gases in the constantly churning chemistry of the atmosphere. It’s impossible to simulate in the model at the moment, and ATom’s flights are the first time its concentration, along with hundreds of other gases, is being measured on a global scale.

What the science team learns from these flights will go toward not only understanding the chemistry along the strip of the ocean their plane flew over but also improving the atmospheric chemistry models that are a tool for looking at what’s happening across the entire globe.

This piece was originally published on the NASA Earth Expeditions blog.

May 7, 2018, 13:26 PDT

Spring has sprung in the Arctic Ocean

By Kathryn Hansen,
NASA's Earth Observatory

Spring has sprung in the Arctic Ocean

With springtime comes sunlight and warmth that advance the melting and breakup of Arctic sea ice. Varied patterns and textures appear across the icescape, and many are visible in this image, which was our Image of the Day on April 30. This satellite image includes the area photographed a day earlier by Operation IceBridge—the same photograph that sparked discussion on our blog and on news and social media about what might have caused the holes in the ice.

The holes were not a research focus of the mission; scientists were flying that day to measure the thickness of sea ice. Rather, as some scientists explain below, the holes were simply a sign of spring, and just one of the many interesting and photogenic sights seen from the aircraft in 10 years of research flights over the Arctic.

Nathan Kurtz, IceBridge project scientist

“The main purpose of these IceBridge flights is to measure the thickness of the sea ice. Ice thickness is an important factor which allows us to assess the health of the pack and its ability to survive the summer melt. It is also an important regulator in the exchange of energy and moisture between the ocean and the atmosphere.

“While on the flights, I’ll stare out the windows for hours looking at the surface. The movement of the ice leads to huge variability over small scales, with many interesting scenes and patterns visible and a variety of color shades. But there’s only so much that can be discerned with human eyes. That is why we have the sensitive instrument suite on the plane: to map the intricacies of the ice cover which may otherwise be invisible to us and to quantify parameters for scientific interpretation.”

Chris Shuman, UMBC glaciologist based at NASA’s Goddard Space Flight Center

“Well back into March, satellites show a whole series of relatively clear images over Mackenzie Bay, indicating lots of sunshine coming in. The ‘holes’ in the sea ice are just a sign of spring, augmented by some particular process—’submarine groundwater discharge,’ large mammals, algae growth, brine pockets draining, or something else entirely. Attributing any particular area of open water to a particular process is speculation. There is always a lot going on in the spring sea ice pack of the Beaufort Sea.”

John Sonntag, IceBridge mission scientist

“As scientists, we have the privilege of witnessing the beauty and mystery of the cryosphere firsthand, even as we work to collect that data. The Beaufort 'ice circles' were among those. We have heard a number of plausible explanations for those fascinating features. In a more personal sense, I have been genuinely gratified to see the high level of interest from the public in the ice circles. The public’s clear enthusiasm for the puzzles of nature matches my own. It’s why I like my job!”

This piece was originally published on the NASA Earth Observatory Earth Matters blog.

May 1, 2018, 13:28 PDT

Team Sea Ice or Team Land Ice?

By Linette Boisvert, Kangerlussuaq, Greenland 

Above Greenland, where land ice meets sea ice and some open water. Credit: NASA/Linette Boisvert

Above Greenland, where land ice meets sea ice and some open water. Credit: NASA/Linette Boisvert

Linette Boisvert is a sea ice scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and researcher with Operation IceBridge. The mission of Operation IceBridge, NASA’s longest-running airborne mission to monitor polar ice, is to collect data on changing polar land and sea ice and maintain continuity of measurements between ICESat missions.

For more about Operation IceBridge and to follow future campaigns, visit http://www.nasa.gov/icebridge.

I am lucky enough to get to travel to Kangerlussuaq—a small town on the southwestern coast of Greenland that means “big fjord” in the Kalaallisut language—to join NASA’s Operation IceBridge for the remainder of their Arctic spring campaign.

I landed in Kanger on the morning of Friday, April 20, after leaving Washington, D.C., Wednesday evening, flying and overnighting in Copenhagen, Denmark, and then taking an Air Greenland flight, crossing the Atlantic Ocean twice in less than 36 hours. (Fun Fact: Greenland is owned by Denmark, so flying through Copenhagen is the only way to get to Greenland commercially.) The flight was on an Airbus, which had a surprisingly large number of passengers aboard.

After landing I thought, hmm, why do all of these people want to go to Kanger? Kanger is a small, roughly 500-person town comprising buildings surrounding the airport. There is a grocery store, a coffee/ice cream shop that never appears to be open, a youth “jail” for all of Greenland, and a Thai restaurant that is known for its pizza. Odd.

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View of the town of Kanger from across the river. Credit: NASA/Linette Boisvert

Regardless, Kanger is pretty, being situated in the fjord valley with a river running through it, although currently it is frozen solid. It is also warmer here than I would have expected for Greenland, with highs in the upper 20’s to low 30’s. For the rest of the campaign, until May 4, I will be in Kanger, with the rest of my “OIB family,” as I call them, living in dorm-style housing and cooking family-style dinners together just about each night.

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Build your own pizza for dinner in our dorm-style housing in Kanger. Credit: NASA/Linette Boisvert

April 21 was our first science flight out of Kanger, and as with the rest of the flights from here, it was a land ice flight. Sidebar: I am a sea ice scientist and have never been on a land ice flight before. There is a friendly rivalry between the land ice and sea ice scientist community (go Team Sea Ice!), and it is clear here that I am the only sea ice fanatic aboard, so I get picked on a bit. For those of you who don’t know, sea ice is frozen seawater that floats around on the ocean, and land ice is snow that is compacted over many, many years and turns into ice and is located on the bedrock of Greenland. Sea ice = salty (good in a margarita), while land ice = fresh (good in a smoothie).

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NASA P-3 aircraft propellers outside the hangar in Kangerlussuaq, Greenland. Credit: NASA/Linette Boisvert
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Photo showing land ice (bottom left corner) flowing down through the channel in the (center), and sea ice (bottom right corner). Credit: NASA/Linette Boisvert

It is not surprising to say that they really wanted to convert me to Team Land Ice, and they couldn’t have chosen a more scenic flight for this attempt. The flight is named Geikie 02 and highlights eight glaciers on the Geikie Peninsula on the eastern coast of Greenland.

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Screen shot of the “Geikie 02” flight line mid-flight. Credit: NASA/Linette Boisvert

Glaciers are slow-moving rivers of ice, where land ice from the Greenland Ice Sheet is transported into the oceans or sea ice pack depending on location and time of year. As the ice gets forced into these channels and around bends, it cracks, making crevasses, similar looking to crocodile skin (or the skin on your elbow) at times.

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Crevassed land ice in the foreground and Greenland mountains behind. Photo credit: NASA/Linette Boisvert

These glaciers have carved out deep channels and fjords in the bedrock over time, making for awe-inspiring views and terrain, especially when you are flying in the P-3 plane at just 1500 feet. There were many times where I would look out the window and see mountains reaching high above us as we flew over the glaciers deep in the fjord valleys and other times where it felt as it we were just skimming the tops of the mountains. This is not something that normally happens on commercial airline flights and is not for the faint of heart, but it is spectacular to behold, and I felt truly lucky to be able to witness this magnificent place.

As we flew out of the fjord to where both land ice and land meets sea, I instantly became overjoyed to view the sea ice (go Team Sea Ice!): all thicknesses, broken up, ridged, consolidated and flooded along with numerous leads and icebergs, which are land ice deposited into the ocean from the glaciers. Sea ice on a land ice flight? I think I could get used to this.

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An iceberg surrounded by sea ice. Credit: NASA/Linette Boisvert
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Sea ice floes, openings, and leads. Photo credit: NASA/Linette Boisvert
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Where sea ice meets Greenland’s cliffs and mountains. Credit: NASA/Linette Boisvert

As we crossed the fjords and the sea ice, we noticed multiple polar bear tracks in the snow (likened to a “polar bear highway”), and multiple holes in the sea ice where seals will come out for air and rest. A few people even claimed they saw a polar bear running on the sea ice after being startled by our plane flying over, but I didn’t see it and I am skeptical. Another highlight of this flight was flying past Greenland’s tallest mountain, Gunnbjorn, which rises 12,000 feet, and the “Grand Canyon of Greenland” – the one not covered by kilometers of ice in the center of the ice sheet that data from a previous IceBridge campaign had recently discovered. Needless to say, I was glued to my window for the majority of this flight. These pictures just don’t do them justice.

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Flying in a fjord valley with the mountains above us. Credit: NASA/Linette Boisvert

Although this flight did not convert me to Team Land Ice, it did reiterate to me that all ice types matter, especially in the broader context of climate change, and it is the main reason for the IceBridge field campaign: to repeatedly gather data of both land and sea ice to determine where, how, and why both ice types are changing. Specifically, melting land ice flows into the ocean and contributes to global sea level rise, whereas the loss of sea ice affects ocean and atmospheric circulation patterns both locally and globally, reminding us that what happens in the Arctic doesn’t stay in the Arctic.

This piece was originally published on the NASA Earth Expeditions blog.

April 26, 2018, 07:49 PDT

See fifteen years of change in the Arctic

By Adam Voiland,
NASA's Earth Observatory

Remember the year 2000? Bill Clinton was president of the United States, Faith Hill and Santana topped Billboard music charts, and the world’s computers had just “survived” the Y2K bug. It also was the year that NASA’s Terra satellite began collecting images of Earth.

Eighteen years later, the versatile satellite — with five scientific sensors —is still operating. For all of that time, the satellite’s Moderate Resolution Imaging Spectroradiometer (MODIS) has been collecting daily data and imagery of the Arctic — and the rest of the planet, too.

If you knew where to look and were willing to wait patiently for file downloads, the images have always been available on specialized websites used by scientists. But there was no quick-and-easy way for the public to browse the imagery. With the recent addition of the full record of MODIS data into NASA’s Worldview browser, checking on what was happening anywhere in the world on any day since 2000 has gotten much easier.

Say you want to check on the weather in your hometown on the day you or your child was born. Just navigate to the date on Worldview, and make sure that the MODIS data layer is turned on. (In the image below, you can tell the Terra MODIS data layer is on because it is light gray.)

Worldview screenshot of first day Terra MODIS data were collected
This Worldview screenshot shows the first day that Terra MODIS collected data — February 24, 2000. The very first Terra scene showed northern Argentina and Chile. Credit: EOSDIS.

One of the things I love about having all this MODIS data at my fingertips is that it makes it possible to see the passage of relatively long periods of time in just a few minutes. Look, for instance, at the animation at the top of this page, generated by Delft University of Technology ice scientist Stef Lhermitte using Worldview.

Lhermitte summoned every natural-color MODIS image of the Arctic that Terra and Aqua (which also has a MODIS instrument) have collected since April 2003. The result — a product of 71,000 satellite overpasses — is a remarkable six-minute time capsule of swirling clouds, bursts of wildfire smoke, the comings and goings of snow, and the ebb and flow of sea ice.

Though beautiful, Lhermitte’s animation also has a troubling side to it. If you look carefully, you can see the downward trend in sea ice extent. Look, for instance, at mid-August and September 2012 — the period when Arctic sea ice extent hit a record-low minimum of 3.4 million square kilometers (1.3 million square miles). Between the heavy cloud cover, you will see lots of dark open water. Compare that to the same period in 2003, when the minimum extent was 6.2 million square kilometers (2.4 million square miles). Scientists attribute the loss of sea ice to global warming.

Arctic sea ice extent
NASA Earth Observatory chart by Joshua Stevens, using data from the National Snow and Ice Data Center.

Earth Matters had a conversation with Lhermitte to find why he made the clip and what stands out about it. MODIS images of notable events that Lhermitte mentioned are interspersed throughout the interview. All of the images come from the archives of NASA Earth Observatory, a website that was founded in 1999 in conjunction with the launch of Terra.

What prompted you to create this animation?

The extension of the MODIS record back to the beginning of the mission in the Worldview website triggered me to make the animation. As a remote sensing scientist, I often use Worldview to put things into context (e.g. for studying changes over ice sheets and glaciers). Previously, Worldview only had data until 2010.

What do you think are the most interesting events or patterns visible in the clip?

I think the strength of the video is that it contains so many of them, and it allows you to see them all in one video. The ones that are most striking to me are:

Barents Sea algal bloom
An Aqua MODIS image of an algal bloom in the Barents Sea on August 14, 2011. Image by Jeff Schmaltz, MODIS Rapid Response Team at NASA's Goddard Space Flight Center.
  • algal blooms in the Barents Sea
  • declining sea ice extent. You can see this both annually and over the longer term.
  • changing snow extent. You can see this each summer, especially over Canada and Siberia.
  • summer wildfire smoke in Canada (2004, 2005, 2009, 2014, 2017) and Russia (2006, 2011, 2012, 2013, 2014, 2016)
  • albedo reductions (reduction in brightness) over the Greenland Ice Sheet in 2010 and 2012 related to strong melt years.
  • overall eastward atmospheric circulation
  • the Grímsvötn ash plume (21 May 2011)

How did you make it? Was it difficult from a technical standpoint?

It was simple. I just downloaded the MODIS quicklook data from the Worldview archive using an automated script. Afterwards, I slightly modified the images for visualization purposes (e.g., overlaying country borders, clipping to a circular area). and stitched everything together in a video.

When you sit back and watch the whole video, how does it make you feel?

On the one hand, I am fascinated by the beauty and complexity of our planet. On the other hand, as a scientist, it makes me want to understand its processes even better. The video shows so many different processes at different scales, from natural processes (annual changes in snow cover and the Vatnajökull ash plume) to climate change related changes (e.g. the long term decrease in sea ice).

Grímsvötn Volcano eruption
Terra MODIS image of the eruption of Grímsvötn Volcano in Iceland on May 22, 2011. NASA image by Jeff Schmaltz, MODIS Rapid Response Team.

There are some gaps during the winter where the extent of the sea ice abruptly changes. Can you explain why?

I used the standard reflectance products, which show the reflected sunlight. I decided to leave all dates out where part of the Arctic is without sunlight during satellite overpasses (approximately 10:30 a.m. and 1:30 p.m. local time). The missing data due to the polar night are very prominent if you compile the complete record including winter months, and I did not want it to distract the viewer from the more subtle changes in the video.

Siberia smoke and fires
A Terra MODIS image of smoke and fires in Siberia on June 29, 2012. NASA image by Jeff Schmaltz, LANCE MODIS Rapid Response.

In the course of your day job as a scientist, do you use MODIS imagery? For what purpose?

Yes, as a polar remote sensing scientist, I tend to work with a range of satellite data sets. MODIS is a unique data product, given its global daily coverage and its long record. Besides the fact that I use MODIS frequently to monitor ice shelves and outlet glaciers, my colleagues and I use it to study snow and ice-albedo processes, snow cover in mountainous areas, vegetation recovery after wildfires, and ecosystem processes. One MODIS animation of ice calving from a glacier in Antarctica actually made it into the Washington Post recently.

This piece was originally published on the NASA Earth Observatory Earth Matters blog.

April 12, 2018, 14:49 PDT

Finding new ways to feed the world

By Adam Voiland,
NASA's Earth Observatory

Chart courtesy of IFPRI.

Chart courtesy of IFPRI.

If you take the long view, our world is much better fed than it used to be. In the 1970s, about one-third of people in developing countries were undernourished; today the number is 13 percent. Even as global population has increased, it has been a long time since the horrific famines that claimed 5 million lives or more in the Soviet Union, China, Europe, and India during the 20th Century.

However, serious food shortages remain a fact of life. Roughly 815 million people were undernourished in 2016, according to the UN Food and Agricultural Organization. That is an increase of 38 million people from 2015, making 2016 the first year in more than a decade that the world grew hungrier. The grim trend was driven largely by armed conflicts in South Sudan, Yemen, Nigeria, and Syria.

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Meanwhile, other problems loom. Climate change is already starting to exacerbate famines, as temperature and precipitation patterns shift. Many experts worry that food production systems may struggle to adapt in coming decades. Even if problems caused by climate change turn out to be modest, global populations are expected to increase to 10 billion people by 2050, and the demand for food will likely go up by 50 percent or more as people in the developing world increase their income and consume foods that require more resources to produce.

Solving global problems sometimes requires a global view, so NASA’s Applied Sciences Program is working to make sure the world’s food systems are ready for the future. Researchers and program managers have created an agency-wide initiative to put remote sensing data and knowledge into the hands of people who can advance agriculture and reduce world hunger.

Earth Matters sat down with Sean McCartney, the coordinator of NASA’s new Food Security Office, to learn more.

Earth Matters: How did NASA get involved with food security?

McCartney: People sometimes forget that NASA’s charter states that one of the agency’s key objectives is “the expansion of human knowledge of the Earth and of phenomena in the atmosphere and space.” There are currently around 20 Earth-observing satellites that collect data on the hydrosphere, biosphere, and atmosphere. NASA has been able to leverage this data through scientific analysis and modeling to better understand food systems on a global scale.

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Chart courtesy of NASA’s Earth Observing System Project Science Office.

The food security initiative is part of our Applied Sciences Program, which does outreach with end users and showcases Earth observations. Through this program, NASA began to work with the United Nations on Sustainable Development Goals (SGDs), a global effort to end poverty, protect the planet, and ensure prosperity for all. Some of the goals relate to water and food security, and NASA leadership believed that that was an area where Earth observations could really contribute. Getting involved with the SGDs dovetailed with the establishment of the Food Security Office.

How do satellites and Earth-observing data relate to the food situation on the ground?

We already do a lot with satellites to monitor major commodity crops like rice, maize, wheat, and soy. We can use satellites to help track key crop characteristics, such as the “greenness” of vegetation (NDVI), crop type, the acreage and distribution of crops, precipitation, soil moisture, evapotranspiration, and more. This sort of environmental data is incorporated into important crop assessment reports, such as the GEOGLAM Crop Monitor, a monthly bulletin on conditions for major crops around the world.

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Likewise, the U.S. Agency for International Development (USAID) uses satellite data as part of its Famine Early Warning Systems Network (FEWS NET), which produces frequent reports on food conditions in 34 of the most famine-prone countries in the world.

What we’re trying to do is optimize programs and tools like these — and develop others — and get them into the right hands at the right time. NASA assets help inform governments, NGOs, the private sector, and other stakeholders to anticipate and react to food shortages.

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Map courtesy of FEWS NET

What are the main priorities of the new office?

A lot of our efforts so far have been through the Earth Observations for Food Security and Agriculture Consortium (EOFSAC), a program led by the University of Maryland. It really is a multidisciplinary group, which is what makes the program so exciting. The consortium has roughly 40 partner organizations from government, NGOs, international organizations, universities, and the private sector all working together. You can see a full list of the partners here.

What is on the consortium’s agenda?

Partnering with both the private and public sector—for instance, USDA and USAID—is one focus. They are going to be looking at innovative ways where Earth observations can provide value to end users. That might involve working with the reinsurance industry to provide them with a broad view of crops or working with USDA’s National Agricultural Statistics Service to develop ways of incorporating more satellite data into their workflow.

What has the office done recently?

In February 2018, the consortium sponsored a workshop at the National Agricultural Library focusing on emerging technologies in Earth observations. Presenters highlighted several new sensors and data sets that are now being applied to agriculture — such as soil moisture, solar induced fluorescence, and satellite-derived precipitation. For a full account of the meeting, you can read the minutes here.

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Photo courtesy of EOFSAC

Is it looking at how climate change will affect food systems?

Yes. A lot of what the folks at NASA’s Goddard Institute for Space Studies are doing is modeling that assimilates Earth observations into long-term forecasts. They’re studying how climate change will affect crop productivity in the future. There’s an international effort called the Agricultural Model Intercomparison Project (AGMIP) that is focused on this and is a rich source of information.

How would you say the world is doing in regards to food security?

It really depends on the country. If you look at overall food production, even in countries that are in need, they might be producing adequate food, but they don’t have access to markets, so they can’t get that food to people before it spoils.

Is it possible to follow some of these organizations and projects on social media?

Yes, check out @EOFSAC, @GEOCropMonitor, @FEWSNET, @G20_GEOGLAM, and @AgMIPnews.

This piece was originally published on NASA Earth Observatory's Earth Matters blog.

April 3, 2018, 06:36 PDT

A is for aerosol

By Adam Voiland,
NASA's Earth Observatory

A smoke plume spans the United States. NASA Earth Observatory image by Jesse Allen, using VIIRS data from the Suomi National Polar-orbiting Partnership.

A smoke plume spans the United States. NASA Earth Observatory image by Jesse Allen, using VIIRS data from the Suomi National Polar-orbiting Partnership.

Aerosol: A collection of microscopic particles, solid or liquid, suspended in a gas. They drift in Earth’s atmosphere from the stratosphere to the surface and range in size from a few nanometers—less than the width of the smallest viruses—to several several tens of micrometers—about the diameter of human hair. Despite their small size, they have major impacts on climate and health.

Different specialists describe the particles based on shape, size, and chemical composition. Toxicologists refer to aerosols as ultrafine, fine, or coarse matter. Regulatory agencies, as well as meteorologists, typically call them particulate matter—PM2.5 or PM10, depending on their size. In some fields of engineering, they’re called nanoparticles. Everyday terms that hint at aerosol sources, such as smoke, ash, haze, dust, pollution, and soot are widely used as well.

Climatologists typically use another set of labels that speak to the chemical composition. Key aerosol groups include sulfates, organic carbon, black carbon, nitrates, mineral dust, and sea salt. In practice, many of these terms are imperfect, as aerosols often clump together to form complex mixtures. It’s common, for example, for particles of black carbon from soot or smoke to mix with nitrates and sulfates, or to coat the surfaces of dust, creating hybrid particles.

Satellite imagery of aerosols:

NASA Earth Observatory image by Joshua Stevens, using Landsat data from the U.S. Geological Survey.
NASA Earth Observatory image by Joshua Stevens, using Landsat data from the U.S. Geological Survey.
NASA images by Jeff Schmaltz and Joshua Stevens, using MODIS data from LANCE/EOSDIS Rapid Response.
NASA images by Jeff Schmaltz and Joshua Stevens, using MODIS data from LANCE/EOSDIS Rapid Response.
Smoke and haze in the Indo-Gangetic Plain. (NASA Earth Observatory image by Joshua Stevens, using data from the Land Atmosphere Near real-time Capability for EOS.)
Smoke and haze in the Indo-Gangetic Plain. NASA Earth Observatory image by Joshua Stevens, using data from the Land Atmosphere Near real-time Capability for EOS.

Aerosols in the news:

Air Quality Suffering in China, NASA Earth Observatory
Tracking Dust Across the Atlantic, NASA Earth Observatory

Where to learn more:

Tiny Particles, Big Impact
Aerosols as explained by the IPCC
Aerosols and Climate Change

Read the alphabet from space

A is for aerosols altering an astronaut’s view of an ancient assemblage of rock in a state adjacent to Arizona!

About this glossary

There are other glossaries out there, but there aren’t many visual earth science glossaries, particularly those with a focus on satellite imagery. To fill that gap, Earth Matters is working on building its own. Have suggestions for what we should include? Comment on a post or send us an email.

This piece was originally published on NASA Earth Observatory's Earth Matters blog.

February 20, 2018, 10:05 PST

What climate change means for glaciers, storms, fires, clouds and more

By Adam Voiland,
NASA's Earth Observatory

What climate change means for glaciers, storms, fires, clouds and more

NASA Earth Observatory readers may recognize this image of a long trail of clouds — an atmospheric river — reaching across the Pacific Ocean toward California. It appeared first as an Image of the Day about how these moisture superhighways fueled a series of drought-busting rain and snow storms.

More recently, we were pleased to see that image on the cover of the Fourth National Climate Assessment — a major report issued by the U.S. Global Research Program. That image was one of many from Earth Observatory that appeared in the report. Since the authors did not give much background about the images, here is a quick rundown of how they were created and how they fit with some of the key points on our changing climate.


Hurricanes in the Atlantic

Found in Chapter 1: Our Globally Changing Climate

Hurricane

What the image shows:
Three hurricanes — Katia, Irma, and Jose — marching across the Atlantic Ocean on September 6, 2017.

What the report says about tropical cyclones and climate change:
The frequency of the most intense hurricanes is projected to increase in the Atlantic and the eastern North Pacific. Sea level rise will increase the frequency and extent of extreme flooding associated with coastal storms, such as hurricanes.

How the image was made:
The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite collected the data. Earth Observatory staff combined several scenes, taken at different times, to create this composite. Original source of the image: Three Hurricanes in the Atlantic


The North Pole

Found in Chapter 2: Physical Drivers of Climate Change

North Pole

What the image shows:
Clouds swirl over sea ice, glaciers, and green vegetation in the Northern Hemisphere, as seen on a spring day from an angle of 70 degrees North, 60 degrees East.

What the report says about climate change and the Arctic:
Over the past 50 years, near-surface air temperatures across Alaska and the Arctic have increased at a rate more than twice as fast as the global average. It is very likely that human activities have contributed to observed Arctic warming, sea ice loss, glacier mass loss, and a decline in snow extent in the Northern Hemisphere.

How it was made:
Ocean scientist Norman Kuring of NASA’s Goddard Space Flight Center pieced together this composite based on 15 satellite passes made by VIIRS/Suomi NPP on May 26, 2012. The spacecraft circles the Earth from pole to pole, so it took multiple passes to gather enough data to show an entire hemisphere without gaps. Original source of the image: The View from the Top


Columbia Glacier

Found in Chapter 3: Detection and Attribution of Climate Change

Columbia glacier

What the image shows:
Columbia Glacier in Alaska, one of the most rapidly changing glaciers in the world.

What the report says about Alaskan glaciers and climate change:
The collective ice mass of all Arctic glaciers has decreased every year since 1984, with significant losses in Alaska.

How the image was made:
NASA Earth Observatory visualizers made this false-color image based on data collected in 1986 by the Thematic Mapper on Landsat 5. The image combines shortwave-infrared, near-infrared, and green portions of the electromagnetic spectrum. With this combination, snow and ice appears bright cyan, vegetation is green, clouds are white or light orange, and open water is dark blue. Exposed bedrock is brown, while rocky debris on the glacier’s surface is gray. Original source of the image: World of Change: Columbia Glacier


Cloud streets

Found in Intro to Chapter 4: Climate Models, Scenarios, and Projections

Cloud streets

What the image shows:
Sea ice hugging the Russian coastline and cloud streets streaming over the Bering Sea.

What the report says about clouds and climate change:
Climate feedbacks are the largest source of uncertainty in quantifying climate sensitivity — that is, how much global temperatures will change in response to the addition of more greenhouse gases to the atmosphere.

How it was made:
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image on January 4, 2012. The LANCE/EOSDIS MODIS Rapid Response Team generated the image, and NASA Earth Observatory staff cropped and labeled it. Original source of the image: Cloud streets over the Bering Sea


Extratropical cyclones

Found in Intro to Chapter 5: Large-scale circulation and climate variability

Extratropical

What it shows:
Two extratropical cyclones, the cause of most winter storms, churned near each other off the coast of South Africa in 2009.

What the report says about extratropical storms and climate change:
There is uncertainty about future changes in winter extratropical cyclones. Activity is projected to change in complex ways, with increases in some regions and seasons and decreases in others. There has been a trend toward earlier snowmelt and a decrease in snowstorm frequency on the southern margins of snowy areas. Winter storm tracks have shifted northward since 1950 over the Northern Hemisphere.

How the image was made:
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image. The LANCE/EOSDIS MODIS Rapid Response Team generated the image and NASA Earth Observatory staff cropped and labeled it. Original source of the image: Cyclonic Clouds over the South Atlantic Ocean


Sea of sand

Found in Chapter 6: Temperature Changes in the United States

Sea of sand

What the image shows: Large, linear sand dunes alternating with interdune salt flats in the Rub’ al Khali in the Sultanate of Oman.

What the report says about drought, dust storms, and climate change:
The human effect on droughts is complicated. There is little evidence for a human influence on precipitation deficits, but a lot of evidence for a human fingerprint on surface soil moisture deficits — starting with increased evapotranspiration caused by higher temperatures. Decreases in surface soil moisture over most of the United States are likely as the climate warms. Assuming no change to current water resources management, chronic hydrological drought is increasingly possible by the end of the 21st century. Changes in drought frequency or intensity will also play an important role in the strength and frequency of dust storms.

How it was made: An astronaut on the International Space Station took the photograph with a Nikon D3S digital camera using a 200 millimeter lens on May 16, 2011. Original source of the image: Ar Rub’ al Khali Sand Sea, Arabian Peninsula


Flooding on the Missouri River

Found in Chapter 7: Precipitation Change in the United States

Flooding

What the image shows:
Sediment-rich flood water lingering on the Missouri River in July 2011.

What the report says about precipitation, floods, and climate change:
Detectable changes in flood frequency have occurred in parts of the United States, with a mix of increases and decreases in different regions. Extreme precipitation, one of the controlling factors in flood statistics, is observed to have generally increased and is projected to continue to do. However, scientists have not yet established a significant connection between increased river flooding and human-induced climate change.

How the image was made:
The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured the data for this natural-color image. NASA Earth Observatory staff processed, cropped, and labeled the image. Original source of the image: Flooding near Hamburg, Iowa


Smoke and fire

Found in Chapter 8: Droughts, Floods, and Wildfires

Smoke

What the image shows:
Smoke streaming from the Freeway fire in the Los Angeles metro area on November 16, 2008.

What the report says about wildfires and climate change:
The incidence of large forest fires in the western United States and Alaska has increased since the early 1980s and is projected to further increase as the climate warms, with profound changes to certain ecosystems. However, other factors related to climate change — such as water scarcity or insect infestations — may act to stifle future forest fire activity by reducing growth or otherwise killing trees.

How it was made: The MODIS Rapid Response Team made this image based on data collected by NASA’s Aqua satellite. Original source of the image: Fires in California


The Colorado River and Grand Canyon

Found in Chapter 10: Changes in Land Cover and Terrestrial Biogeochemistry

Canyon

What the image shows:
The Grand Canyon in northern Arizona.

What the report says about climate change and the Colorado River:
The southwestern United States is projected to experience significant decreases in surface water availability, leading to runoff decreases in California, Nevada, Texas, and the Colorado River headwaters, even in the near term. Several studies focused on the Colorado River basin showed that annual runoff reductions in a warmer western U.S. climate occur through a combination of evapotranspiration increases and precipitation decreases, with the overall reduction in river flow exacerbated by human demands on the water supply.

How the image was made:
On July 14, 2011, the ASTER sensor on NASA’s Terra spacecraft collected the data used in this 3D image. NASA Earth Observatory staff made the image by draping an ASTER image over a digital elevation model produced from ASTER stereo data. Original source of the image: Grand New View of the Grand Canyon


Arctic sea ice

Found in Chapter 11: Arctic Changes and their Effects on Alaska and the Rest of the United States

Sea ice

What the image shows: A clear view of the Arctic in June 2010. Clouds swirl over sea ice, snow, and forests in the far north.

What the report says about sea ice and climate change: Since the early 1980s, annual average Arctic sea ice has decreased in extent between 3.5 percent and 4.1 percent per decade, become 4.3 to 7.5 feet (1.3 and 2.3 meters) thinner. The ice melts for at least 15 more days each year. Arctic-wide ice loss is expected to continue through the 21st century, very likely resulting in nearly sea ice-free late summers by the 2040s.

How it was made: Earth Observatory staff used data from several MODIS passes from NASA’s Aqua satellite to make this mosaic. All of the data were collected on June 28, 2010. Original source of the image: Sunny Skies Over the Arctic


Crack in the Larsen C Ice Shelf

Found in Chapter 12: Sea Level Rise

Larsen

What the image shows:
This photograph shows a rift in the Larsen C Ice Shelf as observed from NASA’s DC-8 research aircraft. An iceberg the size of Delaware broke off from the ice shelf in 2017.

What the report says about ice shelves in Antarctica and climate change?
Floating ice shelves around Antarctica are losing mass at an accelerating rate. Mass loss from floating ice shelves does not directly affect global mean sea level — because that ice is already in the water — but it does lead to the faster flow of land ice into the ocean.

How it was made:
NASA scientist John Sonntag took the photo on November 10, 2016, during an Operation IceBridge flight. Original source of the image: Crack on Larsen C


The Gulf of Mexico

Found in Chapter 13: Ocean Acidification and Other Changes

Gulf

What the image shows:
Suspended sediment in shallow coastal waters in the Gulf of Mexico near Louisiana.

What the report says about the Gulf of Mexico:
The western Gulf of Mexico and parts of the U.S. Atlantic Coast (south of New York) are currently experiencing significant sea level rise caused by the withdrawal of groundwater and fossil fuels. Continuation of these practices will further amplify sea level rise.

How the image was made:
The MODIS instrument on NASA’s Aqua satellite captured this natural-color image on November 10, 2009. Original source of the image: Sediment in the Gulf of Mexico


Farmland in Virginia

Found in Appendix D

Farmland

What the image shows:
A fall scene showing farmland in the Page Valley of Virginia, between Shenandoah National Park and Massanutten Mountain.

What the report says about farming and climate change:
Since 1901, the consecutive number of frost-free days and the length of the growing season have increased for the seven contiguous U.S. regions used in this assessment. However, there is important variability at smaller scales, with some locations actually showing decreases of a few days to as much as one to two weeks. However, plant productivity has not increased, and future consequences of the longer growing season are uncertain.

How the image was made: On October 21, 2013, the Operational Land Imager (OLI) on Landsat 8 captured a natural-color image of these neighboring ridges. The Landsat image has been draped over a digital elevation model based on data from the ASTER sensor on the Terra satellite. Original source of the image: Contrasting Ridges in Virginia


Atmospheric river

Found on the Cover and Executive Summary

Ar2

What the image shows: A tight arc of clouds stretching from Hawaii to California, which is a visible manifestation of an atmospheric river of moisture flowing into western states.

What the report says about atmospheric rivers and climate change:
The frequency and severity of land-falling atmospheric rivers on the U.S. West Coast will increase as a result of increasing evaporation and the higher atmospheric water vapor content that occurs with increasing temperature. Atmospheric rivers are narrow streams of moisture that account for 30 to 40 percent of the typical snow pack and annual precipitation along the Pacific Coast and are associated with severe flooding events.

How it was made: On February 20, 2017, the VIIRS on Suomi NPP captured this natural-color image of conditions over the northeastern Pacific. NASA Earth Observatory data visualizers stitched together two scenes to make the image. Original source of the image: River in the Sky Keeps Flowing Over the West

This piece was originally published on NASA Earth Observatory's Earth Matters blog.

February 7, 2018, 09:46 PST

What caused twin mega-avalanches in Tibet?

By Adam Voiland,
NASA's Earth Observatory

NASA Earth Observatory image by Joshua Stevens, using modified Copernicus Sentinel 2 data processed by the European Space Agency. Image collected on July 21, 2016.

NASA Earth Observatory image by Joshua Stevens, using modified Copernicus Sentinel 2 data processed by the European Space Agency. Image collected on July 21, 2016.

In July 2016, the lower portion of a valley glacier in the Aru Range of Tibet detached and barreled into a nearby valley, killing nine people and hundreds of animals. The huge avalanche, one of the largest scientists had ever seen, sent a tongue of debris spreading across 9 square kilometers (3 square miles). With debris reaching speeds of 140 kilometers (90 miles) per hour, the avalanche was remarkably fast for its size.

Researchers were initially baffled about how it had happened. The glacier was on a nearly flat slope that was too shallow to cause avalanches, especially fast-moving ones. What’s more, the collapse happened at an elevation where permafrost was widespread; it should have securely anchored the glacier to the surface.

Two months later, it happened again — this time to a glacier just a few kilometers away. One gigantic avalanche was unusual; two in a row was unprecedented. The second collapse raised even more questions. Had an earthquake played a role in triggering them? Did climate change play a role? Should we expect more of these mega-avalanches?

Two avalanches
NASA Earth Observatory image by Joshua Stevens and Jesse Allen, using ASTER data from NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Image collected on October 4, 2016.

Now scientists have answers about how these unusual avalanches happened. There were four factors that came together and triggered the collapses, an international team of researchers reported in Nature Geoscience. The scientists analyzed many types of satellite, meteorological, and seismic data to reach their conclusions. They also sent teams of researchers to investigate the avalanches in the field.

First, increasing snowfall since the mid-1990s caused snow to pile up and start working its way toward the front edge of the glaciers (a process known as surging). Second, a great deal of rain fell in the summer of 2016. As a result, water worked its way through crevasses on the surface and lubricated the undersides of the glaciers. Third, water pooled up underneath the glaciers, even as the edges remained frozen to the ground. Fourth, the glaciers sat on a fine-grained layer of siltstone and clay that became extremely slippery.

Silt and clay in the first avalanche's path
Notice the large amounts of silt and clay in the path of the first avalanche. Photo taken on July 15, 2017, by Adrien Gilbert/University of Oslo.

Earth Observatory checked in with Andreas Kääb (University of Oslo), lead author of the study, to find out more about how the avalanche happened and what it means.

These glaciers were not on a steep slope, but the avalanche moved quite quickly. How did that happen?
Strong resistance by the frozen margins and tongues of the glaciers allowed the pressure to build instead of enabling them to adjust. The glaciers were loading up more and more pressure until the frozen margins suddenly failed. Local people reported a load bang. Once the margins failed, there was nothing at the glacier bed to hold it back, just water-soaked clay.

Your study notes that there was “undestroyed grassy vegetation on the lee side of the hills, suggesting that the fast-moving mass had partially jumped over it.” Are you saying the avalanche was airborne? If so, is that unusual?
Yes, for a small part of the avalanche path. We see this for other large-volume, high-speed avalanches, and it really illustrates the massive amount of energy released. You need quite high speeds in order for debris to jump. For us, the phenomenon is important as validation for the speeds obtained from the seismic signals the avalanches triggered and the avalanche modeling that we did.

Would you say these collapses were a product of climate change?
Climate change was necessary, but other factors that had nothing to do with climate were also critical. The increasing mass of the glaciers since the 1990s and the heavy rains and meltwater in 2016 are connected to climate change. The type of bedrock and the way the edges were frozen to the ground had nothing to do with climate change.

Can we expect to see more big glacial collapses as the world gets warmer?
It’s not clear. Climate change could increase or, maybe even more likely, decrease the probability of such massive collapses. Most glaciers on Earth are actually losing mass (not gaining, like the two glaciers in Tibet were). Also, if permafrost becomes less widespread over time and glacier margins melt, it is less likely that pressure will build up in that way that it did in this case.

I know you used several types of satellite data as part of this analysis. Can you mention a few that yielded particularly useful information?
We used a lot of different sources of data: Sentinel 1 and 2, TerraSAR-X/TanDEM-X, Planet Labs, and DigitalGlobe WorldView. Landsat 8 was absolutely critical because it gave the first and critical indication of the soft-bed characteristics. The entire Landsat series was instrumental for checking the glacier history since the 1980s. We also used declassified Corona data back to the 1960s.

Are these sorts of avalanches likely to happen in other parts of the world?
Honestly, I have no clue at the moment, but we would be much less surprised next time. We know now that this type of collapse can happen under special circumstances. (It happened once before in the Caucasus at Kolka Glacier.) One thing that should be investigated is whether there are other glaciers—especially polythermal ones—with these very fine-grained materials underneath them.

3D image of the avalanches
Three dimensional CNES Pléiades image of the avalanches. Processed by Etienne Berthier. Via Twitter.

This piece was originally published on NASA Earth Observatory's Earth Matters blog.

November 8, 2017, 07:13 PST

ACT-America: Settling into the rhythm of the field

By Hannah Halliday / SHREVEPORT, LOUISIANA

A C-130 gets a checkup after a flight. A dedicated flight team keeps the aircraft running and maintained. Credit: NASA/Hannah Halliday.

A C-130 gets a checkup after a flight. A dedicated flight team keeps the aircraft running and maintained. Credit: NASA/Hannah Halliday.

Fieldwork is my favorite part of my job. I have been working as a postdoc at NASA’s Langley Research Center in Hampton, Virginia, for a few days over a year, and I’m still not over the excitement of arriving somewhere new, ready to take measurements and run our instruments.

My background is in chemistry, but I slid into meteorology because I wanted to apply myself to environmental issues that had global impact. That decision put me on a path into the world of air quality research, and ultimately to NASA to work with airborne science. While I’m still new to flying for science, I love working with instruments and taking measurements. Being on an aircraft turns that feeling up to 11.

plane view
The C-130 doesn’t have many windows, but Halliday is lucky to have one beside her seat. Flights often have low-altitude runs, and offer views of the country from unique angles. This is a view of the Mississippi River from the Sunday, Nov. 5, flight. Credit: NASA/Hannah Halliday.

Atmospheric Carbon and Transport-America, or ACT-AMERICA, has been an especially cool project to be involved with because I earned my Ph.D. at Penn State, where principal investigator Ken Davis and other members of the ACT-AMERICA planning team are based. Working with ACT-AMERICA is part serious work and part fun reunion, working with people I know well on a totally new subject and project. I got to fly with the mission last spring, and I’ve come back to join them again for two weeks in Shreveport, Louisiana.

On Saturday, Nov. 4, we took a break from flying to do instrument work and maintenance. For my group, which is tasked with the Atmospheric Vertical Observations of CO2 in the Earth’s Troposphere, or AVOCET, in-situ measurements, that meant calibrating our instruments. When we calibrate, we send our instruments gases that have a known concentration and record what our instruments measure. Doing this regularly allows us to keep track and correct for the instrument drifting over time, and to maintain the accuracy and precision of our measurements.

Our two aircraft, a C-130 and a B-200, are stored in different locations when we’re at our ground sites. The calibration gas tanks are heavy, so for ease of use we’ve built our calibration gas cylinders their own little cart that they live on, which can be towed from one location to another. The cylinders are left on the cart, where we put a regulator on the calibration cylinder we want to use and run a tube into the airplane. It’s a simple solution that lets us easily and quickly use the same calibration gases on two different aircraft.

Hannah Halliday monitors incoming measurements.
Hannah Halliday, right, monitors incoming AVOCET measurements during a Nov. 2 science flight. Next to her are Theresa Klausner and Max Eckle, Ph.D. students with the German Aerospace Center, DLR, which has joined the fall flight campaign to test an instrument that measures methane and ethane. Credit: NASA/David C. Bowman.
Researchers talk during a flight.
Bianca Baier, a postdoctoral researcher with NOAA’s Earth Systems Research Lab in Boulder, Colorado, and Ken Davis, ACT-America principal investigator from Penn State, talk during a flight. Credit: NASA/David C. Bowman.

One of the reasons I love working in science is that our measurements and our work is built on a heap of clever solutions to small problems. While we also stand on the shoulders of scientific giants who had deep insights into the workings of the universe (for instance, Isaac Newton realizing that the gravity affecting an apple also affects the stars), in our day-to-day work we use the cleverness of the people who worked out the universal swage fittings, or the person who figured out how to set up our inlet system to bring air in from outside the plane when we’re at high altitude.

Calibration gas cylinders
Calibration gas cylinders on their transportation cart. During a calibration, scientists use three gases with low, middle and high concentrations, and use this information to understand how the instrument will behave when it “sees” gases in the environment. Credit: NASA/Hannah Halliday.

We’re not all brilliant all the time, but by looking at a problem long enough we can often find a clever solution to a small vexing problem (such as how to quickly transport our calibration cylinders), and that’s where our progress comes from.

On Sunday, Nov. 5, we flew a science mission, measuring the inflow of air from the Gulf of Mexico. It was a busy day for me, because I was both tending my group’s instruments and also taking flask samples for the National Oceanic and Atmospheric Administration (NOAA). NOAA uses glass-lined containers to trap air at specific locations on the flight track. They take these samples back to their lab in Boulder, Colorado, where they measure the greenhouse gases as well as other molecules that help determine whether samples were influenced by other sources, such as traffic or wildfires. My job was to follow their sampling plan, telling their mostly automated system when to collect a sample and coordinating with our in-flight calibrations.

Specialized inlets draw air into the instruments and have different designs based on the needs of the instruments.
Specialized inlets draw air into the instruments and have different designs based on the needs of the instruments. These inlets are located near the front of the aircraft so they don’t sample the exhaust from the engines. Credit: NASA/David C. Bowman.

The flights can be quite busy, and it’s a full day of activity. For the four to five hours that a typical science flight will last, we have an additional three hours of flight prep before we take off, and a debriefing meeting once we land, plus data workup and archiving the preliminary data once we’re back in our hotel rooms.

It’s satisfying work, but it’s important that we have non-flight days like Saturday to catch up on our instrument maintenance as well as personal things—exercise, laundry, even sleep. When we’re in the field there’s no set schedule like when we’re in the office, and it’s important to grab that time when we can, because flight days depend on the weather, and a good measurement day waits for no scientist, not even when they have a plane!

This piece was originally published on the NASA Earth Expeditions blog.