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East and West: The Geography of Antarctica

November 19th, 2014 by George Hale

At first, the geography of Antarctica might seem a little confusing. From space, much of Antarctica looks featureless and white, meaning there are few features to guide you. It’s one thing to know that Pine Island Glacier is in West Antarctica, but for some it might be unclear which part of the frozen continent is which.

In the most general terms, Antarctica can be divided into three major areas: West Antarctica, East Antarctica, and the Antarctic Peninsula.

LIMA_overview_map

An overview map of Antarctica produced by the British Antarctic Survey to accompany the Landsat Image Mosaic of Antarctica, or LIMA.

The Antarctic Peninsula is probably Antarctica’s most prominent geographical feature and home to scientific stations operated by the United States, the United Kingdom, France, Australia, and other nations. This curved extension of the continent extends nearly 250 miles north of the Antarctic Circle and points toward the southern tip of South America. The Antarctic Peninsula has a number of glaciers and floating ice shelves that are changing rapidly because this region is warming faster than the rest of the continent.

Running along the length of the peninsula, and extending across the continent is a mountain chain known as the Transantarctic Mountains. In addition to supplying spectacular views, the Transantarctics serve as a sort of dividing line separating East and West Antarctica.

A view of the Transantarctic Mountains  during IceBridge's 2013 Antarctic campaign.

A view of the Transantarctic Mountains during IceBridge’s 2013 Antarctic campaign.

Although the Antarctic Ice Sheet is a continuous mass of ice, it is sometimes helpful to think of it as two separate masses. The West Antarctic and East Antarctic ice sheets are separated by the Transantarctics, with ice on the west side generally flowing toward the Western Hemisphere and ice on the east side flowing toward the eastern hemisphere. (In both cases, this is actually flowing north…away from the South Pole.)

East Antarctica is considerably larger than West Antarctica, and its ice sheet is thick – nearly three miles (five kilometers) in some regions . The ice surface of East Antarctica is high and home to some of the coldest and driest condition on Earth.

The East Antarctic Ice Sheet is considered to be more stable than the West Antarctic. One reason is the shape and elevation of bedrock beneath the ice. Heavy masses of ice push down on bedrock, depressing some areas below mean sea level. If those low-lying areas happen to be near the edge of the ice sheet — which is the case in much of West Antarctica — then ocean water can make its way under the ice, speeding up glacier flow.

This is one of the reasons that, while both portions of the ice sheet are losing mass, West Antarctica is moving much faster. Recent studies of West Antarctica found that many of its fast-moving glaciers are in an irreversible decline.

sea ice shadow

Shadow of the NASA DC-8 on sea ice in the Weddell Sea. Credit: NASA / Jim Yungel

Antarctica is surrounded on all sides by the Southern Ocean. During the winter, ocean water freezes, forming a layer of sea ice of roughly the same area as the Antarctic continent. In recent years, sea ice around the continent has been increasing.

The ocean around Antarctica is divided into several seas. Starting to the right of the Antarctic Peninsula on the map is the Weddell Sea, which extends to Cape Norvegia, a small point of land jutting off of East Antarctica. Moving clockwise we go around the East Antarctic coast all the way to the Ross Sea, south of New Zealand. Next comes the Amundsen Sea, where large West Antarctic glaciers like Pine Island and Thwaites drain. We complete our trip around Antarctica by coming to the Bellingshausen Sea, to the left of the Antarctic Peninsula.

For maps of Antarctica, including some that use imagery from the Landsat satellite, visit:
http://lima.usgs.gov/download.php

To use an interactive Antarctic atlas, visit:
http://lima.usgs.gov/antarctic_research_atlas

By Air and Sea: An Antarctic Transportation Hub

November 2nd, 2014 by George Hale

At the southern tip of Chile, the city of Punta Arenas is in a prime location for accessing Antarctica. This is one of the reasons IceBridge calls Punta Arenas home for several weeks during Antarctic field campaigns. But IceBridge isn’t the only scientific game in town. The U.S. Antarctic Program (USAP), British Antarctic Survey (BAS) and number of other organizations also rely on the Punta Arenas airport and the town’s ocean access.

DC-8 and Twin Otter

The NASA DC-8 taking off from the Punta Arenas airport. To the right is a Twin Otter aircraft used by the U.S. Antarctic Program. Credit: NASA / Kyle Krabill

The USAP brings two of its ice-capable research vessels, the Palmer and the Gould, to Punta Arenas. From there they carry out research cruises and transport people and cargo to and from Palmer Station, the National Science Foundation’s research base on the Antarctic Peninsula. In addition, USAP will sometimes base aircraft at the Punta Arenas airport on their way to and from Antarctica.

rv palmer

The R/V Nathaniel B. Palmer in the Straits of Magellan just off the coast in Punta Arenas, Chile. Credit: NASA / Michael Studinger

The United States isn’t the only nation with a strong presence in Patagonia. BAS research teams use Punta Arenas as a jumping off point for their research bases such as Rothera Station on the Antarctic Peninsula. In the photo below we can see a BAS Dash-7 and Twin Otter aircraft on the ramp at the Punta Arenas airport.

Dash 7 and Twin Otter

Twin Otter and Dash 7 aircraft operated by the British Antarctic Survey sit at the Punta Arenas airport. Credit: NASA / George Hale

In addition to the various Antarctic research programs working here, a number of companies that transport people, equipment and supplies to Antarctica fly in and out of Punta Arenas during the research season. Below are an IL-76 cargo jet operated by Almaty Air and a ski-equipped DC-3T aircraft flown by Antarctic Logistics Centre International.

dc8-and-il76

An Almaty Air IL-76 cargo jet at the Punta Arenas airport. To the right is one of the NASA DC-8’s engines. Credit: NASA / Jim Yungel

alci-dc-3-

An Antarctic Logistics Centre International (ALCI) DC-3T aircraft taxiing on the ramp on a snowy day at the Punta Arenas airport. Credit: NASA / George Hale

Mangroves, Mud, and More

September 2nd, 2014 by David Lagomasino

Mangrove forests

Flying over the Colombian Andes from Medellin to Nuqui in a small, 20 passenger propeller plane, five scientists peer out the window to look at the bosque (Spanish word for forest) covering the mountains below for as far as they could see. I was one of those scientists. Dotted throughout the forest, I can see indigenous communities thriving in small clearings with smoke billowing from small fire pits. Then, out of nowhere, the mountains drop off, the Pacific Ocean appears, and the plane banks hard to starboard. Finally! My first glimpse and the reason why I was making a trip out to Pacific coast of Colombia: mangroves.

My first trip to Colombia and I get to see some of the most pristine mangroves in the world. Why am I so excited about mangroves? There is something about the smell of the swamp, the harsh conditions, the incredible resilience of the trees, and the complex hydrology that draws me in. Mangrove is the general term used for a group of salt-tolerant tropical hardwood trees. Large communities of mangroves form unique forested ecosystems unlike any other forest found in tropical, temperate, and boreal climates. Though they only cover 0.1% of the earth’s surface, mangrove forests remove more carbon per unit area than any other terrestrial forest, which in turn, may be extremely important with respect to climate change and increasing CO2 concentrations. Most of that carbon from mangroves is sequestered by the thick layers of organic-rich soil that have been deposited and, most importantly, remains in these environments. Mangroves also provide a number of ecosystems services that can add up to billions of dollars in economic value per year. Some services are obvious like fishing, shrimping, timber and other raw resources. Other services are much harder to value but are still extremely important such as coastal protection, cultivating biodiversity, and cultural services. Despite their economic value or maybe because of it, mangrove forests are disappearing faster than any other tropical environment, including terrestrial forest and coral reef ecosystems, because of deforestation, coastal development and other human manipulations.

My trip was part of Vulnerability Assessment of Mangrove Forests in the Americas, a project funded by NASA’s Land Cover and Land Use Change Program and led by Dr. Marc Simard from NASA Jet Propulsion Laboratory (JPL). The project was designed to identify changes to mangrove forest ecosystems through time and space, and to understand how human activities coupled with land use/ land cover (LU/LC) change have altered mangrove environments. Researchers from NASA JPL, NASA Goddard Space Flight Center, Louisiana State University (LSU), and Indiana University (IU) have visited six sites over the course of the three year study to collect detailed mangrove and socio-economic data. This data is instrumental for developing regional models that can be adapted for diverse communities to assess mangrove vulnerability to human and climate drivers.

Our trip to Nuqui, Colombia was an effort to collect field data in pristine mangrove forests along the Pacific coast of the Americas, a location in which scientists know very little about the extent, height, and condition of the mangroves. The field data, which included tree height and tree thickness, will be used to help calibrate and validate or, in other words, make adjustments to and verify our mangrove structure and biomass models developed using a combination of remote sensing techniques. These remote sensing models use a series of mathematical relationships to estimate such things as tree height, biomass productivity, and carbon sequestration. The other collaborators on the project from LSU collected soil cores while IU initiated a locally-lead program to conduct socio-economic surveys. Fifty centimeter soil cores were collected at each of the sites to determine the amount of carbon found in the ground, which is the largest reservoir for carbon in these ecosystems. Socio-economic activity and demographic information collected from detailed surveys will help us to understand the relationship between the human environment and the changes to the mangrove forests.

Figure 1

(Top left) Skype meeting between NASA JPL interns and researchers from MarViva about remote sensing of mangroves. (Top right) Team America reading about the “Plan de Manejo Manglar.” (Center) Mangrove presentation to the community leaders of Nuqui. (Bottom left) “Mangrove 101″ with Edward Castañeda, from LSU. (Bottom right) Team America preparing for meeting with community leaders.

Before any scientific trip to another country, there is a ton of planning and connecting with local agencies to help ensure that you don’t run into any complications. Shortly after our arrival in Nuqui, Colombia, we checked into our hotel and began working on a presentation to show to the local leaders from several small pueblos that comprise the coastal region of the municipality of Nuqui. The presentation was to let the communities know; 1) why we were there, 2) why we are interested in mangroves, and 3) how our research will help the local communities.

The first two points were fairly straightforward. We had preliminary maps from the area which showed us that some very tall, 20-30 meter mangroves were growing in the region. We were there to “groundtruth,” or check out how accurate our modeled tree height estimates were and collect new data to develop better models. Very few studies have investigated mangroves along the Pacific coast and Nuqui was the perfect location to find intact forest ecosystems. Moreover, the coastal communities of Nuqui are dependent on many of the ecosystem services provided by the mangrove forests which include timber/ raw materials, fisheries, coastal protection, and water purification. We tend to forget that we are also part of the ecosystem, and that our actions will have a direct impact on changing the landscape. Nuqui has realized this and has carried out a “Plan de Manejo de Manglar (Mangrove Management Plan)” in the area of Tribugá. The plan includes three “zonas”: de uso sostenible (sustainable use), recuperación (restoration), and preservación (preservation). Mangroves are a necessary part of the coastal Colombian life and rooted deeply into their culture, so much that even the Vice-President of Nuqui, Enrique Murillo-Palacios, was moved to sing about his appreciation for those beloved trees during a dinner we had been invited to.

Mangroves Figure 2

(Top left) Walking home after a long field day in the rain. (Center) Marc Simard, from NASA JPL, measuring tree height. (Top right) Marc Simard showing Hector, from MarViva, how to use the inclinometer. (Bottom left) Cutting soil cores with MarViva and the Vice-President of Nuqui, Enrique. (Bottom right) David Lagomasino, from NASA GSFC, measuring tree diameter above the mangrove prop roots.

We addressed the third objective of our meeting, to show how our research will help the local communities, by working with local community members and local Nonprofits in the field. In addition, we also shared data between groups; some data we collected and other data that MarViva had been previously collecting. Over the course of the field campaign, a handful of local community members and two researchers from MarViva came with us out in the field to collect data. All the groups had their own area of expertise. The locals knew the layout of the land; where the shoals were along the river, where the tallest mangroves were, and a detailed background of the area. MarViva had permanent plots set up at various mangrove sites in the area of Tribugá. And Team America (inside joke: name for the US collaborators of the project) had the expertise in remote sensing, spatial statistics, and mangrove physiology.

While we were out in the field, we showed the locals how to measure tree height using inclinometers, measure tree thickness using diameter tape, and how to collect soil cores. Simple geometry has been integrated into the inclinometer and diameter tape. The inclinometer can estimate tree height by measuring the angles to the base and top of the tree from a set distance from the tree. Two triangles can then be drawn from these measurements using geometric techniques and, voila!: tree height. Old-school surveyors did this all by hand, but nowadays there are fancy inclinometers that integrate all the measurements in a single device with one output… tree height. The diameter tape also integrates geometry by using the relationship between the circumference and diameter of a circle. Collecting soil core tends to be a little more rudimentary, but one must consider a few technical issues first, such as soil compaction and suction, before just hammering a PVC pipe into the ground. From the soil cores we can obtain information about the rate of deposition, the amount of biomass, and the concentration of carbon in the ground. Getting muddy from field work can be one of the best parts of a project. Plus it’s always fun to parkour across a jungle-gym of mangrove prop roots.

Mangroves Figure 3

(Top left) Run-in with a pod of Humpback Whales during our initial site visit. (Top right) Asher Williams and Edward Castañeda, from LSU, learning about a new species of mangroves we had never seen before. (Bottom left) Always, always take a picture of your field book. (Center) Asher admiring one of the only black mangroves (Aviecennia germinans) we came across at our field sites. (Bottom right) Fruit from a mangrove tree.

Edward Castañeda, from LSU, gave an impromptu “Mangrove 101” course to local volunteers while we were taking a break in the field. Professor Castañeda discussed the various physical adaptations that mangroves have developed to cope with the harsh saline environments and remove the high concentrations of salts in the water. Some mangroves can thrive in water with salinities above 90 parts per thousand. That’s almost three times the salt concentrations found in the oceans! There are three main mechanisms that mangroves have developed to allow them to live in salt water: salt exclusion, salt excretion, and shedding. Salt exclusion occurs at the roots where thin membranes prevent salt from entering into the xylem. The excretion technique removes excess salts using glands found in the leaf. You can actually taste and see the salt on the undersides of some leaves. Lastly, some mangrove species can store excess salts in glands from “sacrificial leaves” that fall to the ground, removing the accumulated salts from their system.

Mangroves Figure 4

(Left) Always know where your lines of egress are. (Top) Transportation out of Nuqui. (Right) Marc Simard, from JPL, admiring the mangroves while on a boat ride to our next site. (Bottom) Almost lunch time in town of Tribugá.

After a week of working with the local communities and long days of fieldwork, there were mixed feelings about leaving. Sure, we wanted to get back to hot showers and air conditioning, but being able to see the sites, that we primarily research remotely, we began to formulate more and more questions. What makes the mangroves so big? How does the hydrology influence mangrove communities and tree growth? How deep are the mangrove soils? How far inland to the mangroves extend? Though we may not have an answer for these questions now, it is through collaborations with local agencies and educating local communities that can help us to eventually address research gaps. Town members from Nuqui learned about mangroves and their importance to carbon cycling and MarViva learned about new techniques to survey their field sites. Team America learned much more than we bargained for. Not only did we collect lots of field data for our remote sensing biomass and socio-economic models, but we learned a lot about the culture of Nuqui and how truly important mangroves are in their/our lives.

I stare out into the forest from my perch atop a mangrove prop root, surveying the near-impenetrable entanglement of the forests’ footing. In the distance, calls of “Árbol H6, DAB 4.5, Altura 12 metros” are muffled by the rain. Then I remember that I climbed up here to measure the thickness of the tree… but first, let me take a #selfie.

David Lagomasino

“If there are no mangrove forests, then the sea will have no meaning. It is like having a tree with no roots, for the mangroves are the roots of the sea.”
-Thai Fisherman (Trang Province)

G-LiHT | A View From Above

July 21st, 2014 by Kathryn Hansen

Text by Doug Morton
NASA’s Goddard Space Flight Center

G-LiHT DSLR image of forests and open water near the Tetlin National Wildlife Refuge east of Tok, Alaska. Credit: NASA

G-LiHT DSLR image of forests and open water near the Tetlin National Wildlife Refuge east of Tok, Alaska. Credit: NASA

I have always enjoyed looking out the window of a plane. From the typical cruising altitude of a commercial jetliner, the view of lakes and fields and mountains is familiar (but still fascinating) to a NASA scientist used to looking at Earth from space. Vegetation and land use follow the topography in predictable ways — agricultural fields on the flattest lands and dense forest cover on the warm, south-facing slopes.

Spruce forest in the Yukon-Charley Rivers National Preserve north of Delta Junction, Alaska. Credit: Ross Nelson/NASA's Goddard Space Flight Center

Spruce forest in the Yukon-Charley Rivers National Preserve north of Delta Junction, Alaska. Credit: Ross Nelson/NASA’s Goddard Space Flight Center

In Alaska, the G-LiHT campaign is flying low and slow to provide a very detailed look at forest structure, topography, wetlands, and forest health. At 1,100 feet above ground level, the view from above is stunning. Looking down, you see individual trees, small polygons formed by permafrost, and subtle changes in topography that allow vegetation to flourish on dry ground or wallow in the wetlands of the Tanana flats. Small black spruce trees, barely head high and the width of a dinner plate, are packed together in stands too thick to walk through. Looking out, you can see the vast expanse of the Tanana Valley, a lush green carpet of forest. The braided channels of the river flash in the sunlight as the milky white water heads out of the mountains. Ahead, the steep rise of the Alaska Range signals the end of another flight line.

Seeing the landscape from the same perspective as the G-LiHT sensors provides essential context for the project. The G-LiHT operators on the plane can switch between the real-time view of the incoming data stream and the landscape below. G-LiHT PI Bruce Cook noted, “it’s a little dizzying to watch the imagery fly by on the screen, but matching the bird’s eye view to the data gives an idea of what is possible with the analysis and interpretation of the G-LiHT data.”

Update: As of July 19, the piper had flown more than 70 hours for data collection (9,300 miles), and with more than half of the planned flight lines in the Tanana region completed.

Rainbow over the Tanana River. Credit: Bruce Cook/NASA's Goddard Space Flight Center

Rainbow over the Tanana River. Credit: Bruce Cook/NASA’s Goddard Space Flight Center

 

NASA’s Alaska Forest Survey Kicks Off

July 14th, 2014 by Kathryn Hansen

From early July through mid-August 2014, scientist Doug Morton of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, will be flying low over the treetops of interior Alaska. The purpose? First-of-a-kind look at the state’s forests with a portable, airborne imaging system called G-LiHT to map the composition, structure and function of the ecosystem.

According to Morton, key components of the fieldwork include:

“First, we are partnering with the U.S. Forest Service, as directed by the recently-passed Farm Bill, to incorporate remote sensing technology into forest monitoring efforts. Our pilot study will be the first inventory of forests in interior Alaska; a standard ground inventory (as in the lower 48) has always been too costly or logistically challenging to implement.

Second, we will study post-fire recovery, with plans to sample more than 80 percent of all fires in the Tanana region since 1950.  Fire is the major agent of change in interior Alaska, and understanding the patterns of forest recovery is essential to gauge the vulnerability/resilience of forests to future climate change.

Third, we will benchmark conditions (topography/permafrost, forest cover, forest composition) across a large portion of the Arctic-Boreal Vulnerability Experiment (ABoVE) science domain.”

Follow Morton through the summer as, Internet connection permitting, he sends updates and photos from the field.

 

 

Notes from the Field