 |
|
Satellites can help Arctic grazers survive killer winter storms
March 19, 2008Rain falling on snow sounds like a relatively harmless weather event, but when it happens in the far north it can mean lingering death for reindeer, musk oxen and other animals that normally graze on the Arctic tundra.
That was the case in October 2003 on Canada's Banks Island, at the edge of the Beaufort Sea inside the Arctic Circle. Rain fell for several days on top of a 6-inch snow cover, and the rain seeped through the snow to the soil surface. The temperature then plunged and the water became a thick layer of ice that lasted the winter and prevented browsing animals from reaching their food supply of lichens and mosses at the soil's surface. Some 20,000 musk oxen starved to death.
"Starvation happened over a period of many months and no one knew until they went up to do the population count the next spring," said Thomas Grenfell, a University of Washington research professor of atmospheric sciences who has studied the Banks Island event.
Grenfell and Jaakko Putkonen, a UW research associate professor of Earth and space sciences, have found evidence of the 2003 rain-on-snow occurrence in passive satellite microwave imagery, which they believe could provide a signature to help detect such events anywhere. They detail their work in a paper to be published March 25 in Water Resources Research, a journal of the American Geophysical Union.
Their methods could provide native people, whose livelihood depends on hoofed animals such as musk oxen, reindeer and caribou with a realistic chance of getting food to the herds to prevent mass starvation.
"We are talking about Banks Island, but this applies to the whole Arctic - Alaska, northern Canada, Siberia, Scandinavia - wherever there is permafrost," Putkonen said.
Grenfell has conducted more than 40 field experiments in polar regions and has become quite familiar with precipitation characteristics there. Much of the previous work he did was with researchers who were interested in the nature of the snowpack, but he found that the presence of water interfered with interpreting satellite microwave readings.
But for the new research, the signal from water was key. Grenfell and Putkonen looked for patterns in satellite microwave data that correlated with rain-on-snow events. They examined data from 10 different satellite microwave channels, each providing slightly different information on the condition of the snowpack.
"The subtleties in the microwave levels mean there can be high error margins on this information, but the Banks Island event stood out like a sore thumb in the data," Grenfell said.
The researchers hope to examine other satellite microwave records in search of evidence of rain-on-snow events during the last 30 years that are known from anecdotal information.
The 2003 rain-on-snow event affected the northern part of the 43,000-square-mile Banks Island. The musk oxen population of 70,000 was cut by nearly 30 percent, but a caribou herd on the southern part of the island was unaffected. The closest weather station, about 60 miles from the musk oxen range, didn't record any rainfall at the time of the event that resulted in the massive die off, so few people recognized that the oxen were in distress.
Currently there is no way to know exactly where or how often these potentially devastating rain-on-snow events occur, the researchers say, but using satellite data to locate them could make up for a scarcity of weather stations in the sparsely populated Arctic.
Rain-on-snow events historically have occurred mostly in coastal areas. However, in earlier research Putkonen found that models predict that climate change will push winter rainfall much farther into northern continents and large islands.
While food shortages can trigger a large die off, there also can be severe consequences from milder events that force animals to exert more energy to get food. That reduces body weight and limits reproduction, which in turn can cause long-term damage to herds.
"Because the Arctic stays well below freezing for eight to 10 months of the year, the ice layer can stay around for months. If a rain-on-snow event happens in the fall, these animals can go the whole winter without access to food," Putkonen said. "The native people in the north depend on these animals for food and for many other things."
University of Washington
Grenfell and Jaakko Putkonen, a UW research associate professor of Earth and space sciences, have found evidence of the 2003 rain-on-snow occurrence in passive satellite microwave imagery, which they believe could provide a signature to help detect such events anywhere. They detail their work in a paper to be published March 25 in Water Resources Research, a journal of the American Geophysical Union.
Their methods could provide native people, whose livelihood depends on hoofed animals such as musk oxen, reindeer and caribou with a realistic chance of getting food to the herds to prevent mass starvation.
"We are talking about Banks Island, but this applies to the whole Arctic - Alaska, northern Canada, Siberia, Scandinavia - wherever there is permafrost," Putkonen said.
Grenfell has conducted more than 40 field experiments in polar regions and has become quite familiar with precipitation characteristics there. Much of the previous work he did was with researchers who were interested in the nature of the snowpack, but he found that the presence of water interfered with interpreting satellite microwave readings.
But for the new research, the signal from water was key. Grenfell and Putkonen looked for patterns in satellite microwave data that correlated with rain-on-snow events. They examined data from 10 different satellite microwave channels, each providing slightly different information on the condition of the snowpack.
"The subtleties in the microwave levels mean there can be high error margins on this information, but the Banks Island event stood out like a sore thumb in the data," Grenfell said.
The researchers hope to examine other satellite microwave records in search of evidence of rain-on-snow events during the last 30 years that are known from anecdotal information.
The 2003 rain-on-snow event affected the northern part of the 43,000-square-mile Banks Island. The musk oxen population of 70,000 was cut by nearly 30 percent, but a caribou herd on the southern part of the island was unaffected. The closest weather station, about 60 miles from the musk oxen range, didn't record any rainfall at the time of the event that resulted in the massive die off, so few people recognized that the oxen were in distress.
Currently there is no way to know exactly where or how often these potentially devastating rain-on-snow events occur, the researchers say, but using satellite data to locate them could make up for a scarcity of weather stations in the sparsely populated Arctic.
Rain-on-snow events historically have occurred mostly in coastal areas. However, in earlier research Putkonen found that models predict that climate change will push winter rainfall much farther into northern continents and large islands.
While food shortages can trigger a large die off, there also can be severe consequences from milder events that force animals to exert more energy to get food. That reduces body weight and limits reproduction, which in turn can cause long-term damage to herds.
"Because the Arctic stays well below freezing for eight to 10 months of the year, the ice layer can stay around for months. If a rain-on-snow event happens in the fall, these animals can go the whole winter without access to food," Putkonen said. "The native people in the north depend on these animals for food and for many other things."
University of Washington
Arctic Tundra Current Events and Arctic Tundra News RSSArctic soil reveals climate change clues
Frozen arctic soil contains nearly twice the greenhouse-gas-producing organic material as was previously estimated, according to recently published research by University of Alaska Fairbanks scientists.
Bad sign for global warming: Thawing permafrost holds vast carbon pool
Permafrost blanketing the northern hemisphere contains more than twice the amount of carbon in the atmosphere, making it a potentially mammoth contributor to global climate change depending on how quickly it thaws.
Warming climate may cause arctic tundra to burn
Research from ancient sediment cores indicates that a warming climate could make the world's arctic tundra far more susceptible to fires than previously thought.
Without its insulating ice cap, Arctic surface waters warm to as much as 5 C above average
Record-breaking amounts of ice-free water have deprived the Arctic of more of its natural "sunscreen" than ever in recent summers. The effect is so pronounced that sea surface temperatures rose to 5 C above average in one place this year, a high never before observed, says the oceanographer who has compiled the first-ever look at average sea surface temperatures for the region.
Nitrogen study may improve ecological predictions
The pattern of nitrogen release from decaying plant material is remarkably similar and predictable across the planet, researchers have concluded in a new study, which should make it easier to understand nutrient dynamics, vegetation growth, estimate carbon release and sequestration, and better predict the impacts of climate change.
New Method Confirms Importance of Fungi in Arctic Nitrogen Cycle
A new method to calculate the transfer of nitrogen from Arctic mushrooms to plants is shedding light on how fungi living symbiotically on plant roots transfer vital nutrients to their hosts.
Vegetation growth may quickly raise Arctic temperatures
Warming in the Arctic is stimulating the growth of vegetation and could affect the delicate energy balance there, causing an additional climate warming of several degrees over the next few decades.
More Arctic Tundra Current Events and Arctic Tundra News Articles
 | Arctic Tundra by Donald M. Silver, Patricia Wynne It’s a land of riddles, where a winter night can last for weeks and where the ground is full of water though it rarely rains or snows. Bears, hares, wolves, and foxes roam the ice-crusted earth, as flowers follow the sun as it moves across the sky. Young readers may never come to the Arctic tundra, but now it can come to them—in a book chock full of fun-to-do experiments and activities for... |
 | Arctic Tundra: Land With No Trees (Rookie Read-About Science) by Allan Fowler From friendly dolphins to giant pandas, from icebergs and glaciers to energy from the sun, from magnets to solids, liquids, and gases, Rookie Read-About Science is a natural addition to the primary-grade classroom with books that cover every part of the science curricula. Includes: animals, nature, scientific principles, the environment, weather, and much... |
 | Arctic Tundra (Habitats) by Michael H. Forman Describes the characteristics of the tundra and the plants and animals that live... |
| An Arctic Tundra Food Chain (Nature's Bounty) by A. D. Tarbox | |
| Vegetation and Production Ecology of an Alaskan Arctic Tundra (Ecological Studies) | |
 | Arctic Tundra: Life At The North Pole (Watts Library) by Salvatore Tocci |
| My Adventure to the Arctic Tundra (My Adventure) by Colleen Madonna Flood Williams | |
 | Seasonal protein dynamics in Alaskan arctic tundra soils [An article from: Soil Biology and Biochemistry] by M.N. Weintraub, J.P. Schimel This digital document is a journal article from Soil Biology and Biochemistry, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: In the arctic tundra of Alaska, plant growth is limited by N supply, especially in tussock tundra. Because proteins are the... |
| Changing microbial substrate use in Arctic tundra soils through a freeze-thaw cycle [An article from: Soil Biology and Biochemistry] by J.P. Schimel, C. Mikan This digital document is a journal article from Soil Biology and Biochemistry, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: Recent research has established that microbial processes in the arctic continue even when soils are frozen, and that... |
 | Structural characteristics of a low Arctic tundra ecosystem and the retreat of the Arctic fox [An article from: Biological Conservation] by S.T. Killengreen, R.A. Ims, N.G. Yoccoz, Brathen This digital document is a journal article from Biological Conservation, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.Description: We conducted a large-scale, campaign-based survey in Finnmark, northern Norway to evaluate the proposition that declining... |
| © 2008 BrightSurf.com |