Andrew Yee[_1_]
March 24th 08, 03:15 PM
American Geophysical Union
AGU Contact:
Peter Weiss
Public Information Manager
Phone: +1-202-777-7507
University of Washington (Seattle) contacts:
Vince Stricherz or Sandra Hines
Phone: +1 (206) 543-2580
Contact information for coauthors:
Thomas C. Grenfell, Research Professor of Atmospheric Sciences
(206) 543-9411, (206) 543-4576
Jaakko Putkonen, Research Associate Professor of Earth and Space Sciences
(206) 543-0689
18 March 2008
AGU Release No. 08-10
Arctic herds could get help from satellites
WASHINGTON -- Researchers have used satellite data to detect Arctic
conditions that cause mass starvation of hoofed animals depended on by
native peoples. Some 20,000 musk oxen died on Canada's far-northern Banks
Island because of such conditions during the winter several years ago. Yet,
their deaths went unnoticed until the next spring. The new
satellite-detection method could provide an early warning to native people,
giving them a realistic chance of getting food to herds to prevent mass
starvation.
"We are talking about Banks Island, but this applies to the whole
ArcticAlaska, northern Canada, Siberia, Scandinavia -- wherever there is
permafrost," says Jaakko Putkonen of the University of Washington in
Seattle, who participated in the satellite study.
Banks Island is at the edge of the Beaufort Sea inside the Arctic Circle. In
October 2003, rain fell for several days there on top of a 6-inch snow
cover. 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. It prevented browsing animals from reaching their food supply of
lichens and mosses at the soil's surface.
"Starvation happened over a period of many months, and no one knew until
they went up to do the population count the next spring," says the
University of Washington's Thomas Grenfell, who traced satellite clues of
the Banks Island event with Putkonen.
Rain falling on snow can mean lingering death for musk oxen, reindeer, and
other animals that root through the snow to graze on the Arctic tundra.
Grenfell and Putkonen found evidence for the 2003 rain-on-snow occurrence in
passive satellite microwave imagery, which they believe could provide a
signature to help detect such events anywhere.
In the new study, the scientists examined data from 10 different satellite
microwave channels, each providing slightly different information on the
qualities 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," Grenfell says.
He and Putkonen detail their work in a paper now in press with Water
Resources Research, a journal of the American Geophysical Union.
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. For the new research, the
signal from water was key, he says.
The researchers hope to search other satellite microwave records for
evidence of rain-on-snow events of 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.
Notes for Journalists
Journalists and public information officers of educational and scientific
institutions (only) who have registered with AGU for direct electronic
access and received a username and password, can download a PDF copy of this
paper by clicking on this link:
http://www.agu.org/journals/wr/wr0803/2007WR005929/2007WR005929.pdf
If you need instructions for downloading, please see:
http://www.agu.org/jinstructions.shtml
Or, you may order an emailed copy of the paper by sending a message to Peter
Weiss at pweiss @ agu.org, Vince Stricherz at vinces @ u.washington.edu, or
Sandra Hines at shines @ u.washington.edu . Please provide your name, the
name of your publication, and your phone number. Neither the paper nor this
press release are under embargo.
Images:
A high-resolution image of reindeer grazing on the far-north Norwegian
island of Spitsbergen is available at:
<http://uwnews.org/images/newsreleases/2008/March/20080317_pid40506_aid40505_spitsbergenreindeer_sou rceimage.jpg>
Please credit the image to Jaakko Putkonen.
Title:
"A method for the detection of the severe rain-on-snow event on Banks
Island, October 2003, using passive microwave remote sensing"
Authors:
Thomas C. Grenfell
Department of Atmospheric Sciences
University of Washington, Seattle Washington, USA
Jaakko Putkonen
Department of Earth and Space Sciences
University of Washington, Seattle Washington, USA
Citation:
Grenfell, T. C., and J. Putkonen (2008), A method for the detection of the
severe rain-on-snow event on Banks Island, October 2003, using passive
microwave remote sensing, Water Resour. Res., 44, W03425,
doi:10.1029/2007WR005929.
AGU Contact:
Peter Weiss
Public Information Manager
Phone: +1-202-777-7507
University of Washington (Seattle) contacts:
Vince Stricherz or Sandra Hines
Phone: +1 (206) 543-2580
Contact information for coauthors:
Thomas C. Grenfell, Research Professor of Atmospheric Sciences
(206) 543-9411, (206) 543-4576
Jaakko Putkonen, Research Associate Professor of Earth and Space Sciences
(206) 543-0689
18 March 2008
AGU Release No. 08-10
Arctic herds could get help from satellites
WASHINGTON -- Researchers have used satellite data to detect Arctic
conditions that cause mass starvation of hoofed animals depended on by
native peoples. Some 20,000 musk oxen died on Canada's far-northern Banks
Island because of such conditions during the winter several years ago. Yet,
their deaths went unnoticed until the next spring. The new
satellite-detection method could provide an early warning to native people,
giving them a realistic chance of getting food to herds to prevent mass
starvation.
"We are talking about Banks Island, but this applies to the whole
ArcticAlaska, northern Canada, Siberia, Scandinavia -- wherever there is
permafrost," says Jaakko Putkonen of the University of Washington in
Seattle, who participated in the satellite study.
Banks Island is at the edge of the Beaufort Sea inside the Arctic Circle. In
October 2003, rain fell for several days there on top of a 6-inch snow
cover. 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. It prevented browsing animals from reaching their food supply of
lichens and mosses at the soil's surface.
"Starvation happened over a period of many months, and no one knew until
they went up to do the population count the next spring," says the
University of Washington's Thomas Grenfell, who traced satellite clues of
the Banks Island event with Putkonen.
Rain falling on snow can mean lingering death for musk oxen, reindeer, and
other animals that root through the snow to graze on the Arctic tundra.
Grenfell and Putkonen found evidence for the 2003 rain-on-snow occurrence in
passive satellite microwave imagery, which they believe could provide a
signature to help detect such events anywhere.
In the new study, the scientists examined data from 10 different satellite
microwave channels, each providing slightly different information on the
qualities 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," Grenfell says.
He and Putkonen detail their work in a paper now in press with Water
Resources Research, a journal of the American Geophysical Union.
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. For the new research, the
signal from water was key, he says.
The researchers hope to search other satellite microwave records for
evidence of rain-on-snow events of 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.
Notes for Journalists
Journalists and public information officers of educational and scientific
institutions (only) who have registered with AGU for direct electronic
access and received a username and password, can download a PDF copy of this
paper by clicking on this link:
http://www.agu.org/journals/wr/wr0803/2007WR005929/2007WR005929.pdf
If you need instructions for downloading, please see:
http://www.agu.org/jinstructions.shtml
Or, you may order an emailed copy of the paper by sending a message to Peter
Weiss at pweiss @ agu.org, Vince Stricherz at vinces @ u.washington.edu, or
Sandra Hines at shines @ u.washington.edu . Please provide your name, the
name of your publication, and your phone number. Neither the paper nor this
press release are under embargo.
Images:
A high-resolution image of reindeer grazing on the far-north Norwegian
island of Spitsbergen is available at:
<http://uwnews.org/images/newsreleases/2008/March/20080317_pid40506_aid40505_spitsbergenreindeer_sou rceimage.jpg>
Please credit the image to Jaakko Putkonen.
Title:
"A method for the detection of the severe rain-on-snow event on Banks
Island, October 2003, using passive microwave remote sensing"
Authors:
Thomas C. Grenfell
Department of Atmospheric Sciences
University of Washington, Seattle Washington, USA
Jaakko Putkonen
Department of Earth and Space Sciences
University of Washington, Seattle Washington, USA
Citation:
Grenfell, T. C., and J. Putkonen (2008), A method for the detection of the
severe rain-on-snow event on Banks Island, October 2003, using passive
microwave remote sensing, Water Resour. Res., 44, W03425,
doi:10.1029/2007WR005929.