Washington, March 19 : Researchers at the University of Washington (UW) have indicated that information obtained from passive satellite microwave imagery could help animals in the Arctic survive killer winter storms.
Though rain falling on snow seems like a relatively harmless weather event, but when it happens in the far north, it can prove fatal for reindeer, musk oxen and other animals that normally graze on the Arctic tundra.
An example of the killer effect of these storms was when in October 2003, rain fell for several days on top of a 6-inch snow cover on Canada's Banks Island, at the edge of the Beaufort Sea inside the Arctic Circle.
After the rain seeped through the snow to the soil surface, the temperature 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, resulting in the death of some 20,000 musk oxen by starvation.
"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.
Now, 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.
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," said Grenfell.
"We are talking about Banks Island, but this applies to the whole Arctic - Alaska, northern Canada, Siberia, Scandinavia - wherever there is permafrost," said Putkonen.
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.
Currently, there is no way to know exactly where or how often these potentially devastating rain-on-snow events occur, but using satellite data to locate them could make up for a scarcity of weather stations in the sparsely populated Arctic.