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 Arctic - Alaska, 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.
Peter Weiss | American Geophysical Union
Greenland ice flow likely to speed up: New data assert glaciers move over sediment, which gets more slippery as it gets wetter
17.08.2017 | Swansea University
Climate change: In their old age, trees still accumulate large quantities of carbon
17.08.2017 | Universität Hamburg
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
18.08.2017 | Life Sciences
18.08.2017 | Physics and Astronomy
18.08.2017 | Materials Sciences