U. of Colorado study shows desert droughts lead to earlier annual mountain snow lossJune 26, 2007A new study spearheaded by the University of Colorado at Boulder's National Snow and Ice Data Center indicates wind-blown dust from drought-stricken and disturbed lands in the Southwest can shorten the duration of mountain snow cover hundreds of miles away in the Colorado mountains by roughly a month. Led by Tom Painter, the study found seasonal snow coverage in the sub-alpine and alpine areas of the San Juan Mountains of southwestern Colorado disappeared by about 30 days earlier in 2006 because of heavy dust deposition from the Colorado Plateau roughly 200 miles away. The dust, which probably came from northeast Arizona and northwest New Mexico deserts, reduced the snow's reflectivity, allowing more of the sun's energy to warm the snow pack and cause it to melt earlier. "The connection between dust and lower snow reflectance is already established, but the amount of impact measured and modeled in this system stunned us," said Painter. "The fact that dust can reduce snow cover duration so much - a month earlier -- transforms our understanding of mountain sensitivity to external forcings."
While just three or four significant dust deposition events occurred annually in the San Juan Mountains between 2003 and 2005, eight occurred in 2006, according to the authors. In 2006, the sub-alpine regions of the San Juans melted out 24 to 35 days earlier than previous, relatively dust-free years, according to ground measurements and computer simulations. A paper on the subject was published online June 23 in Geophysical Research Letters. Co-authors on the study included CU-Boulder's Andrew Barrett, Jason Neff, Maureen Cassidy, Corey Lawrence and Lang Farmer, as well as Christopher Landry from the Center for Snow and Avalanche Studies in Silverton, Colo., and Kathleen McBride of Northern Arizona University. The Colorado Plateau is centered in the Four Corners region of Colorado, New Mexico, Arizona and Utah and covers an area of roughly 130,000 square miles. Prior to the widespread ecological disturbance of the Western U.S. in the late 1980s, the high mountain snow would have likely lasted several weeks longer in most regions, according to the researchers. "Recent studies agree that with global warming, the Southwest will be warmer and drier," said Painter. "Enhanced dust deposition is likely, further shortening snow cover duration. Ultimately, a warming climate and the dust it generates will affect river run-off and soil moisture in the mountains, not only in the Western United States but across many of the world's mountains." Snowmelt provides drinking water to one-sixth of the world's population and provides important agricultural and recreational resources for the Western United States, said Painter. The progression of climate change may alter the reliability of spring snowmelt, including its quantity, timing and duration, he said. University of Colorado at Boulder | |||||||||||||||||||||
|
Related Snow Cover News Articles Thawing permafrost likely to boost global warming The thawing of permafrost in northern latitudes, which greatly increases microbial decomposition of carbon compounds in soil, will dominate other effects of warming in the region and could become a major force promoting the release of carbon dioxide and thus further warming, according to a new assessment in the September 2008 issue of BioScience. Climate change and species distributions Scientists have long pointed to physical changes in the Earth and its atmosphere, such as melting polar ice caps, sea level rise and violent storms, as indicators of global climate change. Study: Future snowmelt in West twice as early as expected; threatens ecosystems and water reserves According to a new study, global warming could lead to larger changes in snowmelt in the western United States than was previously thought, possibly increasing wildfire risk and creating new water management challenges for agriculture, ecosystems and urban populations. Indigenous peoples hardest hit by climate change describe impacts Indigenous peoples have contributed the least to world greenhouse gas emissions and have the smallest ecological footprints on Earth. Satellites can help Arctic grazers survive killer winter storms Rain 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. Dust in West up 500 percent in past 2 centuries, says CU-Boulder study The West has become 500 percent dustier in the past two centuries due to westward U.S. expansion and accompanying human activity beginning in the 1800s, according to a new study led by the University of Colorado at Boulder. Rising CO2 signals wetter storms for Northern Hemisphere, says CU-Boulder study While two new studies by researchers at the University of Colorado at Boulder's Cooperative Institute for Research in Environmental Sciences predict wetter storms for the Arctic and for the Northern Hemisphere because of global warming, whether or not this means more net precipitation depends on the latitude. Scientists Verify Predictive Model for Winter Weather Scientists have verified the accuracy of a model that uses October snow cover in Siberia to predict upcoming winter temperatures and snowfall for the high- and mid-latitudes of the Northern Hemisphere. By ice floe to the North Pole At the end of August, an unusual expedition under Russian leadership will leave for the Arctic Ocean. One of the participants is Jürgen Graeser of the Alfred Wegener Institute for Polar and Marine Research, one of the research centres of the Helmholtz Association. Scientists to track impact of Asian dust and pollution on clouds, climate change Scientists using one of the nation's newest and most capable research aircraft are launching a far-reaching field project this month to study plumes of airborne dust and pollutants that originate in Asia and journey to North America. More Snow Cover News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||