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Your
query was:
an="b41d-0225"
HR: 0800h
AN: B41D-0225
TI: Impact of Desert
Dust on Meltrates and Runoff from Mountain Snowpacks
AU: * Barrett, A P
EM: apbarret@kryos.colorado.edu
AF: NSIDC-CIRES University of Colorado, 449 UCB,
Boulder, CO 80309 United States
AU: Painter, T H
EM: tpainter@nsidc.org
AF: NSIDC-CIRES University of Colorado, 449 UCB,
Boulder, CO 80309 United States
AU: Landry, C
EM: clandry@snowstudies.org
AF: Center for Snow and Avalanche Studies, PO Box
190, Silverton, CO 81433 United States
AB: Dust, entrained from desert regions of the
Colorado Plateau, is deposited over large areas of the mountain snow pack of
the San Juan Mountains, Southwest Colorado. Anecdotal evidence from avalanche
forecasters, backcountry rangers and Ute tribal representatives suggests that
extensive dust layers occur in most years. Multiple dust layers were found in
snowpacks in this region in 2003, 2004 and 2005. Dust, exposed at the snow
surface, decreases albedo and increases absorption of solar radiation of the
snowpack. In the 2004-2005 snow accumulation and melt season, measurements of
surface energy fluxes, snow temperature and snow water equivalent were made
at two meteorological towers in the Senator Beck Study Basin, San Juan
Mountains, to examine the impact of dust on snowmelt processes. Stream stage
at four sites within the basin and at the basin outflow point was also
measured to investigate the impact of dust integrated to the basin scale.
Dust was first exposed on April 13 but was covered by snowfall on April 23.
Dust was exposed again on May 5. Before dust was exposed at the snow surface,
broadband albedo at the two towers was between 0.7 and 0.9. After exposure of
dust, albedo fell to 0.6. Shortwave radiative fluxes increased from 100 W m-2
to 400 W m-2 over 10 days as a result of dust exposure in April; and
increased from 100 W m-2 to 500 W m-2 over 25 days in May. Dust exposure in
April coincided with an increase in snowpack temperature in the top layers, a
proxy for snowpack internal energy within these layers, from -5C to 0C. In
May, dust exposure coincided with an increase in stream stage. Exposure of
dust at the snow surface enhanced the role of shortwave radiative fluxes in
both ripening the snowpack and in runoff generation.
DE: 1804 Catchment
DE: 1809 Desertification
DE: 1839 Hydrologic scaling
DE: 1863 Snow and ice (0736, 0738, 0776, 1827)
DE: 1878 Water/energy interactions (0495)
SC: Biogeosciences [B]
MN: Fall Meeting 2005
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