where deserts and mountains collide the implications of accelerated snowmelt by disturbed desert...
TRANSCRIPT
Where Deserts and Mountains Collide
The Implications of Accelerated Snowmelt
by Disturbed Desert Dust Thomas H. PainterSnow Optics LaboratoryUniversity of Utah
Snowmelt and Water• 75% of freshwater comes
from snow in the Western US
• Mountain snowpack provides enormous, critical reservoir capacity
• Early snowmelt increases growing season length, evapotranspiration, and temperatures
• Rate of snowmelt controls water management and yield
Photo: Chris Landry, Center for Snow and Avalanche Studies
Reflectivity = 72%
Absorption = 28%
Reflectivity =43%
Absorption = 57%
Snow Albedo
Reflect
ivit
y
Impact of Dust: A Perfect Storm
Dust is well timed
Dust is well placed
Dust is, well, darker than snow
April 2009 May 2009
Changes in Dust Loading
Post-disturbance
~ 1850 AD
Pre-disturbance
From Neff et al (2008), Nature GeosciencesFrom lake sediments in the Colorado Rockies
Present
Photo: McKenzie Skiles, Snow Optics Laboratory
Phoenix 2006
Future Dust Loading
albedo = 0.72
Before disturbance
albedo = 0.43
After disturbance
Snowmelt Modeling
Senator Beck Basin Study Area, Colorado, 2006
Snow
wate
r equiv
ale
nt
(mm
)
Cleaner (before disturbance)Dirtier (after disturbance )
Informing Water Managers
Colorado River Basin
May 6, 2009
MODIS-DRFS
Daily
sun
light a
bso
rbed b
y d
ust
(W/m
2)
Water in the Colorado River Basin
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