HR: 1340h
AN: C13B-0272    [Abstracts]
TI: Climatic Impacts of Snow Depth Anomalies over Frozen Ground
AU: Entekhabi, D
EM: darae@mit.edu
AF: Massachusetts Institute of Technology, Ralph M. Parsons Lab Room 48-331, Cambridge, MA 02139 United States
AU: * Gong, G
EM: gg2138@columbia.edu
AF: Columbia University, Earth and Environmental Engineering, 500 West 120th Street, MC 4711, New York, NY 10027 United States
AU: Cohen, J
EM: jcohen@aer.com
AF: Atmospheric and Environmental Research, Inc., 131 Hartwell Avenue, Lexington, MA 02421 United States
AB: Frozen ground may be overlain by snow cover of varying thickness, or in the case of seasonally frozen ground may be at times snow-free. Anomalous snow cover is known to suppress local surface temperatures, and it is commonly presumed that the higher (lower) albedo associated with the presence (absence) of snow is primarily responsible for this response. In this study, numerical general-circulation model experiments are performed to investigate the atmospheric response to snow presence vs. snow depth anomalies, and the relevant surface thermodynamic processes involved. Results indicate that snow depth anomalies and associated insulative properties of the snowpack (e.g., thermal conductivity and latent heat flux) suppress local temperatures to an extent comparable to the snow presence / albedo mechanism. Furthermore, we find that realistic, continental-scale snow presence and snow depth anomalies acting in conjunction can not only suppress local temperatures, but can also produce a hemispheric-scale climate system response. The specific influence of snow depth anomalies on local and regional climate adds new insight to our understanding of the climatic impacts of changes in frozen ground, especially in permafrost regions where snow depth anomalies are more likely than snow presence anomalies.
DE: 3322 Land/atmosphere interactions
DE: 1823 Frozen ground
DE: 1833 Hydroclimatology
DE: 1863 Snow and ice (1827)
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting