HR: 11:10h
AN: OS11B-04    [PDF]
TI: Orographic and Geographic Constraints on a Modeled Siberian Snow - Arctic Oscillation Teleconnection Pathway
AU: * Gong, G
EM: gavin.gong@verizon.net
AF: Columbia University, Department of Earth and Environmental Engineering 918 Seeley Mudd Building, New York, NY 10027
AU: Entekhabi, D
EM: darae@mit.edu
AF: Massachusetts Institute of Technology, Ralph M. Parsons Laboratory Building 48-331, Cambridge, MA 02139
AU: Cohen, J
EM: jcohen@aer.com
AF: Atmospheric and Environmental Research, Inc., 131 Hartwell Ave, Lexington, MA 02421
AB: Land surface anomalies have recently been recognized as influential to the Arctic Oscillation (AO), and thus represent a potentially important but relatively untapped research direction, with possible ramifications for seasonal prediction. Previous publications by the authors have identified a surface-troposphere-stratosphere teleconnection pathway linking observation-based early season Siberian snow perturbations to a modulation of the winter AO mode. In this study, the key roles of orography and geography in producing this modeled teleconnection is explicitly investigated using numerical GCM experiments. First, the climatic response to the same snow perturbation is compared between observed and suppressed orographic barriers in southern and eastern Siberia. Second, the AO mode response to realistic land surface snow forcings is evaluated for two different forcing regions, Siberia and North America. Results indicate that the combination of a large snow-forced local diabatic heating anomaly over a region of substantial (orographically-forced) stationary wave activity is required to produce strong upward wave activity flux anomalies which initiate the teleconnection pathway. These features are unique to Siberia, making it a critical region for reproducing the snow - winter AO statistical relationship evident in the observational record, and potentially for improving seasonal prediction of the winter AO mode.
DE: 1620 Climate dynamics (3309)
DE: 1833 Hydroclimatology
DE: 1863 Snow and ice (1827)
DE: 3322 Land/atmosphere interactions
DE: 3362 Stratosphere/troposphere interactions
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting