HR: 09:10h
AN: C11C-04 [Abstracts]
TI: Change in Winter-to-Spring Interactions Between Snow and Atmosphere in Eurasia Examined by an
AGCM
AU: * Saito, K
EM: ksaito@jamstec.go.jp
AF: Frontier Research Center for Global Change, JAMSTEC, 3173-25 Showa-machi, Kanazawa-ku, Yokohama,
236-0001
Japan
AU: Cohen, J L
EM: jcohen@aer.com
AF: Atmospheric and Environmental Research, Inc., 131 Hartwell Avenue, Lexington, MA 02421
United States
AU: Yasunari, T
EM: yasunari@hyarc.nagoya-u.ac.jp
AF: Frontier Research Center for Global Change, JAMSTEC, 3173-25 Showa-machi, Kanazawa-ku, Yokohama,
236-0001
Japan
AU: Yasunari, T
EM: yasunari@hyarc.nagoya-u.ac.jp
AF: Hydrospheric Atmospheric Research Center, Nagoya University, Furo-cho, Chigusa-ku, Nagoya, 464-8601
Japan
AB:
Eurasian snow cover extent anomaly and the dominant mode of the extratropical atmospheric circulation variabilities have been
shown to correlate at the seasonal to sub-decadal time scales in the recent three decades. The inter--seasonal correlation
from winter to spring, however, exhibited a change at the mid 1980s. Only after the change, snow cover and the circulation
anomalies showed persistent correlation from winter to the following spring. The latitudinal pressure gradient in winter is
strong in the North Atlantic before the change, while it is in the west Eurasia after the change.
We hypothesized that the circulation anomaly pattern difference in winter may have resulted in the strengthened interactions,
for the latter period, through positive feedbacks between snow, temperature, and pressure in the Continent. We examined the
hypothesis by two ensemble runs of an atmospheric general circulation model from winter to spring, where the difference is
only in the initial pressure anomaly pattern. The simulation successfully reproduced the difference in the
correlation pattern, favoring our hypothesis.
DE: 0736 Snow (1827, 1863)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1620 Climate dynamics (0429, 3309)
SC: Cryosphere [C]
MN: Fall Meeting 2005