Tropical Pacific impacts of convective momentum transport in the SNU coupled GCM

被引:69
作者
Kim, Daehyun [2 ]
Kug, Jong-Seong [1 ]
Kang, In-Sik [1 ,2 ]
Jin, Fei-Fei [3 ]
Wittenberg, Andrew T. [4 ]
机构
[1] Seoul Natl Univ, Climate Environm Syst Res Ctr, Seoul, South Korea
[2] Seoul Natl Univ, Sch Earth & Environm Sci, Seoul, South Korea
[3] Univ Hawaii, SOEST, Dept Meteorol, Honolulu, HI 96822 USA
[4] NOAA, Geophys Fluid Dynam Lab, Princeton, NJ USA
基金
美国海洋和大气管理局; 美国国家科学基金会;
关键词
D O I
10.1007/s00382-007-0348-4
中图分类号
P4 [大气科学(气象学)];
学科分类号
0706 ; 070601 ;
摘要
Impacts of convective momentum transport (CMT) on tropical Pacific climate are examined, using an atmospheric (AGCM) and coupled GCM (CGCM) from Seoul National University. The CMT scheme affects the surface mainly via a convection-compensating atmospheric subsidence which conveys momentum downward through most of the troposphere. AGCM simulations-with SSTs prescribed from climatological and El Nino Southern Oscillation (ENSO) conditions-show substantial changes in circulation when CMT is added, such as an eastward shift of the climatological trade winds and west Pacific convection. The CMT also alters the ENSO wind anomalies by shifting them eastward and widening them meridionally, despite only subtle changes in the precipitation anomaly patterns. During ENSO, CMT affects the low-level winds mainly via the anomalous convection acting on the climatological westerly wind shear over the central Pacific-so that an eastward shift of convection transfers more westerly momentum toward the surface than would occur without CMT. By altering the low-level circulation, the CMT further alters the precipitation, which in turn feeds back on the CMT. In the CGCM, CMT affects the simulated climatology by shifting the mean convection and trade winds eastward and warming the equatorial SST; the ENSO period and amplitude also increase. In contrast to the AGCM simulations, CMT substantially alters the El Nino precipitation anomaly patterns in the CGCM. Also discussed are possible impacts of the CMT-induced changes in climatology on the simulated ENSO.
引用
收藏
页码:213 / 226
页数:14
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