Relationship between trends in land precipitation and tropical SST gradient

被引:26
作者
Chung, Chul Eddy [1 ]
Ramanathan, V. [1 ]
机构
[1] Scripps Inst Oceanog, Ctr Clouds Chem & Climate, La Jolla, CA 92093 USA
关键词
D O I
10.1029/2007GL030491
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
Land precipitation trend from 1951 to 2002 shows widespread drying between 10 degrees S to 20 degrees N but the trend from 1977 to 2002 shows partial recovery. Based on general circulation model sensitivity studies, it is suggested that these features are driven largely by the meridional SST gradient trend in the tropics. Our idealized CCM3 experiments substantiate that land precipitation is more sensitive to meridional SST gradient than to an overall tropical warming. Various simulations produced for the IPCC 4th assessment report demonstrate that increasing CO2 increases SST in the entire tropics non- uniformly and increases land precipitation only in certain latitude belts, again pointing to the importance of SST gradient change. Temporally varying aerosols in the IPCC simulations alter meridional SST gradient and land precipitation substantially. Anthropogenic aerosol direct solar forcing without its effects on SST is shown by the CCM3 to have weak but non- negligible influence on land precipitation.
引用
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页数:5
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