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Relationship between trends in land precipitation and tropical SST gradient
Author(s) -
Chung Chul Eddy,
Ramanathan V.
Publication year - 2007
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl030491
Subject(s) - precipitation , zonal and meridional , climatology , environmental science , forcing (mathematics) , atmospheric sciences , tropics , general circulation model , latitude , climate change , geology , meteorology , geography , oceanography , geodesy , fishery , biology
Land precipitation trend from 1951 to 2002 shows widespread drying between 10°S to 20°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 CO 2 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.