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The effect of subtropical aerosol loading on equatorial precipitation
Author(s) -
Dagan G.,
Chemke R.
Publication year - 2016
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 - 10.1002/2016gl071206
Subject(s) - aerosol , water vapor , hadley cell , environmental science , atmospheric sciences , precipitation , advection , climatology , walker circulation , atmosphere (unit) , subtropics , general circulation model , meteorology , climate change , geology , geography , physics , fishery , biology , oceanography , thermodynamics
Cloud‐aerosol interactions are considered as one of the largest sources of uncertainties in the study of climate change. Here another possible cloud‐aerosol effect on climate is proposed. A series of large eddy simulations (LES) with bin microphysics reveal a sensitivity of the total atmospheric water vapor amount to aerosol concentration. Under polluted conditions the rain is suppressed and the total amount of water vapor in the atmosphere increases with time compared to clean precipitating conditions. Theoretical examination of this aerosol effect on water vapor transport from the subtropics to the tropics, and hence on the equatorial rain and Hadley circulation, is conducted using an idealized general circulation model (GCM). It is shown that a reduction in the subtropical rain amount results in increased water vapor advection to the tropics and enhanced equatorial rain and Hadley circulation. This joins previously proposed mechanisms on the radiative aerosol effect on the general circulation.