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A GCM study of effects of radiative forcing of sulfate aerosol on large scale circulation and rainfall in East Asia during boreal spring
Author(s) -
Kim MaengKi,
Lau William K. M.,
Kim KyuMyong,
Lee WooSeop
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 - 10.1029/2007gl031683
Subject(s) - aerosol , climatology , atmospheric sciences , radiative forcing , environmental science , forcing (mathematics) , radiative transfer , sulfate aerosol , precipitation , radiative cooling , east asia , geology , meteorology , physics , geography , china , archaeology , quantum mechanics
The effect of sulfate aerosol radiative forcing on spring rainfall in East Asia are studied based on numerical simulations with the NASA finite‐volume General Circulation Model (fvGCM) forced with monthly varying three‐dimensional aerosol distribution from the Goddard Ozone Chemistry Aerosol Radiation and Transport model (GOCART). Result shows that radiative forcing of sulfate aerosol leads to cooling of the land surface and reduction in rainfall over central East Asia. The maximum reduction in precipitation is shifted northward relative to the maximum aerosol loading region as a result of dynamical feedback. The anomalous thermal gradient by aerosol cooling near the land surface, reduces the baroclinicity of the atmosphere, leading to a deceleration of the upper level westerly flow. The westerly deceleration induces, through ageostrophic wind adjustment, anomalous meridional secondary circulation at the entrance region of the East Asian jetstream, with strong sinking motion and suppressed precipitation near 30°N, coupled to weak rising motion and moderately enhanced precipitation over southern China and the South China Sea. These results suggest that the radiative forcing of aerosol through induced dynamical feedback with the atmospheric water cycle, may be a causal factor in the observed spring precipitation trend over East Asia.