Estimation of Asian dust aerosol effect on cloud radiation forcing using Fu-Liou radiative model and CERES measurements

[摘要] The impact of Asian dust on cloud radiative forcing during 2003–2006 isstudied by using the Clouds and Earth's Radiant Energy Budget Scanner(CERES) data and the Fu-Liou radiative transfer model. Analysis of satellitedata shows that the dust aerosol significantly reduced the cloud coolingeffect at TOA. In dust contaminated cloudy regions, the 4-year mean valuesof the instantaneous shortwave, longwave and net cloud radiative forcing are−138.9, 69.1, and −69.7 Wm⁻², which are 57.0, 74.2, and 46.3%,respectively, of the corresponding values in pristine cloudy regions. Thesatellite-retrieved cloud properties are significantly different in thedusty regions and can influence the radiative forcing indirectly. Thecontributions to the cloud radiation forcing by the dust direct, indirectand semi-direct effects are estimated using combined satellite observationsand Fu-Liou model simulation. The 4-year mean value of combination of dustindirect and semi-direct shortwave radiative forcing (SWRF) is 82.2 Wm⁻², which is 78.4% of the total dust effect. The dust directeffect is only 22.7 Wm⁻², which is 21.6% of the total effect.Because both first and second indirect effects enhance cloud cooling, theaerosol-induced cloud warming is mainly the result of the semi-direct effectof dust.

[学科分类] 大气科学