Skip all navigation and jump to content Jump to site navigation
About MODIS News Data Tools /images2 Science Team Science Team Science Team

   + Home
MODIS Publications Link
MODIS Presentations Link
MODIS Biographies Link
MODIS Science Team Meetings Link



Wang, MH; Ghan, S; Liu, XH; L'Ecuyer, TS; Zhang, K; Morrison, H; Ovchinnikov, M; Easter, R; Marchand, R; Chand, D; Qian, Y; Penner, JE (2012). Constraining cloud lifetime effects of aerosols using A-Train satellite observations. GEOPHYSICAL RESEARCH LETTERS, 39, L15709.

Aerosol indirect effects have remained the largest uncertainty in estimates of the radiative forcing of past and future climate change. Observational constraints on cloud lifetime effects are particularly challenging since it is difficult to separate aerosol effects from meteorological influences. Here we use three global climate models, including a multi-scale aerosol-climate model PNNL-MMF, to show that the dependence of the probability of precipitation on aerosol loading, termed the precipitation frequency susceptibility (S-pop), is a good measure of the liquid water path response to aerosol perturbation (lambda), as both S-pop and lambda strongly depend on the magnitude of autoconversion, a model representation of precipitation formation via collisions among cloud droplets. This provides a method to use satellite observations to constrain cloud lifetime effects in global climate models. S-pop in marine clouds estimated from CloudSat, MODIS and AMSR-E observations is substantially lower than that from global climate models and suggests a liquid water path increase of less than 5% from doubled cloud condensation nuclei concentrations. This implies a substantially smaller impact on shortwave cloud radiative forcing over ocean due to aerosol indirect effects than simulated by current global climate models (a reduction by one-third for one of the conventional aerosol-climate models). Further work is needed to quantify the uncertainties in satellite-derived estimates of S-pop and to examine S-pop in high-resolution models. Citation: Wang, M., et al. (2012), Constraining cloud lifetime effects of aerosols using A-Train satellite observations, Geophys. Res. Lett., 39, L15709, doi:10.1029/2012GL052204.



NASA Home Page Goddard Space Flight Center Home Page