87th AMS Annual Meeting

Wednesday, 17 January 2007: 2:00 PM
A Diurnal Radiative Forcing of Dust Aerosols over East Asia
214B (Henry B. Gonzalez Convention Center)
Ji-Young Kim, University of Albany/SUNY, Albany, NY; and W. C. Wang
Mineral dust aerosols change the regional and global radiative energy balance at the top of the atmosphere (TOA) and at the surface by scattering and absorbing short-wave and long-wave radiation. East Asia is one of the largest source regions of dust aerosols and is one of the strongest dust radiative forcing regions (IPCC, 2001). Hence, numerous studies have been performed to simulate their transport and to calculate dust radiative forcing over this region. This study is focused on the diurnal cycle of dust radiative forcing along with dust loading and surface temperature.

SUNYA regional climate model (RCM; Cheng and Wang, 2006) was incorporated with available dust emission, transport, and deflation modules of Wang et al. (2000) and Chen et al. (2004). On-line experiment was conducted for April of 2001 and 2003. ECMWF TOGA and NCEP reanalysis datasets were used for the initial and boundary conditions. For the model validation, TOMS AI data was compared with aerosol mass concentration. The SSiB scheme, which is designed for land-surface interactions, in SUNYA-RCM is a useful tool to study this topic.

For the basic climatology validation, the overall spatial distribution and temporal evolution of wind speed, relative humidity, and temperature are reasonably well captured, while they have mean bias errors. Since sensitivity test reveals surface wind speed and relative humidity as the most critical factors affecting dust emission, their mean bias errors were corrected for model application. Therefore, the model-observation comparisons suggest that the model is capable of simulating the evolution of the dust storms over this region.

Model-simulated aerosol mass concentration was validated against satellite and surface station datasets. Moreover, to investigate the relationship between dust and the climate system, the diurnal variations of dust loading and dust radiative forcing were examined and as well surface temperature.

It is expected that a diurnal cycle of dust radiative forcing is closely related to those of dust loading and surface temperature.

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