P37  Modeling the Transport and Radiative Forcing of Taklimakan Dust over the Tibetan Plateau in Summer

Chen, Siyu, Pacific Northwest National Laboratory, Richland, WA, USA, Jianping Huang, Lanzhou University, China, Chun Zhao, Yun Qian, L. Ruby Leung, and Ben Yang, Pacific Northwest National Laboratory, Richland, WA, USA

Dust from the Taklimakan Desert (TD) plays an important role in affecting the radiative budget over the Tibetan Plateau (TP), with local and remote atmospheric response. The Weather Research and Forecasting model with chemistry (WRF-Chem) is used to study a case of intense dust storm over the northern slope of TP in summer, when synoptic condition is most favorable for aggregation of TD dust through the year. The model successfully reproduces the spatial distribution of dust during the dust storm compared to the observations. Both observation and simulation show that the dust storm is initiated by the approach of a strong cold front system over the TD. In summer, the meridional transport of TD dust to the TP is enhanced due to weakening of the intensity of westerly at the lower atmosphere over the TD. As a result, a large amount of TD dust is transported by the northeasterly to the TP. During this dust storm, TD dust breaks through the planetary boundary layer (PBL) and extends to a high level reaching up to about 8-10 km above the mean sea level over the TP. The dust loading in the atmosphere decays quickly (by half from 33 Gg to 16.9 Gg) during the southward migration (from 34.5oN to 35.2oN) over the TP due to dry deposition. The simulations show that the TD dust significantly heats the atmosphere with a maximum rate of 3 K day-1 at ~6 km and reduces the solar radiation at the surface by 28.7 W m-2. The promising performance of WRF-Chem in simulating the dust and its radiative forcing provides confidence to use the model for further investigation of dust climatic impact over the TP.