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.