Asian Dust Storm Prediction Using Atmosphere-Chemistry-Land Surface Coupled Data Assimilation System

Asian dust storms (ADSs) occur in the spring and early summer and transport mineral dust particles from the source regions --- Gobi Desert, Inner Mongolia, and Northeast China --- over long distances to countries such as South Korea and occasionally to Europe. To improve the ADS prediction, accurate atmospheric and surface conditions are necessary. For example, soil moisture, representing the wetness conditions over the land surfaces of the source regions, can affect ADSs along with the wind variables. A coupled DA system can provide consistent initial conditions for a coupled prediction model with various components, including atmosphere, land, and chemistry observations. Aiming at developing a triple-coupled DA system for the coupled atmosphere-land-chemistry prediction system, we first use the coupled atmosphere-land surface DA system to investigate the sensitivity of dust variables propagated from both atmospheric and soil moisture observations. Next, we used a triple-coupled atmosphere-land-chemistry DA system to understand the real environments of ADSs. For this purpose, we implemented the Maximum Likelihood Ensemble Filter (MLEF) into the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) and conducted a preliminary study on an Asian dust event that occurred in March 2021.