Impact of high-frequency observations on fog forecasting: A case study of OSSE

As the measure of visibility of air environment, it directly affects societal economic activities and daily lives. As more and more high-frequency observations (observations with short time intervals) become available, understanding how to make full use of such observed data to improve fog forecasting is an important and urgent research topic.

Based on the Weather Research and Forecasting (WRF) Model and an observation simulation system experiment (OSSE) framework, this study explores a modified three-dimensional variational (3D-Var) data assimilation (DA) scheme to address the utilization of high-frequency observations on fog forecasting. In the modified 3D-Var scheme, the large-scale analysis constraint (LSAC) method is employed to the WRF 3D-Var. A dense fog event, which occurred in the North of China in 2007, is selected for the case study.