Observational analysis and numerical simulation of an advection-radiation sea fog event in winter

In this study,a dense fog event occurred around the coastal of Bohai Sea and Huanghai Sea from 23^th to 24^th in Dec.2003,is analyzed with observational data and investigated with numerical model.During the fog days,about 100 thousands of square kilometers of area from of fing to inland was covered,partly with visibility less than 200 m,which led to a great influence for the traffic both on sea,land and in air.So almost all available observational data are used to analyze the evolutionary process of the fog from it's formation to dissipation,and it's concluded that it's a typical advection-radiation fog occurred over the sea-land int erface in winter.Then fog event is simulated with the RAMS(Regional At mospheric Modeling System) model.The horzontal visibility distribution of lower at mosphere and the vertical distribution of the cloud mixing ratio are calculated based upon the model out puts,the results indicates that,the shape of fog area,the time when fog formed and dissipated,as well as the thickness of the fog which derived from the simulation agrees with the observation data well.