Simulation and Analysis of Winter Advection Fog in Beijing Area

Fog is a disruptive weather phenomenon in many parts of the world.While direct loss of life does not approach that due to severe convective storms or snow,its economic effect through transport disruption is considerable. Beijing was hit by a heavy fog since the morning on 14 Jan 2006, and the minimum visibility at the Beijing Capital International Airport was fewer than 50 meters. The lower visibility maintained about 5 hours. More than 500 flights were delayed and about near ten thousands people was held back in the Airport. In this paper, the advection fog on 14 Jan 2006 in Beijing area is simulated and diagnosed with WRF(Weather Research & Forecasting) nonhydrostatic model.It shows that the advection fog was formed when warm and moist air lied on the SEAE and S of Beijing area was moved to the cooler ground.The continues and weak southern wind was one of the factors that the fog could maintain.The other important reason is that inversion layer were lifted from the ground to lower level of the air and maintained. The cold air intrusion resulted in the fog dispersion.Potential ability of prediction the advection fog by WRF model is proved to some extent.