摘要
In this paper, a heavy sea fog event occurring over the Yellow Sea on 11 April 2004 was investigated based upon observational and modeling analyses. From the observational analyses, this sea fog event is a typical advection cooling case. Sea surface temperature(SST) and specific humidity(SH) show strong gradients from south to north, in which warm water is located in the south and consequently, moisture is larger in the south than in the north due to evaporation processes. After fog formation, evaporation process provides more moisture into the air and further contributes to fog evolution. The sea fog event was reproduced by the Regional Atmospheric Modeling System(RAMS) reasonably. The roles of important physical processes such as radiation, turbulence as well as atmospheric stratification in sea fog's structure and its formation mechanisms were analyzed using the model results. The roles of long wave radiation cooling, turbulence as well as atmospheric stratification were analyzed based on the modeling results. It is found that the long wave radiative cooling at the fog top plays an important role in cooling down the fog layer through turbulence mixing. The fog top cooling can overpower warming from the surface. Sea fog develops upward with the aid of turbulence. The buoyancy term, i.e., the unstable layer, contributes to the generation of TKE in the fog region. However, the temperature inversion layer prevents fog from growing upward.
In this paper, a heavy sea fog event occurring over the Yellow Sea on 11 April 2004 was investigated based upon obser- vational and modeling analyses. From the observational analyses, this sea fog event is a typical advection cooling case. Sea surface temperature （SST） and specific humidity （SH） show strong gradients from south to north, in which warm water is located in the south and consequently, moisture is larger in the south than in the north due to evaporation processes. After fog formation, evaporation process provides more moisture into the air and further contributes to fog evolution. The sea fog event was reproduced by the Re- gional Atmospheric Modeling System （RAMS） reasonably. The roles of important physical processes such as radiation, turbulence as well as atmospheric stratification in sea fog＇s structure and its formation mechanisms were analyzed using the model results. The roles of long wave radiation cooling, turbulence as well as atmospheric stratification were analyzed based on the modeling results. It is found that the long wave radiative cooling at the fog top plays an important role in cooling down the fog layer through turbulence mixing. The fog top cooling can overpower warming from the surface. Sea fog develops upward with the aid of turbulence. The buoyancy term, i.e., the unstable layer, contributes to the generation of TKE in the fog region. However, the temperature inversion layer prevents fog from growing upward.
基金
supported by the 201205010-5 program of the State Oceanic Administration of China and the Natural Science Foundation of China under the grant 41306028
partly supported by the National Natural Science Foundation of China under the grant number, 406750060 and 41275049
the Chinese Ministry of Science and Technology under the 863 Project grant number 2006 AA09Z151
the Chinese Meteorological Administration under the grant number GYHY(QX)200706031
the China Scholarship Council for the financial support to his study in NOAA from 2008 to 2010, which enables him to participate in the present work
supported by China postdoctoral funding under the grant 2012M511545
the Natural Science Foundation of China under the grant 41305086
supported by the open project of the Lab. of Physical Oceanography, Ocean University of China
