A Heavy Sea Fog Event over the Yellow Sea in March 2005:Analysis and Numerical Modeling

【作者】 高山红； 林行； 吴增茂； 沈飚；

【Author】 Gao Shanhong1 Lin Hang2 Wu Zengmao1, Shen Biao1 1 Physical Oceanography Laboratory, Ocean University of China, Qingdao 266003 2 Marine Meteorology Institute, Qingdao Observatory, Qingdao 266003

【机构】 Physical Oceanography Laboratory, Ocean University of China； Marine Meteorology Institute, Qingdao Observatory；

【Abstract】 In this paper, a heavy sea fog episode that occurred over the Yellow Sea on 9 March 2005 is investigated. The sea fog patch, with a spatial scale of several hundred kilometers at its mature stage, reduced visibility along the Shandong Peninsula coast to 100 meters or much less on some sites. Satellite images, surface observations and soundings at islands and coasts, and analyses of Japan Meteorology Agency (JMA) are used to describe and analyze this event. This sea fog belongs to typical advection cooling fog. The main features of this sea fog in terms of fog area and its movement are reasonably reproduced by the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5). The environmental conditions (sea surface winds, difference between air temperature and sea surface temperature (SST)) and planetary boundary layer (PBL) structure that are related to the sea fog formation and evolution are discussed in detail. Model results suggest the formation and evolution of this sea fog can be outlined as the following: (1) southerly warm moist advection resulted in a sea-surface-based inversion with a thickness of 600 meters or so; and (2) because of cold sea surface, turbulence mixing transferred heat to sea surface that led to a thermal internal boundary layer (TIBL) forming within the inversion, and then sea fog grew in this layer due to humidification and cooling by turbulence mixing; and (3) sea fog developed following movement of the TIBL pushed by southerly wind; and (4) strong cold northerly wind destroyed the TIBL and soon dispersed sea fog. In addition, a series of experiments are performed to test sensitivity of the modeling result to horizontal and vertical resolutions, SSTs, schemes of PBL, and initial and lateral conditions. These tests indicate that modeling result strongly depends on PBL scheme, as well as initial and lateral conditions including SST. The study in this paper indicates that it is a feasible approach to predict sea fog over the Yellow Sea using a numerical model and it may be more efficient and promising through ensemble numerical modeling.更多还原