Identification of the Beginning of the Sea-fog Season Over the Yellow Sea and Its Inter-annual Variation
|School||Ocean University of China|
|Keywords||Sea fog Start Date Yellow Sea|
Sea fog is a great danger of maritime disasters, weather phenomena, and the Yellow Sea in northern China in recent Sea fog-prone waters, so to improve and master the northern waters of the Yellow Sea, the sea fog formation mechanism and dissipation law to protect the northern Yellow Sea maritime transportation and harbors and waterways safety significance, especially mastered time can provide reference and guidance for the arrangement of production operations at sea fog season began, has important academic significance and economic and social value. In this paper, the 14 meteorological stations in Shandong Province, 1979-2007 4 times daily visibility observations, NCEP / NCAR and JRA reanalysis data and other data, by calculating sea fog-related physical changes, the use of synthetic analysis and case analysis means the atmospheric circulation in the northern Yellow Sea fog before and after the start of the season, atmospheric stratification stability, temperature inversion, sea surface temperature and sea temperatures and poor physical difference, and made specific factors affect the start time of the fog season analysis, summed up the start time of the northern Yellow Sea fog season. The main conclusions in this paper are as follows: 1. Determine the standard of the Yellow Sea fog season began: defined based on the of pentad mean frequency of fog anomalies cumulative index, used to represent the year in fog frequency trends over time. Under sea temperatures difference is less than 0 ° C and the conditions, fog frequency anomaly accumulation index increases continuously over two waiting, to start to increase as the beginning of the fog season and which designate the fog. By this standard can be determined Yellow Sea climate average fog season started in the first 20 candidates. 2. 21-22 designate fog season begins, the Yellow Sea, northwest prevails southerly over the Yellow Sea is the humidity advection and warm advection at 925hPa over the Yellow Sea, is conducive to the establishment of the inversion layer, which are conducive to the generation of advection fog. Yellow Sea northwest southerly airstream over the Yellow Sea almost no positive humidity advection 925hPa over the Yellow Sea no apparent background conditions such as warm advection fog season before the start of the 18-19 climate in stark contrast. The fog season starts sooner or later the time differences between different years. Selection of fog season began early 2007 and the fog season began late 2005 comparison: under the more favorable conditions of the sea - air temperature difference and static stability, sustained more than one candidate before the start of the foggy season southerly and The larger positive humidity advection northern Yellow conveying sufficient water vapor, which plays an important role in the beginning of the fog season. Fog season began to partial early years and fog season began partial composite analysis of his later years: the continuing southerly winds and moisture transport over the Yellow Sea may affect the fog season to start sooner or later one of the reasons, this analysis consistent with the typical year. China Yellow East Sea SST configuration also began to contribute to the northern Yellow Sea fog season, the East China Sea temperature positive (negative) anomalies stronger than the northern East China Sea, the Yellow Sea south of SST positive (negative) anomalies when the northern Yellow Sea fog season start time earlier (late). Sooner or later have a more pronounced effect on the sea surface temperature anomalies in the East China Sea and the Yellow Sea, the sea fog season. Although the sea - the temperature difference is less than 0 ℃ is the prerequisite of sea fog season began, but no significant effect on the sea fog season start sooner or later. The height of the inversion layer may affect the occurrence of sea fog season, the the fog season began partial early years of the inversion layer closer to the ground.