Analysisi Of The Meteorology And Hydrology Condition Of Interannual Change Of Sea Fog Over The Adjacent Marginal Sea Of Qingdao In Summer: Discussion About The Water Vapor Source

This paper analyze and discuss the meteorological and hydrological conditions of sea fog without the influence of precipitation over the adjacent marginal sea of Qingdao in summer, using the monthly foggy days data from 1980 to 2009, the visibility observation data from 1970 to 2007, and the ground-based observations data from MICAPS system and the reanalysis data from JRA-25. After statistical and compositive analysis of the physical fields of the years with more foggy days and years with less foggy days, the main conclusions are as follows:(1) Composing the physical field by taking advantage of the monthly data of years with more foggy days and years with less foggy days. The key area which influence on the source of water vapor lies at 123°E-129°E and 23°N-30°N has been found, associating with the interannual changes of SST in the Kuroshio of the East China Sea in June; And in July, the the key area lies at 123°E-130°E and 26°N-32°N, associating with the interannual changes of SST in the south of Japan Island in July; Sea surface temperature(SST) plays different roles in the formation of the sea fog in the Yellow Sea and the East China Sea. In years with more foggy days, the the SST is higher and the sea surface evaporation is larger in the East China Sea which provide heat and moisture for the low-level flow while the SST is lower and the sea surface evaporation is smaller in the Yellow Sea which are propitious to the cooling of low-level flow's and humidification, and the local sea surface evaporation of the Yellow Sea contributes little, the delivery of low-level warm and moist advection from the sea area of the East China Sea to the Yellow Sea northwardly play an important role in foggy formation. On the other way, the SST is lower and sea surface evaporation is smaller in the East China Sea, while saturation water vapor pressure is increasing, accompanying with SST is increasing in the Yellow Sea which are adverse to the formation of the sea fog. It shows that the formation of sea fog over the adjacent marginal Sea of Qingdao in Summer, which is close to the evaporation of warm sea surface in the sea area of the east of Taiwan, the Kuroshio of the East China Sea and the south of Japan Island, by the transportation of the advecation, and sensitive heat and turbulence on the cool sea surface in the Yellow Sea.(2) Excluding the influence of precipitation and dust on the visibility, focusing lagging and simultaneous statistics correlation analysis which is between the specific humidity around the Qingdao and the advection of specific humidity over the other sea areas on the 26 foggy days in June and 16 foggy days in July during 2005-2007. It shows that the transport of water vapor which is from the Kuroshio of the East China Sea to the adjacent marginal sea of Qingdao is significant in June; and the transport of water vapor which is from the south of the Japan Island to the adjacent marginal sea of Qingdao is significant in July.The path tracking of moisture source on 9 foggy days evidence that the path of the water vapor is from the East China Sea under the guidance of low-level southly wind to the adjacent marginal sea of Qingdao in the synoptic time scale in June, while the path tracking of moisture source on 7 foggy days is a evidence that the path of the water vapor is from the south of Japan Island under the guidance of low-level southeasterly wind to the adjacent marginal sea of Qingdao in the synoptic time scale in July.(3) The position of the characteristic area northward companies with anticyclone northward over the Northwest Pacific in June and July around the adjacent marginal sea of Qingdao, in other words, the amount of sea fog is affected by the interannual changes of the position and the strength of the high pressure over the Northwest Pacific. For years with more foggy days in June, the geopotential height is anomaly higher at 925hPa and 500hPa over the Kuroshio of the East China Sea, the SST is higher under the high pressuer, the southly anomaly is propitious to the transport of the warmer and moister advection from the south to the north. In other way, Years with less foggy days in June, the geopotential height is anomaly lower at 925hPa and 500hPa over the Kuroshio of the East China Sea, the SST is lower under the high pressuer, the northly anomaly is not propitious to the transport of the warmer and moister advection from the southeast to the northwest. For years with more foggy days in July, the geopotential height is anomaly higher at 925hPa and 500hPa over the south of Japan Island, the SST is higher under the high pressuer, the southeastly anomaly is propitious to the transport of the warmer and moister advection from the southeast to the northwest. In other words, Years with less foggy days in July, the geopotential height is anomaly lower at 925hPa and 500hPa over the south of Japan Island, the SST is lower under the high pressuer, the northwestly anomaly is not propitious to the transport of the warmer and moister advection.(4) From the perspective of the influence of tropical convection activity on geopotential height at middle latitude, discussing about the influence of the thermal of the tropical western Pacific and convective activity around Philippines on high pressure over the Yellow sea and the East China sea in years with more foggy days and years with less foggy days. It shows that the anticyclone anomaly at 925hPa and 500hPa over the Kuroshio of the East China Sea is strongly affected by the tropical convection anomaly around Philippines (120°E-135°E, 8°N-16°N) for years with more foggy days in June; the anticyclone anomaly at 925hPa and 500hPa over the south of Japan Island, is strongly affected by the tropical convection anomaly around Philippines (122°E-135°E,17°N-23°N) for years with more foggy days in July. These indicate that the amount of sea fog around the adjacent marginal sea of Qingdao, associating with the changes of the position and the strength of the anomaly high pressure over the Yellow sea and the East China sea closely, while the changes of the position and strength of the nomaly high pressure closely associates with the nomaly convection activity around Philippines.