The Characteristics Of Atmospheric Boundary Layer And The Relationship With The Distributions Of Sea Fog/low Cloud At Yellow-East Sea

L band radar sounding data and surface observation data of Qingdao and Taizhou,CFSR data, OAFlux data, ICOADS data have been used to study that the boundarylayer characteristics of Qingdao and Taizhou, the boundary layer basic characteristicat Yellow-East Sea and the relationship with distribution of low cloud. Theconclusions are as follows:The stable boundary layer occurrence frequencies at Qingdao have two top value,respectively in April and November, the frequency of occurrence of the convectiveboundary layer changes little, and lower than which of stable boundary layer all theyear around. There are higher frequencies of stable boundary layer in winter andspring at Taizhou, the lowest in summer. The occurrence frequencies of convectionboundary layer are the highest in summer, next in spring, the minimum in autumn andwinter. The stable boundary layers of Qingdao and Taizhou occur almost all in rear ofabnormal high pressure or in front of low pressure, there is abnormal southerly wind.Convective boundary layers occur in front of the abnormal high pressure or the rear ofabnormal low pressure, there is abnormal northern wind.There are important influences of SST and sea surface wind distribution on thedistribution of boundary layer height. Effects of advection of the prevailing wind andthe characteristics of underlying surface combination have a result of low levelstability changes, also make yellow sea boundary layer height lower in summer,higher in winter, lower in the northern, higher in the southern, lower in the western,higher in the Eastern. The analysis of EOF modal shows that the boundary layerheight at Yellow-East Sea has one year period cycle. The first mode is consistent inthe space, and show the difference between summer and winter. This character showsthe air-sea temperature difference. It shows the effect of the large scale circulation. The second mode shows the difference between spring and autumn. There are twoopposite distribution type at the space, East increase by west decrease and Eastdecrease by west increase. The seasonal change of ocean front, cold and warm watertongue determines the lower atmospheric stability, then influence the boundary layerheight. The time of the maximum value and the size of the boundary layer height ismore consistent. The minimum values decrease from the ocean fronts to the northern,and to the southern there is little changes. The time of the minimum has large changesat Yellow-East Sea. The difference of time is mainly due to the seasonal changes ofEast China Sea and Yellow Sea cold tongue.The frequencies of sea fog in Qingdao are higher than that in Taizhou, but thefrequencies of low cloud is higher in Taizhou. L band radar data of the two stationsshow this character by the vertical distribution of difference between temperature anddew point. The northern frequencies of sea fog are higher than the southern; the cloudfrequencies of low level cloud are less than the southern. The western frequencies ofsea fog are higher than the eastern; the cloud frequencies of low level cloud are lessthan the eastern. The lower boundary layers correspond to the higher frequencies ofthe sea fog. The boundary layer heights are relatively lower when sea fog occurs, buthave less relationship with the lifting condensation level. The boundary layer heightsare higher when low-level cloud occurs, although it isn’t right all the times, but it canbe said that the boundary layer height is generally higher than the lifting condensationlevel.