鄱阳湖地区湖陆风特征及成因分析

Analysis of the Phenomenon of Lake-Land Breeze in Poyang Lake Area

利用2006-2010年鄱阳湖地区德安、鄱阳、湖口、进贤和星子站风向、风速常规气象观测资料,分析了鄱阳湖地区湖陆风的特点及季节性变化。结果表明,鄱阳湖地区有湖陆风现象存在。平均而言,东西方向湖陆风强度为0.5~0.7 m·s-1,湖西侧湖陆风转换时间较湖东侧早2 h左右,而南北方向的湖陆风强度相对较弱,为0.3 m·s-1左右,湖北侧的湖陆风转换时间较湖南侧提前近5 h。湖陆风存在季节变化,夏季湖陆风表现得相对更强一些,而秋季表现异于其他季节。利用2010年8月中尺度自动气象站逐时观测资料得到,湖区的湖陆风现象与湖陆热力差异有关。采用浅水波模型对鄱阳湖地区湖陆风形成原因进行了模拟分析,结果与实际现象基本一致,能反映湖陆风的一些特征。

Using the 2006-2010 conventional observed wind data from De' an,Poyang,Hukou,Jinxian and Xingzi,the lake-land breeze in Poyang Lake area was analyzed. These five observation stations are located within about 50 km radius of the Poyang Lake,which are respectively in the west,east,north,south and northwest parts of the Lake. The results show that lake-land breeze in Poyang Lake region occurs through the whole year,although it varies seasonally. Averagely,the strength of the zonal lake-land breeze is larger than the strength of the meridional lake-land breeze,with the values of 0. 5 ~ 0. 7 m ·s-1and 0. 3 m ·s-1respectively.The transition of lake-land breeze in the west of Lake is about two hours earlier than that in the east of Poyang Lake,and the transition of lake-land breeze in the north of Poyang Lake is about five hours earlier than that in the south of Poyang Lake. Analyses of the wind and temperature data in August 2010 from the 153 automatic meteorological stations in the Poyang Lake region show that the lake-land breeze presents diurnal variation obviously due to the lake-land temperature difference. The shallow wave model is employed to study the cause of the lake-land breeze in Poyang Lake region by setting the heating term as the Poyang Lake,and the model can simulate the land breeze during the night and lake breeze during daytime.