海南岛海风三维结构的数值模拟  

NUMERICAL SIMULATION OF THE 3-D STRUCTURE OF SEA BREEZES OVER THE HAINAN ISLAND

作　　者：王语卉 苗峻峰[1] 蔡亲波[2] 

机构地区：[1]南京信息工程大学大气科学学院,江苏南京210044 [2]海南省气象台,海南海口570203

出　　处：《热带气象学报》2016年第1期109-124,共16页Journal of Tropical Meteorology

基　　金：公益性行业(气象)科研专项经费项目(GYHY201306009)资助

摘　　要：利用中尺度模式WRF对2012年4月12日海南岛在无明显天气系统强迫下产生的一次典型的海风个例进行了数值模拟,目的在于揭示海南岛海风的三维结构及其演变特征。通过与观测资料的比较可以看出,WRF模式能够较合理地模拟出此次海南岛海风的演变特征。海风环流开始时间较我国其他地区偏晚,午后开始形成,15—18时达强盛时期,夜间21时海风转为陆风环流。南北向的海风维持时间和强度明显大于东西向的海风环流,而东西部的海风环流开始时间、维持时间和强度都相差不大。午后辐合线主要分布在岛屿城市较密集的北部和西北部沿海地区,污染物不易扩散而导致灰霾等天气,这样的分布与岛屿形状及地形密切相关。在向岸型背景风作用下,岛屿南部海风环流向内陆传播了约80 km,远大于东西部;岛屿西南部五指山和鹦哥岭两座山岭之间形成了强烈的沿峡谷分布的西南气流。垂直方向:白天岛屿西南部山地对海风起到抬升、加强的作用,大地形结合向岸型背景风共同作用使得高空回流减弱;东部和北部平原地区的海风环流结构较完整,东部海风垂直伸展达1.8 km,而北部18时海风环流高度可达2.5 km。12时,海南海岸线附近的位温梯度大幅增大,从而激发了四面的海风;海风锋后是水汽储备的大值区,18时,岛屿山脉南侧(迎风坡)和岛屿中心东北部极易产生暴雨等强对流天气。To study the three-dimensional structure of sea breezes and its diurnal evolution, a non-hydrostatic mesoscale model WRF, version 3.5, is used to simulate a typical case of sea breeze day on April 12, 2012 over the Hainan Island. Compared with observational data, the results show that the evolution and characteristics of sea breezes can be reasonably simulated by WRF. Sea breezes over the Hainan Island begin later than other regions in China. Sea breezes occur in the afternoon, develop intensely during 15：00--18：00 LST and change in- to land breezes at about 21：00 LST. Sea breezes in the north and south stay longer and develop stronger than those in the east and west. At 18：00 LST, two significant convergence lines are located in the north and northwest to the island which is the urban area, with a large convergence zone in the centre. As the convergence lines are mainly distributed in urban areas over the islands, it is easy to gather pollutants and cause hazy weather. Horizontally, owing to the effect of an onshore background flow, sea breezes in the south penetrate approximately 80 km, which is far more than those in other parts of the island. Vertically, the mountains in the southwest play a role in lifting and intensifying sea breezes and the dynamic effect of topography contributes to the development of land breezes in the evening as well. In addition, the return current is weakened by the effect of topography and the onshore background flow and can be shown clearly only in the north and east. Therefore, the structure of sea breezes is the most complete in the eastern and northern plain areas. Sea breezes in the east can reach the height of 1.8 km, and that in the north can extend as far as 2.5 km. The potential temperature over Hainan Island enhances significantly since 12：00 LST, and the gradient near the coastline increases substantially, which generates sea breezes. The gradient reaches the maximum at 15：00 LST in the vicinity of a sea breeze front and sea breezes develop intensely. The wate

关 键 词：天气学 海风环流 高分辨率数值模拟 三维结构 全物理过程 岛屿 复杂下垫面 

分 类 号：P435[天文地球—大气科学及气象学]