海南岛地形对局地海风降水强度和分布影响的数值模拟  

A Numerical Study of Impact of Topography on Intensity and Pattern of Sea Breeze Precipitation over the Hainan Island

作　　者：王莹 苗峻峰[1] 苏涛[1,2] 

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]湖南省气象台,湖南长沙410118

出　　处：《高原气象》2018年第1期207-222,共16页Plateau Meteorology

基　　金：公益性行业(气象)科研专项(GYHY201306009)

摘　　要：利用高分辨率模式WRF对2013年5月31日发生在海南岛的一次海风降水过程进行数值模拟,通过不同地形高度及裸土化的敏感性试验,探讨了地形对局地海风降水模拟的影响。结果表明,随着海风环流的不断发展,海风锋与降水落区几乎同相向内陆推进,降水落区主要分布在岛屿西部的黎母岭山前。海南岛海风降水的强度及分布特征与当地四周低平、中间高耸的地形特点密不可分,地形在整个海风降水期间存在动力、热力作用的交替演变。11:00(北京时,下同)-16:00,降水主要由岛屿单侧海风锋引起,由于海风所经之处地形坡度较低,地形对海风的影响以热力增强为主,地形高度越大,驱动海风发展的海陆感热通量差异越大,海风环流发展越旺盛,降水强度也越大。17:00-21:00,降水主要由东南、西北向海风锋正向碰撞造成,随着海风不断向内陆传播,地形的动力阻挡作用越来越强,当地形坡度增加到一定程度时,这种阻挡作用可以迅速削弱海风环流,使降水强度减小。裸土化试验进一步表明,地形高度变化导致的以上影响依赖于下垫面的非均匀特征,地形和植被的共同作用可使地表能量的分配产生更大的差异,进而对局地降水产生较大的影响。Sea Breeze is a common local circulation driven by differential heating between land and sea, which has been studied observationally, experimentally, theoretically and numerically for a long time. Previous studies have shown that sea breeze can be strongly influenced by complex inland topography, theoretically from dynamic and thermodynamic aspects. The studied area Hainan Island which has high occurrence of sea breeze also has spe- cial terrain characteristics, therefore the sea breeze is different from other coastal areas, and the sea breeze pre- cipitation is one of the most important precipitation regimes in Hainan according to previous studies. In this pa- per, the sea breeze precipitation over the Hainan Island on May 31, 2013 was simulated by high-resolution nu- merical model WRF, the impact of topography on intensity and pattern of local sea breeze precipitation was stud- ied by designing different topography experiments. The results show that, WRF model can simulate the surface wind and sea breeze precipitation intensity reasonably, and the time evolution of simulation and actual precipitati- on generally approaches well. With the continuous development of sea-breeze circulation, the timing and place- ment of convective precipitation as well as the sea breeze front almost move inland in phase, and the precipitation area mainly distribute in the front of Li Mu Mountain, which is located in the southwest of studied area. The rain- fall structural characteristics are closely associated with the topography feature which is high and upright in the middle area while relatively lower all around in the Hainan Island, the dynamic and thermodynamic influence of terrain has alternate evolution in the whole process of sea breeze precipitation. During 11：00 -- 16：00 BST, pre- cipitation was mainly caused by single sea breeze front. The primary mechanism was thermal enhancement duing to the lower height of topography at this stage, and the sea-land thermal flux difference which essentially drive the development of

关 键 词：热带岛屿 复杂地形 海风辐合线 海风锋 海风降水 

分 类 号：P458.2[天文地球—大气科学及气象学]