纳木错湖夏季典型大气边界层特征的数值模拟  

Numerical Simulation of Typical Atmospheric Boundary Layer Characteristics over Lake Namco Region,Tibetan Plateau in Summer

作　　者：吕雅琼[1] 马耀明[1] 李茂善[2] 杨显玉[2] 

机构地区：[1]中国科学院青藏高原研究所,北京100085 [2]中国科学院寒区旱区环境与工程研究所西部气候环境与灾害实验室,甘肃兰州730000

出　　处：《高原气象》2008年第4期733-740,共8页Plateau Meteorology

基　　金：国家自然科学基金项目“青藏高原纳木错地区近地层能量交换及环流变化观测研究”(40675012);国家基础发展规划项目“青藏高原环境变化及其对全球变化的响应与适应对策”(2005CB422003);“西藏高原能量水循环降雨共同观测研究”(40520140126)共同资助

摘　　要：为了进一步检验分析纳木错湖对当地地方性环流、湖气能量交换及大气边界层的影响,在本文中使用美国NCAR新版MM5V3.7非静力中尺度模式,设计了有湖面、3/4湖面、1/2湖面及无湖四组试验,以NCEP再分析资料做初、边值条件,做了48 h三重嵌套模拟试验,对比中国科学院"纳木错圈层相互作用"综合观测站实测资料,说明该模式模拟性能良好。白天在纳木错湖风与念青唐古拉山北坡谷风共同作用下,在念青唐古拉山脊处汇合,形成一强水平切变及辐合上升运动,造成了该地夏季白天复杂多变的天气;夜间由于南岸湖风与山风叠加,使得整个区域为强大南风气流控制,这也补给了水汽和热量,也为白天不稳定运动提供了能量。对大气边界层特征的模拟结果表明:由于白天(夜晚)纳木错湖的存在有很好的降温(保温)作用,该湖表现出了明显的冷(暖)湖效应;纳木错湖对感热和潜热的影响有很强的日变化,白天湖面感热、潜热均小于周围陆地,夜间湖面有强潜热通量;纳木错湖使得白天湖区边界层顶低,陆区边界层顶高,夜间相反。这样的地方性环流和大气边界层特征的配合,是该地中小尺度天气剧烈变化的重要原因。In this investigation, four set of triple experiments which include with lake experiment, 3/4 lake experiment, 1/2 lake experiment, without lake experiment were conducted by using NCAR non-hydrostatic mesoscale model （MM5V3.7）. The simulation results are reasonable compared with the observations data from Namco Monitoring and Research Station. The main result show： （1） Combined with the lake-land breeze and mountain-valley winds, in daytime, there is a clear shear line on the Mt. Nyainqentanglha in horizontal direction and a strong up flow in vertical direction, in nighttime, the whole area was controlled by south flow which provide the water vapor and support the day time instability movement. （2） The existence of lake has a strong cold （warm） lake effect to the summer atmospheric boundary layer characteristics over the lake Namco region in daytime （night）. （3） Lake Namco has significant day change impact on sensible heat flux and latent heat flux. Both sensible heat flux and latent heat flux is small in day, and in night, there is strong latent heat flux over the lake. （4） Lake Namco makes atmospheric boundary layer height over the lake lower than the land.

关 键 词：纳木错湖 冷湖效应 湖陆风 山谷风 嵌套数值模拟 

分 类 号：P404[天文地球—大气科学及气象学]