WRF模式对黄土高原丘陵地形条件下夏季边界层结构的数值模拟  

Numerical Simulation of Summer Boundary Layer Structure over Undulating Topography of Loess Plateau Simulated by WRF Model

作　　者：王腾蛟[1] 张镭[1] 胡向军[1,2] 赵世强[1,3] 王瑾[1] 

机构地区：[1]半干旱气候变化教育部重点实验室/兰州大学大气科学学院 [2]兰州中心气象台 [3]中国人民解放军93808部队

出　　处：《高原气象》2013年第5期1261-1271,共11页Plateau Meteorology

基　　金：国家自然科学基金项目(41075104);国家重点基础研究发展规划项目(2010CB428604)

摘　　要：利用中尺度数值模式WRF提供的两种边界层参数化方案(YSU和MYJ方案),选取2009年7月27-29日作为夏季个例,对黄土高原丘陵地形条件下大气边界层结构及地表能量场特征进行了较为细致的模拟研究。结果表明,WRF模式较好地模拟出黄土高原夏季边界层结构的日变化及近地面温度场、风场、净辐射通量、感热通量和潜热通量等要素的变化特征。WRF模式对温度的模拟最好,相关系数达到了0.95,对风速的模拟则较差,这与风场本身的随机多变性有很大的关系;WRF模式提供的土地利用类型、土壤类型以及NCEP提供的初始场土壤湿度与实际不符,是造成白天地表能量场模拟效果较差的主要原因;黄土高原半干旱区对流边界层最大高度可达到2 500m,夜间稳定边界层高度可达到700m左右。两种方案的对比分析表明,加入了非局地混合作用以及边界层顶夹卷作用的YSU方案能更好地模拟出对流边界层结构特征,而MYJ局地闭合方案则对稳定边界层的模拟表现更优。Two planetary boundary layer （PBL） parameterization （YSU and MYJ） schemes in Weather Re- search Forecasting （WRF） numerical model were used to simulate the PBL structure, net radiation flux, sensible heat flux, latent heat flux and soil heat flux in the undulating topography of Loess Plateau during July 27--29, 2009. The two schemes include a first-order closure schemes： the Yonsei University （YSU） PBL scheme, and a turbulent kinetic energy （TKE） closure schemes （the Mellor-Yamada-Janjic （MYJ） PBL scheme）. The simulated results are compared with the observations provided by Semi-Arid Climate Observatory Laboratory （SACOL） of Lanzhou University. The compared results reveal that WRF model has good quality in simulating the diurnal characteristic of surface temperature. On the other hand, the simulation of the wind speed is poor, that has a great relationship with the random variability of the wind field itself. The landuse type, soil type and soil moisture provided by model have a great influence on la- tent heat flux simulated during the day. The maximum height of convective boundary layer of semi-arid ar- ea of the Loess Plateau can reach 2 500 m, the nighttime stable boundary layer height at the generally ex- ceeds 700 m. In regard to PBL structure, a non-local scheme with the Entrainment flux proportional to the surface flux is favourable under unstable conditions. Under the stable condition, the local TKE closure scheme perform better than the first-order approaches.

关 键 词：WRF模式 边界层参数化方案 黄土高原 潜热通量 感热通量 

分 类 号：P435[天文地球—大气科学及气象学]