【作者】 王腾蛟； 张镭； 胡向军； 赵世强；

【Author】 Wang Tengjiao1,Zhang Lei1,Hu Xiangjun1,2,Zhao Shiqiang1,3,Wang Jin1(1.Key Laboratory for Semi-Arid Climate Change of the Ministry of Education,Lanzhou University,Lanzhou,730000;2.Lanzhou Central Meteorological Observatory,Lanzhou,730020;3.Unit of 93808 of People’s Liberation Army,Yuzhong,Gansu,730109)

【机构】 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； 兰州中心气象台； 93808部队；

【摘要】 利用WRF中尺度数值模式提供的两种边界层参数化方案(YSU和MYJ),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模式能够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;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以达到2500m,夜间稳定边界层高度可以达到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方案能够更好地模拟出对流边界层的的结构特征,而MYJ局地闭合方案则对稳定边界层的模拟表现更优。更多还原

【Abstract】 Two planetary boundary layer(PBL) parameterizations(YSU and MYJ) schemes in Weather Research Forecasting(WRF) numerical model are 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 comparison results reveal that WRF model has good quality in simulating the diurnal characteristics 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 fields itself.The landuse type,soil type and soil moisture provided by model have a great influence on latent heat flux simulation during the day.The convective boundary layer maximum height of semi-arid areas of the Loess Plateau can reach 2500m,the nighttime stable boundary layer height generally exceeds 700m.In regard to PBL structures,a non-local scheme with the entrainment flux proportional to the surface flux is favourable under unstable conditions.Under stable conditions,the local TKE closure schemes perform better than the first-order approaches.更多还原