土地利用类型变化对城市大气边界层特征影响的数值模拟  

Numerical simulations of effects on urban PBL characters with landuse categeories modification

作　　者：张弛[1] 束炯[1] 

机构地区：[1]华东师范大学地理信息科学教育部重点实验室,上海200062

出　　处：《华东师范大学学报（自然科学版）》2011年第4期83-93,共11页Journal of East China Normal University(Natural Science)

基　　金：国家自然科学基金(40671176);上海市基础重点项目(08JC1408500;072512021);上海市环保局重点项目

摘　　要：利用ENVI和IDL,GIS以及上海市航片,将ARW-WRF中尺度模式中的下垫面土地利用类型数据中上海市部分做了修正:对照模式中24种土地类型分类,将原本定义为农作物耕地和草场,草地,灌木丛,以及沙土和淤泥的部分,根据实际情况改为城区和在建城区,扩大了城市的范围,获取城市建筑物高度信息以得到更精确地粗糙度数据,使其与实际情况更相符.对上海地区春季大气边界层的风场、温度场以及边界层高度等特征值分别进行了土地利用数据修正前后的数值模拟研究,对比结果,发现下垫面土地利用类型由耕地等类型变为城市后,水平风速显著减小,呈现明显城市拖曳作用;垂直速度增大,并由于白天陆面加温作用更为显著,在地面风场的作用下高温中心出现偏于下风方向;近地面气温和边界层高度均更贴近实测值.由上述结果引出讨论了下垫面土地利用分类在模式模拟中的重要地位及其他可能原因.ENVI,IDL,GIS and aerial photographs were used to modify landuse data in ARW-WRF within Shanghai area.Firstly,grids were gained with GIS into the same resolution with the input data in WRF,which is too old for present landuse situation in Shanghai.Secondly,irrigated cropland and pasture,grassland,shrubland,loamy sand and silt were partly changed into urban and built-up land grid by grid,so as to be more closer to real situation,and the distribution of buildings was gained,helping to reach more accurate roughness value in UCM according to the 24 landuse categories defined in WRF model.Lastly,both modified and original data were input into WRF in case simulations.The wind field,temperature,and other characters of PBL in spring of Shanghai were gained in the simulation results.It shows that because of landuse types modification,horizontal wind velocity decreases obviously,displaying the urban dragging effects.Meanwhile,the vertical wind velocity increases,being greatly affected by surface warming effects.The higher temperature centers appear in the downwind direction by the effects of surface wind fields.Surface temperature and PBL height are both closer to observation values.The results lead us to discuss the importance of landuse categories input in models,and some other possible reasons causing the difference were mentioned.

关 键 词：WRF模式 下垫面土地利用类型 城市建筑物 大气边界层 数值模拟 

分 类 号：P4[天文地球—大气科学及气象学]