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使用地球观测系统的中分辨率成像光谱仪(EOS-MODIS)提供的归一化植被指数(NDVI)产品估算植被覆盖度和航天飞机雷达地形测绘任务(SRTM)制成的数字高程模型(DEM)数据遥感产品替换WRF模式默认的植被覆盖度和地形高度,并且利用WRF模式及其先进的三维变分同化系统(WRF-3DVar)循环同化东北半干旱区自动气象站近地面气象要素,对东北半干旱区的温度场、湿度场、风场和能量场的结构及其日变化特征进行了较为细致的模拟研究.通过4组数值模拟试验分别探讨了同化气象要素与改变模式地表参数引起的不同下垫面潜热、感热的分配关系和降水、土壤湿度变化引起的地表能量通量模拟效果,并利用通榆站、奈曼站、锦州站、和密云站2009年6~8月的通量观测资料与模拟结果对比检验.结果表明,WRF模式能够较好地模拟出东北半干旱区夏季的近地面温度、风向、净辐射、感热和潜热等要素的变化特征及日变化规律.同化试验(Case 2)模拟的近地面气温、相对湿度、风速相比控制性试验(Case 1)有所改善;陆面参数试验(Case 3)和集合试验(Case 4)改善了感热和地表热通量的模拟.WRF模式能较好地模拟出下垫面土壤湿度随时间变化的规律,集合试验(Case 4)土壤湿度模拟结果与4个通量站观测值相比无太大差别,但降水的模拟有待改善.本研究利用卫星遥感资料改善模式下垫面陆面参数,利用气象资料同化改善近地面大气要素模拟精度,这是将各种不同空间和时间尺度的多源数据与数值模拟融合的有益尝试.此研究生成的东北地区资料同化数据集可用于气候变化、干旱监测等方面,对深入了解半干旱区气候的形成和维持机理具有重要的意义.
Estimating vegetation cover using the Normalized Vegetation Index (NDVI) product provided by the Earth Observation System’s Medium Resolution Imaging Spectrometer (EOS-MODIS) and Digital Elevation Model (DEM) data from the Space Shuttle Radar Topography Mission (SRTM) Remote sensing products replace WRF model default vegetation cover and terrain height, and WRF-3DVar (WRF-3DVar) is used to assimilate near-surface meteorological elements of automatic meteorological stations in northeast semi-arid region using WRF model and its advanced semi-arid semi-arid The structure of the temperature field, the humidity field, the wind field and the energy field and the diurnal variation characteristics of the field are studied in detail.Four groups of numerical simulations are used to investigate the effects of assimilating meteorological elements and changing surface parameters Surface latent heat, sensible heat distribution and surface water flux caused by precipitation and soil moisture change. By using the flux observation data of Tongyu Station, Naiman Station, Jinzhou Station and Miyun Station from June to August in 2009 The results show that the WRF model can simulate the near-surface temperature, wind direction, net radiation, sensible heat Latent heat and other characteristics and diurnal variation.Comparison of Case 2 with Case 2 shows that Case 2 is better than Case 1 in Case 2 and Case 2, Case 4 improved the simulation of sensible heat and surface heat flux.WRF mode can well simulate the law of soil moisture change with time in the underlying surface. Case 4 soil moisture simulation results and 4 pass However, the simulation of precipitation has yet to be improved.In this study, satellite remote sensing data were used to improve the land surface parameters in the mode, and the meteorological data assimilation was used to improve the simulation accuracy of the near-surface atmospheric components, Different spatial and temporal scales of multi-source data and numerical simulation.This dataset of data assimilation in northeastern China can be used in climate change and drought monitoring and so on, which has the important significance for understanding the formation and maintenance mechanism of climate in semi-arid region Significance.