基于MODIS的青海冷湖地区大气水汽含量时空分布特征研究

Research of spatial and temporal distribution characteristics of precipitable water vapor in Lenghu area of Qinghai based on MODIS

为了解青海冷湖地区大气水汽含量时空分布特征,确定天文台选址和最佳观测时间段,本研究利用2015—2020年的1931景MODIS日尺度提取了冷湖地区大气水汽含量数据,并结合NCEP再分析资料对其结果进行验证,对冷湖地区长时序大气水汽含量时空分布特征和土地覆盖类型等因素进行分析。结果表明:(1)研究区2015—2020年年平均大气水汽含量为059 g/cm^(2),冬季大气水汽含量最低,为009~251 g/cm^(2);(2)研究区土地覆盖类型与大气水汽含量存在明显相关性,草地和裸地共占研究区总面积的852%,其大气水汽含量平均值低于06 g/cm^(2);(3)从大气水汽含量季节性分布特征来看,研究区春、秋、冬三个季节大气水汽含量常年为03~1 g/cm^(2),且冬季大气水汽含量为0~03 g/cm^(2)的地区占研究区总面积的9751%。研究结果可为确定研究区天文台选址和最佳观测时间段提供理论依据。

The data of Precipitable Water Vapor(PWV)in Lenghu area of Qinghai are extracted by using MODIS daily scale of 1931 scenes from 2015 to 2020 in order to understand the temporal and spatial distribution characteristics of PWV in the area as well as determine the astronomical site and the best observation time.The temporal and spatial distribution characteristics of long-time PWV and land cover types in the area are also analyzed in this paper combined with NECP reanalysis da?ta.The results show that:(1)The average content of PWV in the study area from 2015 to 2020 is059 g/cm^(2),and that of winter is the lowest(009~251 g/cm^(2));(2)There is a significant corre?lation between land cover types and PWV in the area.Grassland and bare land account for 854%of the study area,while their average content of PWV is less than 06 g/cm^(2);(3)According to the seasonal distribution characteristics of PWV,the content of PWV in spring,autumn and winter in the study area is 03~1 g/cm^(2)all the year.The area with PWV of 0~03 g/cm^(2)in winter accounts for9751%of the total area.The results can provide a theoretical basis for determining the astronomical site and the best observation time in the study area.