柴达木盆地降水的时空分布特征

利用柴达木盆地11个国家气象站(2017年3月—2018年2月)及28个区域气象站(2017年6—8月)月降水量资料,运用线性回归订正法和比值订正法推算柴达木盆地的年降水量,进一步分析柴达木盆地降水量季节变化及空间分布特征。结果表明:(1)柴达木盆地降水量年内分配极不均匀,呈单峰性,峰值出现在7月,5—9月(汛期)降水量占全年的87.4%。季节差异非常明显,降水主要集中在夏季;(2)年降水量空间分布特征:柴达木盆地年降水量各地差异极为显著,降水量整体表现为从东向西逐渐减少。最大值出现在天峻,最小值出现在冷湖。用2种方法推算的年降水量最大值出现在柴达木盆地东北部祁连山南麓的木里镇,其次在格尔木市南部出现了两个相对的大值中心,中间区域(93°～97°E)由四周山区向盆地中心逐渐减少的形势表现得更加清晰。夏季降水量的空间分布与年降水量的空间分布完全一致。(3)国家气象站模型中降水量分布只受经度和海拔高度的影响,而线性回归法和比值订正法模型中降水量的分布不仅受经度和海拔高度的影响,还受纬度的影响,三者的贡献率由大到小的排序是经度海拔高度纬度。

Spatial and temporal distribution of precipitation in qaidam basin

Using monthly precipitation data of 11 national meteorological stations (March 2017-February 2018) and 28 regional meteorological stations (June-August 2017) in Qaidam Basin, The annual precipitation in Qaidam Basin was estimated by using linear regression correction method and ratio correction method, and the seasonal variation and spatial distribution characteristics of precipitation in Qaidam Basin were further analyzed. The results show: (1)the precipitation distribution in Qaidam Basin was extremely uneven, and the peak occured in July, the precipitation in May to September (flood season) accounts for 87.4% of total annual precipitation. The seasonal difference was very obvious, and the precipitation mainly concentrated in summer. (2)The spatial distribution features of annual precipitation in Qaidam Basin: the annual precipitation in study area varied greatly from place to place, and the overall precipitation gradually decreases from east to west. The maximum value appears in Tianjun, and the minimum value appears in Lenghu. The spatial distribution of annual precipitation calculated by the linear regression method and the ratio correction method was basically same, and this result also basically same as the national meteorology station. There were some differences between the spatial distribution of national meteorology stations and two methods, first, the maximum annual precipitation center located in the Qilian mountain foothill, northeastern Qaidam Basin, second , two relatively large values center appeared in the south of Geermu, third, The gradual decreasing trend of the middle area (93 E-97 E) from the surrounding mountainous area to the center of the basin was more obvious. The spatial distribution of summer precipitation was identical with that of annual precipitation. (3)The precipitation distribution in the national weather station model of periphery was only affected by longitude and altitude, while the precipitation distribution in the model of linear regression method and ratio correction method was not only affected by longitude and altitude, but also by latitude. The order of contribution rate of the three was longitude > altitude > latitude.