西藏地区复杂地形下的降水空间分布估算模型

A statistic model for the spatial distribution of precipitation estimation over the Tibetan complex terrain

本文提供了一个描述西藏地区年、季降水量空间分布的估算模型.利用卫星遥测数字化地形高程资料和西藏地区仅有的2 7个常规气象站的多年平均降水整编资料,根据地形坡向站点分为三类.再采用多元逐步回归方法,建立西藏地区的年、季降水量和经度、纬度、海拔高度、坡度、坡向、遮蔽度等6个地理、地形因子之间的关系模型,估算西藏地区降水量的空间分布.结果表明,此方法建立的关于西藏地区降水量与诸因子之间方程的相关性显著,平均绝对误差、相对误差分别为0 93mm和1 16 % ,对估算模型进行F检验,均通过置信度为0 95的相关检验,回归效果较显著.分析表明估算降水能够定量、定性地再现西藏地区的实际降水分布.

We propose a statistic model for spatial distribution of precipitation estimation in Tibet by using both digit elevation data retrieved from satellite and precipitation data reorganized from all the twenty-seven synoptic stations in Tibet. The stations are divided into three kinds according to their terrain sloping directions. The data of precipitation of each kind is analyzed using the multinomial regression of the ordinary least-square method to establish the regression equation between precipitation and its impact factors such as longitude, latitude, height, slope, sloping direction, and close limit. The results show that the correlation between precipitation and impact factors are very significant. The mean absolute error is 0 93 mm, and the mean relative error is 1 16%. The estimated precipitation correctly replicates real distribution of precipitation qualitatively and quantitatively.