基于GIS降水空间分析的逐步插值方法

THE STEPWISE INTERPOLATION APPROACH OF PRECIPITATION FOR SPATIAL ANALYSIS BASED ON GIS

中文关键词:  长江中上游，降水资源，空间分析，逐步插值

英文关键词:The upper-middle reaches of Yangtze river, Precipitation resource, Spatial analysis.

中文摘要:

      根据长江中上游697个气象观测站1971—2000年30年降水资料，利用逐步回归方法和地理信息技术(GIS)，建立了平均季降水和年降水与4 km分辨率的DEM、坡向、坡度等地形数据的回归方程，并通过了信度为0.05的F检验，将降水量中地形影响部分分离出来。在此基础上，发展了逐步插值方法（SIA），并与GIS技术和多元逐步回归方法结合，显著提高了年、季降水空间分布的计算精度。结果表明：SIA季节降水空间分布的相对误差为6.86%，绝对误差为13.07 mm，平均变差系数为0.070，平均相关系数为0.9675；年降水量的绝对误差为72.1 mm，相对误差为7.34%，平均变差系数为0.092，相关系数达到了0.9605。对SIA年平均降水量的分析表明，采用3—5步的SIA计算，就可以显著提高计算精度，绝对误差由211.0 mm下降到62.4 mm，相对误差由20.74%下降到5.97%，变差系数从0.2312下降到0.0761，相关系数由0.5467提高到0.9619，SIA方法50步的计算表明，SIA计算的结果一致收敛于观测值。

英文摘要:

      The regression equations of the precipitation and the topographical data in the upper-middle reaches of Yangtze basin were established based on the 30 years seasonal and annual average precipitation of 697 meteorological stations, from 1971 to 2000. The topographical data include the elevation, aspect and slope. The regression equations had passed 0.05 F confidence tests. The effect of topographyon precipitation is extract from the total annual and seasonal precipitation. Then, the improved Stepwise Interpolation Approach （SIA）was combined with the GIS technique and the multi-variable successive regression equations. SIA considerably improves the accuracy of the annual and seasonal spatial interpolation. The results show that the relative error of the seasonal precipitation interpolation is 6.86%, the absolute error is 13.07 mm, the average coefficient of variation is 0.070, the average correlation coefficient is 0.9675; the absolute error of the annual average precipitation is 72.1 mm,the relative error is 7.34%,the average coefficient of variation is 0.092，the correlation coefficient is 0.9605.The analysis of the annual mean precipitation in terms of SIA showes that the SIA calculation with 3—5 steps considerably improves the interpolation accuracy, such as decreasing the absolute error form 211.0 mm to 62.4 mm, the relative error from 20.74% to 5.97%, the coefficient of variation from 0.2312 to 0.0761, and increasing correlation coefficient from 0.5467 to 0.9619. The SIA iterative results after 50 steps identically converges at the observed precipitation.