资水流域柘桃区间中小河流域面雨量算法比较分析

为探国家气象信息中心多源融合格点降水实况产品在中小河流面雨量计算中的可行性，该文以湖南省资水流域柘桃区间为例，利用泰森多边形法、算术平均值法、克里金插值法以及国家气象信息中心多源融合格点降水实况产品，以2020年9月为代表，对4种方法计算的面雨量结果进行了比较分析。结果表明：（1）4种方法的计算结果相关性显著，均能较好反应出不同强度降水及不同子流域之间的差异。大多数情况下算术平均值法的结果偏大，多源融合格点实况法的结果偏小，插值法和泰森多边形法的结果介于二者之间。（2）当地面雨量站分布密集或降水空间分布均匀时，4种方法计算结果的标准差较小；当地面雨量站分布稀疏或降水空间分布不均时，4种方法的结果标准差较大，此时采用多源融合格点实况法比算术平均值法、泰森多边形法更合理可靠。（3）对于地形地貌复杂多变的山区，尤其是暴雨以上强降水天气，降水空间分布十分不均，多源融合格点实况产品对降水实际分布的反演可信度仍有待研究，计算面雨量时需要结合多种方法综合判断。实际计算中小河流域面雨量时，针对不同的子流域、不同的天气过程，应当根据天气系统及降水空间分布综合分析，合理利用多种方法才能准确把握面雨量的大小和可能的误差。

Comparative studies of areal rainfall algorithms for small and medium rivers in Zhetao section of Zishui river basin

Taking the Zhetao section of the Zishui River Basin in Hunan Province as an example, the application of the multi-source observed precipitation products developed by National Meteorological Information Center in the area rainfall calculation of small and medium rivers is discussed.The areal rainfall for small and medium river in Zhetao interval of Zishui river basin were calculated based on 4 different algorithms namely Tyson polygon, arithmetic mean, Kriging interpolation, merging of multi-source observed precipitation products.The results show that: 1) The calculation results of the four methods have significant correlations, all can reflect the differences between intensities of precipitation and sub-basins. In most cases, the result of the average method is larger, the result of the merging of multi-source observed precipitation products is smaller, and the results of the Kriging interpolation and Tyson polygon are somewhere in between. 2) For precipitation above moderate rainfall, when the local area rainfall stations are densely distributed or the distribution of precipitation is uniform, the standard deviation of the results is smalller; when the local area rainfall stations are sparsely distributed or the precipitation is unevenly distributed, the standard deviation is larger. At this time, the merging of multi-source observed precipitation products is more reliable than others. 3) For mountainous areas with complex and changeable topography, especially heavy rainfall or above, the spatial distribution of precipitation is very uneven.In the actual calculation of areal rainfall, the above four methods have their own advantages and disadvantages. The multi-source fusion grid precipitation live product of the National Meteorological Information Center has high credibility.For different sub-basins and weather processes, a comprehensive analysis should be made based on the weather system and the spatial distribution of precipitation. When using grid-point live products to calculate the areal rainfall, a variety of methods should be reasonably used to accurately grasp the magnitude and possible errors of the areal rainfall.