Rainwater content estimated using polarimetric radar parameters in the Heihe River Basin
Rainwater content estimated using polarimetric radar parameters in the Heihe River Basin
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DOI：
10.1016/j.atmosres.2012.08.011
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发表时间：
2013-02
影响因子：
5.5
通讯作者：
Zhaopei Guo;Chu Rongzhong;Tong Zhang;Jia Wei
中科院分区：
文献类型：
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作者：
Zhaopei Guo;Chu Rongzhong;Tong Zhang;Jia Wei
寒区和干旱区雨水含量具有较强的时空异质性。高分辨率表达雨水含量有助于了解内陆河流域水循环特征，提高水文模型的预报精度。数据来源于黑河流域联合遥测试验研究(水)项目，黑河流域是中国西北干旱区第二大内河流域。我们利用雨滴大小分布来改进气象雷达对雨水含量的估计，以获得该地区准确的雨水含量数据。随后，对极化雷达中应用的四种估计方法进行了测试。非线性回归分析结果表明，M(KDP、ZH、ZDR)对雨水含量的测量精度最高。最后，将空间雨水含量测量公式应用于X波段(714XDP)极化雷达。雨滴大小分布(DSD)对公式M(KDP，ZH，ZDR)的影响最小，其原因可解释如下。一方面，雷达的水平和垂直锋面反射截面不同，因此KDP与雨滴直径的3次方成正比。另一方面，雷达的后横截面与雨滴直径的六次方成正比。降雨的空间含水率M与雨滴直径的3次方成正比，因此雨滴大小分布(DSD)对KDP的影响远小于ZH。
The rainwater content of cold and arid regions has strong spatial and temporal heterogeneity. Representing rainwater content at high resolution can help us understand the characteristics of inland river basin water cycles and improve the prediction accuracy of hydrological models. Data were used from the Watershed Allied Telemetry Experimental Research (WATER) project of the Heihe River Basin, which is the second largest inland river basin in the arid regions of northwest China. We used raindrop size distributions to improve the rain water content estimation of meteorological radar and to obtain accurate rain water content data in this area. Subsequently, four estimation methods applied in the polarimetric radar were tested. The results of a non-linear regression method show that M(KDP, ZH, ZDR) has the highest accuracy for measuring rain water content. Finally, the formula for measuring the spatial rain water content was applied to a polarimetric radar with an X-band (714XDP). The influence of raindrop size distribution (DSD) on the formula M(KDP, ZH, ZDR) is lowest sensitivity, and it can be explained as follows. On the one hand, the horizontal and vertical front reflection cross sections of the radar are different, so KDPis proportional to the 3rd power of the raindrop diameter. On the other hand, the rear cross section of the radar is proportional to the sixth power of the raindrop diameter. The rainfall's spatial water content M is proportional to the 3rd power of the raindrop diameter, so the influence of the drop size distribution (DSD) on KDPis much smaller than that of ZH.