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雨滴谱仪网数据在雷达定量降水估测中的应用

Application of raindrop size distribution data from a disdrometer network to quantitative precipitation estimation

  • 摘要: 为了探讨利用雨滴谱数据验证雷达观测的回波强度的偏差和实时拟合反射率因子(Z)与降水强度(R)的关系(即Z-R关系)进行定量降水估测的可能性,以发生在江苏南部的三次大范围降水过程为例,首先分析雨滴谱数据、雷达数据和雨量计数据的一致性,然后利用雨滴谱仪网法和传统方法分别进行降水估测,并对比两种方法的降水估测效果。结果表明:雷达和雨滴谱仪观测的回波强度具有较好的一致性;采用雨量计数据和雨滴谱计算的平均降水强度存在一定差异,但其变化趋势基本一致。相对于层状云降水,两种方法对对流云降水估测的误差更大,对层状云降水的估测,雨滴谱仪网法略优于传统方法,但对对流云降水的估测,雨滴谱仪网法更具优势。总体上,雨滴谱仪网法估测的降水,其偏差和相对误差更小,估测值总量与雨量计观测雨量更接近,估测降水的效果更好。

     

    Abstract: The objective of this study is to investigate the possibility of using drop size distribution data to assess the bias of radar echo intensity and to estimate precipitation quantitatively by fitting Z-R relationship in real time. Taking three precipitation processes occurred in the south of Jiangsu Province as examples, we have analyzed the consistency among the raindrop size distribution data, radar data and the rain gauge data, and then estimated precipitation by using disdrometer network method and traditional method, respectively, with comparing the precipitation estimation's accuracy of the two methods. The results show that the echo intensity observed by radar and disdrometers have a good consistency. While the averaged rainfall intensities calculated by rain gauge data and disdrometers data have some differences in magnitude, their trends showed a general consistency. Error of the two methods is bigger for convective than for the stratiform precipitation estimates. The disdrometer network method has a clear advantage with respect to the traditional method when the convective precipitation is estimated. But when the stratiform precipitation is estimated, the disdrometer network method is slightly better than the traditional method, whose bias and relative error are smaller and the estimated precipitation total is closer to rain gauge observation. From overall evaluation results, the skill of precipitation estimation by using disdrometer network method is better than the traditional method.

     

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