Estimating the scaling of rain rate moments from radar and rain gauge
Estimating the scaling of rain rate moments from radar and rain gauge
复制标题
通过雷达和雨量计估计降雨率矩的比例
DOI：
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
X. Zhang
中科院分区：
文献类型：
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作者：
K. Paulson;X. Zhang
[1]降雨率是一个物理参数，它只定义在一些空间或时空积分体。由相同形状和大小范围的积分体的测量值计算的雨率场的矩通常用作雨率过程的概括统计量。尺度的范围被称为随机尺度，无论是简单的或多尺度，当时刻是一个积分体积大小的幂律。尺度范围的确定提供了有关导致降雨率变化的主要物理过程的信息，并允许设计模拟模型。利用雷达资料对雨场的空间矩标度统计量进行了多次估计。在本文中，三个真实的和潜在的问题与报告的统计，即，存在的时刻没有得到验证，没有考虑到插值的影响，并引入了不均匀性的变化，雷达样本量与距离已被忽略。本文分析了英国Chilbolton CAMRA雷达的数据，证明了各阶正矩的存在性。一个算法已经实现了从空间平均降雨数据的时刻计算一个规则的极地网格。由此产生的时刻是一致的，与同地点的雨量计数据，并显示在考虑的尺度，300米至10公里和10秒至6小时的平滑变化。由此产生的时刻是很好的近似两个多尺度范围的尺度突破约3公里或300秒。
[1] Rain rate is a physical parameter that is only defined over some spatial or spatial-temporal integration volume. The moments of rain rate fields calculated from measurements derived from integration volumes of the same shape and a range of sizes are commonly used as a summarizing statistic of the rain rate process. Ranges of scales are known as stochastically scaling, either simple or multiscaling, when the moments are a power law of integration volume size. The identification of scaling ranges provides information about the dominant physical processes leading to rain rate variation and allow simulation models to be devised. The spatial moment scaling statistics of rain fields have been estimated from radar data many times. In this paper, three real and potential problems with the reported statistics are identified; that is, the existence of moments is not verified, the effects of interpolation have not been considered and the inhomogeneity introduced by variation in radar sample volume with range has been ignored. Radar data from the Chilbolton CAMRa radar in the UK are analyzed, and the existence of positive moments of all orders is demonstrated. An algorithm has been implemented for the calculation of moments from spatially averaged rain data on a regular polar grid. The resulting moments are consistent with cosited rain gauge data and show smooth variation across the scales considered, 300 m to 10 km and 10 s to 6 hours. The resulting moments are well approximated by two multiscaling ranges with a scale break around 3 km or 300 s.