Elevation Influence on Rainfall and a Parameterization Algorithm in the Beijing Area
Elevation Influence on Rainfall and a Parameterization Algorithm in the Beijing Area
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DOI：
10.1007/s13351-019-9072-3
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发表时间：
2019-08
影响因子：
3.2
通讯作者：
Linye Song;Mingxuan Chen;Feng Gao;Cong-Lan Cheng;Min Chen;Lu Yang;Yong Wang
中科院分区：
文献类型：
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作者：
Linye Song;Mingxuan Chen;Feng Gao;Cong-Lan Cheng;Min Chen;Lu Yang;Yong Wang
本研究利用高密度自动气象站（AWS）每小时降雨观测数据集，研究了北京地区降雨量与海拔之间的关系，并进一步提出了一种考虑每小时时间尺度上海拔对降雨量影响的降雨量相关参数化算法。参数化方程被定义为分段非线性模型，该模型将山区降雨量计算为山谷降雨量的函数。结果表明，北京地区降雨量存在明显的高程效应增强现象。特别是在较高的山区，降雨量普遍较大，尤其是小雨和中雨。此外，分别选择位于山谷和山区的六个代表性站对来估计参数化方程中的最优参数值。与没有高程依赖的参数化算法相比，高程依赖的参数化算法可以减少均方根误差，并获得更接近观测值的山区降雨总量。此外，当考虑海拔依赖性时，山区降雨的空间分布更加真实和准确。本研究有助于了解北京地区复杂地形下的降雨变化情况，并为小时时间尺度上的降雨-海拔关系参数化提供了一种可能的方法。
Using a high-density automatic weather stations (AWS) dataset of hourly rainfall observations, the present study investigates the relationship between rainfall and elevation in the Beijing area, and further proposes a rainfall amount dependent parameterized algorithm considering the elevation effect on rainfall on hourly timescale. The parameterization equation is defined as a segmented nonlinear model, which calculates the mountain rainfall as a function of valley rainfall amount. Results show that there exists an evident enhancement of rainfall amount by elevation effect in the Beijing area. In particular, larger rainfall amount is generally found in higher mountains, especially for slight rain and moderate rain. Furthermore, six representative station pairs located in valleys and on mountains respectively are selected to estimate the values of optimal parameters in the parameterization equation. The parameterization algorithm of elevation dependence can produce a reduction in the root-mean-square error and obtain a much closer mountain rainfall total to the observations compared with those using no elevation dependence. Furthermore, the spatial distribution of rainfall is more realistic and accurate in mountainous terrain when elevation dependence is considered. This study helps to understand the variability of rainfall with complex terrain in the Beijing area, and gives a possible way to parameterize rainfall-elevation relationship on hourly timescale.