Effects of Improved Simulation of Precipitation on Evapotranspiration and Its Partitioning Over Land
Effects of Improved Simulation of Precipitation on Evapotranspiration and Its Partitioning Over Land
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DOI：
10.1029/2021gl097353
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发表时间：
2022-02
影响因子：
5.2
通讯作者：
Zeyu Cui;Yong Wang;Guang J. Zhang;Mengmiao Yang;Jane Liu;Linyi Wei
中科院分区：
文献类型：
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作者：
Zeyu Cui;Yong Wang;Guang J. Zhang;Mengmiao Yang;Jane Liu;Linyi Wei
蒸散是全球水文循环的一个重要组成部分，它受不同降雨强度的强烈调制。全球气候模型(GCM)普遍存在“小雨过多”和蒸腾作用(T)与蒸腾速率(T/ET)之间的负偏差。目前还不清楚这些偏见是否相关。结果表明，在NCAR CESM1.2中采用随机对流参数化抑制小雨发生的降雨强度概率密度函数的改进模拟中，热带森林的冠层温度增加，而冠层截留和裸地蒸发减少。模拟的T/ET在全球范围内增加了2.5%，在区域上增加了8%，这主要是由于尽管强度很小，但由于小雨频率较低，湿叶比例减少。这些结果表明，过多的小雨是造成GCMS T/ET负偏差的一个重要原因。
Evapotranspiration (ET) is a key component of the global hydrological cycle, which is strongly modulated by the occurrence of different rainfall intensities. Global climate models (GCMs) commonly suffer from “too much light rain” and a negative bias in the ratio of transpiration (T) to ET (T/ET). It is unclear whether these biases are related. Here we show that with the improved simulation of probability density functions of rainfall intensity by suppressing light‐rain occurrence using a stochastic convection parameterization in the NCAR CESM1.2, the canopy T increases in tropical forests while evaporation from canopy interception and bare soil decreases. The simulated T/ET is increased by 2.5% globally and up to 8% regionally, primarily attributable to reduced fraction of wet leaves due to less frequent light rain despite its weak intensity. These results imply that excessive light rain is an important cause of the negative T/ET bias in GCMs.