Effects of spectral nudging on precipitation extremes and diurnal cycle over CORDEX‐East Asia domain
Effects of spectral nudging on precipitation extremes and diurnal cycle over CORDEX‐East Asia domain
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DOI：
10.1002/joc.5706
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发表时间：
2018-07
期刊：
影响因子：
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通讯作者：
Jianping Tang;Xuguang Sun;Pinhong Hui;Yan Li;Qi Zhang;Jianyong Liu
中科院分区：
文献类型：
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作者：
Jianping Tang;Xuguang Sun;Pinhong Hui;Yan Li;Qi Zhang;Jianyong Liu
利用WRF模式，研究了谱微推（SN）对协调区域气候降尺度试验-东亚（CORDEX-EA）区域极端降水和降水日变化的模拟效果。模拟是在1989-2007年期间进行的，由ERA-中期再分析数据驱动，采用不同的SN实验。很明显，WRF有能力重现亚洲的长期气候和极端气候，而在没有SN的实验中（NOSN）会产生偏差。采用SN模式，特别是SN 6（波数为6的SN模式）和SN 3-UVT模式（波数为3的SN模式），可以有效地降低降水频率和强度以及除连续干旱日数（CDD）外的极端指数的偏差，提高模式的模拟能力。WRF能很好地模拟降水频率和降水量的日谐波，SN实验也比NOSN实验表现得更好，其中SN 3-UVT表现得最好。然而，只有风的SN在模拟日循环方面表现出很小的改进，并且温度的额外推动只能改善华南和印度支那的模拟。结果表明，Nudging参数的强弱对降水模拟效果有显著影响，Nudging参数越强，模拟效果越好。此外，额外的温度微调也可以改善模拟。
In this study, by using the Weather Research and Forecasting (WRF) model, the impact of spectral nudging (SN) on simulating the precipitation extremes and diurnal cycle of precipitation over Coordinated Regional Climate Downscaling Experiment‐East Asia (CORDEX‐EA) domain is evaluated. The simulations are conducted during 1989–2007 driven by the ERA‐Interim reanalysis data with different SN experiments. It is clear that WRF has the ability to reproduce the long‐term climatology as well as the extremes over Asia, while biases are generated in the experiment without SN (NOSN). The simulations with SN, especially SN6 (SN with wavenumber 6) and SN3‐UVT (SN with wavenumber 3 applied to wind and temperature), can efficiently improve the model's skill by reducing the biases of precipitation frequency and intensity as well as the extreme indices except for the consecutive dry days (CDD). The diurnal harmonics of precipitation frequency and amount are well produced by WRF, and the SN experiments also perform better than the NOSN experiment, with SN3‐UVT showing the best skill. However, the SN only with winds shows little improvement in simulating the diurnal cycles, and the additional nudging of temperature can improve the simulation only over south China and Indo‐China. It can be concluded that the strength of nudging parameters can significantly affect the simulation of precipitation, with better performance under the stronger nudging. Moreover, additional nudging of temperature can also improve the simulation.