The Value of High-Resolution Met Office Regional Climate Models in the Simulation of Multihourly Precipitation Extremes
The Value of High-Resolution Met Office Regional Climate Models in the Simulation of Multihourly Precipitation Extremes
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DOI：
10.1175/jcli-d-13-00723.1
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发表时间：
2014-08-15
影响因子：
4.9
通讯作者：
Ferro, Christopher A. T.
中科院分区：
文献类型：
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作者：
Chan, Steven C.;Kendon, Elizabeth J.;Ferro, Christopher A. T.
极值理论被用作两个高分辨率（12公里参数化对流和1.5公里显式对流）气象局区域气候模式（RCM）模拟的诊断。在亚日时间尺度上，12公里的模拟有较弱的6月至8月（JJA）短重现期回报水平比1.5公里的RCM，但12公里的RCM有过大的高回报水平。与观测结果的比较表明，1.5公里的RCM比12公里的RCM更成功地代表（多）小时。JJA非常极端的事件。随着累积周期向日时间尺度的增加，错误的12公里降水极值变得更具有可比性的观测和1.5公里的RCM。12公里的RCM未能捕捉到观察到的低敏感性的增长率积累期的变化，这是成功地捕捉到的1.5公里的RCM。这两个模拟有可比的12月-2月（DJF）极端，但DJF极端一般弱于JJA在日常或更短的时间尺度。案例研究表明，“网格点风暴”是12公里区域协调机制中不切实际的极端事件的原因之一。在解释12公里RCM JJA极端事件的现实性时需要谨慎，包括重现期短的事件，其重现值更接近观测值。有明确的证据表明，在模拟JJA极端情况时，1.5公里的RCM比12公里的RCM具有更高程度的真实性。
Extreme value theory is used as a diagnostic for two high-resolution (12-km parameterized convection and 1.5-km explicit convection) Met Office regional climate model (RCM) simulations. On subdaily time scales, the 12-km simulation has weaker June-August (JJA) short-return-period return levels than the 1.5-km RCM, yet the 12-km RCM has overly large high return levels. Comparisons with observations indicate that the 1.5-km RCM is more successful than the 12-km RCM in representing (multi)hourly.JJA very extreme events. As accumulation periods increase toward daily time scales, the erroneous 12-km precipitation extremes become more comparable with the observations and the 1.5-km RCM. The 12-km RCM fails to capture the observed low sensitivity of the growth rate to accumulation period changes, which is successfully captured by the 1.5-km RCM. Both simulations have comparable December February (DJF) extremes, but the DJF extremes are generally weaker than in JJA at daily or shorter time scales. Case studies indicate that "gridpoint storms" are one of the causes of unrealistic very extreme events in the 12-km RCM. Caution is needed in interpreting the realism of 12-km RCM JJA extremes, including short-return-period events, which have return values closer to observations. There is clear evidence that the 1.5-km RCM has a higher degree of realism than the 12-km RCM in the simulation of JJA extremes.