Can a climate model reproduce extreme regional precipitation events over England and Wales?
Can a climate model reproduce extreme regional precipitation events over England and Wales?
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DOI：
10.1002/qj.2428
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发表时间：
2015-04-01
影响因子：
8.9
通讯作者：
Hodges, K. I.
中科院分区：
文献类型：
--
作者：
Pearson, K. J.;Shaffrey, L. C.;Hodges, K. I.
高分辨率全球环境监测（HiGEM）气候模式的能力，以代表高影响，区域降水事件的两种方式进行了研究。第一个重点是极端的区域积累的降水在2007年7月20日整个英格兰南部的夏季热带气旋的通道，导致在全国洪水紧急情况的案例研究。气候模式与全球数值天气预报（NWP）模式和高分辨率，嵌套有限区域模式进行了比较。虽然气候模式没有像NWP模拟那样准确地模拟气旋和相关降水的时间和位置，但所有模式中的总累积降水量与英格兰和威尔士的雨量计估计相似。区域积累的事件是不敏感的水平分辨率的网格间距范围从90-4公里。其次，自由运行的气候模式再现了英格兰-威尔士降水记录中观测到的日降水累积的统计分布。模型分布越来越偏离记录较长的积累期，与一个一致的代表性不足，更激烈的多日积累。这可能表明缺乏与天气状况持续性相关的低频变率。尽管如此，该模型的总体季节和年度降水总量仍与ERA-Interim的结果相当。
The ability of the High-Resolution Global Environmental Monitoring (HiGEM) climate model to represent high-impact, regional precipitation events is investigated in two ways. The first focuses on a case study of extreme regional accumulation of precipitation during the passage of a summer extratropical cyclone across southern England on 20 July 2007 that resulted in a national flooding emergency. The climate model is compared with a global numerical weather prediction (NWP) model and higher-resolution, nested limited-area models. While the climate model does not simulate the timing and location of the cyclone and associated precipitation as accurately as the NWP simulations, the total accumulated precipitation in all models is similar to the rain-gauge estimate across England and Wales. The regional accumulation over the event is insensitive to horizontal resolution for grid spacings ranging from 90-4 km. Secondly, the free-running climate model reproduces the statistical distribution of daily precipitation accumulations observed in the England-Wales precipitation record. The model distribution diverges increasingly from the record for longer accumulation periods, with a consistent under-representation of more intense multiday accumulations. This may indicate a lack of low-frequency variability associated with weather regime persistence. Despite this, the overall seasonal and annual precipitation totals from the model are still comparable to those from ERA-Interim.