Evaluation of convection-permitting WRF CONUS simulation on the relationship between soil moisture and heatwaves
Evaluation of convection-permitting WRF CONUS simulation on the relationship between soil moisture and heatwaves
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DOI：
10.1007/s00382-018-4508-5
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发表时间：
2018-10
期刊：
影响因子：
4.6
通讯作者：
Zhe Zhang;Yanping Li;Fei Chen;M. Barlage;Zhenhua Li
中科院分区：
文献类型：
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作者：
Zhe Zhang;Yanping Li;Fei Chen;M. Barlage;Zhenhua Li
土壤水分在调节区域气候中起着重要的作用。特别重要的是，土壤水分亏缺可以通过土壤水分-温度反馈放大夏季热浪（HWs），对社会，经济和人类健康产生重要影响。在这项研究中，我们评估了长达十年的对流允许天气研究和预报（WRF）模型模拟在美国连续的热浪和它们的关系与前期土壤水分使用密集的观测网络。我们发现，WRF模式是能够捕捉到的空间模式的温度阈值来定义HWS，虽然模拟显示了一个温暖的偏差在中西部和寒冷的偏差在西部山区。两个HW指数，基于频率（HWF）和幅度（HWM），进行了评估。在除南太平洋沿岸外的大部分地区，都发现了前期土壤湿度和HW指数之间的显着反相关性。对中西部和南部大平原地区进行了详细的研究，在过去的十年里，那里发生了两次热浪。在这两个地区，高分位数的HWF分布表现出强烈的依赖于前期土壤水分：干燥的土壤导致更大的增加上分位数的HWF比它在较低的分位数。土壤水分对HWM高端的影响不像低端那么强：湿润的前期土壤对应于HWM低分位数的较大下降。WRF捕获的异质性响应干燥土壤上HWF分布在这两个地区，但高估了这些HWM响应在中西部和低估他们在南部大平原。我们的研究结果表明，WRF的能力来模拟HW特性和前期土壤水分对HWs的影响的信心。这对利用高分辨率允许对流模式研究陆-气耦合具有重要意义。
Soil moisture plays an important role in modulating regional climate from sub-seasonal to seasonal timescales. Particularly important, soil moisture deficits can amplify summer heatwaves (HWs) through soil moisture-temperature feedback which has critical impacts on society, economy and human health. In this study, we evaluate decade-long convection-permitting Weather Research and Forecast (WRF) model simulations over the contiguous US on simulating heatwaves and their relationship with antecedent soil moisture using a dense observational network. We showed that the WRF model is capable of capturing the spatial patten of temperature threshold to define HWs, though the simulation shows a warm bias in the Midwest and cold bias in western mountainous regions. Two HW indices, based on frequency (HWF) and magnitude (HWM), are evaluated. Significant anti-correlations between antecedent soil moisture and both HW indices have been found in most parts of the domain except the South Pacific Coast. A detailed study has been conducted for the Midwest and South Great Plains regions, where two heatwaves had occurred in the last decade. In both regions, the high quantile of the HWF distribution shows a strong dependence on antecedent soil moisture: drier soil leads to much larger increase on the upper quantile of HWF than it does on the lower quantile. Soil moisture effects on the higher end of HWM are not as strong as on the lower end: wetter antecedent soil corresponds to a larger decrease on the lower quantile of HWM. WRF captures the heterogeneous responses to dry soil on HWF distribution in both regions, but overestimates these HWM responses in the Midwest and underestimates them in the South Great Plains. Our results show confidence in WRF’s ability to simulate HW characteristics and the impacts of antecedent soil moisture on HWs. These are also important implications for using high-resolution convection-permitting mode to study the coupling between land and atmosphere.