Sensitivity studies and comprehensive evaluation of RegCM4.6.1 high-resolution climate simulations over the Tibetan Plateau
Sensitivity studies and comprehensive evaluation of RegCM4.6.1 high-resolution climate simulations over the Tibetan Plateau
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RegCM4.6.1青藏高原高分辨率气候模拟敏感性研究及综合评价
DOI：
10.1007/s00382-020-05205-6
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发表时间：
2020
期刊：
影响因子：
4.6
通讯作者：
Xiaoyan Wang
中科院分区：
文献类型：
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作者：
Gu Huanghe;Zhongbo Yu;W. Richard Peltier;Xiaoyan Wang
本研究首次对青藏高原 (TP) 地区的区域气候模型 4.6.1 版 (RegCM4) 进行了全面评估。使用不同的参数化分析了各种模型配置，用于表示积云对流（Kuo、Grell、Emanuel、Kain 和 Tiedtke）、陆地表面过程（BATS 和 CLM）、行星边界层湍流（Holtslag 和 UW PBL）和辐射（CCM3 和 RRTM）。除了上述30公里水平分辨率的实验外，还进行了基于双嵌套动态降尺度方法构建10公里分辨率的模拟实验，研究模型分辨率的敏感性。我们根据 1989 年至 2008 年期间基于地面和卫星的观测，评估了 20 年降水量、云量、地表辐射收支、2 米气温和地表大气环流的模拟。在敏感性分析的因素中，毫不奇怪地发现降水对积云参数化方案敏感，并且发现与 BATS 相比，CLM 减少了降雨，这对于 Emanuel 和 Tiedtke 方案都是令人满意的。与积云对流方案相比，云量和地表辐射预算对地表、PBL 和辐射方案敏感。总体而言，与 BATS 相比，CLM 的特点是平均云量减少，地表长波和短波辐射增强。相反，与 RegCM4 中的默认选项相比，UW PBL 和 RRTM 辐射方案会导致云量增加和地表辐射减少。除采用 Kuo 方案的实验外，所有实验都相当好地代表了平均 2 米气温和区域环流模式。在流域尺度上，尽管温度场得到了很好的再现，但大多数模型配置并不能很好地描述降水的季节周期和年际变化。综合考虑所有分析变量，Tiedtke 方案与 CLM 地表模型相结合，被证明可以在 TP 上提供最佳性能。然而，该模型的高分辨率版本显着改善了降水模拟，特别是在位于喜马拉雅山北部的雅鲁藏布江流域。
This study provides the first comprehensive assessment of Regional Climate Model version 4.6.1 (RegCM4) for the Tibetan Plateau (TP) region. A wide range of model configurations were analyzed with different parameterizations employed to represent cumulus convection (Kuo, Grell, Emanuel, Kain, and Tiedtke), land surface processes (BATS and CLM), planetary boundary layer turbulence (Holtslag and UW PBL), and radiation (CCM3 and RRTM). In addition to the above experiments at a 30-km horizontal resolution, another experiment was conducted based upon the use of a double-nested dynamic downscaling method to construct a simulation at a 10-km resolution to study the sensitivity to the model resolution. We evaluated a 20-year simulation for precipitation, cloud cover, surface radiation budget, 2-m air temperature, and the surface atmospheric circulation against ground and satellite-based observations during the period 1989–2008. Among the factors analyzed regarding sensitivity, precipitation was unsurprisingly found to be sensitive to the cumulus parameterization scheme, and the CLM is found to reduce rainfall compared with BATS, which is satisfactory for both the Emanuel and Tiedtke schemes. Compared with the cumulus convection schemes, the cloud cover and surface radiation budget are sensitive to the land surface, PBL, and radiation schemes. Generally, the CLM is characterized by reduced mean cloud cover and enhanced surface longwave and shortwave radiation compared with BATS. Conversely, the UW PBL and RRTM radiation schemes result in increased cloud cover and less surface radiation compared with the default options in RegCM4. All experiments, except those employing the Kuo scheme, represent the mean 2-m air temperature and regional circulation patterns reasonably well. At the basin scale, the seasonal cycle and interannual variations of precipitation are found to be not well depicted by most model configurations, although the temperature field was well reproduced. Considering all the analyzed variables collectively, the Tiedtke scheme combined with the CLM land surface model is demonstrated to provide the best performance over the TP. However, the higher-resolution version of the model improves the precipitation simulation significantly, particularly in the Brahmaputra river basin, which is located in the north of the Himalayas.