The Effects of a Well-Resolved Stratosphere on the Simulated Boreal Winter Circulation in a Climate Model
The Effects of a Well-Resolved Stratosphere on the Simulated Boreal Winter Circulation in a Climate Model
复制标题
气候模型中解析良好的平流层对模拟北方冬季环流的影响
DOI：
10.1175/jas-d-18-0206.1
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发表时间：
2019
影响因子：
3.1
通讯作者：
Yamashita Yousuke
中科院分区：
文献类型：
--
作者：
Kawatani Yoshio;Hamilton Kevin;Gray Lesley J.;Osprey Scott M.;Watanabe Shingo;Yamashita Yousuke
使用气候大气环流模型跨学科研究模型 (MIROC-AGCM) 研究平流层表示的影响，该模型在不同的模型盖高度和平流层垂直分辨率下运行，但水平分辨率 (~1.125°) 和亚网格参数化保持不变。该模型的一百年积分是使用具有 34、42、72 和 168 个垂直层的配置以及 ~27 km (L34)、47 km (L42)、47 km (L72) 和 100 km (L168) 的模型盖高度进行的。结果分析主要集中在北半球的冬季。与L42模型相比，L34模型对平流层下部的平流层布鲁尔-多布森环流（BDC）的模拟效果较差，极地下降流较弱，伴随着冷极和西风急流偏差。西风偏向延伸到对流层甚至地表。对流层西风带和斜压波活动区北移；地表压力在高（中）纬度地区存在负（正）偏差，并伴随着降水变化。 L72 和 L168 模型产生准两年振荡 (QBO)，而 L34 和 42 模型则不会。 L168 模型包括中间层，因此解析了 BDC 的上分支。 L72 模型模拟的与 BDC 相关的极地下降流比 L42 模型更强。然而，对热带平流层风进行规定微移的实验表明，QBO 表示的差异不能解释气候极地夜间急流结构中 L72 – L42 的差异。结果表明，平流层垂直分辨率和完整中层大气的包含对对流层环流有显着影响。
The impact of stratospheric representation is investigated using the Model for Interdisciplinary Research on Climate Atmospheric General Circulation Model (MIROC-AGCM) run with different model-lid heights and stratospheric vertical resolutions, but unchanged horizontal resolutions (~1.125°) and subgrid parameterizations. One-hundred-year integrations of the model were conducted using configurations with 34, 42, 72, and 168 vertical layers and model-lid heights of ~27 km (L34), 47 km (L42), 47 km (L72), and 100 km (L168). Analysis of the results focused on the Northern Hemisphere in winter. Compared with the L42 model, the L34 model produces a poorer simulation of the stratospheric Brewer–Dobson circulation (BDC) in the lower stratosphere, with weaker polar downwelling and accompanying cold-pole and westerly jet biases. The westerly bias extends into the troposphere and even to the surface. The tropospheric westerlies and zone of baroclinic wave activity shift northward; surface pressure has negative (positive) biases in the high (mid-) latitudes, with concomitant precipitation shifts. The L72 and L168 models generate a quasi-biennial oscillation (QBO) while the L34 and 42 models do not. The L168 model includes the mesosphere, and thus resolves the upper branch of the BDC. The L72 model simulates stronger polar downwelling associated with the BDC than does the L42 model. However, experiments with prescribed nudging of the tropical stratospheric winds suggest differences in the QBO representation cannot account for L72 − L42 differences in the climatological polar night jet structure. The results show that the stratospheric vertical resolution and inclusion of the full middle atmosphere significantly affect tropospheric circulations.