| “21.7”河南暴雨暖湿季风输送带加强及关键天气流型的准地转位涡反演 |
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| 引用本文： | 谢作威,布和朝鲁,诸葛安然,连汝续,廖振杨,阎洁,林大伟.“21.7”河南暴雨暖湿季风输送带加强及关键天气流型的准地转位涡反演[J].大气科学,2022,46(5):1147-1166. |
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| 作者姓名： | 谢作威 布和朝鲁 诸葛安然 连汝续 廖振杨 阎洁 林大伟 |
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| 作者单位： | 1.中国科学院大气物理研究所国际气候与环境科学中心, 北京100029 |
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| 基金项目： | 国家自然科学基金项目41630424、41875078，华能集团总部科技项目“海上风电与智慧能源系统”科技专线（一期）HNKJ20-H88 |
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| 摘 要： | 本文使用站点降水资料和欧洲中期天气预报中心第五代再分析数据，利用准地转位涡分部反演，重点分析了2021年7月18～21日（简称“21.7”）河南极端暴雨中暖湿季风输送带加强的机理及其关键环流特征。结果表明:副热带高压持续西伸至中国东部地区，其西南部宽广的东南风将暖湿气流和河南地区高位涡输送至西北地区；同时，西北地区阿拉善高原热低压受感热加热而加强，在近地面层及其东侧的河套地区对流层中低层（750～650 hPa）产生正位涡异常，与河南地区低压环流形成大范围高位涡异常，从而与副热带高压形成较大范围的对峙。准地转位涡反演结果表明，对流层中低层这一天气流型导致河南南部南风的加强，有效地将暖湿输送带中高温高湿的气块输送至河南地区，成为7月20日极端暴雨发生的关键因子之一。对于7月20日河南地区的南风，主要来自于副热带高压的贡献，其次是河套地区对流层中低层高位涡异常，而河南局地低压环流的贡献略小。
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| 关 键 词： | 河南暴雨 暖湿输送带 位涡反演 副热带高压 热低压 |
| 收稿时间： | 2022-02-18 |
An Intensification of the Warm and Moist Conveyor Belt of the Asian Summer Monsoon in the “21.7” Henan Rainstorm and Its Key Circulation from the Quasi-geostrophic Potential Vorticity Perspective |
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| Abstract: | This study uses rain-gauge observation data, the fifth reanalysis dataset of the European Center for Medium-Range Weather Forecasts, and the piecewise quasi-geostrophic potential vorticity (QGPV) inversion to mainly investigate the intensification of the warm and moist conveyor belt of the Asian summer monsoon of the Henan extreme rainstorm and its key circulation during July 18–21, 2021. The result shows that the continual westward extension of the subtropical high covered eastern China, on whose southwestern flank, broad southwesterlies transported not only a warm and moist air mass but also a high QGPV over Henan to northwestern China. Meanwhile, in northwestern China, the sensible heating of the Alxa Plateau maintained and deepened a local thermal low, which generated high QGPV anomalies in the near-surface layer of the low-pressure center and the middle and lower tropospheres (750–650 hPa) over the Hetao region. Thus, an extensively high QGPV was formed with low-pressure circulation over Henan, which yielded an extensive confrontation with the subtropical high. The QGPV inversion results show that this meteorological circulation pattern in the middle and lower tropospheres intensified the southerly over Henan. The amplified southerly effectively transported a hot and humid air mass of the warm and moist conveyor belt to the Henan region, which was a key factor for the extreme downpour on July 20. The southerly over Henan on July 20 was primarily contributed by the subtropical high, with secondary contributions from the positive QGPV anomaly at the middle and lower tropospheres over Hetao, while the contribution of the local low-pressure circulation over Henan was slightly smaller. |
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