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牛苗苗, 张杰, 马茜蓉, 等. 2023. 印度洋偏暖对春末夏初西天山极端降水的影响研究[J]. 大气科学, 47(2): 295−310. doi: 10.3878/j.issn.1006-9895.2108.21102
引用本文: 牛苗苗, 张杰, 马茜蓉, 等. 2023. 印度洋偏暖对春末夏初西天山极端降水的影响研究[J]. 大气科学, 47(2): 295−310. doi: 10.3878/j.issn.1006-9895.2108.21102
NIU Miaomiao, ZHANG Jie, MA Qianrong, et al. 2023. Influence of Indian Ocean Warming on Extreme Precipitation in the Western Tianshan Mountains from Late Spring to Early Summer [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 47(2): 295−310. doi: 10.3878/j.issn.1006-9895.2108.21102
Citation: NIU Miaomiao, ZHANG Jie, MA Qianrong, et al. 2023. Influence of Indian Ocean Warming on Extreme Precipitation in the Western Tianshan Mountains from Late Spring to Early Summer [J]. Chinese Journal of Atmospheric Sciences (in Chinese), 47(2): 295−310. doi: 10.3878/j.issn.1006-9895.2108.21102

印度洋偏暖对春末夏初西天山极端降水的影响研究

Influence of Indian Ocean Warming on Extreme Precipitation in the Western Tianshan Mountains from Late Spring to Early Summer

  • 摘要: 利用NOAA(美国国家海洋和大气管理局)气候预测中心的逐日格点降水资料分析了春末夏初(5、6月)天山极端降水时空变化以及印度洋海盆一致模(IOBM)影响极端降水的机制。结果表明:春末夏初天山极端降水变化具有明显的空间差异,西天山地区极端降水显著增加,其他区域极端降水变化不显著。诊断分析和数值模式模拟结果表明,春末夏初西天山地区极端降水增加与同期IOBM正异常促进冷暖气流在西天山地区交汇有关。IOBM正异常,一方面有利于东欧至中亚北部反气旋异常加强,促进冷空气向南输送。另一方面使得印度洋海温非均匀增暖,产生异常垂直环流,其下沉支使阿拉伯海和印度半岛产生反气旋异常,异常反气旋和偏南气流共同促进印度洋暖湿水汽向西天山输送,从而有利于西天山地区极端降水增加。

     

    Abstract: The National Oceanic and Atmospheric Administration Climate Prediction Center’s daily grid precipitation data is used to analyze the spatial–temporal change of extreme precipitation in the Tianshan Mountains from late spring to early summer (May and June), as well as the mechanism of the Indian Ocean Basin Mode (IOBM) on extreme precipitation. The results show a clear spatial difference in extreme precipitation in the Tianshan Mountains from late spring to early summer. Extreme precipitation increased dramatically in the western Tianshan Mountains, whereas other regions experienced little variation. The diagnostic and numerical simulation results consistently showed that the increase in extreme precipitation in the western Tianshan Mountains was caused by a coetaneous positive anomaly of IOBM, which promoted the convergence of warm and cold airflows in the western Tianshan Mountains. On the one hand, the positive anomaly of IOBM strengthened the anticyclonic anomalies located in Eastern Europe and the northern part of Central Asia, promoting cold airflow southward transportation. On the other hand, it induced the Indian Ocean to warm unevenly, resulting in abnormal vertical circulation and subsidence, which caused the anticyclonic anomalies in the Arabian Sea and the Indian peninsula. Warm moisture from the Indian Ocean was delivered to the western Tianshan Mountains by the anomalous anticyclone and southerly airflow, which aided in the increase of extreme precipitation in the western Tianshan Mountains.

     

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