雷徐奔,张文君,刘超. 2022. 夏季印度洋MJO活跃时间对中国长江流域降水日数的影响[J]. 气象学报, (4):-, doi:[doi]
夏季印度洋MJO活跃时间对中国长江流域降水日数的影响
Influence of MJO active days over the Indian Ocean on precipitation days in reaches of the Yangtze River
投稿时间:2021-12-20  修订日期:2022-03-13
DOI:
中文关键词:  MJO, 降水日数,年际变率,长江中下游地区
英文关键词:MJO, precipitation days, interannual variability, middle and lower reaches of the Yangtze River
基金项目:国家自然科学基金
作者单位邮编
雷徐奔 南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心 210044
张文君 南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心 210044
刘超 南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心 210044
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中文摘要:
      本文利用1980-2020年中国753站逐日降水资料、NCEP/NCAR大气再分析资料以及哈德莱中心的海表温度资料和实时多变量 MJO指数,研究了MJO在印度洋地区(1-3位相)活跃日数对长江流域夏季降水日数的影响。结果表明两者存在统计显著的联系,在MJO活跃日数偏多的年份,MJO相关的西北太平洋反气旋环流异常有利于长江中下游地区的水汽输送,进而导致长江流域中下游范围内降水日数的增加,且这种影响主要体现在降水等级为大雨(25mm/天)及以上强度的日数上。进一步研究发现,MJO在印度洋活跃日数与长江中下游夏季降水日数的关系存在年代际变化,两者显著的联系仅出现在2000年之后,在之前的时段两者联系则较弱。这种关系的转变可能与印度洋海表温度变率减弱的背景有关。印度洋海洋年际变率变弱导致其对于长江中下游地区的影响减弱,进而使得MJO的调控作用凸显出来。
英文摘要:
      The study investigates influences of the active days of Madden-Julian oscillation (MJO) over the Indian Ocean on summer precipitation days over middle and lower reaches of the Yangtze River, based on the daily averaged precipitation data of 753 stations, monthly SST data from the Hadley Centre, daily mean reanalysis datasets from the National Centers for the Environmental Prediction/National Center for the Atmospheric Research (NCEP/NCAR), and all-season real-time multivariate Madden-Julien Oscillation (RMM) index during 1980-2020. The results show that the active days of MJO over the Indian Ocean has significant statistical relationship with the precipitation days over the middle and lower reaches of the Yangtze River, especially for the heavy precipitation days, since the MJO related circulation anomalies could continuously transport the water vapor to eastern China. Further research found that the relationship between active days of MJO over the Indian Ocean and the precipitation days over the middle and lower reaches of the Yangtze River has experienced a decadal change with their relationship being significant since the 2000s. The decadal change of this relationship might be due to the decreased sea surface temperature (SST) anomaly variability in the Indian Ocean. This decreased interannual variability of SST suggests the weakened modulation effect on the precipitation over middle and lower reaches of the Yangtze River by the tropical Indian Ocean. By contrast, the MJO effects on the precipitation days over the middle and lower reaches of the Yangtze River turn to be significant after the 2000s due to less disturbance from the Indian Ocean SST.
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