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陈沛宇, 彭京备, 布和朝鲁, 等. 2022. 亚洲中高纬度地区春夏季节转换早晚与梅雨期中国东部降水异常的联系[J]. 气候与环境研究, 27(3): 421−435. doi: 10.3878/j.issn.1006-9585.2021.21057
引用本文: 陈沛宇, 彭京备, 布和朝鲁, 等. 2022. 亚洲中高纬度地区春夏季节转换早晚与梅雨期中国东部降水异常的联系[J]. 气候与环境研究, 27(3): 421−435. doi: 10.3878/j.issn.1006-9585.2021.21057
CHEN Peiyu, PENG Jingbei, BUEH Cholaw, et al. 2022. Connection of the Summer Onset in Northern Asia with the Precipitation Anomalies in Eastern China during the Meiyu Period [J]. Climatic and Environmental Research (in Chinese), 27 (3): 421−435. doi: 10.3878/j.issn.1006-9585.2021.21057
Citation: CHEN Peiyu, PENG Jingbei, BUEH Cholaw, et al. 2022. Connection of the Summer Onset in Northern Asia with the Precipitation Anomalies in Eastern China during the Meiyu Period [J]. Climatic and Environmental Research (in Chinese), 27 (3): 421−435. doi: 10.3878/j.issn.1006-9585.2021.21057

亚洲中高纬度地区春夏季节转换早晚与梅雨期中国东部降水异常的联系

Connection of the Summer Onset in Northern Asia with the Precipitation Anomalies in Eastern China during the Meiyu Period

  • 摘要: 6月初,亚洲中高纬地区的气温迅速增暖后趋于稳定,大气环流由冬季环流转变为夏季环流。根据1951~2017年间各年亚洲中高纬地区春夏季节转换(以下简称季节转换)的时间,基于NCEP再分析资料和中国地区的观测资料,研究了季节转换发生早晚对梅雨期中国地区降水及环流的影响。在季节转换偏早(晚)年的梅雨期,对流层中层(500 hPa)高度距平场从东北亚中高纬、中国东北和日本以南地区出现“+ − +”(“− + −”)的经向波状结构。在850 hPa距平风场上,也有相近的波状结构。当东北亚脊偏强(弱)时,东北地区为气旋式(反气旋式)环流距平,西太平洋副热带为反气旋式(气旋式)距平。环流异常导致东北地区降水异常偏多(少),长江流域降水偏少(多)。本文还初步探讨了亚洲中高纬地区入夏时间的早晚如何影响梅雨期大气环流和中国东部降水异常的途径。在季节转换偏早(晚)年,东北亚高压脊建立较早(晚),强度偏强(弱),而且对应的东北亚脊异常往往可持续到梅雨期结束,从而有利于东亚沿岸 “+ − +”(“− + −”)经向波状环流及相应雨带的形成。

     

    Abstract: In early June, there normally appears a rapid increase followed by a near steadiness of area-mean temperature of northern Asia, which features the transition of general circulation from winter to summer. Based on the timing of summer onset in northern Asia each year (hereafter referred to as summer onset) from 1951 to 2017, along with NCEP reanalysis data and the observation data in China, the connection of the summer onset with the precipitation and circulation anomalies in China during the Meiyu period is studied. It is attained that in the early (late) summer onset years, there is a “+ − +” (“− + −”) meridional wave train like structure of anomaly geopotential height field at mid-troposphere (500 hPa) ranging from northeast Asia, northeast area of China, and western Pacific Ocean. Similarly, a wave train structure is also found in the anomaly wind field at 850 hPa, i. e. a cyclonic (anticyclonic) circulation over northeastern area of China and an anticyclonic (cyclonic) circulation over the subtropical western Pacific. These circulation anomalies lead to a less (more) precipitation in the Yangtze River basin, and flood (drought) in the Northeast China during the Meiyu period. In the paper, a preliminary investigation on the approach by which the timing of summer onset influences the anomaly circulation and precipitation in Meiyu period is also attempted. It is shown that in the early (late) summer onset years, the ridge over northeastern Asia is established earlier (later) and stronger (weaker) than the normal. The time of the summer onset affects the ridge over northeastern Asia and the circulation and precipitation anomalies in the Eastern China during Meiyu period. The anomalous ridge over northeastern Asia maintains till the end of Meiyu. As the ridge over northeastern Asia is stronger (weaker) favors the formation and maintenance of “+ − +” (“− + −”) meridional wave train along the coast of East Asia, hence the distribution of rain belt.

     

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