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梁平德, 刘爱霞, 段丽瑶, 等. 亚洲中部春夏季大气环流持续性异常与我国东部夏季旱涝的关系[J]. 大气科学, 2008, 32(5): 1174-1186. DOI: 10.3878/j.issn.1006-9895.2008.05.15
引用本文: 梁平德, 刘爱霞, 段丽瑶, 等. 亚洲中部春夏季大气环流持续性异常与我国东部夏季旱涝的关系[J]. 大气科学, 2008, 32(5): 1174-1186. DOI: 10.3878/j.issn.1006-9895.2008.05.15
LIANG Pingde, LIU Aixia, DUAN Liyao, et al. The Relationship between the Persistent Anomaly of Spring and Summer Atmospheric Circulation in the Middle Part of Asia and the Summer Drought/Waterlogging in Eastern China[J]. Chinese Journal of Atmospheric Sciences, 2008, 32(5): 1174-1186. DOI: 10.3878/j.issn.1006-9895.2008.05.15
Citation: LIANG Pingde, LIU Aixia, DUAN Liyao, et al. The Relationship between the Persistent Anomaly of Spring and Summer Atmospheric Circulation in the Middle Part of Asia and the Summer Drought/Waterlogging in Eastern China[J]. Chinese Journal of Atmospheric Sciences, 2008, 32(5): 1174-1186. DOI: 10.3878/j.issn.1006-9895.2008.05.15

亚洲中部春夏季大气环流持续性异常与我国东部夏季旱涝的关系

The Relationship between the Persistent Anomaly of Spring and Summer Atmospheric Circulation in the Middle Part of Asia and the Summer Drought/Waterlogging in Eastern China

  • 摘要: 通过对北半球(20oN以北)1958~2002年 500 hPa月平均高度场各格点的点对点月际相关系数的分析,探讨了环流的持续性。结果表明,亚洲中部上空存在着北半球中高纬度唯一的显著的高度场持续区,它的中心区位于(30oN~50oN, 70oE~110oE),这里正是广袤的青藏高原北坡、蒙古高原及黄土高原地区,一年中各月的持续性有明显的季节变化,冬末春初的2月对3月和3月对4月基本上没有持续性可言;4~5月出现了明显的持续性,相关系数突然增长到0.6;5月对6月的持续性继续增加,相关系数达到0.8。夏季至初秋(6~9月)各个月际稳定地保持着0.8的高相关系数。秋、冬各月持续性逐渐减弱,直至春季降到了最低。将1958~2002年中5~9月的月平均高度距平正、负持续最明显的两个7年的逐月环流和季环流作对比分析,得知在正持续年夏季东亚中纬度大气环流呈“西高东低”型;而负持续年的夏季则是“东高西低”型。它们都具有气候意义的稳定性。相应的,在明显正持续年夏季中国东部降水分布呈“北少南多”;而在明显负持续年则是“北多南少”。在这45年间,夏季亚洲中纬度500 hPa的月高度距平由负持续转为正持续,与中国东部降水由“北多南少”转为“南多北少”是对应的。分区逐日识别500 hPa天气系统的结果表明,正持续年亚洲中纬地区盛行高脊,长江中下游地区多低槽和辐合流型;负持续年则盛行低槽,长江中下游多副高控制和西南流型。揭示了中国夏季发生区域旱涝灾害的两种不同的气候进程和盛行天气过程。这样在5、6月份即可预测东亚夏季或盛夏环流形势与中国的降水趋势。

     

    Abstract: Based on the analysis of the point-to-point correlation coefficient of the monthly mean 500-hPa geopotential height in the Northern Hemisphere (north of 20°N) from 1958 to 2002, the persistence of circulation is investigated. It is shown that there is a significant persistent area in middle latitudes of Asia, and this area is only one in the extratropics of the Northern Hemisphere. The central area is located in (30°N-50°N, 70°E-110°E), which is over the Tibetan Plateau, the Mongolian Plateau and the Loess Plateau . The persistence varies clearly with season. The persistence between February and March is little, between March and April is little too. Then persistence between April and May increases sharply, the inter-monthly correlation coefficient reaches 0.6; between May and Jun, it increases to 0.8. For summer to early autumn (June-September) every inter-monthly correlation coefficient remains over 0.8 stably. In autumn and winter the persistence weakens month by month, until early spring, reaches the lowest point.  The analysis is made from May to September during the most significant positive persistent seven years and negative persistent seven years in 1958-2002. It is shown that in the most significant positive persistent years circulation pattern “west-high-east-low” appears in middle latitudes of East Asia in summer; in the most significant negative persistent years circulation pattern “west-low-east-high” appears. In the positive persistent years eastern China summer rainfall is “north-below average-south-abundant”; in the negative persistent years summer rainfall is “north-abundant-south-below average”. The mean 500-hPa height anomaly changes from negative persistence to positive persistence during the 45 years, and correspondingly the eastern China summer rainfall pattern changes from “north-abundant-south-below average” to “north-below average-south-abundant”. The day-to-day recognition for weather system shows that high and ridge are prevailing over the middle part of Asia, trough and convergence zone systems are prevailing over the middle and lower reaches of the Yangtze River during the summer of positive persistent years; low and trough are prevailing over the middle part of Asia, subtropical high and southwest pattern are prevailing during the summer of negative persistent years. It is shown that there are two kinds of climatic courses and prevailing weather processes for summer drought and water logging in China. So, this work may be beneficial to predicting summer rainfall trend in China and summer circulation over East Asia in May and June.

     

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