学术
云南夏季旱涝与前期冬季环流变化的关系
晏红明[1] 王灵[2] 周国连[2] 鲁亚斌[2]
[1]云南省气候中心,昆明650034 [2]云南省气象台,昆明650034
摘 要:
夏季气候异常的前期信号特征分析一直是短期气候预测工作的重点。利用1948--2004年NCEP／NCAR月平均再分析资料、1961-2004年云南124个站的月平均降水和1948-2003年英国Hadley中心的月平均海温资料，分析了云南夏季旱涝的时空特征，探讨了云南夏季旱涝与前期大气环流和大气热力状态变化的关系，发现云南夏季旱涝前冬12月-1月，特别是1月东亚中高纬度地区的大气环流变化和赤道附近高低层大气的热力状态对云南夏季旱涝有重要的指示意义，当前冬东亚大槽强（弱），冬季风强（弱），赤道附近高低层大气温度偏低（高）时，后期云南夏季降水偏多（少）。同时，初步探讨了东亚冬夏季风环流变化的相互联系及热带海温变化的可能影响，指出冬季到夏季印度洋和赤道西太平洋地区持续的海温异常有可能通过改变夏季海陆的热力对比，进而影响夏季风活动和云南夏季降水的变化。[著者文摘]
文章出处:
《应用气象学报》-2007年18卷3期 -340-349页
栏目信息:
分 类 号:
The Relationship Between Rainfall in Yunnan Summer and the Circulation in Preceding Winter
Yan Hongming, Wang Ling, Zhou Guolian, Lu Yabin （1. Climate Center of Yunnan Province, Kunming 650034;2. Yunnan Provincial Meteorological Bureau, Kunming 650034）
Abstract:
At present, in view of the limitation of the understanding of the atmospheric movement, the climate change projection depending completely on general circulation model （GCM） is in an immature period, and relying on the anomalous characteristic of early general circulation is still one of the main methods, particularly in provincial and regional meteorological observatory. So investigating on the prediction clue from early circulation anomalies is very important work, which may provides some scientific evidences to accurately predict the following climate anomalies. A lot of previous researches show the close inter-season linkage between early wintertime circulation and the following summer climate anomalies, the precipitation variations in different regions are not only the sig nificant difference, but also the relationships between them, and early circulation anomalies are distinctly different which needs to be further investigated. Yunnan Province is located in Asian monsoon region and is commonly affected by East Asian monsoon and South Asian monsoon. Its climate anomaly is very complicated and different from those in other regions. Further study on the relationship between early circulation anomalies and Yunnan summer precipitation will be beneficial to improving the forecast accuracy and providing the accurate weather information for government＇s decision-making to prevent and mitigate the damages resulting from disastrous weather. Based on the monthly NCEP/NCAR reanalysis dataset from 1948 to 2004, 124 stations rainfall from 1961 to 2004 and sea surface temperature of the UK Hadley Center from 1948 to 2003, the temporal and spatial variation features of Yunnan summer （JJA） precipitation are firstly analyzed by using EOF and Morlet wavelet analysis method. Secondly, the relationship between the rainfall and preceding general circulation, air temperature is further investigated by using correlation and composite analysis methods. Yunnan summer precipitation in different regions trends to have the similar variation, and has a significant inter-annual variability and period circle feature with 2 and 4 years. The circulation anomalies in mid-high latitude region of Eastern Asia and atmospheric thermal situation from low-high layer in tropical India Ocean and Pacific Ocean in preceding December and January, particularly in January are significant signals indicating the following climate variation of Yunnan. The rainfall increases when East Asian trough deepens and East Asian winter monsoon （EAWM） strengthens, air temperature from low-high layer is cold. The opposite situation occurs when early East Asian trough weakens, EAWM weakens, and air temperature from low-high layer is warm. Furthermore, the anomalous characteristics of SST in tropical Ocean and its possible effect on the linkage relationship between East Asian winter monsoon and summer monsoon are also investigated. The results show that SSTA in tropical Indian Ocean and western Pacific Ocean keep unchanged from winter to summer, which will impact possibly EASM and rainfall in Yunnan summer by changing land-sea thermal contrast.[著者文摘]
Key words:
drought and flood in summer of Yunnan; preceeding general atmospheric circulation anomalies; East Asian winter monsoon （EAWM） ; East Asian summer monsoon （EASM）
基金资助:
云南省自然科学基金项目（2002D0082M）和国家自然科学基金项目（40675045）共同资助.
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