学术
摘 要:
利用NCEP/NCAR提供的1951-2000年全球月平均海表温度距平资料及中国160个测站的月降水资料,采用相关关系分析、合成分析方法,研究了前期热带太平洋、印度洋海温异常对长江流域及以南地区6月降水的影响。结果表明：（1）Nino3指数与印度洋偶极子指数（IODI）有明显的季节变化,且两者同期相关关系随季节不同,以秋季的相关关系最好,相关系数达0.523,并且这时两种指数的强度也较大。作秋季ENSO和印度洋偶极子同时发生年至次年6月的时间序列,发现两事件存在2月左右的位相差,IODI在9-10月达到峰值,Nino3指数在12月达到峰值。说明在相关最好的秋季两事件并不是完全同步的;（2）前期秋季Nino3指数、印度洋偶极子指数及新定义的同时考虑两种指数的一个综合指数-IODN3这3种指数与中国6月降水的相关系数分布有相似特征,主要表现为相关显著区都在长江流域及以南地区。3种指数与降水的相关中,以IODN3与降水相关关系最为显著,显著区范围也最大;（3）前期秋季El Ni^-no和印度洋偶极子正位相同时发生年6月的500 hPa位势高度、垂直速度、水汽输送等异常分布与其前期秋季反位相年6月的异常分布有相反的特征,表明海温异常对长江流域及以南地区降水有重要影响,对应该地区6月降水偏多或偏少;（4）前期秋季El Ni^-no和印度洋偶极子正位相同时发生使菲律宾反气旋加强和维持,形成有利于降水的环流形势。[著者文摘]
文章出处:
《气象学报》-2007年65卷3期 -393-405页
栏目信息:
分 类 号:
EFFECTS OF ANOMALOUS SST IN TROPICAL INDIAN OCEAN AND PACIFIC OCEAN ON NEXT JUNE RAINFALL OVER THE YANGTZE RIVER BASIN AND AREA SOUTH OF THE BASIN
Li Yan ,Wang Yafei, Wei Dong （State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081）
Abstract:
Based on the Sea Surface Temperature Anomaly （SSTA） of NCEP/NCAR data and rainfalls at 160 stations in China from 1951 to 2000, we examined the impact of SSTAs in tropical Indian Ocean and tropical Pacific Ocean on next June rainfall in the Yangtze River basin and area south of the basin by the correlation coefficient analysis and composite analysis. The results show as follows： the contemporaneous correlation between the Indian Ocean dipole （IOD） index and Nino3 index varied with season, with the closest correlation being 0. 523 （P 〈0.01） in autumn, and in the autumn El Ni^-no/IOD positive phase year, the Nino3 index lagged the IOD index by about two months, with the former＇ s peak value in December and the latter＇ s in September-October; the correlation coefficients of autumn Nino3 index, IOD index, and newly constructed IODN3 index （a mix of Nino3 index and IOD index） with the next June rainfall exhibited a similar distributive character-the significant correlation area in the Yangtze River basin and area south of the basin, but IODN3＇s correlation is most significant, and the area of significant correlation is also largest; June anomalous 500 hPa geopotential heights, vertical motion, and water vapor fluxes after an autumn E; Ni^-no/IOD positive phase year displayed distributive characters opposite to those after an autumn El Ni^-no/IOD negative phase year, indicating that the SSTAs significantly affected precipitation over the Yangtze River basin and area south of the basin, leading to more and less June rainfall over the basin in the next year, respectively; if Nino3/IOD positive phases con-occurred in autumn, then the anticyclonic circulation around the Philippine Islands would tend to enhance and maintain in next June, which is favor to precipitation in the Yangtze River basin.[著者文摘]
Key words:
Tropical Indian Ocean dipole, El Ni^-no, Yangtze River basin, June rainfall.
基金资助:
资助课题：科技部973项目（2004CB418300）,国家自然基金委项目（40675034）及JICA中日政府间合作项目.
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