摘要
利用云南省大理州12个气象站1962～2008年共47a雨季开始期资料及NCEP／NCAR高度场及风场资料分析了大理雨季开始期的时空分布特征及异常年环流特征。EOF分析表明，大理雨季开始期存在多种空间分布类型，主要的分布型是一致偏早（晚）型及东南一西北型。Morlet小波分析表明，大理雨季开始期在20世纪60年代初到70年代中期偏早，70年代中期至90年代初偏晚，90年代初至今偏早；且存在约2a和10a的特征时间周期变化。异常偏早年5月高度距平场上北半球经向上呈“-＋-”的分布，异常偏晚年则相反，呈“＋-＋”的分布。异常年5月高、中低层的距平风场同样存在明显差异，异常偏早年高层存在增强伊朗高压的反气旋环流，低层存在偏强的南亚季风环流，异常偏晚年则是相反的环流特征。
The data of the beginning of the rainy season of 12 weather stations in Dali from 1962 to 2008 and height,wind fields from NCEP/NCAR were used to analyze the characteristics of spatial and temporal distribution and anomalous circulation on the beginning of the rainy season in Dab. The results of EOF analysis indicates that there are several kinds of spatial patterns about the beginning of the rainy season in Dab, and the major patterns are the earlier（ or later） in the whole area and the southeast -northwest pattern. The results from Morlet wavelet transform shows that the beginning of the rainy season there was earlier from the1960s to the middle of the 1970s and later from the middle of the 1970s to the 1990s then earlier after the 1990s. It also shows that the beginning of the rainy season presented periodic variation of 2 and 10 years. It is a ＂ - ＋ - ＂ distribution along meridional over the Northern Hemisphere in the height departure field in May of the earlier years of rainy season, but a ＂ ＋ - ＋ ＂ distribution in May of the later years of rainy season. It is obviously different of wind departure field at upper and lower level in anomalous years of the beginning of rainy season. There is an anticyclonic circulation to strengthen the Iran high at the upper level and a stronger South Asia monsoon circulation in the earlier years of rainy season, but it is the opposite circulation in the later years of rainy season.
出处
《干旱气象》
2009年第4期334-339,共6页
Journal of Arid Meteorology
基金
云南省气象局2008年"短平快"科研项目(D200808)资助
关键词
雨季开始期
演变规律
环流特征
the beginning of the rainy season
spatial and temporal evolution
circulation characteristics
