摘要
Using the data of summer(June—August)precipitation during the period of 1951—1990 in 14 stations over North China,the wetness probability(WP)series based on gamma distribution has been built.Main temporal and spatial char- acteristics for the series of WP in the stations are extracted by using empirical orthogonal functions(EOFs).The spatial patterns show that the dryness/wetness variations in the stations in the area are consistent with each other and its main characteristics can be represented by the WP series in Beijing. Having analysed the WP series of 120 years(1870—1989)in Beijing,the results show that the dry tendency has a re- sponse to the global warming.The variation of the dryness/wetness in the stations is associated with the temperature variation in the Northern Hemisphere.Their relation is negative.The degree of the reliance is associated with the century variation of the temperature.
Using the data of summer(June—August)precipitation during the period of 1951—1990 in 14 stations over North China,the wetness probability(WP)series based on gamma distribution has been built.Main temporal and spatial char- acteristics for the series of WP in the stations are extracted by using empirical orthogonal functions(EOFs).The spatial patterns show that the dryness/wetness variations in the stations in the area are consistent with each other and its main characteristics can be represented by the WP series in Beijing. Having analysed the WP series of 120 years(1870—1989)in Beijing,the results show that the dry tendency has a re- sponse to the global warming.The variation of the dryness/wetness in the stations is associated with the temperature variation in the Northern Hemisphere.Their relation is negative.The degree of the reliance is associated with the century variation of the temperature.
