关键词: 降水, EOF, SVD, 高原加热场

Abstract:

Based on the monthly precipitation data from 20 meteorological stations in Ningxia during 1961-2012, the temporal and spatial variation characteristics of precipitation in four seasons were analyzed by using trend analysis and EOF methods, firstly. Combined the heating field data over Tibetan Plateau, the responses of monthly precipitation to heating field over Tibetan Plateau were researched by SVD method. The results showed that the annual precipitation in Ningxia during 1961-2012 presented a declining trend on the whole, especially it was obvious in southern mountainous region. The precipitations in spring, summer and autumn decreased from 1961 to 1982, especially the declining rate was the fastest in autumn, while it increased in winter, and the change degree gradually increased from south to north. In addition, the correlation between the heating field from last November to January over Tibetan Plateau and precipitation in June in Ningxia was negative, while it was positive with precipitation in November. The influence of heating fields from April to May on precipitation in July and August was significant, the former was positive correlation, while the latter was negative correlation. During the influence of heating field over Tibetan Plateau on precipitation in Ningxia, the sensitive areas were different. The highly sensitive areas in June located in Yinchuan, Longde and the border of Haiyuan, Tongxin, Zhogning, and in the middle arid area in July, especially in Haiyan and Zhongwei, in irrigation area and Longde in August, and the southern mountainous region in November.

Key words: precipitation, EOF, SVD, heating field over Tibetan Plateau