Spatial-temporal distribution characteristics of precipitation in Inner Mongolia from 1961 -2007
Inner Mongolia locates in the interior of China, whose climate characteristics are drought and little precipitation. Meanwhile, Inner Mongolia is along the edge of areas which are influenced by southeast monsoon , as well as in the transitional region between different climatic zones. As a result, it is considered as one of the most sensitive regions in China. Inner Mongolia Autonomous Region has a great span and complex terrain. The uneven spatio-temporal distribution of precipitation brings great inconvenience to people normal life, however the driving factors of precipitation cannot be clearly identified. Therefore, the comprehensive analysis at multi-scale, multi-level and long time series in this area can provide people an important basis for understanding the characteristics of climate change, as well as give some services for the region ecological and productive construction. Based on longtime-series precipitation data from 1961 to 2007, including 43 meteorological sites in Inner Mongolia, this paper analyzes the distribution of annual and seasonal precipitation in Inner Mongolia with empirical orthogonal function (EOF) method, power spectrum function and spatial analysis tools of GIS in temporal and spatial scale. The results show that there are roughly two major pattern fields of annual precipitation: all-consistency type, multi-regional opposite-phase in northeast-southwest direction type and mixed type. Seasonal precipitation is divided into several types:all-consistency type ,multi-regional opposite-phase in northeast-southwest direction type, east-west type, mixed type and so on. Among these distribution types, multi-regional opposite-phase in northeast-southwest direction type appears several times in annual and seasonal precipitation pattern fields,which is the typical distribution types in Inner Mongolia. The formation of this type is affected by the northeast-southwest climate gradients along the Inner Mongolia terrain. The time coefficients of each distribution types could describe time-varying characteristics of each types in order to study the typical period of each distribution types. The time coefficient fluctuates intensely. It indicates a larger inter-annual oscillation of annual and seasonal precipitation. With the help of power spectrum function, the periodic variation of precipitation spatial structure is studied at the 0.1 significance level, which shows that the annual and seasonal precipitation in Inner Mongolia have multi-time scale features. Particularly, annual、 spring、 autumn、and winter precipitation have the periods of 2 -8 years high frequency change,summer precipitation simultaneously has 2 -3 years high frequency change and 16 years Iow frequency change. This potential period characteristics conform with the variation discipline in large-scale climate system.
国家科技期刊平台
NSTL
万方数据
维普
