| It is very important and has great theoretical and practical significance to study the changes of regional precipitation characteristics and its infected factors under the background of global change. Compared with the changes of global temperature, it is more remarkable about the laws of space-time characteristics of regional precipitation. With the global shortage of water resources in some area, people paid more and more attention to national and regional water security, especially in some special area it has become decisive factors of the social, economic stability and development, so the law of precipitation has always been understanding and concerned. And people's understanding of precipitation expanded from the basic characterization to the analysis of physical processes and exploring of predicting long-term changes in the region.Because of these ,the article mainly study the arid and semi-arid area of northern China, based on the date of the precipitation of recent 45a and by the means of kriging interpolate,spectrum Analysis,Wavelet analysis and correlation analysis, to research the spatial and temporal characteristics of precipitation changes in the last 45 years, and compared this with the solar activity characteristics (including the number of sunspot cycle, solar magnetic field index) ENSO index MEI, AO, NAO, potential height of polar vortex and pressure intensity of semi-tropical in the same period to explore the general characteristics and the regional differences of precipitation causes. Several conclusions were drawn in this paper as follows:1) From space aspect, precipitation in the northern arid and semi-arid zones shows the grading rules from southeast to northwest, from time aspect, precipitation is differences as well. Precipitation since 90s, that is, a marked increase from the western region to the east generally.2) Fluctuations in precipitation in northern China generally show the cycle of 2a, 5a, 8a, 11a ,17-18a and 22a, which showing changes with background of solar activity precipitation (sunspot number and magnetic cycle), air-sea activities and the impact on tidal cycle.3) Solar activity impacting on precipitation in the northern region is mainly embodied in the solar magnetic field changes in the course of the cycle and it will affect the gradual decline from north to south, but in terms of the phenomenon, due to changes in a magnetic field along with two sunspot cycle, so in the north (including the eastern part of Xinjiang and Inner Mongolia) precipitation at the same time to show the cycle of 11a and 22a.4) In north-eastern part of Inner Mongolia Plateau and Loess Plateau, the precipitation associated with ENSO have typical pertinence, its border is between Xilinhot to Zhurihe, precipitation of Zhurihe and its monsoon-affected zone and the western Loess Plateau is mainly the negative correlated with ENSO and ENSO is the negative correlated with ENSO the east of Xilinhot. When El Nino occurred, the eastern part of Inner Mongolia has more precipitation, when El Nino weakening, La Nina occurred that will increase precipitation in the Loess Plateau Area.5) AO and NAO have a good relativity with the precipitation of Xinjiang, which reflect that the AO and the NAO have been controlled by the activities of Polar vortex, thus causing the westerlies swing between 45-50N, which decision the precipitation of Xinjiang is fluctuation especially in north-western.6) Coupling of the Pacific subtropical high, the Walker circulation and ENSO have a great significance for the regional precipitation, when Outbreak of El Nino, not only the island of Tahiti embankment pressure drop in the sea, the North Pacific subtropical high strength have reduced simultaneously, the East Asian monsoon have weakened, while the convergence center low-pressure moving eastward resulted in water vapor of high-altitude is decreased in Sea Surface of eastern Pacific, water vapor transmission capacity in depth is reduce, the front of rainfall towards the south-east, mainly landing in the eastern part, so more precipitation in the eastern part of Inner Mongolia, on the contrary, the precipitation of annual in the eastern part of Inner Mongolia is reduce relatively to normal year, the precipitation of the central of Inner Mongolia and the Loess Plateau is increase.7) Circulation, such as frontal cyclone of summer of the center of Cold and Drought in the Northern Tibetan Plateau have an effects on distribution of semi-ring precipitation in south-east of Qinghai. In addition, such as circulation Superposition with topographic factors have a impact on regional precipitation, such as the north-western of the Tianshan Mountains, southeastern of the Qilian Mountains , south of the Yinshan and east of the Liupanshan have more precipitation.But because of lack of the knowledge about the physical mechanism of solar activity and earth system ,because of the error of using the analytical methods, the complex factors affecting regional precipitation need be paid more attention.
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