Study On Climate Change Of The Farming-pastoral Zone In The Eastern Inner Mongolia In Recent 60 Years

Under the background of global warming, climate change has attracted much attention. China’s climate change is not only consistent with global climate change, but also has many differences with it. The farming-pastoral zone of Inner Mongolia is a transition region of agricultural ecological system to the grassland ecological system, and the ecological environment there is very fragile. This vulnerability leads to its extreme sensitivity to global climate change and human disturbance. And because it is an important ecological barrier of China, and has play a decisive role position in social and economic development in china. Therefore, it is necessary to carry on further research on climate change in this region.Based on the precipitation and temperature data of four meteorological stations(Ongniud Bannar(1957-2013), Ar Horqin Banner(1959-2013), Jarud Banner(1953-2013),Horqin Right Wing Middle Banner(1953-2013)) of the eastern part of farming-pastoral zone of Inner Mongolia, this paper has analyzed the climate change of it in the recent 60 years with the climate tendency rate method, the moving average method, the anomaly method, the accumulative anomaly method and the calculation method of dryness(DE Mar tonne). The study found that its climate has got drier and warmer in recent 60 years. The principal conclusions of this analysis are as follows:(1)the average annual precipitation tended to reduce, and the variation of overall trend was small; for many years the average precipitation was347-389mm; the rainy period and rainless period appeared alternately, it was basically at the relatively rainy period during the early 80’s to the mid-90’s,afterwards, it belonged to relatively rainless period. Precipitation mainly concentrated in the summer and autumn, and the winter rainfall was less; the spring tended to be wet, however, the average precipitation of the summer and the autumn had a decreasing trend. The winter of AR Khorchin banner and Horqin Right Middle Banner tended to be slightly moist, but it became dry inthe Jarud banner and Ongniud Banner. The precipitation of growing season was 61-70 mm, showing a decreasing trend, and the rainy period and less one appeared alternately during the growing season. For nearly 60 years 400 mm isohyet agro pastoral ecotone in Inner Mongolia east tended to move up towards the East south.(2) In the whole temperature has a increasing trend, and the growth rates of the average temperature among the years, seasons and the growing seasons temperatures are higher than the average level in the same period of global and Northern Hemisphere, but lower than that in the whole of Inner Mongolia(0.42 degrees /10a) [51]. The annual average temperature is more than 6degrees, and that in the growing season is above 19 degrees. The average temperatures of years, seasons and the growing seasons all mutated, and mutation period of average annual temperatures appeared around 1987, the average temperatures of four seasons jump latest in summer(all around 1993),earlier in spring and winter(all around 1987), and the mutation of the average temperature in growing seasons happened from 1992 to 1993.(3)This area has got drier in nearly 60 years. And the moderate drought season appeared about 48 years. The driest season occurred in the first 10 years of this century.