Variations of dry and wet climate in the semi-humid and semi-arid transition zone of Inner Mongolia:Taking the comparison between Chifeng and Hulun Buir as an example
The observation data of 12 meteorological stations in Chifeng City and Hulun Buir City from 1978 to 2018 were used to analyze the variation characteristics of precipitation and temperature in the two cities with methods of linear regression and sliding average. Moreover, the effects of dry and wet climate changes in the two cities were compared and analyzed using M-K test method and Morlet wavelet analysis method. The results showed that in terms of temperature, the average annual temperature of Chifeng and Hulun Buir showed a trend of fluctuated increase from 1978 to 2018, with the increase rates of 0.11 ℃/10a and 0.25 ℃/10a, respectively. The average annual temperature of the two cities changed dramatically in 1982, and the main cycle of average annual temperature change was 14 a and 10 a, respectively. In terms of precipitation, the increase rate of annual precipitation in Chifeng was 2.43 mm/10a, and that in Hulun Buir was -9.76 mm/10a, with the highest rate of precipitation inclination occurred in summer, which were 6.71 mm/10a and -11.09 mm/10a, respectively. The annual precipitation of the two cities has undergone several abrupt changes, and the main change cycles of annual precipitation were 12 a and 8 a, respectively. From 1978 to 2018, the climate of Chifeng City became warmer and wetter, whereas that of Hulun Buir City turned warmer and drier. These phenomena had a great impact on the agricultural production of the two cities located in the borderline between the lands of agriculture and animal husbandry. Therefore, it is necessary to formulate timely and practical plans for the agriculture and animal husbandry of these two cities.