Unsymmetrical Variation of the Maximum and Minimum Air Temperatures in Wengniute Banner,Horqin Sandland

In this paper,the monthly average,minimum and maximum air temperatures in Wengniute Banner located in the Horqin Sandland since 1957 are analyzed.The results are as follows:(1) The annual average air temperature and the annual average daily maximum and minimum air temperatures are in an increase trend,the increase of annual average daily minimum temperature is more significant than that of annual average daily maximum temperature,and the effect of annual average daily minimum temperature on the annual average temperature is higher than that of annual average daily maximum temperature;(2) The increase of daily average minimum air temperature in January in Wengniute Banner is higher than that of annual average temperature and annual average daily minimum temperature,the change of daily average maximum temperature in January is not so significant and even decreased slightly in the 1990s;(3) The change of monthly temperature,average daily minimum and maximum temperatures in July is not so significant since recent 50 years,they have increased since recent 30 years,especially the average daily minimum temperature;(4) The linear change rate of minimum air temperature in January is 8.77 ℃/100 a,and that of maximum air temperature in July is 3.12 ℃/100 a;(5) The annual average air temperature and the daily maximum and minimum air temperatures have sharply increased since the late-1980 s.