Characteristics of climate change in Horqin Sandy Land in past 56 years

Based on the 1951-2006 air temperature and precipitation data from seven meteorological stations in Horqin Sandy Land, the past 56-year climate change characteristics in this semi-arid area with vulnerable eco-environment and severe land desertification were analyzed. From 1951 to 2006, the mean annual air temperature in this area increased by 0. 28 °C. • 10 a^-1 , much higher than the global average value of 0. 13 °C • 10 a ^-1 in recent 50 years. The increasing trend of the temperature appeared in all four seasons, but was only significant in winter and spring (P <0. 01 ) , with an increasing rate of 0. 46 °C • 10 a^-1 and 0. 39 °C 10a^-1, respectively. Both the maximum and the minimum mean annual temperatures increased significantly (P <0. 01 ), and the increasing rate was about 0. 17 °C • 10 a^-1 and 0.42 °C 10a^-1, respectively. The annual precipitation fluctuated among years, with no obvious change trend at yearly and seasonal scales, while the precipitation days decreased significantly at yearly scale (1.3 d • 10 a^-1 ) but not at seasonal scale. No obvious change patterns were observed in the precipitation intensity both in yearly and seasonal scales. The annual light-rain days decreased significant (P<0.05) in arate of 1.0 d • 10 a^-1.