近56年来科尔沁沙地气候变化特征

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

根据1951—2006年的气温和降水资料,研究了干旱少雨、生态环境脆弱、土地荒漠化严重的科尔沁沙地近56年的气候变化特征。结果表明:1951—2006年,科尔沁沙地的气温以0.28℃.10a-1的速度上升,远大于全球近50年来0.13℃.10a-1的平均增温速率;各季节气温都呈上升趋势,冬、春季增温速率极显著(P<0.001),增温速率分别为0.46和0.39℃.10a-1;年最高气温(0.17℃.10a-1)与年最低气温(0.42℃.10a-1)均呈极显著地增加趋势(P<0.01);降水量年际间波动较大,无明显的变化趋势,各季节降水量也没有明显的变化规律;年降水日数呈显著减少趋势(1.3d.10a-1),各季的降水日数虽都有逐年减少趋势,但没有达到显著水平;年降水强度和各季降水强度都没有明显的变化规律;年总小雨日数呈显著的减少趋势(P<0.05),减少速率为1.0d.10a-1。

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 semiarid 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℃·10a^-1, much higher than the global average value of 0. 13 ℃·10a^-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 ℃·10a^-1l and 0. 39 ℃·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 ℃·10a^-1 and 0.42 ℃·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 ·10a^-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 a rate of 1.0 d ·10a^-1.