毛乌素沙地气候变暖停滞现象及其气温和降水特征

Climate warming hiatus and characteristics of air temperature and precipitation in Mu Us Sandy Land

1998-2012年气候变暖停滞(hiatus)是全球气候变暖过程中的特殊现象,该现象表现为气温增速变缓、不变或出现下降趋势。毛乌素沙地生态环境脆弱,对气候变化较为敏感,研究该区域气候变暖停滞现象及其气温和降水变化特征,对于科学调整区域植被生态环境保护政策具有重要参考价值。基于1970-2019年毛乌素沙地气温和降水地面观测数据,利用线性趋势法、Mann-Kendall突变检验法等对气候变暖停滞现象及其气温和降水变化特征进行了分析。结果表明:1970-2019年,毛乌素沙地年际和季节平均气温、降水量均呈显著增加趋势(P<0.05),表现出“暖湿化”特征;1998-2012年,毛乌素沙地年平均气温变化速率为-0.70℃/10a(P<0.05),存在明显的hiatus现象。Hiatus现象发生期间,各季节平均气温均呈下降趋势,其中春季和冬季降温速率最高,年降水量仍呈增加趋势,其中夏季和秋季增加速率最高;hiatus现象结束后(2012-2019),毛乌素沙地年际和季节平均气温变化速率达到1970-2019年的2~3倍;年降水量呈减少趋势,其中秋季减少速率最高,春季增加速率最高。Hiatus现象发生期间和结束后的年际和季节平均气温、降水量变化呈明显相反的变化过程。研究认为毛乌素沙地1998-2012年存在明显的hiatus现象,表现为年平均气温显著下降、年降水量增加的特征。Hiatus现象发生期间和结束后的气温、降水反向变化需引起重视,可能会对毛乌素沙地植被生态环境变化造成一定影响。

As a special phenomenon in the process of global warming, climate warming hiatus is characterized by slow, stagnated or decreased growth of air temperature. The ecology of the Mu Us Sandy Land is fragile and sensitive to climate change, the research on the hiatus and the characteristics of air temperature and precipitation has important referential value for the appropriate adjustment of regional vegetation ecology protection policies in this area. Based on the ground observation data of air temperature and precipitation in the Mu Us Sandy Land during 1970-2019, we adopted the linear trend method and the Mann-Kendall test method to analyze the hiatus and the characteristics of air temperature and precipitation in this area. The results showed the inter-annual and seasonal average air temperature and precipitation increased significantly(P<0.05), presenting the characteristics of “warm and humid” in the Mu Us Sandy Land during 1970-2019. From 1998 to 2012, the annual average air temperature change rate was-0.70 ℃/10 a(P<0.05), hiatus was readily recognized. During the occurrence of hiatus, the average air temperature in each season showed a downward trend, with the highest decreasing rate in spring and winter;whereas the annual precipitation still showed an increasing trend, with the highest increasing rate in summer and autumn. After the hiatus(2012-2019), the change rates of the inter-annual and seasonal average air temperature reached 2-3 times of those of 1970-2019, and the annual precipitation showed a decreasing trend, with the highest decreasing rate in autumn and the highest increasing rate in spring. The inter-annual and seasonal air temperature and precipitation changes during and after the hiatus showed obvious opposite change processes. It is concluded that there was an obvious hiatus in the Mu Us Sandy Land during 1998-2012, which was characterized by a significant decrease in annual average air temperature and an increase in annual precipitation. Attention should be paid to the reverse changes of air temperature and precipitation during and after the occurrence of the hiatus, which may have a certain impact on the vegetation ecology change in the Mu Us Sandy Land.