毛乌素沙地1960-2013年极端气温变化

毛乌素沙地处于多层次生态地理景观过渡带,拥有丰富的自然及人文资源.研究该生态脆弱区极端气温变化,有利于揭示全球气温变化与局地气温响应之间的复杂关系,为当地的可持续发展和气象灾害预防提供参考。通过线性趋势分析、累计距平、Mann-Kendall法、因子分析、R/S分析等方法,分析了该地极端气温指数的变化特征,突变特点、相互关系,探讨了该地区气温变化的空间差异和极端气温未来的变化趋势。结果表明:(1)极端最低气温、极端最高气温、夏日日数、热夜日数、暖夜日数、暖日日数分别以不同的速率上升;冰日日数、霜冻日数、冷夜日数、冷日日数分别以不同的速率下降。(2)除极端最高气温、极端最低气温外,其余8项极端气温指数均发生突变,突变年份集中在20世纪90年代。(3)冷指数大幅下降是毛乌素沙地极端气温变化的主要特点,并且各冷指数间、各暖指数间相关关系显著。(4)毛乌素沙地极端气温在空间上表现出不同的变化特点,东北方向(榆林及鄂托克旗)冷指数呈现大幅减少,西南方向(横山及盐池)暖指数呈现大幅增加。(5)ENSO事件具有使毛乌素沙地极端最高气温降低的作用以及使极端最低气温升高的作用。(6)10项极端气温指数的Hurst指数均大于0.5,表明未来毛乌素沙地极端气温仍将呈现冷指数下降、暖指数上升的变化趋势。

Variation of Extreme Air Temperature in Mu Us Sandy Land during 1960-2013

The Mu Us Sandy Land is located in the transitional zone of multi-level ecological geographic landscape types. Study on the extreme air temperature change in the ecological fragile region is helpful to reveal the complex relationship between the global air temperature change and the local temperature response, and provide a reference for the local environmental sustainable development and the prevention of meteorological disasters. The methods of linear trend analysis, accumulative anomaly, Mann-Kendall examination, factor analysis and R/S analysis are employed to analyze the temporal variability of extreme air temperature change in Mu Us Sandy Land during 1960-2013. Results show that: (1)The extreme minimum air temperature, extreme maximum air temperature, summer days, tropical nights, warm nights and warm days increased at different rates, and ice days, frost days, cold nights, cold days decreased at different rates. (2)In addition to the extreme maximum air temperature and extreme minimum air temperature, the remaining eight extreme air temperature indices took place abrupt change in 1990s. (3)Cold index decrease was the main characteristics of the extreme air temperature change, and the cold indices were positively correlated with each other as well as warm indices. (4)The extreme air temperature exhibited spatial distribution difference, cold index significantly reduced in northeast (Yulin and Etuoke Banner), and warm indices significantly increased in south-west(Hengshan and Yanchi). (5)The ENSO events caused extreme maximum air temperature decrease and extreme minimum air temperatures increase. (6)The Hurst index of 10 extreme air temperature indices were all greater than 0.5, which indicated that cold indices would decrease and warm indices would increase in the future in Mu Us Sandy Land.