1971—2018年西藏羌塘国家级自然保护区地表湿润指数的变化趋势  

Climate change tendency of surface humidity index in Chang Tang Nature Reserve of Tibet from 1971 to 2018

作　　者：杜军 周刊社[3] 袁雷[3] DU Jun;ZHOU Kanshe;YUAN Lei(Tibet Institute of Plateau Atmospheric and Environmental Science Research, 850001, Lhasa, China;Tibet Key Laboratory of Plateau Atmospheric and Environmental Science Research, 850001, Lhasa, China;Tibet Autonomous Region Climate Centre, 850001, Lhasa, China)

机构地区：[1]西藏高原大气环境科学研究所,拉萨850001 [2]西藏高原大气环境研究重点实验室,拉萨850001 [3]西藏自治区气候中心,拉萨850001

出　　处：《中国水土保持科学》2021年第4期13-23,共11页Science of Soil and Water Conservation

基　　金：国家自然科学基金“羌塘国家级自然保护区气候变化及其对生态环境的影响”(41765011);2019年西藏自治区科技重点研发计划“西藏主要地表特征科学考察及研究”;中国气象局软科学项目“青藏高原气候与生态环境变化应对策略研究”(2019ZDIANXM10)。

摘　　要：研究地表湿润指数Hi的时空变化特征,是认识区域水文过程及其对气候变化响应的重要途径,可为生态环境变化监测提供依据。根据1971—2018年西藏羌塘国家级自然保护区5个气象站逐日地面观测资料,应用PenmanMonteith模型计算潜在蒸散量和湿润指数,采用线性倾向估计、MannKendall方法分析Hi的年际与年代际变化、突变特征,基于数据处理系统,利用主成分回归方法讨论影响Hi的主导因子。结果表明:1)1971—2018年自然保护区年平均气温以0.046℃/a的速度显著升高,年降水量每年增加1.18 mm,暖湿化气候特征明显,但年Hi却没有表现出明显的增大趋势,仅为0.001/a,不过夏季Hi增幅明显;20世纪70—90年代保护区表现出以低湿为主的年际变化特征,进入21世纪代后气温持续升高,Hi明显增加,表现出暖湿型的气候特征。2)年Hi在1996年出现由偏干转偏湿的突变,1996—2018年Hi比1971—1995年增加了19.1%。3)主成分回归分析显示,降水量是影响年Hi变化的主导因子(正贡献),日照时间也起着次要作用(负贡献);在季节上影响Hi变化的主导因子都是降水量(正贡献),次要因子有所不同:春、秋2季是日照时间(负贡献)、夏季是气温日较差(负贡献)、冬季是平均气温(负贡献)。1996年转折前后影响年Hi的主导因子都是降水量,不过次要因子存在差异,突变前后分别是气温日较差(负贡献)和日照时间(负贡献)。[Background]There is a unique alpine desert ecology in the Chang Tang Nature Reserve of Tibet(CTNRT),it is an important and indispensable pathway to explore the temporal and spatial variation of humidity index Hi in CTNRT and its driving factors under the background of global warming,in order to provide sharp insight into the regional hydrological process and its response to climate change,also it can provide a scientific basis for monitoring the ecological environment.[Methods]Based on daily meteorological data over 5 weather stations in CTNRT from 1971 to 2018,we computed the potential evapotranspiration and Hi using the FAO Penman-Monteith formula.The long-term trend and inter-annual variability of Hi in CTNRT were analyzed using linear tendency estimation and Mann-Kendall test.Moreover,the dominant influential factors explaining the changes of Hi were identified based on Data Processing System and principal component analysis.[Results]1)In the past 48 years(1971-2018),the annual mean temperature in CTNRT presented a significant increasing trend with a rate of 0.046℃/a,the annual precipitation increased remarkably at the rate of 1.18 mm/a,and the annual mean Hi changed over time with a rate of 0.001/a,suggesting weak increasing trend,despite significant increasing trend observed in summer.From the 1970s to the 1990s,the Hi was featured with lower humidity characteristics in CTNRT.After the 2000s,the air temperature rose steadily,and Hi increased obviously,indicative of a warmer and wetter climate in CTNRT.2)It was found that the annual mean Hi experienced an abrupt change from relatively dry to wet phase in 1996.On average,the Hi was found to increase by 19.1%during 1996-2018 compared with the period 1971-1995.3)The principal component regression analysis showed that the precipitation(positive contribution)dominated the change of annual Hi,followed by the sunshine duration(negative contribution).The precipitation was the dominant factor for affecting the changes in seasonal mean Hi,but secondary factor diffe

关 键 词：变化趋势 湿润指数 影响因素 主成分回归 羌塘国家级自然保护区 

分 类 号：S161[农业科学—农业气象学]