岷江上游流域植被返青期对气候暖干化的响应特征  

Responses of Vegetation Green-up Dynamics to Warmer and Drier Spring Climate in Mountainous Watershed in Southwest China

作　　者：周俸嘉 刘超[1] 金中武[2] 张岚斌 陈心怡 陆钰 刘铁刚[1] ZHOU Feng-jia;LIU Chao;JIN Zhong-wu;ZHANG Lan-bin;CHEN Xin-yi;LU Yu;LIU Tie-gang(State Key Laboratory of Hydraulics and Mountain River Engineering,College of Water Resource and Hydropower,Sichuan University,Chengdu 610065,Sichuan Province,China;River Department,Yangtze River Scientific Research Institute,Wuhan 430010,Hubei Province,China)

机构地区：[1]四川大学水力学与山区河流保护国家重点实验室水利水电学院,四川成都610065 [2]长江科学院河流研究所,湖北武汉430010

出　　处：《中国农村水利水电》2023年第2期66-73,共8页China Rural Water and Hydropower

基　　金：国家重点研发计划项目(2019YFC1510704);国家自然科学基金项目(42071038)。

摘　　要：植被的物候变化反映了生态系统对气候变化的动态响应,是研究陆地生态系统变化的重要指标。其中返青期作为最重要的物候指标之一,其变化趋势对生态系统的水碳过程会产生重要影响。多项研究标明,返青期的变化方向和幅度取决于所在区域的气候条件。岷江上游是西南山区典型流域,植被具有明显的垂直分异特征,且其气候具有明显的暖干化趋势。采用MCD12Q2物候产品,结合气象、高程数据,运用趋势检验和相关性分析等方法研究2001-2016年岷江上游草地、混交林和落叶阔叶林返青期的时空分布特征及其对气候暖干化的响应。结果表明:2001-2016年岷江上游草地、混交林和落叶阔叶林的返青期差异较大,其均值分别为第124.5±12.5 d、105.0±14.5 d和113.2±10.5 d。3种植被类型的返青期具有明显垂直分异性,返青期都随海拔升高而推迟,且在高海拔段(>3 500 m)推迟幅度更大。在春季气候暖干化影响下,草地和落叶阔叶林的返青期均呈显著提前趋势(p <0.05),混交林呈不显著提前趋势(p> 0.05)。3种植被返青期变化趋势在垂直分布上存在3500 m海拔分界线,分界线以上返青期提前速率更高,趋势更显著。岷江上游春季4月最低气温升高是植被返青期提前主要原因。该研究结果可服务于岷江上游生态系统生态过程的进一步研究。Phenology reflects the responses of ecosystem to climate change, and is considered as a major indicator of terrestrial ecosystem changes. As one of the most important phenological indicators, the trend of green-up dates(GUD) has an important impact on the water and carbon processes of the ecosystem. A number of studies have shown that the change direction and amplitude of green-up dates(GUD) depend on the climatic conditions of the region. The upper Minjiang River(UMR) is a typical mountainous watershed in southwest China, where vegetation has a vertical distribution pattern,and climate has a warming-drying trend. In this study, based on the MCD12Q2 products, the green-up dynamics of the major three vegetation types in UMR from 2001 to 2016 and its driving factors are analyzed by tendency test and or relation analysis. The results show that the average GUD are DOY 124.5±12.5, 105.0±14.5 and 113.2±10.5 for grass land(GL), mixed forest(MF) and deciduous broadleaved forest(DBF). The vertical distribution of the average GUD in UMR has obvious altitude differences. The average GUD has increasing trends with altitude for the three vegetation types. The GUD shows significantly decreasing trends(p<0.05) for both GL and DBF, and insignificant decreasing trend(p> 0.05) for MF. The altitude boundary line of 3 500 m is found for the GUD trend distribution, above which the advancing rates of GUD are significant and higher. The advances of the GUD for the three vegetation types in the UMR during 2001-2016 mainly results from the warmer and drier spring climate, and the minimum temperature and precipitation in March and April are main driving factors. The research findings can serve a further research on the ecological process of ecosystem in UMR.

关 键 词：物候 返青期 海拔 气温 降水 岷江上游 

分 类 号：P467[天文地球—大气科学及气象学] S162.5[农业科学—农业气象学]