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2001-2017年新疆NDVI变化及其对极端气候的响应
张晋霞1,2, 徐长春1,2, 杨秋萍1,2
1.新疆大学 资源与环境科学学院, 新疆 乌鲁木齐 830046;2.新疆大学 绿洲生态教育部重点实验室, 新疆 乌鲁木齐 830046
摘要:
[目的] 研究新疆2001—2017年植被覆盖变化,并分析其与气候指数之间的响应特征,以期为该地区生态环境保护和区域可持续发展提供理论依据。[方法] 基于2001—2017年的MOD13Q1 NDVI数据,采用最大合成法、Savitzky-Golay(SG)滤波法和相关分析等方法,并结合同期气温和降水数据,分析新疆生长季归一化植被指数(NDVI)和极端气候之间的响应关系。[结果] ①2001—2017年,新疆地区植被覆盖普遍不高,自2009年开始表现出缓慢改善趋势,且未来一段时间内,该趋势具有一定的持续性;②NDVI总体上呈西北向东南降低趋势,天山山脉和伊犁河谷地区是NDVI高值区,北疆各子区域生长季NDVI普遍高于南疆地区;③NDVI在北疆中部和南疆西南部等地区与极端气温指数多呈负相关,日平均温差(DTR)和冷夜日数(TN10p)是主要的影响指数;NDVI与平均气温指数在沙漠地区多呈负相关,在部分山区呈正相关,这主要与年平均气温(Ty)的变化有关;④NDVI与降水指数之间多呈正相关,且单日最大降水量(RX1 d),连续5日最大降水量(RX5 d)和年降水量(TPy)对NDVI的影响都很显著。[结论] 新疆植被覆盖总体向良好方向发展。NDVI对降水指数的响应高于气温指数,其中,降水指数以正向影响为主,气温指数则以负向影响为主,降水对新疆植被改善有着明显的促进作用。
关键词:  归一化植被指数(NDVI)  时空动态  极端气温指数  极端降水指数  新疆
DOI:10.13961/j.cnki.stbctb.2020.05.036
分类号:Q948.1
基金项目:国家自然科学基金项目“基于水资源变化的干旱内陆区典型流域绿洲适宜规模研究”(41561023)
NDVI Variations and Its Response to Extreme Climate in Xinjiang Uygur Autonomous Region During 2001-2017
Zhang Jinxia1,2, Xuchang Chun1,2, Yang Qiuping1,2
1.College of Resource and Environment Sciences, Xinjiang University, Urumqi, Xinjiang 830046, China;2.MOE Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi, Xinjiang 830046, China
Abstract:
[Objective] The vegetation cover in Xinjiang Uygur Autonomous Region from 2001 to 2017 and its response to the extreme climate index were analyzed in order to provide a theoretical basis for the ecological-environmental protection and sustainable development of the region.[Methods] Data of the MOD13Q1 normalized difference vegetation index (NDVI), temperature, and precipitation during the period from 2001 to 2017 were used along with the maximum synthesis method, Savitzky-Golay (SG) filtering method, and a correlation analysis to investigate the relationship between the NDVI and the extreme climate index during the growing season.[Results] ① The vegetation cover in Xinjiang was not high overall from 2001 to 2017, with a slowly improving trend since 2009, which is likely to continue in the future. ② In general, the NDVI decreased from northwest to the southeast. The Tianshan Mountains and Ili River valley were the areas with the highest values, and the NDVI in the sub-regions of Northern Xinjiang was generally higher than that of the Southern Xinjiang. ③ The NDVI was negatively correlated with the extreme temperature index in the central part of Northern Xinjiang and the southwest part of Southern Xinjiang. The diurnal temperature range (DTR) and number of cool nights (TN10p) were the main influencing indices. The NDVI was negatively correlated with the average temperature index in desert areas, whereas it was positively correlated in some mountainous areas, which was mainly due to the variation of the annual average temperature (Ty). ④ The NDVI was positively correlated with the precipitation index. The maximum 1-day precipitation amount (RX1 d), maximum 5-day precipitation amount (RX5 d), and annual precipitation (TPy) were the main contributors.[Conclusion] The vegetation coverage in Xinjiang is developing in a positive direction. The response of the NDVI to the precipitation index was higher than its response to the temperature index. The precipitation index mainly exhibited a positive influence, while the temperature index had a negative influence. Precipitation had an obvious promoting effect on the improvement of vegetation in Xinjiang.
Key words:  normalized difference vegetation index (NDVI)  spatiotemporal dynamics  extreme temperature index  extreme precipitation index  Xinjiang Uygur Autonomous Region