摘要
全球变化背景下气候因子与地表植被的相互作用过程是地球科学领域的研究重点和热点。利用重庆市50年来气象站点数据和1999年以来的SPOT4-VGT NDVI数据,采用Mann-Kendall检验、时空分析、相关分析等方法,对年均温、年降水时空变化特征及其与植被活动变化之间的关系进行了分析。结果表明,重庆市50 a间年均温、年降水量波动明显,其中年均温2002年以后增温趋势显著。植被覆盖近10 a呈明显增加趋势,且存在显著的时空差异。空间上,三峡库区及长江、嘉陵江沿岸NDVI增加最为明显;时间上,春季、秋季NDVI增加最为显著。植被覆盖年内周期变化与降水、特别是气温的相关性显著,但年际变化与年均温和年降水量变化相关性不显著。初步分析表明,人类活动,特别是农业生产、耕地保护和植被生态建设等,是近10 a重庆市植被覆盖上升的首要因素。
The characters of climatic factors variation and the interaction between climatic factors variation and vegetation cover are important in geosciences and has become a research focus in the global and regional scales in recent years. Constituting eighty five percent of the Three Gorges Reservoir area, Chongqing is in an important ecological, hydrological and wildlife conservation area in Southwestern China. Examining the vegetation dynamics and environmental changes over this region plays a critical role in studying the environment and ecosystems in China. On the basis of previous researches, Based on SPOT -4 VEGETATION NDVI datasets at 1 km spatial resolution and temperature and precipitation datasets of meteorological stations from Chongqing and its neighboring city during the period 1961--2010, the spatial and temporal characteristics of temperature ＆ precipitation variation in Chongqing were statistically analyzed. The response of vegetation Coverage Change to major climate factors and its relationship with temperature and precipitation in Chongqing is explored by extracting each pixel g information between 1999 and 2010. The results show that： 1 ） From 1961 to 2010, the annual mean precipitation and temperature in Chongqing was highly fluctuant. The annual mean precipitation exhibited a small decreasing trend; and the increasing trend of annual mean temperature was highly significant. 2） From the time point of view, the annual and monthly variability of the vegetation dynamics have the increasing trend in Chongqing. It has obvious seasonal difference, from the spatial perspective, the averaged annual NDVI in Chongqing showed a steady upward trend during the last decade. Especially, vegetation increased significantly on both sides of the Yangtze River and the southeastern part area of Chongqing. And vegetation degraded areas are mainly concentrated water-fluctuating zones of Three Gorges Reservoir and around urban of Chongqing city as well as the periphery of the Three Gorge Reservoir Region in Chongqing. So obviously, the reason is enlargement of city and fluctuating of water area. 3 ） The monthly variability of vegetation index and temperature, precipitation exist significant correlation. Both air temperature and precipitation have an influence on NDVI, but air temperature plays a more prominent role. The correlation coefficient of the annual year or month vegetation index and climatic factors is not significant in the entire region. That is to say the human factors, such like agricultural production, farmland protection and the implementation of largescale vegetation construction, have resulted in the increase of NDVI and have led to some beneficial effect in ecology.
出处
《山地学报》
CSCD
北大核心
2014年第6期717-724,共8页
Mountain Research
基金
国家自然科学基金(41101563)
重庆市自然科学基金(CSTC
2011BB1114)
重庆师范大学基金项目资助(12XLZ14)
重庆市教委理科项目(KJ080808)~~
