气候因子与植被的时滞相关分析——以广西为例

广西地区地下河发育，地表水缺乏，生态系统脆弱、抗干扰能力低，灾害频繁，森林生态系统严重退化，石漠化程度加剧，属于生态脆弱区域，而植被变化是生态系统对气候变化响应的指示器，其变化研究对该地区生态环境建设具有重要意义。文章基于1999--2010年气温与降水数据和GIMMS．NDVI（GlaobalInventoryModellingandMappingMtudies-NormalDifferenceVegetionIndex）数据集，研究近12年来广西地区植被覆盖时空特征。通过时滞相关分析法，分析研究区不同植被类型受气温和降水的影响，即植被NDVI对气温和降水的响应程度。结果表明，（1）植被NDVI与温度的时滞相关程度强于降水，而响应时间刚好相反，植被NDVI对降水的响应比对温度的响应程度要快。（2）植被NDvI与降水的时滞相关规律呈桂南较弱—桂中较强—桂北较弱，但响应时间刚好相反，即桂南较快一桂中较慢—桂北较快。（3）植被NDvI与温度的时滞相关性变化规律呈由南向北递减，响应时间由南向北变快。（4）植被NDVI与气候因子时滞相关越强，响应的时间就越迟缓，反之越快。（5）不同的植被类型对水热条件响应程度不同，与水热条件时滞相关越强的植被则滞后时间相对越久。

Analysis on the time-lag correlation between vegetation and climatic factors --,Take Guangxi as an example

Based on time lag cross-correlation, using the ten-day mean temperature and precipitation data and GIMMS-NDVI （ Glaobal Inventory Modelling and Mapping Mtudies -Normal Difference Vegetation Index ） of Guangxi from 1999 to 2010, we analyzed the relationship between temperature, precipitation and NDVI of different vegetation types. Results show that, （1） the related degree between NDVI and temperature is powerful than precipitation, and response time on the contrary, the speed between NDVI and precipitation is faster than temperaatre. （2） the time-lag rule between NDVI and precipitation is： weaker in south and north Guangxi, and high in the middle area, but the response time is just the opposite： faster in south and north Guangxi, and slower in the middle Guangxi. （3） the correlation between NDVI and temperature decrease progressively from the south to the north, but the sensibility increase. （4） the higher the correlation between NDVI and climate factors is, the slower response time. （5） the response degree of different vegetation types shows different condition, and the stronger the correlation between vegetation cover and hydro-thermal condition, the longer lag time.