陇东地区植被指数NDVI与降水的关系研究

摘要

利用1982～2003年NOAA/AVHRR(advanced very high resolution rediometer)资料及同期的降水资料,对甘肃省陇东地区半干旱区环县和半湿润区西峰的植被指数NDVI与不同时间尺度的标准化降水指数SPI进行相关分析.结果表明:在植被生长季,植被对降水的敏感程度半干旱区大于半湿润区;大多数月NDVI与3-SPI的相关系数较高,而与1-SPI较低;半干旱区和半湿润区NDVI的年变化幅度分别为:-12%～10%和-10%～13%,半干旱区NDVI的年变化与SPI变化趋势吻合较好,显著相关(P<0.05),而在半湿润区二者并不显著;半干旱区的年NDVI与四季降水均显著相关(P<0.05),而半湿润区年NDVI只与冬春季的降水显著相关(P<0.05).%Normalized difference vegetation index (NDVI) can be characterized as an indicator of vegetable growing conditions while precipitation resources is a key factor to affect the vegetable growing conditions and ecological construc-tion in Longdong of Gansu. The correlation between NDVI and different-temporal-scale standard precipitation index (SPI) in Longdong of Gansu are studied based on the data of NOAA/AVHRR and precipitation over the same period in 1982 ～ 2003. The results show: (1) The sensitivity of vegetable to precipitation is more significant to semi-arid area than semi-humid area in vegetable growing season; (2) The most significant correlation is found in NDVI and 3 - SPI while the most insignificant is in NDVI and 1 - SPI; (3) The annual-variational amplitudes of NDVIs are - 12% ～ 10% in semi-arid area and - 10% ～ 13% in semi - humid area, respectively, which agree well with SPI in the former at 95% significant level(P <0.05) , but not significant in the latter; (4) Annual NDVIs are significantly correlated with the precipitations of four seasons in arid area(P < 0.05) while significant only in winter and spring in semi-humid area.