1982-1999年珠江流域归一化植被指数与降水年际变化分析

摘要

Based on the monthly normalized difference vegetation index (NDVI) and precipitation data in the Pearl River Basin from 1982 to 1999, the relationship between NDVI and precipitation anomaly on the annual and interannual time scales are analyzed using empirical orthogonal function (EOF) method. Correlation coefficients between NDVI, precipitation, and other climatic factors are also analyzed. There is a good spatial coincidence between the variation of NDVI and that of precipitation anomaly in terms of annual variability, with NDVI lags one month. The interannual anomalies of NDVI and precipitation have obvious difference in their spatial distributions. Positive correlation is found in the west of the Pearl River Basin, while negative correlation is found in the east. The relationships between NDVI and climate factors are different in different seasons and different domains. The correlation coefficient between NDVI and precipitation is negative in the east and positive in the west. The relationship between NDVI and temperature is positive in the east and not significant in the west;same for the relationship between NDVI and solar radiation. In summer, the NDVI and precipitation have negative relationship, which reverses in spring and fall.%利用1982-1999年月平均归一化植被指数(normalized difference vegetation index,NDVI)和降水资料,采用经验正交函数(EOF)方法分别研究了珠江流域的NDVI和降水在年和年际尺度上的异常关系,并分析了NDVI与降水及其他一些气象因子的相关关系.研究发现流域NDVI和降水在年内异常上具有较好的空间一致性,在时间上具有1-2个月的滞后；年际尺度上两者异常空间差异明显,流域东部(下游)异常为负相关,西部(上游)异常为正相关.NDVI和各气候因子的相关关系存在明显的空间和季节差异:流域东部NDVI和降水负相关明显,和温度及太阳短波辐射正相关明显；流域西部NDVI和降水滞后正相关明显,和温度相关不明显；NDVI在夏季和降水呈显著负相关,在春、秋季节滞后于降水,呈明显正相关,且滞后3个月正相关最为明显.