老哈河流域NDVI动态变化及其与气候因子的关系

利用1982~2006年GIMMS/NDVI数据,赤峰气象站的气温数据和流域内52个雨量站的降水数据,采用一元线性回归分析、简单相关分析以及偏相关分析方法对老哈河流域内林地、灌丛、草地、耕地4种植被类型NDVI年内和年际变化及其与气温、降水的关系进行了研究.结果表明:老哈河流域NDVI年内变化呈单峰型,年最大值出现在8月份,月NDVI和气温、降水之间均具有显著的正相关关系,且存在滞后现象,林地与灌丛、草地相比,其NDVI受降水影响相对较小,气温对植被年内生长的影响大于降水;1982~2006年流域年均NDVI呈上升趋势,其中20世纪90年代流域植被覆盖水平最好;夏季NDVI与同期和前期的气温呈显著的负相关,与前期降水呈显著的正相关,在老哈河流域夏季气温升高会导致植被覆盖减少,而降水增加有利于植被的生长.

Dynamic variation of NDVI in Laoha River Basin and its relationship with climatic factors

The annual and inter-annual variation of the NDVI of forest land, shrubs, grassland and farmland and its relationship with the air temperature and precipitation in Laoha River Basin were studied using unary linear regression analysis, Pearson correlation analysis and partial correlation analysis based on GIMMS/NDVI data, temperature data from the Chifeng meteorological station and precipitation data from 52 stations from 1982 to 2006. The test results show that the annual variation of NDVI is unimodal, and the maximum value occurs in August. The monthly NDVI exhibits a positive correlation with the air temperature and precipitation and shows a logging phenomenon. The influence of the precipitation on NDVI in the forest land is relatively smaller than that in the shrubs and grassland. The influence of the air temperature on the annual growth of vegetation is larger than that of the precipitation. The average inter-annual NDVI in the basin had an increasing tendency from 1982 to 2006, and the most satisfactory performance of NDVI appeared in the 1990s. The NDVI during summer is negatively correlated with the air temperature in the corresponding and previous periods and positively correlated with the precipitation in the previous period. The increase of the air temperature in summer in Laoha River Basin results in a decrease of vegetation, and the increase of the precipitation supports the growth of vegetation.