西辽河流域归一化植被指数与气象因子相关性分析

Correlation analysis of NDVI and meteorological factors in the West Liao River Basin

为了解西辽河流域归一化植被指数(NDVI)的分布规律、变化趋势及对气候变化的响应,利用2000—2018年西辽河流域11个气象站逐日气象资料和MODIS归一化植被指数数据集,通过线性回归和相关分析,探讨了生长季各月NDVI与气象因子的时滞性,以及气象站周围10 km缓冲区内不同植被类型NDVI与气象因子的相关性。结果表明:西辽河流域年平均气温、最高气温、最低气温和降水量均呈上升趋势。NDVI呈上升趋势,植被有所改善,不同植被类型NDVI均呈增加趋势,耕地增加趋势最快,耕地长势受益于农事活动的完善和增进。NDVI空间分布呈现中间低,四周高特点。生长季各月NDVI与降水量存在明显的滞后性,滞后期为1个月;仅8月NDVI与前1个月平均气温和最高气温存在滞后性。不同植被类型NDVI与平均气温、最高气温的相关性密切。耕地NDVI与气象因子的相关性较好。研究结果可为维护西辽河流域生态系统平衡提供参考。

The paper aims to understand the distribution rule and trend change of the normalized difference vegetation index(NDVI)and its response to climate change in the West Liao River Basin.Linear regression and correlation analysis were used to analyze the delay of NDVI and meteorological factors in each month of the growing season,and the correlation between NDVIs of different vegetation types and meteorological factors in the 10 km buffer zone around the meteorological station based on the daily meteorological data of 11 meteorological stations and MODIS normalized difference vegetation index data set from 2000 to 2018.The results showed that the annual temperature,the highest temperature,the lowest temperature,and the precipitation in the West Liao River Basin all saw an uptrend.The NDVI of different vegetation types was on the rise in the West Liao River Basin,and the vegetation was improved.The increased rate of cultivated land was the largest,which benefited from the improvement and promotion of agricultural activities.The spatial distribution of NDVI was characterized by low value in the middle and high value around the West Liao River Basin.NDVI in each month lagged obviously behind precipitation in the growing season with a lag period of one month,only the NDVI in August lagged behind the average and maximum temperatures in the previous month.NDVIs of different vegetation types were closely related to the average and maximum temperatures in the West Liao River Basin.There were better correlations between NDVI of cultivated land and meteorological factors.The results provide a reference for maintaining the balance of the ecosystem in the West Liao River Basin.