北江流域植被覆盖时空变化及其对降水的响应

Spatial-Temporal Variation of Vegetation Cover and Its Response to Precipitation in Beijiang River Basin

本文采用2000~2019年MODIS NDVI数据及同期降水数据,利用数理统计方法,主要分析了北江流域月度植被、降水时空变化及两者间的响应关系。结果表明:1) 流域NDVI年均值为0.58,年内分布方面,2月份最低(0.41),2~9月逐渐上升,9月最高(0.72),9月~次年2月逐渐下降。流域NDVI整体呈波动上升趋势;从年内变化看,下半年(7~12月)上升较快。植被覆盖较低的区域主要分布在流域南部及中北部的河谷平原。2) 流域降水呈下降趋势,月降水空间分布大致分为由东南部向周边递减、由南向北递减、由北向南递减及无明显变化趋势四种类型。3) NDVI与同期及前期降水的相关性分析表明,1、2、11、12月,NDVI与同期及前期1~3月降水主要表现为正相关,4~9月,NDVI与同期及前期1~3月降水主要表现为负相关。

Using MODIS NDVI data from 2000 to 2019 and precipitation data of the same period, this paper mainly analyzed the spatiotemporal changes of monthly vegetation and precipitation in Beijiang River Basin and the response relationship between them by mathematical statistics. The results showed as follows: 1) The annual average of NDVI was 0.58. In terms of the distribution within the year, the lowest was in February (0.41), and gradually increased from February to September. The highest was in September (0.72), and gradually decreased from September to the following February. NDVI showed an overall fluctuating up-ward trend. From the perspective of annual change, the second half year (July-December) increased rap-idly. Areas with low vegetation cover were mainly distributed in the southern and north-central valley plains. 2) The annual precipitation showed a downward trend, and the spatial distribution of monthly pre-cipitation was roughly divided into four types: decreasing from southeast to the periphery, decreasing from south to north, decreasing from north to south, and no obvious change trend. 3) The correlation analysis between NDVI and precipitation in the same period and the previous quarter showed that NDVI was mainly positively correlated with precipitation in the same period and the previous quarter in Janu-ary, February, November and December, while NDVI was mainly negatively correlated with precipitation in the same period and the previous quarter from April to September.