北部湾沿海流域植被覆盖动态变化及其驱动因素

基于2000—2018年的中分辨率成像光谱仪13Q1数据,利用修正的变化矢量分析、变异系数、Hurst指数等方法分析北部湾沿海流域植被覆盖动态变化趋势及其持续性、预测未来植被覆盖变化情况以及植被覆盖变化的驱动因素.研究表明:北部湾沿海流域植被覆盖度较高,且年际变化幅度较小,多年植被指数均值表现出从陆地到滨海、从流域外边界到河流中心逐渐递减的规律.2000—2018年以来,流域内植被覆盖改善区域(73.6％)大于退化区域(26.3％),河口、滨海区不仅为植被退化明显区域,且为植被变化波动性较强区域.未来流域内植被覆盖变化波动性较强,其中持续改善区域仅占19.6％,持续退化区域占8％,其余的72.4％为波动性变化区域.流域内植被覆盖变化趋势与人为因素和气候因素相关性较高,与地形特征相关性较低.

Analysis of Dynamic Changes and Driving Factors of Vegetation Coverage in the Beibu Gulf Coastal Watershed

Based on the MODIS 13Q1 data from 2000 to 2018, the modified CVA (Change Vector Analysis), coefficient of variation and Hurst index ware used to analyze the dynamic change trend and continuity of the vegetation coverage in the Beibu Gulf Coastal Watershed Coverage changes and the drivers of vegetation cover changes. The research shows that the vegetation coverage of the Beibu Gulf coastal watershed is high and the interannual variation is small. The average NDVI for many years shows a law of gradual decrease from land to coastal, from the outer boundary of the watershed to the river center. Since 2000-2018, the vegetation coverage improvement area (73.6%) in the watershed is larger than the degradation area (26.3%). The estuaries and coastal areas are not only areas with obvious vegetation degradation but also areas with strong volatility of vegetation changes. In the future, the change of vegetation cover in the watershed is highly volatile, of which the continuous improvement area accounts for only 19.6%, the continuous degradation area accounts for 8%, and the remaining 72.4% is the volatility change area. The trend of vegetation cover change in the watershed is highly correlated with human factors and climatic factors, and is less correlated with terrain features.