粤港澳大湾区植被覆盖变化及其影响因素分析

Changes in vegetation coverage and its influencing factors across the Guangdong-Hong Kong-Macao Greater Bay Area

针对粤港澳大湾区城市化和生态环境需求间存在的冲突,基于Google Earth Engine云计算,利用MOD13Q1-NDVI数据、夜间灯光数据和气象数据,采用趋势分析、Mann-kendall检验、重标极差分析和偏相关性分析等方法,探讨了粤港澳大湾区长时间序列植被覆盖变化及其与气象因子和人类活动的关系。结果表明:2001—2019年粤港澳大湾区植被覆盖增速为0.15%·10a^(-1)(P<0.01);空间上,植被覆盖格局呈现“中间低、四周高”的分布特征,植被NDVI极显著上升面积占46.82%,而极显著下降面积仅占3.27%;粤港澳大湾区植被NDVI的Hurst指数大于0的面积占85.65%,持续改善面积占72.18%;植被NDVI与人类活动的偏相关系数整体最高,其次是气温。实验证明,粤港澳大湾区植被覆盖整体呈上升趋势,植被NDVI呈改善的面积明显要高于呈退化的面积。未来趋势特征上,粤港澳大湾区植被覆盖同向特征显著,持续改善占主体,主要分布在肇庆、惠州、香港等地区。与气象因子相比,人类活动对植被覆盖的影响占主导地位,而就气象因子而言,气温是影响粤港澳大湾区植被覆盖的主要因子,植被NDVI与气温主要以正相关关系为主。

As the forefront of China’s economic reform,Guangdong-Hong Kong-Macao Greater Bay Area has become a typical example of conflicts between land-centered urbanization and eco-environmental needs.Clarifying the evolution of vegetation growth in this area and its influencing factors are the key to promoting the sustainable development of urban green.Based on Cloud computing of Google Earth Engine,this study uses MOD13Q1-NDVI data,nighttime light data and meteorological data,adopts trend analysis,Mann-Kendall test,rescaled range analysis and partial correlation analysis,etc.The temporal and spatial variation of vegetation coverage and its relationship with meteorological factors and human activities in Guangdong-Hong Kong-Macao Greater Bay Area are discussed in this paper.The results showed that vegetation coverage in the Greater Bay Area increased by 0.15%·10a^(-1)(P<0.01);Spatially,the vegetation coverage in Guangdong-Hong Kong-Macao Greater Bay Area presents a pattern of“low in the middle and high around”.The area of vegetation NDVI increased significantly in 46.82%,while the area of vegetation NDVI decreased significantly in 3.27%.In the Guangdong-Hong Kong-Macao Greater Bay Area,the area with Hurst index greater than 0accounts for 85.65%,and the area with continuous improvement accounts for 72.18%.The partial correlation coefficient between vegetation NDVI and human activities was the highest,followed by air temperature.Experiments showed that the vegetation coverage in Guangdong-Hong Kong-Macao Greater Bay Area increased between 2001and 2019.The area where the vegetation coverage is improved is significantly higher than the area that is degraded.From the perspective of future trend,the co-directional characteristics of vegetation coverage in Guangdong-Hong Kong-Macao Greater Bay Area are significant,with continuous improvement accounting for 72.18%,mainly distributed in Zhaoqing,Huizhou,Hong Kong and other regions.Compared with meteorological factors,the impact of human activities on the vegetation coverage in Guangdong-Hong Kong-Macao Greater Bay Area occupies a dominant position.As far as meteorological factors are concerned,temperature is the main factor affecting the vegetation coverage in Guangdong-Hong Kong-Macao Greater Bay Area,and the NDVI of vegetation is mainly positively correlated with air temperature.