[Analysis of Vegetation Changes and Influencing Factors in Guiyang City over the Past 33 Years Based on the kNDVI and OPGD Model].

The vegetation index is a critical indicator for monitoring changes in terrestrial ecosystems， and understanding the spatiotemporal characteristics of vegetation changes and their potential driving factors is essential for improving regional ecological protection and management. This study utilized eight periods of Landsat remote sensing images from 1990 to 2023 to calculate the kernel normalized difference vegetation index （kNDVI） for Guiyang City using the Google Earth engine （GEE） platform. The Theil-Sen + Mann-Kendall trend analysis method was applied to assess the trends and significance levels of kNDVI changes， and the Hurst index was used to evaluate the persistence and future trends of kNDVI. Additionally， the optimal parameters geographic detector （OPGD） was employed to analyze the driving mechanisms behind the spatial differentiation of kNDVI. The study produced the following results： ① From 1990 to 2023， the kNDVI in Guiyang City exhibited a fluctuating upward trend over four distinct phases， with significant spatial differentiation， generally displaying a north-high， south-low distribution pattern. ② Over the 33 years， 74.62% of the area in Guiyang City experienced improvement in vegetation cover， while 25.14% showed signs of degradation. ③ The average Hurst index was 0.610 2， indicating weak persistence and suggesting a trend of continued improvement into the future for vegetation kNDVI in Guiyang City. ④ The land-use type factor （0.231 2） showed the strongest explanatory power for the spatial differentiation of vegetation kNDVI. The interactions between factors exhibited both nonlinear enhancement and bi-factor enhancement， with the combination of land use and other factors synergistically explaining the spatial differentiation of kNDVI more effectively.