Responses of vegetation growth conditions to meteorological drought in Shanxi Province from 2000 to 2020

Based on the standardized precipitation index (SPI) and vegetation condition index (VCI) from 2000 to 2020, this study analyzed the trends in meteorological drought across different vegetation types in Shanxi Province using methods such as variational mode decomposition (VMD), Mann-Kendall trend analysis, and Pearson correlation coefficient. Accordingly, this study quantified the response time of vegetation growth conditions to meteorological drought. The results indicate that from the beginning of the 2000s, the overall meteorological drought in Shanxi Province has gradually eased. However, on a seasonal scale, areas with increasingly aggravated drought continuously expand from spring to winter. Meteorological drought has alleviated across various vegetation types, with the alleviation becoming increasingly significant with an increase in the time scale. In contrast, on a seasonal scale, the drought relief gradually weakens from spring to winter, during which drought aggravation progressively strengthens. Vegetation growth conditions are significantly influenced by meteorological drought. On the annual scale, there is a predominantly positive correlation between both. On the seasonal scale, areas with a strong correlation between both gradually contract from spring to winter, when such areas are dominated by the northwestern and northeastern areas of the province. Additionally, the response time of vegetation to drought is longer in spring and winter compared to autumn and summer. Across different vegetation types, the responses of vegetation growth conditions to meteorological drought prove the most rapid during the summer, and cultivated lands are identified as the most sensitive land type to meteorological drought.