ABSTRACT Shallow groundwater levels directly influence and regulate meteorological variables, the normalized vegetation cover index (NDVI), and river water levels, particularly in arid and semi‐arid regions. However, the coupling mechanism among groundwater, meteorology, and hydrological factors at different times cales is still unclear, especially the lack of mechanisms for multi‐time scale collaborative response. Based on the basic principles of hydrology and remote sensing, this study proposed the following hypothesis: There is a multi‐time scale coupling relationship among shallow groundwater depth, meteorology, and river level, and it has an optimal response to vegetation growth within a specific depth range. By analyzing the time series of river water level, meteorology, groundwater depth, and NDVI, combined with the cross wavelet transform method, the results revealed a strong consistency and synchronization between river stage and meteorological factors. Furthermore, a cross‐wavelet transform identified prominent periodic characteristics between groundwater depth and meteorology at the 32–64‐day scale, indicating a strong coupling between groundwater depth and meteorological variables over this timescale. Additionally, the temporal trend of the subsurface groundwater depth was consistent with the river water level. The average NDVI value was largest at groundwater depths of 25–30 m, indicating that these areas had the largest vegetation cover and the most suitable groundwater depth for plant growth. This study revealed the coupling law and mutual feedback mechanism of groundwater‐meteorology‐vegetation‐river water from the perspective of multi‐time scale coupling, and accurately quantified the appropriate threshold of groundwater depth for vegetation growth in the study area. The results of the study provided a quantitative scientific basis and practical reference for the fine regulation of groundwater resources, the hydrological adaptation design of vegetation restoration and reconstruction, and the coordinated protection and management of hydrological ecosystems and water resources in the study area. It plays an important scientific value and application significance for improving the efficiency of regional water resources utilization and ecological protection.
Zhao et al. (Wed,) studied this question.