Regional Drought Monitoring Using Satellite-Based Precipitation and Standardized Palmer Drought Index: A Case Study in Henan Province, China

Drought poses significant challenges to agricultural productivity and water resource sustainability in Henan Province, emphasizing the need for effective monitoring approaches. This study investigates the suitability of the TRMM 3B43V7 satellite precipitation product for drought assessment, based on monthly data from 15 meteorological stations during 1998–2019. Satellite-derived precipitation was compared with ground-based observations, and the Standardized Palmer Drought Index (SPDI) was calculated to determine the optimal monitoring timescale. Statistical metrics, including Nash–Sutcliffe Efficiency (NSE = 0.87) and Pearson correlation coefficient (PCC = 0.88), indicate high consistency between TRMM data and ground measurements. The 12-month SPDI (SPDI-12) was found to be the most effective for capturing historical drought variability. To support integrated drought management, a regionally adaptive framework is recommended, balancing agricultural demands and ecosystem stability through tailored strategies such as enhanced irrigation efficiency in humid regions and ecological restoration in arid zones. These findings provide a foundation for implementing an operational drought monitoring and response system in Henan Province.