Identifying the spatio-temporal pattern and driving factors of drought in Fujian Province, China

Fujian Province, with abundant water resources and favorable agricultural conditions, is a key base for forestry and specialty agriculture in China. However, climate change has led to more frequent regional droughts, impacting agricultural productivity and socio-economic development. Identifying the spatio-temporal patterns and driving factors of drought is therefore crucial for effective mitigation strategies. In this study, Fujian is divided into 11 sub-basins based on topography and river networks. Using the Google Earth Engine platform, four drought indices, VCI, NVSWI, TVDI, and eTVDI, are calculated for 2000–2023 to examine their spatio-temporal distribution and driving factors. Spatial analysis shows that most areas are minimally affected by drought, while some coastal basins (Southeastern Coastal Rivers, Mulan, Jinjiang, Jiulong) frequently experience mild to severe droughts. Temporal trends, assessed using Theil-Sen slope and the Mann-Kendall test, indicate an overall improvement in drought conditions: VCI (48.7%), NVSWI (45.5%), TVDI (7.2%), and eTVDI (20.2%) of areas show significant alleviation (p < 0.05). Drought indices correlate positively with temperature but weakly with precipitation. Low vegetation cover (bare land, urban surfaces) leads to low drought index values, while steep slopes and loose soils are more drought-prone. Soil type also influences drought response, with alluvial and anthropogenic soils being more susceptible. These findings provide insights for regional drought assessment and sustainable development planning.