Spatial Relationships Between Flash Drought and Rice Production in a Tropical River Basin Using Geographically Weighted Regression

Flash droughts have become a significant hydroclimatic hazard threatening agricultural production amid increasing climate variability. However, studies examining the spatial relationship between flash drought indicators and rice production in the humid tropics are limited. This research aims to assess the impacts of flash droughts on rice production in Bengawan Solo River Basin using a GIS-based geographically weighted regression (GWR) method. Soil moisture (SM), land surface temperature (LST) and rainfall (RF) were employed as independent variables and rice production (RP) as the dependent variable. The results show that flash droughts significantly reduce paddy yield, with all the independent variables having a significant influence (R² = 71.43%). Residual Moran’s I analysis indicated no significant spatial autocorrelation (z-score = -0.5; p-value = 0.6), confirming the robustness of the model. Among the three independent variables, SM and LST were the most statistically significant (probability t value < 0.05). Based on a simulation using the average local GWR coefficient, a 1% decrease in SM combined with a 1% increase in LST potentially reduced rice production by up to 9.62%. These findings demonstrate a strong spatial relationship between flash drought indicators and declining rice production. Consequently, the importance of strengthening mitigation and adaptation strategies to reduce potential future losses in rice production is emphasised.