Fig 1.
The geographical location map of the study area (a) displays the elevation distribution and meteorological station locations in the Beijing-Tianjin-Hebei-Shandong-Henan region, while the land cover map (b) categorizes all land types into seven classes: forest, grassland, wetland, cropland, urban, barren, and water.
Table 1.
Data sources and specifications of remote sensing variables used for drought monitoring.
Table 2.
Drought classification criteria based on SPEI values.
Table 3.
Definition, calculation formula, and source references of drought monitoring indices used in this study.
Fig 2.
Flowchart of the drought prediction model construction.
Fig 3.
A comparison of annual total rainfall (mm) recorded by 30 ground-based observation stations with CHIRPS data, along with their linear regression curves, is presented.
Fig 4.
A comparison of the monthly mean rainfall (mm) data with CHIRPS records.
The inset in the upper left corner shows boxplots of precipitation in spring, summer, autumn, and winter.
Fig 5.
Maps illustrating the spatial distribution patterns of 5-year average rainfall in the Beijing-Tianjin-Hebei-Shandong-Henan Region from 2000 to 2020.
Fig 6.
Scatter plots comparing drought predictions from an ensemble ML model with observed values across four spatial/temporal scales:
(a) SPEI-1, (b) SPEI-3, (c) SPEI-6, and (d) SPEI-12, respectively.
Table 4.
Drought categorization consistency rate at each scale (n = 5016).
Fig 7.
Correlation heatmap (* indicates significance, ***, **, * represent P < 0.001, P < 0.01, P < 0.05 respectively), with histograms of frequency distributions for each variable displayed along the diagonal.
Fig 8.
Bar and hive plots depicting variable importance based on SHAP values for the RF model’s prediction of SPEI-3 (SPEI-3 characterizes agricultural drought).
Fig 9.
Time series curves of two temporal scales (SPEI-1, SPEI-6) and sites PDSI bar charts calculated from observational data (2017–2020).
Fig 10.
Spatial Distribution of Drought Severity Classifications at Two Temporal Scales (SPEI-1 and SPEI-6) in the Beijing-Tianjin-Hebei-Shandong-Henan Region.