
This dataset and scripts accompanies the manuscript "Tracking Drought Propagation in a Changing Climate: A Nonstationary Copula-Wavelet Framework". It contains monthly gridded drought indices derived from harmonized GLDAS Noah monthly 0.25° product over South Asia during 1975-2024.
SouthAsia_DI.mat contains harmonized GLDAS-derived Standardized Precipitation Index (SPI), Standardized Soil Moisture Index (SMI), and Standardized Runoff Index (SRI) datasets at accumulation timescales of 1–6 months, together with the geographic coordinates and land mask used in the analysis. NS_Result_C8.mat contains the eight-cluster spatial assignment and associated PCA and k-means clustering outputs.
The MATLAB workflow consists of four principal scripts: stationary drought-propagation analysis (RUN1_DP_S.m), PCA and k-means clustering (RUN2_PCA_CLUSTER.m), non-stationary drought-propagation analysis (RUN3_DP_NS.m), and wavelet-based propagation-time analysis (RUN4_WAVELET.m). The helper function select_best_copula_builtin.m is used for copula-family selection in the stationary analysis. Detailed file descriptions, software requirements, execution order, and expected outputs are provided in README.md.