Dataset and Analysis Code Supporting “Asymmetric Impacts of Supply- and Demand-Driven Flash Droughts on Leaf Senescence”

This repository contains the processed datasets and R scripts supporting the manuscript entitled “Asymmetric impacts of supply- and demand-driven flash droughts on leaf senescence.” The study investigates the asymmetric effects of supply-driven flash droughts, mainly associated with precipitation deficits, and demand-driven flash droughts, mainly associated with enhanced atmospheric evaporative demand, on vegetation leaf senescence across the Northern Hemisphere during 2001–2024.

The repository contains the processed datasets supporting the analyses and visualizations. Owing to repository file-size constraints, some processed datasets are provided as ZIP archives. Compression does not alter the data content, and the files should be extracted before use. Phenology_North_poly.csv contains annual satellite-derived vegetation phenological metrics for each grid cell across the Northern Hemisphere and was used for phenological quality control and anomaly calculation. all_GS_FD_years.csv contains the grid-year combinations with at least one FD overlapping the growing season and was used to identify non-FD years for calculating the phenological baseline. dEOS_poly.csv contains the resulting LSD anomalies derived from the enhanced vegetation index (EVI) and solar-induced chlorophyll fluorescence (SIF). The term “EOS” used in the file name and scripts denotes the end-of-season phenological metric and corresponds to the leaf senescence date (LSD) used in the manuscript. phenology_poly_pentad.csv records the long-term mean timing of the start, peak, and end of the growing season, expressed as the corresponding 8-day periods for each grid cell. SMrz_drought_events.csv contains the flash drought events identified from root-zone soil-moisture percentiles using 01_FD_detection.R, including the original P1–P4 event timing indices, minimum soil-moisture percentile, onset rate, and cumulative severity.

SMrz_drought_events_mean_environment_anomaly.csv contains flash drought events overlapping the growing season and their mean environmental anomalies calculated over the complete, untruncated P1–P4 event periods. These variables were used to characterize the hydroclimatic conditions of the events and as inputs for their subsequent classification into supply- and demand-driven flash droughts.

final_FD_events.csv is the final analytical dataset and contains 1,141,551 event records. It retains the original, untruncated P1–P4 indices and was constructed by (1) retaining FD events that overlapped the growing season, (2) retaining phenological observations within the grid-specific median ± 2.5 median absolute deviations and grid cells with an LSD variance no greater than 30, (3) retaining only grid-year combinations with a single FD overlapping the growing season, and (4) excluding non-target l