# Nonlinear increase of compound drought-heatwave events since the early 2000s Dataset DOI: [10.5061/dryad.7pvmcvf6n](https://doi.org/10.5061/dryad.7pvmcvf6n) ## Description of the data and file structure This repository contains the datasets and scripts required to reproduce the figures presented in the manuscript: **“Nonlinear increase of compound drought–heatwave events since the early 2000s.”** ### Files and variables #### File: preprocessed_data.zip **Description:** This zip file contains the datasets required to reproduce the main figures. #### File: hw_dr_pair_num.nc **Description:** This file includes the detected heatwave-leading CDHE information over study period. #### File: dr_hw_pair_num.nc **Description:** This file includes the detected drought-leading CDHE information over study period. #### File: hw_dr_pi.nc **Description:** This file includes the detrended daily land-atmosphere coupling strength during heatwave-leading CDHEs #### File: dr_hw_pi.nc **Description:** This file includes the detrended daily land-atmosphere coupling strength during drought-leading CDHEs #### File: pi_detrend_all_warm_ann_from_daily.nc **Description:** This file includes the calculated land-atmosphere coupling strength (warm season averaged for each year) #### File: pi_detrend_all_warm_daily.nc **Description:** This file includes the calculated daily land-atmosphere coupling strength. #### File: t2m_ann_mean_1980_2023.nc **Description:** This file includes the annual mean 2m temperature over the study period. (Derived from ERA5-Land dataset) #### File: IPCC_region_id_hexagon.csv **Description:** This file includes the hexagon information for each IPCC subregion. This was used for generating the regional hexagon plot. #### File: pi_slope.csv **Description:** This file includes the calculated regional sensitivity value of heatwave- and drought-leading CDHEs to land-atmosphere coupling. #### File: pi_slope_change.csv **Description:** This file includes the change of calculated regional sensitivity value of heatwave- and drought-leading CDHEs to land-atmosphere coupling. #### File: skewness_alpha_11y_m_affected_area.csv **Description:** This file includes the nonlinearity index of each subregion. (heatwave-leading CDHE case) #### File: t2m_region_11y_m_affected_area.csv **Description:** This file includes the regional 11-year running window averaged temperature. #### File: hw_dr_region_11y_m_affected_area.csv **Description:** This file includes the regional 11-year running window averaged affected area of heatwave-leading CDHEs. #### File: temp_thres_11yr_m_affected_area.csv **Description:** This file includes the regional temperature threshold which detected from the Pettitt's test. #### File: thres_year_11y_m_affected_area.csv **Description:** This file includes the regional threshold year which detected from the Pettitt's test. #### Folder: IPCC_subregion_masked_file **Description:** This folder contains files listed below. * subregion_masked_file subfolder : contains each IPCC subregion's masked file. * subregion_shapefile subfolder : contains each IPCC subregion's shapefile. #### ## Code/software We used Python version 3.10.16 ([https://www.python.org/downloads/release/python-31016/](https://www.python.org/downloads/release/python-31016/)) for all data processing, analysis, and graphical representation. #### File: Figure_1.py **Description:** This file contains the code required to reproduce Figure 1. #### File: Figure_2.py **Description:** This file contains the code required to reproduce Figure 2. #### File: Figure_3.py **Description:** This file contains the code required to reproduce Figure 3. #### File: Figure_4.py **Description:** This file contains the code required to reproduce Figure 4. #### File: Figure_5.py **Description:** This file contains the code required to reproduce Figure 5. ## Access information Other publicly accessible locations of the data: * ERA5-Land and ERA5 dataset can be downloaded from Copernicus Climate Data Store (CDS) at [https://cds.climate.copernicus.eu/datasets](https://cds.climate.copernicus.eu/datasets). * GLEAM 4.2a dataset is freely available online at [https://www.gleam.eu/#downloads](https://www.gleam.eu/#downloads).

Compound drought–heatwave events (CDHEs) have significantly increased since the early 2000s, posing elevated risks to socio-ecosystems. However, the physical characteristics of drought- and heatwave-leading CDHEs and their relative contributions to the overall increase remain unexplored. Using a multi-hazard pair generation algorithm with daily reanalysis data, we show that this increase is primarily driven by heatwave-leading CDHEs, with the slope of increase in affected land area rising nearly eightfold, from 1.6% to 13.1% per °C since the early 2000s. This pattern is evident at the global scale but also shows considerable regional variation. We find that the nonlinear amplification of land–atmosphere coupling since the late 1990s has not only induced the emergence of a statistically significant positive sensitivity but has also resulted in a marked increase in sensitivity in high occurrence regions. These findings highlight the importance of considering the regional risks associated with heatwave-leading CDHEs when adapting to climate change.