DOI: 10.5061/dryad.7pvmcvf6n
title: Nonlinear increase of compound drought-heatwave events since the early 2000s

description: 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.
description: # 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).