Dheed: an ERA5 based global database of compound dry and hot extreme events from 1950 to 2023

Revised manuscript submitted as data description paper to ESSD

Revised abstract
The intensification of climate extremes is one of the most immediate effects of global climate change. Heatwaves
and droughts have uneven impacts on ecosystems that can be exacerbated in case of compound events. To comprehensively study these events, e.g. with local high-resolution remote sensing or in-situ data, a global catalogue of compound dry and hot (CDH) events is essential. Here, we propose a database of large-scale dry and hot extreme events based on ERA5 climate reanalyis data. Drought indicators are constructed based on the balance between reference evapotranspiration and precipitation averaged over 30, 90 and 180 days. Extreme events are detected with absolute local thresholds for the 1950–2023 period. Extremes are defined as daily maximum temperature at 2 m exceeding a 99% threshold based on the experimental probability distribution, combined with any of the three drought indicators falling short of the 1% threshold. Unique labels are assigned to CDH events lasting at least three days using a connected component analysis. Their spatiotemporal extent and summary statistics are extracted for all labelled events. The identified CDH events are validated against extreme events reported in the literature. Out of 40 events listed a priori, 38 could be associated with labelled CDH events. All 10 largest and 10 longest labelled CDH events could be linked to droughts and/or heatwaves reported in the scientific or grey literature. The Dheed database of connected compound dry and hot extreme events is available from zenodo/10.5281/zenodo.11546130 (Weynants et al., 2025).