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Drought portal - Knowledge resources on integrated drought management

Input data

Climate data
The climatic data required for simulations using the AquaCrop model include daily maximum and minimum temperatures at 2 meters, precipitation, and reference evapotranspiration (ETo) (Raes et al., 2023). For simulating drought impacts under the historical scenario, climate data were sourced from the ERA5 reanalysis dataset (spatial resolution of 0.25 degrees) of the European Centre for Medium-Range Weather Forecasts (ECMWF). These essential climate variables were accessed using the Open-Meteo API for the period spanning 1960 to 2022. 

The projected climate data for the future scenarios were obtained from the database of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP). This unique cross-sectoral, cross-scale organization is designed to complement intra-sectoral research efforts to ultimately provide a comprehensive picture of climate change risks at different levels of global warming. ISIMIP employs multi-model ensembles so that uncertainties at the different modelling stages considered can be assessed quantitatively.

The ISIMIP framework includes bias-adjusted climate-input datasets on a global grid of 0.5° x 0.5° resolution, with daily time steps, alongside socioeconomic scenarios. Specifically, for d-iap, the latest phase of the protocol (ISIMIP3b) was selected, based on results from phase 6 of the Coupled Model Intercomparison Project (CMIP6). Daily projections of six variables (Near-Surface Relative Humidity, Precipitation, Surface Downwelling Shortwave Radiation, Near-Surface Wind Speed, Daily Maximum Near-Surface Air Temperature, and Daily Minimum Near-Surface Air Temperature) were extracted from five CMIP6 general circulation models.

These models include three with low climate sensitivity (GFDL-ESM4, MPI-ESM1-2-HR, MRI-ESM2-0) and two with high climate sensitivity (IPSL-CM6A-LR, UKESM1-0-LL). The periods 2041-2060 and 2081-2100 were chosen to represent mid-century and end-century intervals, respectively. Three Shared Socioeconomic Pathways (SSP1-2.6, SSP3-7.0 and SSP5-8.5) were utilized, encompassing a range of plausible climate futures. The SSP numbering corresponds to radiative forcing in watts per square meter (W m⁻²) projected for 2100. SSP1-2.6 represents a low greenhouse gas (GHG) emissions scenario, where CO  levels remain around current levels until mid-century, while SSP3-7.0 and SSP5-8.5 reflects high and very high GHG emissions with CO  levels, respectively. Bulk download of climate data files was facilitated through the ISIMIP repository's API. Subsequently, daily reference evapotranspiration (ETo) was estimated using a publicly available Python library.