DOI: 10.48364/isimip.942125
title: ISIMIP3 soil input data

description: The Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) provides a framework for the collation of a consistent set of climate impact data across sectors and scales. It also provides a unique opportunity for considering interactions between climate change impacts across sectors through consistent scenarios.<br>The ISIMIP3a part of the third simulation round is dedicated to i) impact model evaluation and improvement and ii) detection and attribution of observed impacts according to the framework of IPCC AR5 Working Group II Chapter 18. To this end all simulations are driven by observed socio-economic information combined with either observed (factual) climate data or a detrended (counterfactual) version of the observed climate allowing for the generation of a "no climate change" baseline.<br>The ISIMIP3b part of the third simulation round is dedicated to a quantification of climate-related risks at different levels of global warming and socio-economic change. ISIMIP3b group I simulations are based on historical climate change as simulated in CMIP6 combined with observed historical socio-economic forcing. ISIMIP3b group II simulations are based on climate change according to the CMIP6 future projections combined with socio-economic forcings fixed at 2015 levels. ISIMIP3b group III simulations additionally account for future changes in socio-economic forcing.<br>Soil properties are highly relevant for many impact simulations, for instance plant growth and hydrology are influenced by their characteristics. Therefore ISIMIP provides global soil maps on the native ISIMIP grid to modellers.<br>In ISIMIP 3a/3b two soil data sets are provided. The first provides an upscaled map of soil textures that is based on the HWSD 1.1 soil data and was already used in ISIMIP2a. The second, newer one, is provided by the AgMIP project and gives the properties of a grid cell's dominant soil texture as well the properties of the soil predominantly occurring on crop lands.
description: The first data set, already used in ISIMIP2a, is based on HWSD 1.1 (Nachtergaele et al. 2009) and has been upscaled to the ISIMIP 0.5°×0.5° grid by means of the GSWP3 upscaling method A (Koirala 2013). The data sits in the file gswp3_hwsd.nc and the variable "soiltexture" is provided.<br>The second, newer data set, was provided by C. Müller of the "Global Gridded Crop Model Intercomparison" Phase 3 project. It updates the data set foundation to HWSD 1.2 (Nachtergaele et al. 2012) and provides two data files, hwsd_soil_data_all_land.nc and hwsd_soil_data_on_cropland.nc (for an extensive description see ggcmi_phase3_soil_input.pdf referenced below). Both files give the properties USDA soil texture class dominant HWSD on cropland ("texture_class"), dominant HWSD soil mapping unit within dominant USDA soil texture class on cropland ("mu_global"), topsoil pH("H2O") ("soil_ph"), topsoil calcium carbonate ("soil_caco3"), topsoil bulk density ("bulk_density"), topsoil cation exchange capacity ("soil") ("cec_soil"), topsoil organic carbon ("oc"), depth of obstacles to roots ("esdb") ("root_obstacles"), depth of impermeable layer ("esdb") ("impermeable_layer"), available water content ("awc"), topsoil sand fraction ("sand"), topsoil silt fraction ("silt"), topsoil clay fraction ("clay"), topsoil gravel content ("gravel"), topsoil salinity ("ece"), topsoil base saturation ("bs_soil") and a flag for valid soils ("issoil").<br>One file, hwsd_soil_data_all_land.nc, gives the properties of the dominant soil type within a grid cell and is therefore suitable for all sectors. The other file hwsd_soil_data_on_cropland.nc provides the soil type predominantly occurring in a grid cell's cropland and therefore should be used by modellers investigating crop growth in the agriculture sector.