CHELSA-TraCE21k v1.0. Downscaled transient temperature and precipitation data since the last glacial maximum

Abstract

Abstract. High resolution, downscaled climate model data are used in a wide variety of applications in environmental sciences. Here we present the CHELSA-TraCE21k downscaling algorithm to create global monthly climatologies for temperature and precipitation at 30 arcsec spatial resolution in 100 year time steps for the last 21,000 years. Paleo orography at high spatial resolution and at each timestep is created by combining high resolution information on glacial cover from current and Last Glacial Maximum (LGM) glacier databases with the interpolation of a dynamic ice sheet model (ICE6G) and a coupling to mean annual temperatures from CCSM3-TraCE21k. Based on the reconstructed paleo orography, mean annual temperature and precipitation was downscaled using the CHELSA V1.2 algorithm. The data were validated by comparisons with the glacial extent of the Laurentide ice shield based on expert delineations, proxy data from Greenland ice cores, historical climate data from meteorological stations, and a dynamic simulation of species a distribution throughout the Holocene. Validations show that CHELSA TraCE21k output creates a reasonable representation of the distribution of temperature and precipitation through time at a high spatial resolution, and simulations based on the data are capable of detecting effective LGM refugia of species.