Global climate-related predictors at kilometer resolution for the past and future

Abstract. A multitude of physical and biological processes on which ecosystems and human societies depend are governed by the climate, and
understanding how these processes are altered by climate change is central
to mitigation efforts. We developed a set of climate-related variables at
as yet unprecedented spatiotemporal detail as a basis for environmental and ecological analyses. We downscaled time series of near-surface relative
humidity (hurs) and cloud area fraction (clt) under the consideration of orography and wind as well as near-surface wind speed (sfcWind) using the delta-change
method. Combining these grids with mechanistically downscaled information on
temperature, precipitation, and solar radiation, we then calculated vapor pressure deficit (vpd), surface downwelling shortwave radiation (rsds), potential
evapotranspiration (pet), the climate moisture index (cmi), and site water balance (swb) at a monthly temporal and 30 arcsec spatial resolution globally from 1980 until 2018 (time-series variables). At the same spatial resolution, we
further estimated climatological normals of frost change frequency (fcf), snow
cover days (scd), potential net primary productivity (npp), growing degree days
(gdd), and growing season characteristics for the periods 1981–2010, 2011–2040,
2041–2070, and 2071–2100, considering three shared socioeconomic pathways
(SSP126, SSP370, SSP585) and five Earth system models (projected variables).
Time-series variables showed high accuracy when validated against
observations from meteorological stations and when compared to alternative products. Projected variables were also highly correlated with observations,
although some variables showed notable biases, e.g., snow cover days.
Together, the CHELSA-BIOCLIM+ dataset presented here (https://doi.org/10.16904/envidat.332, Brun et al., 2022) allows improvement to
our understanding of patterns and processes that are governed by climate,
including the impact of recent and future climate changes on the world's ecosystems and the associated services on societies.
