European-wide climate indicators for 1961-2020 derived from daily data at 30x30 arc sec resolution

High-resolution climate data provide great benefits for ecological and environmental climate impact studies where data need to represent local climate conditions. Especially in mountainous terrain, high resolution can accurately resolve mountain valleys and peaks and thus better represent topography-related aspects of meteorological variables. 

CHELSA-W5E5 v1.1 fulfills the need for daily data at a high spatial resolution of 30x30 arcseconds, but only covers the period 1979-2016 and does not provide certain daily variables necessary for more complex estimations of the water budget with potential evapotranspiration. Given that the current climate is usually referred to 1991-2020, a period already significantly influenced by anthropogenic climate change, the previously established standard period of 1961-1990 is still recommended for observing long-term climate development. This is particularly relevant in forestry where the main growth phases of current trees date back several decades.

 To extend the temporal coverage of CHELSA-W5E5 v1.1 from the initial span of 38 years (1979-2016) to 60 years (1961-2020) across Europe, we used ERA5-Land data set and applied quantile mapping with CHELSA on each grid cell. Variables such as wind speed and vapor pressure deficit are only provided on a climatological monthly basis from the similar data set CHELSA V2.1 and had to be newly generated for daily values. The result of this procedure is a 60-year long representation of Europe’s historical climate useful for applications in ecological and environmental sciences.

A strength of this data set is its temporal consistency as it is based on ERA5-Land, and high spatial resolution as it is based on CHELSA. Averaged climate indicators for the periods 1961-1990 and 1991-2020 are available for download (DOI 10.5281/zenodo.10623854). Validation shows that CHELSA lacks accurate temperature values in some mountainous locations, as shown with weather station data in the Alps. Thus, it is desirable for future versions of CHELSA to improve the accuracy of the vertical lapse rate in mountainous terrain for a more precise representation of valleys.