Recent improvements in the E-OBS gridded data set for daily mean wind speed over Europe in the period 1980-2021

The provision of authoritative information about the past, present, and future climate in Europe is one of the principal objectives of the Copernicus Climate Change Service (C3S). In the past decades, the KNMI has been actively contributing to this endeavor through the ECA&D and E-OBS initiatives, which, among responsibilities, periodically release via C3S European-wide gridded observational datasets (E-OBS) of the principal weather variables (e.g. temperature, precipitation) that are fundamental for climate research.  Recently, the KNMI has released E-OBS version 25.0e, which includes the first release of gridded daily mean wind speed that covers most of Europe.   

The E-OBS wind speed data set covers the period 1980 – 2021. This newly developed gridded dataset applies a combination of spatial regression methods with local uncertainty estimates using a 20-member ensemble. When creating this gridded data set, the daily mean wind speed is modeled using an array of auxiliary variables (e.g. topography, distance to coast, surface roughness) and the ensemble ensures that a measure of uncertainty is provided along with the mean wind speed. In this presentation, we focus on three main parts: 1) general characteristics of the wind dataset; 2) improvements with respect to the previous version (e.g. spatial coverage); and 3) how the use of auxiliary variables characterization of the surroundings of the monitoring station with environmental variables improves the spatial resolution of the grid. 

Nevertheless, a pertinent question that follows the creation of the E-OBS daily mean wind dataset is: how does it compare to other well-consolidated data products stemming from numerical weather prediction? In this work, we carry out different statistical comparisons between the daily wind speed provided by E-OBS and ERA5-Land to gain insights about the observed similarities and differences. One of the aspects we consider are possible climatological trends in wind speed over Europe. For example, in the E-OBS data set we see a reduction in yearly mean wind speed around 1990. Is this effect significant, and do we also observe it in ERA5-Land? The comparison of E-OBS and ERA5-Land data for wind speed can provide useful information about their strengths and weaknesses, suggesting directions for future model improvement and improvement of the analysis of observations. Furthermore, this information may be valuable for the proper interpretation of both ERA5-Land and E-OBS data by various users.