New developments in long-term spatial climate datasets for Switzerland and the European Alps

For several years now, MeteoSwiss has been developing and producing monthly grid datasets for temperature and precipitation that extend over 150 years in the past and are highly consistent over time. Therefore, they are particularly suitable for applications requiring high standards in temporal consistency, such as climate monitoring, trend calculation, and the study of long-term climate variations. Long-term climate datasets are generated using statistical reconstruction methods that explicitly avoid artefacts from variations in observational density over time.

In this contribution, we present two recent developments in our suite of long-term climate datasets: Firstly, a new dataset has been developed for relative sunshine duration. Despite the methodological experience from previous reconstructions, this development was particularly challenging due to the scarcity of the available measurements and the related complications for homogenization in the complex terrain of Switzerland. We outline the necessary methodological adjustments, illustrate results from interesting example cases, and present results on the temporal and spatial changes in sunshine duration in Switzerland since the beginning of the 20^th century. A brief excursus refers to the absolute sunshine duration, which is now also available as a grid product.

Secondly, we present an update of the pan-Alpine long-term precipitation dataset “LAPrec”, developed during the COPERNICUS C3S_311a_Lot4 Project. The update builds on a substantial extension of the period for calibrating the reconstruction method. This was possible thanks to the longer availability of one of the key data sources of LAPrec, the high-resolution dataset “APGD”, which newly extends from 1971 to 2019. The long-term station data used in the update was collected and homogenized at Geosphere Austria. Results from the updated LAPrec will be presented on long-term precipitation changes in the Alps. The dataset is available in the Copernicus climate data store.