Hydrometeorological raster datasets (HYRAS) - Description and new developments

In order to be able to analyse the past weather and climate, high-resolution (5 km x 5 km) observational gridded data sets over long periods are required. The HYRAS data sets are based on daily data from meteorological stations in Germany and its river catchment areas for the parameters daily minimum, mean, and maximum temperature, relative humidity, global radiation and precipitation. Hence all for the water sector important parameters are included and the HYRAS grids thus allow many applications in the field of climatology and hydrology as well as in other sectors affected by climate change. The data covers the period from 1951 to 2020, except precipitation, which is on the one hand daily updated for the area of Germany and on the other hand covers the period since 1931 with a horizontal resolution of 1 km x 1 km. The data sets have been developed at Deutscher Wetterdienst (DWD) in two large research programs (KLIWAS and BMDV network of experts) financed by the German Federal Ministry for Digital and Transport. Nowadays, the DAS (Deutsche Anpassungsstrategie) core service “Climate and Water”, which is an operational climate service for climate and water in Germany, is responsible for the operational production of the HYRAS data sets.

 

With the new version of HYRAS (v5.0), the input station data control has been considerably improved. Digitisation and data control made it possible to use more and qualitatively better station data compared to the previous versions. New data sources (precipitation totaliser data in the alpine region) improved the background field used for the interpolation of precipitation. For a broader usability of the dataset, the netCDF attributes have been revised. This allows the data to be read in more easily by common software packages like ArcGIS, QGIS and Panoply. Due to the longer time period covered by the new version, the climatological long-term averages for the most recent climatological period 1991-2020 can now be provided.

We will give an overview of the HYRAS data sets and show a few examples of validation. Furthermore, we will provide some insights into broad applications of these data sets.