HYRAS-DE-TASMAX

v6-1

The data is extended every day. It should be noted that at the beginning and middle of each month, the previous month is recalculated with

quality-controlled measurements and the data of the current year is overwritten.

To improve quality, station data from neighboring countries is also taken into account where available. This currently applies from 1951-2020.

The DWD reserves the right to update or provide a new version of the data set at its own discretion.

Uncertainties may result from the interpolation method used. Incorrect measurements also result in uncertainties in the grid field. For the interpolation of the grids, a different number of stations were used over time, as the measurement network has changed. This must be considered when comparing different years. Please also note the recommendations on uncertainties and interpretation of grid points of station-based grid data (Recommendations for raster data).

Temperature (TAS, TASMIN, TASMAX) and relative humidity (HURS) are based on a combination of nonlinear temperature profiles with non-Euclidean residual interpolation (Krähenmann et al., 2019). The creation of the background field is based on a nonlinear regression at each time step (estimation of regional vertical profiles for 13 subregions subdivided based on weather divides, coastal distance and north-south extent). This also allows temperature inversions to be taken into account. Cold pole stations were identified separately for each time step and excluded for the profile determination. For the residual interpolation, a 5-dimensional inverse distance weighting (5D-IDW cf. Eiselt et al., 2017) is applied, which depends on the geographical longitude and latitude, altitude, coastal distance and heat island effect. For the interpolation of the minimum (TASMIN) and maximum (TASMAX) temperature, the deviations between extreme temperature and mean temperature are interpolated (non-linear regression + residual interpolation) as in TAS and then added to the mean temperature field. This ensures the consistency of the temperature fields with each other (TASMIN <= TAS <= TASMAX). For the interpolation of the relative humidity, the temperature station data was first converted into the dew point temperature and then interpolated in the same way as the temperature data and finally calculated back into the relative humidity using the temperature grid data. During the interpolation, it is ensured afterwards that a maximum humidity of 100 % is achieved.

ISO 19115-2 Geographic information Metadata Part 2: Extensions for imagery and gridded data

ISO 19115-2:2009-02-15

urn:wmo:md:de-dwd-cdc:ec363a6b-e628-4a9b-bde4-fdddd2db67e9