CAMELS-CZ: A catchment attribute database for hydrological and climatological studies using a large sample of catchments

Hydrological methods based on the analysis of data from a large sample of catchments with different characteristics (large-sample hydrology; comparative hydrology) allow a comprehensive analysis of the hydrological regime and thus a description of hydrological variability and change in the components of the water balance. These methods provide insight into hydrological processes shaped by environmental and climatic factors and allow more general conclusions to be drawn. However, besides climate and runoff data, catchment attributes, such as geology, soils, topography and vegetation, are essential for effective hydrological behaviour analysis. For these reasons, the global hydrological community has recently developed a number of freely available large-scale datasets known as CAMELS (Catchment Attributes and MEteorology for Large-sample Studies), which provide catchment attributes, as well as hydrological and meteorological time series, in a comparable structure at national scales. The aim of this contribution is to present the current state of preparation of the CAMELS database for Czechia (CAMELS-CZ) as a reference data platform for analysis and modelling, using a large sample of catchments. The database contains 389 catchments in Czechia maintained by the Czech Hydrometeorological Institute (CHMI) for which daily runoff data are available for at least 30 years. Catchments cover a variety of elevations (200–1600 m a.s.l) and runoff regimes (from pluvial to nival). Climate attributes were calculated from newly created daily climate grids (mean daily precipitation, mean daily air temperature) available in spatial resolution 1 km. Vegetation attributes are calculated based on Landsat data and the Corine Land Cover database. Soil texture database, hydraulic soil characteristics and geology maps are used for soil and geology attributes calculation. The subset of the catchments included in the upcoming CAMELS-CZ database has already been used for several purposes, mostly in mountain areas to analyse changes in snow cover and their influence on both low and high flows. For this subset, simulations of the conceptual hydrological model have been performed and used. The future goal is to prepare runoff simulations for all catchments included in the CAMELS-CZ database which will be publicly available for use among the hydrological community.