The implementation of an operational nation-wide CDS is supported. The hydrological cycle has links with almost all compartments of the climate system. Rainfall feeds rivers and the biosphere over land. Ice-caps and glaciers are created by snowfall, which impact on sea levels. Evaporation may create deserts.
Evaporation cools oceans and increases their salt concentration.
Water vapour condenses into clouds, which affect radiative transfer. Latent heat release influences pressure distributions and atmospheric circulations etc. It is clear that the hydrological cycle plays a key-role in the climate system. The hydrological cycle has different characteristics over different regions and in different seasons. Therefore, regional climate studies are an appropriate way to investigate the role of the hydrological cycle in the global climate system.