A core activity of the Rossby Centre is the development of both global and regional climate models, which are utilized extensively in national and international projects and collaborations, to provide information on the future climate for policy and decision makers.
Climate models are the only tools society has to deter-mine how the future climate may look. The Rossby Centre is at the forefront of the development of three-dimensional climate models that mathematically describe the climate system and interactions between its components (atmosphere, ocean, land, ice).
This includes responsibility for the development of an upgraded Earth System Model version of EC-Earth for participation in the Climate Model Intercomparison Project Phase 6 (CMIP6), as part of a European wide consortium of climate research units. The new version of EC-Earth, to be released in 2017, includes options for atmospheric composition, dynamic vegetation, ocean bio-geo-chemistry and a Greenland ice sheet. Current versions of EC-Earth are being used widely in many of the international projects the Rossby Centre is involved in.
Global climate models provide the large-scale picture of the climate and the climate change signal. To serve as a national planning instrument, robust assessment of that signal is necessary at regional to local scales where the impact is felt and adaptation needs exist. This requires higher spatial resolution than global models can provide. Regional features such as steep orography, varying soil and vegetation properties, and small-scale landscape heterogeneities are strongly shaping the climate signal, including climate events and probabilities of short-term extremes. Regional climate models are applied downstream of the global models with enhanced grid resolution that allows for a more realistic regional climate response. Since 1997 the Rossby Centre has developed an international standing in the field of regional climate modelling with the development of the atmospheric model RCA, the ocean-atmosphere coupled version RCA-NEMO and a version of RCA including interactive vegetation processes, RCA-GUESS.
Currently, the next generation very high resolution regional climate model, HARMONIE-Climate, is being developed at SMHI. HARMONIE-Climate can operate at spatial scales down to a few kilometers. HARMONIE-Climate simulations over areas with good observational coverage indicate strong progress towards more realistic precipitation.