![]() Regional models were originally developed to serve weather forecasting and regional process studies. Typical simulations encompass time periods in the order of days or weeks. Thereafter regional models were also used more and more as regional climate models for longer integrations and climate change downscaling. Regional climate modeling or regional dynamic downscaling, which are used interchangeably, developed as its own branch in climate research since the end of the 1990s out of the need to bridge the obvious inconsistencies at the interface of global climate research and climate impact research. The primary aim of regional downscaling is to provide consistent regional climate change scenarios with relevant spatial resolution to serve detailed climate impact assessments. Other connectors may be used but these are the most common. Similar to global climate modeling, the early attempts at regional climate modeling were based on uncoupled atmospheric models or stand-alone ocean models, an approach that is still maintained as the most common on the regional scale. However, this approach has some fundamental limitations, since regional air-sea interaction remains unresolved and regional feedbacks are neglected. This is crucial when assessing climate change impacts in the coastal zone or the regional marine environment. To overcome these limitations, regional climate modeling is currently in a transition from uncoupled regional models into coupled atmosphere-ocean models, leading to fully integrated earth system models. Coupled ice-ocean-atmosphere models have been developed during the last decade and are currently robust and well established on the regional scale. Their added value has been demonstrated for regional climate modeling in marine regions, and the importance of regional air-sea interaction became obvious. Coupled atmosphere-ice-ocean models, but also coupled physical-biogeochemical modeling approaches are increasingly used for the marine realm. First attempts to couple these two approaches together with land surface models are underway. Physical coupled atmosphere-ocean modeling is also developing further and first model configurations resolving wave effects at the atmosphere-ocean interface are now available. These new developments now open up for improved regional assessment under broad consideration of local feedbacks and interactions between the regional atmosphere, cryosphere, hydrosphere, and biosphere. Coupled air-sea models are today state-of-the-art in global climate research and increasingly used for regional climate modeling. The general aim of this article is to provide an overview of the field of regional coupled air-sea modeling. After a general introduction, the historic development of the field is briefly summarized and model concepts are introduced. Thereafter, major methodological issues and recent advancements are discussed and key scientific challenges are highlighted. The relevance of air-sea interaction is briefly discussed for selected exemplary case studies and state-of-the-art in the field is explored. Regional coupled air-sea models are increasingly used for climate change downscaling to regional systems. The recent progress here is reviewed and key challenges and the added value of regional coupled downscaling vs. Stand-alone atmosphere or ocean downscaling are discussed. Finally an outlook on remaining challenges and future developments is given. Como descargar videos que no sean de youtube. Coupling to Wave Models A particular challenge in coupled air-sea modeling relates to the influence of waves on the air-sea energy and mass fluxes. The coupled air-sea models discussed so far considered an instantaneous balance between momentum transfer from the atmosphere to the ocean and energy removed from the wind field is directly transferred into energy gain of the surface currents.
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