North Atlantic forcing of climate and its uncertainty from a multi-model experiment

• Published in: Quarterly Journal of the Royal Meteorological Society
• Main Authors: Rodwell, M. J., Drévillon, M., Frankignoul, Claude, Hurrell, J. W., Pohlmann, H., Stendel, M., Sutton, R. T.
• Other Authors: Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), CERFACS, Laboratoire d'océanographie dynamique et de climatologie (LODYC), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, Danish Climate Centre, Danish Meteorological Institute (DMI)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2004
• Subjects: NORTH ATLANTIC OSCILLATION; INTERTROPICAL CONVERGENCE ZONE; ASIAN MONSOON; AIR-SEA INTERACTION; [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; North Atlantic; North Atlantic oscillation
• Online Access: https://hal.archives-ouvertes.fr/hal-00770792; https://doi.org/10.1256/QJ.03.207

International audience To understand recent climate change in the North Atlantic region and to produce better climate forecasts with uncertainty estimates it is important to determine the atmospheric 'response' to Atlantic sea-surface temperature (SST) forcing. There have been conflicting results regarding the strength, character and tropicalversus-extratropical origin of this response. For model-based studies, this may indicate differing sensitivities to Atlantic SST, but the comparison is complicated by changes in experimental design. Here, a highly controlled experiment with five atmospheric models is undertaken. The influence of realistic (if reasonably strong) and optimally chosen North Atlantic (equator to 70° N) SST anomalies is isolated. Unexpected global agreement between the models is found (e.g.the North Atlantic Oscillation (NAO), Eurasian temperatures, rainfall over the Americas and Africa, and the Asian monsoon). The extratropical North Atlantic region response appears to be associated with remote Caribbean and tropical Atlantic SST anomalies, and with local forcing. Some features such as the European winter-temperature response would be stronger than atmospheric 'noise' if the prescribed SST anomalies persisted for just two years. More generally, Atlantic air-sea interaction appears to be important for climate variability on the 30-year timescale and, thus, to be important in the climate-change context. The multimodel mean response patterns are in reasonable agreement with observational estimates, although the model response magnitudes may be too weak. The similarity between their responses helps to reconcile models. Intermodel differences do still exist and these are discussed and quantified.