IMPACT OF LOCALIZED TROPICAL AND EXTRATROPICAL SST ANOMALIES IN ENSEMBLES OF SEASONAL GCM INTEGRATIONS

• Published in: Quarterly Journal of the Royal Meteorological Society
• Main Authors: Ferranti, L, Molteni, F, Palmer, T
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Pacific; North West Atlantic
• Online Access: https://doi.org/10.1002/qj.49712052009; https://ora.ox.ac.uk/objects/uuid:ba640ee2-6a53-4adb-81da-f69666117226

A series of 120-day ensemble intergrations of a general circulation model, designed to assess the impact of geographically localized sea surface temperature (SST) anomalies in both the tropics and extratropics, are described. Overall it is found that SST anomalies associated with El Nino and La Nina have a larger and more reproducible impact on the extratropics than the chosen extratropical SST anomalies. These extratropical anomalies were localized to the north-west Pacific, and north-west Atlantic, with realistic amplitude. Overall it is concluded that the northern large-scale flow is influenced by such extratropical SST anomalies. The response to idealized tropical SST anomalies was also studied. In particular, a localized anomaly over Indonesia had a very substantial impact on the Hadley circulation, on zonal flow, and on blocking frequency over the North Pacific and Europe. -Authors