The impact of surface temperature variability on the climate change response in the Northern Hemisphere polar vortex

• Published in: Geophysical research letters 2011-04, Vol.38 (8), p.np-n/a
• Main Authors: Winter, Barbara, Bourqui, Michel S.
• Format: Article
• Language: English
• Subjects: Atmospheric sciences; Carbon dioxide; Climate change; Climate models; Climate science; Earth sciences; Earth, ocean, space; Exact sciences and technology; Global warming; Greenhouse gases; Land; Mathematical models; Northern Hemisphere; Ocean temperature; Oceans; Sea surface temperature; Stratosphere; surface forcing; Surface temperature; Vortices
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2011GL047011

This study investigates the importance of the timescales of variability of land and ocean surface temperatures in the stratospheric response to increased atmospheric greenhouse gas concentrations. We present results from five pairs of 100‐year (timeslice) simulations – control and 2 × CO2 – carried out with the coupled chemistry‐climate model IGCM‐FASTOC, in which land and/or sea surface temperatures are either calculated interactively, prescribed and interannually varying, or prescribed with a climatological seasonal cycle. The strongest response to CO2‐doubling in the Northern Hemisphere high‐latitude winter stratosphere is found when surface temperatures are calculated interactively by a coupled slab ocean and a land surface scheme. Both the interannual variability in ocean and land temperatures, and the adjustment of oceans and lands to the atmosphere and to one another, are important in order to maintain realistic stratospheric forcing by planetary waves and to adequately capture the stratospheric response to global warming. Key Points The strongest climate change response occurs when a CCM is coupled to an ocean NH winter lower stratosphere warms by 3–4 C in a 2 × CO2 climate (coupled ocean) Wave forcing of the 2 × CO2 stratosphere begins 1 month earlier (coupled ocean)