Changes in the Arctic Oscillation under increased 1 atmospheric greenhouse gases
نویسندگان
چکیده
13 The Arctic Oscillation (AO) under increased atmospheric concentration of greenhouse gases 14 (GHG) was studied by comparing an ensemble of simulations from 13 coupled general circulation 15 models with GHG at the pre-industrial level and at the late 20th century level, for November to 16 March. The change in the linear AO pattern as GHG increased reveals positive sea level pressure 17 (SLP) anomalies centered over the Gulf of Alaska, and weaker negative SLP anomalies over east18 ern Canada and North Atlantic – a pattern resembling the nonlinear AO pattern arising from a 19 quadratic relation to the AO index. This quadratic AO pattern itself has positive SLP anomalies 20 receding from Europe but strengthening over the Gulf of Alaska and surrounding areas as GHG 21 increased. This study points to the importance of the nonlinear structure in determining how the 22 linear oscillatory pattern changes when there is a change in the mean climate. 23
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