Projected Strengthening of the Extratropical Surface Impacts of the Stratospheric Quasi‐Biennial Oscillation
Jian Rao, Chaim I. Garfinkel, Ian White
Abstract
Abstract Using state‐of‐the‐art models with a spontaneous quasi‐biennial oscillation (QBO) from the Coupled Model Intercomparison Project Phases 5 and 6 (CMIP5/6), this study explores projected changes in the Holton‐Tan (HT) relationship and the near‐surface response to the QBO. Most models project an enhanced surface response to the QBO via a strengthened HT relationship in the future. Specifically, the North Atlantic Oscillation‐like response is projected to double and shift eastward in the future in the high‐end emission scenarios compared with the historical simulation. This strengthening occurs even as the amplitude of the QBO in the tropical stratosphere weakens from the historical simulation to the future projections. The seemingly contradictory projections of future changes in the QBO and the HT relationship might imply that the HT relationship changes nonlinearly with the QBO intensity, and the coherent changes in the background circulation structure should also be highlighted.