#33 Surface wind stress biases in the Southern Ocean

Abstract

Surface wind stress in the Southern Ocean (SO) in both the ACME and CESM are high relative to several data sets, including the QuikSCAT-based Large-Yeager (2004, LY04) observational estimates. While surface stress estimates are uncertain, LY04 is actually high compared with other wind stress estimates in the SO e.g., ERA, NOC1.1, arguing that the models’ high values are in fact unrealistic.

High SO wind stress in ACME/CESM is a remarkably resilient feature of the model climate, persisting though major changes to both vertical resolution and boundary layer scheme. In this presentation, we will focus on the impact of gravity wave (GW) and subgrid orographic surface stress parameterizations on SO wind stress. Results using enhanced southern hemispheric orographic GW drag are shown, and contrasted with modifications to other GW sources.