Modification of the Gravity Wave Parameterization in the Whole Atmosphere Community Climate Model: Motivation and Results

作者：Rolando R. García, Anne K. Smith, Douglas Edward Kinnison, Álvaro de la Cámara, D. J. Murphy · 发表于：Journal of the Atmospheric Sciences · 年份：2016 · DOI：10.1175/jas-d-16-0104.1 · 被引用次数：335 · 研究领域：Atmospheric Ozone and Climate、Climate variability and models、Ionosphere and magnetosphere dynamics

Abstract The current standard version of the Whole Atmosphere Community Climate Model (WACCM) simulates Southern Hemisphere winter and spring temperatures that are too cold compared with observations. This “cold-pole bias” leads to unrealistically low ozone column amounts in Antarctic spring. Here, the cold-pole problem is addressed by introducing additional mechanical forcing of the circulation via parameterized gravity waves. Insofar as observational guidance is ambiguous regarding the gravity waves that might be important in the Southern Hemisphere stratosphere, the impact of increasing the forcing by orographic gravity waves was investigated. This reduces the strength of the Antarctic polar vortex in WACCM, bringing it into closer agreement with observations, and accelerates the Brewer–Dobson circulation in the polar stratosphere, which warms the polar cap and improves substantially the simulation of Antarctic temperature. These improvements are achieved without degrading the performance of the model in the Northern Hemisphere stratosphere or in the mesosphere and lower thermosphere of either hemisphere. It is shown, finally, that other approaches that enhance gravity wave forcing can also reduce the cold-pole bias such that careful examination of observational evidence and model performance will be required to establish which gravity wave sources are dominant in the real atmosphere. This is especially important because a “downward control” analysis of these results sugge...