Balance of drag between the middle and lower atmospheres in a global atmospheric forecast model

摘要: [1] A global atmospheric forecast model that includes the middle atmosphere is used to investigate systematic biases. As in many other models, Northern Hemispheric winter simulations from vertically extended Navy Operational Global Atmospheric Prediction System reveal an unrealistic vertical tilt of polar-night jet associated with a temperature bias northern polar atmosphere. This has important implication for satellite data assimilation inaccurate background field can cause system reject useful observation data. Efforts are made alleviate this using improved radiation and orographic gravity wave drag parameterizations, latter which provide adequate amount greatly reduce bias, but at cost overestimated surface pressure. To understand fix secondary study addresses effect terms balance mechanisms between lower atmospheres as well within Disruption these balances argued lead degradation simulation by reasonable despite improvement circulation. An experimental treatment limiting parameterized atmosphere, similarly done spectral parameterization, shown largely bias. discusses results series multiyear simulations, schematically illustrates model, investigates conservation angular momentum.