Insights Into Gravity Wave Predictability in the Troposphere and Stratosphere During DEEPWAVE

Gravity waves play an important role in regulating the momentum budget of the global circulation as they propagate vertically from source regions in the troposphere through the stratosphere and into the mesosphere. Therefore, it is critical to understand the predictive capability of gravity waves in numerical weather prediction. In this talk we will examine the predictability of orographic and non-orographic gravity waves generated over the South Island of New Zealand and Tasman Sea during the DEEPWAVE field campaign. The Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS) will be used in an ensemble mode to diagnose the characteristics of initial condition perturbation growth in gravity waves as they transit from the troposphere into the stratosphere. A 40-member ensemble is run at 2 km horizontal resolution for several cases during DEEPWAVE. Results show that the location of the most rapidly growing perturbations can be either in the troposphere or stratosphere, depending on the nature of the incoming flow. The mechanisms behind the different ensemble behavior will be discussed.