Exploring Gravity Wave Dynamics and Predictability: Preliminary Results from DEEPWAVE

Preliminary results from the DEEP propagating gravity WAVE program (DEEPWAVE) will be presented. Our focus in this study is on gravity wave dynamics in the presence of vertical and horizontal wind shear, as deduced through numerical simulations and analysis based on observations taken during the DEEPWAVE field phase. We will also address dynamical issues that impact gravity wave predictability.

DEEPWAVE is a comprehensive, airborne and ground-based measurement and modeling program centered on New Zealand and focused on providing a new understanding of GW dynamics and impacts from the troposphere through the mesosphere and lower thermosphere (MLT). This program employs the NSF/NCAR GV (NGV) research aircraft from a base in New Zealand in a 6-week field measurement campaign in June-July 2014. The NGV will be equipped with new lidar and airglow instruments for the DEEPWAVE measurement program, providing temperatures and vertical winds spanning altitudes from immediately above the NGV flight altitude (~13 km) to ~100 km. Given large-amplitude GWs that propagate routinely into the MLT, the New Zealand region offers an ideal natural laboratory for studying important GW dynamics and effects impacting weather and climate over a much deeper atmospheric layer than previous campaigns have attempted (0-100 km altitude).

Preliminary results will be presented from high-resolution and adjoint models with deep domains for cases over New Zealand during DEEPWAVE that feature GW wave propagation. Comparisons will be made with DEEPWAVE observations. These high-resolution models highlight the role of lateral shear from the jet stream that refracts vertically propagating gravity waves generated by regions of high terrain, such as New Zealand. The predictability links between the tropospheric fronts, cyclones, jet regions, and GWs that vertically propagate upward through the stratosphere are quantified using a nonhydrostatic adjoint model. Preliminary results will be presented that quantify the degree to which forecasts of GW launching and characteristics are sensitive to the model initial state and in particular to synoptic-scale and mesoscale characteristics of mid-latitude cyclones.