Collaborative Research: Gravity Wave-Airglow Interactions in Multiple Emission Layers

Perturbations in the neutral density in the Earth's middle and upper atmosphere known as gravity waves (GWs) are thought to be an important driver of physical and chemical processes in the mesosphere and lower thermosphere (MLT) atmospheric region. GWs influence tidal and planetary wave dynamics as well as general circulation and transport processes across many atmospheric layers. The goal of this project is to investigate the interaction of GWs and airglow, faint optical emission emitted by atoms and molecules in MLT during the night. Through this, a better understanding of the impact of GWs on chemical species in the MLT region will be achieved. This project will conduct observations in multiple airglow layers with a chain of airglow imagers near the Andes Lidar Observatory (ALO) in Chile, a well-known GW 'hotspot'. This will be complemented by observations with the collocated lidar and meteor radar, satellites, and results from time-dependent, nonlinear atmospheric models. This project will promote education by supporting a graduate student and an undergraduate student and contribute to broadening participation by supporting the team that includes members from underrepresented groups.

The work will involve characterization of GW activity near ALO based on the imaging airglow data and comparison of simulation results of GW-airglow interactions with imaging observations. Recent modeling results using a 2D, nonlinear, time-dependent OH Chemistry-Dynamics (OHCD) model and a Multiple-Airglow Chemistry-Dynamics (MACD) models have shown that a transient dissipating GW packet can induce significant variations in the concentrations of the minor species, in the airglow intensity, and in exothermal heating. The variations appear to be aperiodic but are often mistaken for long-period waves. These are secular variations which are a result of a net cycle-averaged transport of chemically-active minor species. The project will simulate secular variations in airglow causes by GWs by using a model of GW propagation together with airglow chemistry models, OHCD and MACD, in conjunction with optical, lidar, and meteor radar observations at ALO complemented by spacecraft data from SABER and SCIAMACHY.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.