Estimation of Mesoscale Momentum Flux Frequency Spectra in the Mesosphere and Lower Thermosphere Using Multistatic Specular Meteor Radar Wind Fields

Mitra G.; Chau J.L.; Conte J.F.; Urco J.M.; Renkwitz T.; Jacobi C. · Journal of Geophysical Research: Space Physics (2026) · DOI: 10.1029/2026ja035433

Resumen

A spectrally resolved observational methodology is introduced to estimate mesoscale momentum flux frequency spectra in the mesosphere and lower thermosphere (MLT). The method is applied to four-dimensional wind fields reconstructed with the physics-informed neural network approach called the Hydrodynamic Point-wise Environment Reconstructor (HYPER) on multistatic specular meteor radar observations. Unlike conventional radar-based approaches that provide only bulk and band-limited momentum flux estimates, this framework explicitly separates tidal and non-tidal contributions in the frequency domain and enables direct estimation of momentum flux spectra over a finite observational domain. Application to a year-long data set over northern Germany in 2024 reveals mesoscale spectral signatures at periods shorter than the inertial period and pronounced frequency-dependent and seasonal variability in both zonal and meridional momentum fluxes. The inferred fluxes are dynamically consistent with the background wind structure, demonstrating the potential of the method to provide new observational constraints on mesoscale momentum flux and its role in driving MLT circulation.

Instituciones: Pontificia Universidad Católica del Perú