Frequency Characteristics Of Acoustic-Gravity Eigenwaves Of The Nonadiabatic Atmosphere

TL;DR

This study investigates how non-adiabatic processes affect the eigenmodes of acoustic-gravity waves in the atmosphere, revealing frequency decreases and phase velocity changes with altitude compared to adiabatic models.

Contribution

It provides a detailed analysis of non-adiabatic effects on atmospheric eigenwaves, including dispersion relations and mode growth at various altitudes.

Findings

Frequencies decrease with altitude compared to adiabatic predictions

Phase velocities are reduced at higher altitudes

Eigenmode growth rates vary with altitude

Abstract

The main objective of the given work consists in the account of the basic mechanisms, which decline processes in atmosphere from adiabaticity approach, and in the study of effect non-adiabaticity on the swing of eigenmodes of atmosphere at various altitudes. The dispersion equation is solved, dispersion curves for acoustic and gravity branches are explored. The increment of growth of eigenmodes at various altitudes of atmosphere is explored. Frequencies (real part) both for acoustic, and for gravity branches acoustic-gravity waves (AGW) in nonadiabatic atmosphere, coinciding with frequencies of the adiabatic model for the same wave vectors at low altitudes, smoothly decrease with altitude. It leads to decrease of a phase velocity for both branches at larger altitudes in a real atmosphere in comparison with predicted by the adiabatic model.