Analysis of Energy Transfer Between Background Flow and Various-Scale Waves in the Mesopause Region During Gravity Wave Breaking: Insights from a High-Resolution Atmospheric Model

We analyzed the gravity wave (GW) breaking process from an energy perspective using data from a high-resolution compressible atmospheric model. This study emphasized the energy conversions and transfers occurring during GW breaking. We quantified the total kinetic energy change and the energy transformation to internal and potential energy within a specified region.

Before the GW breaking, potential energy is partially transformed into kinetic energy, which is predominantly transported out of the selected region. After the GW breaks, a portion of the potential energy is again converted to kinetic energy, with the majority of this converted kinetic energy subsequently transformed into internal energy.

We also calculated the kinetic energy transfer among different-scale GWs and the background (BG) within the chosen region, alongside the contributions from various interactions, including those between the BG and GWs and between two different scales of GWs. As the GW breaking progresses, large-scale GWs transfer energy to the background. In the early stages of GW breaking, small-scale GWs (SGWs) gain energy through interactions between the two GW scales and between the BG and SGWs. Once the SGWs accumulate sufficient energy, they begin to absorb energy from the background while transferring energy to the large-scale GWs (LGWs).

The study also explores instabilities at various stages of the GW-breaking process. The simulations indicate that GW propagation leads to instabilities, which are crucial for GW breaking. As the intensity of SGWs increases, they mitigate convective instability in the affected region.