[A-CG47] Dynamics of Oceanic and Atmospheric Waves, Vortices, and Circulations

[ACG47-P02] Revealing the circulation of wave energy in the atmosphere: Difference between neutral and unstable waves

*Hidenori AIKI¹, Yuki Kanno², Yayoi Harada³, Chiaki Kobayashi³, Takahiro Toyoda³, Motoki Nagura⁴, Tomomichi Ogata⁴, Shunsuke Noguchi⁵, Hatsuki Fujinami¹ (1.Nagoya University, 2.Central Research Institute of Electric Power Industry, 3.Meteorological Research Institute, 4.Japan Agency for Marine-Earth Science and Technology, 5.Kyushu University)

This study addresses the challenge of bridging equatorial and quasi-geostrophic dynamics to diagnose group velocity vectors continuously across all latitudes. The theoretical advancements by Aiki, Greatbatch, and Claus (2017) and Aiki et al. (2021) resolved this issue, enabling seamless visualization of wave energy circulation patterns and advancing research into ocean wave phenomena linked to mechanisms such as the Indian Ocean Dipole Mode, the Atlantic Niño/Niña, and the El Niño-Southern Oscillation.The AGC diagnostic scheme is applied to an atmospheric reanalysis product in this study, focusing on the January monthly climatology for 1990–2009. The analysis shows that diabatic processes a drive and dissipate waves. Group velocity is directed downward in the lower troposphere, explained by the energy-wave-activity ratio, and eastward in the upper troposphere, attributed to unstable waves. In off-equatorial regions, the AGC energy flux and the quasigeostrophic energy flux are consistent in magnitude and structure.This is attributed to the finding that most atmospheric waves in the mid-latitude troposphere exhibit characteristics similar to unstable waves the Eady problem with the arbituraral vertical structure of basic flow.