Work

Observational Evidence of Distinct Excitation Pathways for Migrating and Non-Migrating Tides in the Mesosphere-Lower Thermosphere During the 2021 Sudden Stratospheric Warming

Year: 2025

Type: article

Abstract: We investigate the excitation and variability of migrating and non-migrating diurnal and semi-diurnal tides in the mesosphere and lower thermosphere (MLT) during the 2021 Northern Hemisphere sudden stratospheric warming (SSW). Zonal wind data from MERRA-2 reanalysis are decomposed into tidal components using a two-dimensional least-squares harmonic fitting technique. The migrating diurnal tide (DW1) strengthens at low latitudes following the SSW onset, whereas the migrating semi-diurnal tide (SW2) intensifies at high latitudes. Non-migrating diurnal tides (D0, DW2, DW3) arise from nonlinear interactions between DW1 and stationary planetary waves (SPWs), while non-migrating semi-diurnal tides (SW1, SW3) are modulated by stratospheric ozone variability linked to planetary-wave activity. The zonally symmetric semi-diurnal tide (S0) responds primarily to dynamical perturbations associated with the SSW. Eastward non-migrating diurnal tides (DE2, DE3) correlate strongly with total precipitable water vapor (TPWV), indicating tropospheric latent-heat forcing, whereas DE1 exhibits weak coupling. These results reveal distinct, latitude-dependent excitation pathways connecting stratospheric and tropospheric dynamics to tidal variability in the MLT during major SSW events.

Source: Atmosphere

DOI: 10.3390/atmos16111254

Authors: Reuben Acheampong Asamoah, Gizaw Mengistu Tsidu, Gemechu Fanta Garuma, Leonard Kofitse Amekudzi

Institutions: Addis Ababa University, Botswana International University of Science and Technology, Kwame Nkrumah University of Science and Technology

Language: English

Topic: Ionosphere and magnetosphere dynamics

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $2,896