GSWM‐98: Results for migrating solar tides

TLDR

The study presents new GSWM‑98 predictions for the migrating solar tide across the troposphere to lower thermosphere and compares them with earlier GSWM‑95 results. GSWM‑98 incorporates an updated gravity‑wave stress parameterization, a revised background atmosphere from six‑year UARS climatologies, and defines tidal sources using UARS HALOE and MLS ozone data with background winds from UARS HRDI zonal means. The revised parameterization produces seasonal variability predictions that agree with observed diurnal amplitudes in the upper mesosphere and lower thermosphere, though discrepancies between HRDI and other wind climatologies still influence MLT tidal predictions.

Abstract

We report on new global‐scale wave model (GSWM) predictions for the migrating solar tide in the troposphere, stratosphere, mesosphere and lower thermosphere. The model revision, hereafter GSWM‐98, includes an updated gravity wave (GW) stress parameterization and modifications to the background atmosphere based on 6‐year monthly averaged Upper Atmosphere Research Satellite (UARS) climatologies. UARS Halogen Occultation Experiment and Microwave Limb Sounder ozone data are used to define the strato‐mesospheric tidal source, while GSWM‐98 background winds are based on UARS High Resolution Doppler Interferometer (HRDI) zonal mean zonal wind data. We quantify and interpret differences between previous diurnal and semidiurnal predictions, hereafter GSWM‐95, and GSWM‐98 results. The revised GW stress parameterization accounts for the most profound changes and leads to seasonal variability predictions that are consistent with diurnal amplitudes observed in the upper mesosphere and lower thermosphere. Unresolved differences between HRDI and other wind climatologies significantly affect MLT tidal predictions.