Climatology of mesospheric and lower thermospheric diurnal wind tides over Jicamarca: Observations and simulations

Characterizing the dynamics of the mesosphere and lower thermosphere (MLT) is valuable for improving our understanding of coupling mechanisms between different atmospheric layers. This work shows a three-year climatology of horizontal wind components of the dominant diurnal tide, obtained from measurements made by a multistatic specular meteor radar over Jicamarca, Peru (12°S, 77°W). Our observations show that the meridional component is more intense than the zonal component, the meridional component reaches their maxima displaced from the austral equinoxes (i.e., the main peak occurs in August-September, and the second one occurs in April-May), and the zonal component only shows a clear maximum in August-September. This observational climatology is compared to a climatology obtained with the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension (WACCM-X). Single-point seasonal comparisons indicate that model amplitudes are at least 50% smaller than observations. The WACCM-X results are also used in combination with observed altitude profiles of tidal phases to understand the contributions of migrating and non-migrating components. Based on this, we infer that the migrating diurnal tide (DW1) is dominant in general, and from June to September (November to July) the DE3 (DW2) could have a significant contribution to the zonal (meridional) component. Finally, applying a wavelet analysis to the diurnal tide amplitudes, periods between 8-60 days are observed. These modulations might be associated to large-scale tropospheric oscillations