Coordinated Observations of Migrating Tides by Multiple Meteor Radars in the Equatorial Mesosphere and Lower Thermosphere

Abstract

We present the migrating tidal winds decomposed jointly from multiple meteor radars in four longitudinal sectors situated in the equatorial mesosphere and lower thermosphere. The radars are located in Cariri, Brazil (7.4°S, 36.5°W), Kototabang, Indonesia (0.2°S, 100.3°E), Ascension Island, United Kingdom (7.9° S, 14.4° W), and Darwin, Australia (12.3°S, 130.8°E). Harmonic analysis was used to obtain amplitudes and phases for diurnal and semidiurnal solar migrating tides between 82 and 98 km altitude during the period 2005–2008. To verify the reliability of the tidal components calculated by the four meteor radar wind measurements, we also present a similar analysis for the Whole Atmosphere Community Climate Model winds, which suggests that the migrating tides are well observed by the four different radars. The tides include the important tidal components of diurnal westward‐propagating zonal wavenumber 1 and semidiurnal westward‐propagating zonal wavenumber 2. In addition, the results based on observations were compared with the Climatological Tidal Model of the Thermosphere (CTMT). In general, in terms of climatic features, our results for the major components of migrating tides are qualitatively consistent with the CTMT models derived from satellite data. In addition, the tidal amplitudes are unusually stronger in January–February 2006. This result is probably because tides were enhanced by the 2006 Northern Hemisphere stratospheric sudden warming event.

Influence of Sudden Stratospheric Warmings on the Migrating Diurnal Tide in the Equatorial Middle Atmosphere Observed by Aura/Microwave Limb Sounder

“…This change in the propagation conditions of DW1 explains the tidal variability in DW1 after SSWs and the modulation of DW1 by upwardly propagating planetary waves. Different to [22], an enhancement in DW1 was observed by meteor radars at low latitudes after the SSW of 2006 [24].…”

“…The study of [22] utilised TIMED/SABER observations and found a reduction in the DW1 amplitude after SSW events. However, other studies predicted other responses of solar tides to SSWs (e.g., [24,45]). Thus, it makes sense to utilise the Aura series and to perform a composite analysis of 17 major SSWs and their influence on the deseasonalised, equatorial DW1 proxy.…”

Meteor Radar for Investigation of the MLT Region: A Review

“…In contrast, MFPRs can measure winds in the 60 to 80 km height region during the day. There are now more MLT (meteor) radars overall, and this has led to an improvement in the study of wave modes for planetary scale waves and tides (see e.g., [94]). However, the daytime radar winds in the 60 to 80 km height region previously provided by these radars are now not as generally available.…”

Dual-Frequency, Dual-Mode Reconfigurable Digital Atmospheric Radar Receiver Design

“…Atmospheric radio radars, such as medium frequency radars [1,2], meteor radars [3], and MST radars [4], play a significant role in the study of the dynamics and coupling of middle atmosphere and ground weather. They contribute to understanding the physics of atmospheric motion and sudden weather processes, establishing high-precision and high-resolution atmospheric models [5][6][7].…”