Quasi‐2‐Day Wave in Low‐Latitude Atmospheric Winds as Viewed From the Ground and Space During January–March, 2020

다국어 초록 (Multilingual Abstract)

Horizontal winds from four low‐latitude (±15°) specular meteor radars (SMRs) and the Michelson Interferometer for Global High‐resolution Thermospheric Imaging (MIGHTI) instrument on the ICON satellite, are combined to investigate quasi‐2‐day waves (Q2DWs) in early 2020. SMRs cover 80–100 km altitude whereas MIGHTI covers 95–300 km. Q2DWs are the largest dynamical feature of the summertime middle atmosphere. At the overlapping altitudes, comparisons between the derived Q2DWs exhibit excellent agreement. The SMR sensor array analyses show that the dominant zonal wavenumbers are s = +2 and + 3, and help resolve ambiguities in MIGHTI results. We present the first Q2DW depiction for s = +2 and s = +3 between 95 and 200 km, and show that their amplitudes are almost invariant between 80 and 100 km. Above 106 km, Q2DW amplitudes and phases present structures that might result from the superposition of Q2DWs and their aliased secondary waves.
In the mesosphere and lower‐thermosphere, quasi‐2‐day waves are spectacular planetary‐scale oscillations. Almost all relevant observational studies are based on ground‐based single‐station or single‐satellite methods and therefore cannot determine the zonal wavenumber unambiguously. In the current work, we employ a series of multi‐station methods on winds measured by four longitudinally separated low‐latitude ground‐based radars. These methods help us to determine two dominant zonal wavenumbers at 80–100 km altitude. These results are used to complement satellite measurements. The agreement between datasets is extraordinary, allowing us to extend the characteristics of the waves to higher altitudes using satellite measurements.



The quasi‐2‐day waves (Q2DW) wind field at 80–200 km altitude is delineated from combining ground and space data in the low‐latitude region (+/−15°)

Zonal wavenumber components s = +2 and s = +3 are the dominant ones in our observations, and their wave periods evolve differently with time

The quasi‐2‐day waves s = +3 exhibits an excellent quantitative agreement between two datasets at 95–100 km, serving as a validation of the ICON‐MIGHTI winds


The quasi‐2‐day waves (Q2DW) wind field at 80–200 km altitude is delineated from combining ground and space data in the low‐latitude region (+/−15°)
Zonal wavenumber components s = +2 and s = +3 are the dominant ones in our observations, and their wave periods evolve differently with time
The quasi‐2‐day waves s = +3 exhibits an excellent quantitative agreement between two datasets at 95–100 km, serving as a validation of the ICON‐MIGHTI winds