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Author: Forbes, Jeffrey M. × Start date: 2021 × DDC: 550 × Has files: Yes × Type: Text × WGL Institute: IAP ×

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    Mesospheric Q2DW Interactions With Four Migrating Tides at 53°N Latitude: Zonal Wavenumber Identification Through Dual‐Station Approaches
    (Hoboken, NJ : Wiley, 2021) He, Maosheng; Forbes, Jeffrey M.; Li, Guozhu; Jacobi, Christoph; Hoffmann, Peter
    Mesospheric winds from two longitudinal sectors at 53°N latitude are combined to investigate quasi-two-day waves (Q2DWs) and their nonlinear interactions with tides. In a summer 2019 case study, we diagnose the zonal wavenumber m of spectral peaks at expected frequencies through two dual-station approaches, a phase differencing technique (PDT) on individual spectral peaks and a least squares procedure on family batched peaks. Consistent results from the approaches verify the occurrences of Rossby-gravity modes (m = 3 and 4 at periods T = 2.1 and 1.7 days), and their secondary waves (SWs) generated from interactions with diurnal, semi-diurnal, ter-diurnal, and quatra-diurnal migrating tides. We further extend the PDT to 2012–2019, illustrating that Q2DWs exhibit significant interannual variability. Composite analysis reveals seasonal and altitude variations of the Rossby-gravity modes and their SWs. The Rossby-gravity modes maximize in local summer, whereas their 16- and 9.6-h SWs appear more in winter.
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    Quasi‐2‐Day Wave in Low‐Latitude Atmospheric Winds as Viewed From the Ground and Space During January–March, 2020
    (Hoboken, NJ : Wiley, 2021) He, Maosheng; Chau, Jorge L.; Forbes, Jeffrey M.; Zhang, Xiaoli; Englert, Christoph R.; Harding, Brian J.; Immel, Thomas J.; Lima, Lourivaldo M.; Bhaskar Rao, S. Vijaya; Ratnam, M. Venkat; Li, Guozhu; Harlander, John M.; Marr, Kenneth D.; Makela, Jonathan J.
    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.