Open AccessQuasi‐90‐day oscillation observed in the MLT region at low latitudes from the Kunming meteor radar and SABER
Author(s) -
Yi Wen,
Xue XiangHui,
Chen JinSong,
Chen TingDi,
Li Na
Publication year - 2019
Publication title -
earth and planetary physics
Language(s) - English
Resource type - Journals
ISSN - 2096-3955
DOI - 10.26464/epp2019013
Subject(s) - thermosphere , meteor (satellite) , mesosphere , atmosphere (unit) , atmospheric sciences , oscillation (cell signaling) , daytime , depth sounding , madden–julian oscillation , climatology , environmental science , geology , physics , stratosphere , meteorology , ionosphere , geophysics , oceanography , convection , biology , genetics
Observations of a quasi‐90‐day oscillation in the mesosphere and lower thermosphere (MLT) region from April 2011 to December 2014 are presented in this study. There is clear evidence of a quasi‐90‐day oscillation in temperatures obtained from the Kunming meteor radar (25.6°N, 103.8°E) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), as well as in wind observed by the Kunming meteor radar. The quasi‐90‐day oscillation appears to be a prominent feature in the temperatures and meridional wind tides and presents quite regular cycles that occur approximately twice per year. The amplitudes and phases of the quasi‐90‐day oscillation in the SABER temperature show a feature similar to that of upward‐propagated diurnal tides, which have a vertical wavelength of ~20 km above 70 km. In the lower atmosphere, a similar 90‐day variability is presented in the surface latent heat flux and correlates with the temperature in the MLT region. Similar to the quasi‐90‐day oscillation in temperature, a 90‐day variability of ozone (O 3 ) is also present in the MLT region and is considered to be driven by a similar variability in the upwardly‐propagated diurnal tides generated in the lower atmosphere. Moreover, the 90‐day variability in the absorption of ultraviolet (UV) radiation by daytime O 3 in the MLT region is an in situ source of the quasi‐90‐day oscillation in the MLT temperature.