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Intraseasonal Variations of Nonmigrating Tides Observed Near the Mesopause
Author(s) -
Liu Guiping,
Janches Diego,
Lieberman Ruth S.
Publication year - 2018
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1029/2018ja025709
Subject(s) - mesopause , troposphere , microwave limb sounder , atmospheric sciences , atmosphere (unit) , atmospheric tide , climatology , madden–julian oscillation , oscillation (cell signaling) , environmental science , amplitude , convection , forcing (mathematics) , geology , mesosphere , ionosphere , thermosphere , stratosphere , meteorology , geophysics , physics , quantum mechanics , biology , genetics
Nonmigrating tides excited in the tropical troposphere by latent heat release from deep convection are known to be responsible for introducing the longitudinal structures in the upper atmosphere and the ionosphere. This study presents for the first time an extensive analysis of the prominent wave‐3 and wave‐4 longitudinal structures using nearly 14 years of temperature observations by the Microwave Limb Sounder instrument operated on the Aura satellite from 2004 to 2017. The observations reveal significant intraseasonal (~30–60 days) periodic variations in the amplitudes of these wave structures at ~97‐km altitude near the mesopause. Some large wave amplitudes accompany strong activity of the Madden‐Julian Oscillation. Rainfall data from the Tropical Rainfall Measuring Mission are used as a proxy of latent heating to investigate the source of these variations. Intraseasonal signatures in the wave structures are observed to coincide with the rainfall variations, indicating that the tropospheric 30‐ to 60‐day oscillation is an important driver of the same periodic changes in the upper atmosphere. Given that not all intraseasonal oscillations in the lower atmosphere have corresponding signatures in the longitudinal wave structures, the atmospheric conditions and other influences are important. This study provides evidence on the connection between intraseasonal variations of tides in the upper atmosphere and the changes in the forcing by latent heat release in the troposphere.