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Evidence for stratospheric sudden warming effects on the upper thermosphere derived from satellite orbital decay data during 1967–2013
Author(s) -
Yamazaki Yosuke,
Kosch Michael J.,
Emmert John T.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2015gl065395
Subject(s) - thermosphere , atmospheric sciences , sudden stratospheric warming , orbital decay , environmental science , perturbation (astronomy) , physics , polar vortex , earth's magnetic field , climatology , satellite , stratosphere , ionosphere , geology , geophysics , astronomy , quantum mechanics , magnetic field
We investigate possible impact of stratospheric sudden warmings (SSWs) on the thermosphere by using long‐term data of the global average thermospheric total mass density derived from satellite orbital drag during 1967–2013. Residuals are analyzed between the data and empirical Global Average Mass Density Model (GAMDM) that takes into account density variability due to solar activity, season, geomagnetic activity, and long‐term trend. A superposed epoch analysis of 37 SSW events reveals a density reduction of 3–7% at 250–575 km around the time of maximum polar vortex weakening. The relative density perturbation is found to be greater at higher altitudes. The temperature perturbation is estimated to be −7.0 K at 400 km. We show that the density reduction can arise from enhanced wave forcing from the lower atmosphere.