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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Evidence for stratospheric sudden warming effects on the upper thermosphere derived from satellite orbital decay data during 1967–2013
AU - Yamazaki (YY), Yosuke
AU - Kosch, Michael
AU - Emmert, John
N1 - ©2015. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2015 American Geophysical Union
PY - 2015/8/13
Y1 - 2015/8/13
N2 - 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.
AB - 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.
U2 - 10.1002/2015GL065395
DO - 10.1002/2015GL065395
M3 - Journal article
VL - 42
SP - 1
EP - 9
JO - Geophysical Research Letters
JF - Geophysical Research Letters
SN - 0094-8276
IS - 15
ER -