TY - JOUR
T1 - Vertical Structure of Terdiurnal Tides in the Antarctic MLT Region
T2 - 15-Year Observation Over Syowa (69°S, 39°E)
AU - Liu, Huixin
AU - Tsutsumi, Masaki
AU - Liu, Hanli
N1 - Funding Information:
We thank A. Smith and A. Richmond for helpful comments and discussions. This work is supported by JSPS KAKENHI grants 18H01270, 18H04446, and 17KK0095. The data used in this study are publicly available at the Zenodo website (https://doi.org/10.5281/zenodo. 2574994).
Publisher Copyright:
©2019. American Geophysical Union. All Rights Reserved.
PY - 2019/3/16
Y1 - 2019/3/16
N2 - The terdiurnal tide (TDT) in the Antarctic mesosphere and lower thermosphere region is poorly known. This study examines TDT using neutral wind observations at Syowa during years of 2004–2018. TDT is found to be a significant tidal component with distinct vertical structures and seasonal evolution. (1) It shows a prominent height-dependent seasonal variation with phase reversal at 94 km. (2) The vertical wavelength in summer is ∼40 km shorter than in winter. These features differ largely from those in the Arctic, indicating hemispheric asymmetry. The phase structure reveals a dominant upward propagating mode in local summer but superposition of more than one mode in other seasons. A downward propagating mode above 94 km in winter suggests Joule heating/ion drag as additional tidal sources to lower atmosphere ones. These results provide new constrains and benchmarks for model simulations that seek to understand terdiurnal tidal forcing mechanisms in polar regions.
AB - The terdiurnal tide (TDT) in the Antarctic mesosphere and lower thermosphere region is poorly known. This study examines TDT using neutral wind observations at Syowa during years of 2004–2018. TDT is found to be a significant tidal component with distinct vertical structures and seasonal evolution. (1) It shows a prominent height-dependent seasonal variation with phase reversal at 94 km. (2) The vertical wavelength in summer is ∼40 km shorter than in winter. These features differ largely from those in the Arctic, indicating hemispheric asymmetry. The phase structure reveals a dominant upward propagating mode in local summer but superposition of more than one mode in other seasons. A downward propagating mode above 94 km in winter suggests Joule heating/ion drag as additional tidal sources to lower atmosphere ones. These results provide new constrains and benchmarks for model simulations that seek to understand terdiurnal tidal forcing mechanisms in polar regions.
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U2 - 10.1029/2019GL082155
DO - 10.1029/2019GL082155
M3 - Article
AN - SCOPUS:85062697196
SN - 0094-8276
VL - 46
SP - 2364
EP - 2371
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 5
ER -