Seasonal variation of wave activities near the mesopause region observed at King Sejong Station (62.22°S, 58.78°W), Antarctica

Lee, Chang-Sup; Kim, Yong Ha; Kim, Jeong‐Han; Jee, Geonhwa; Won, Young-Shin; Wu, Dong L.

doi:10.1016/j.jastp.2013.07.006

Cited by 23 publications

(51 citation statements)

References 43 publications

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“…The King Sejong Station (KSS) is a Korean Antarctic station located at (62.221°S, 58.781°W), between the Andes and Antarctic Peninsula. Daily averaged variances of MLT horizontal winds have been acquired from the meteor radar observation since 2007 [ Lee et al , ]. We calculate monthly mean values of the daily variances (m 2 /s 2 ) during local daytime (09–18 LT) and take the square root (m/s): hereafter, termed “KSS GW strength.” This procedure is applied separately to different altitude ranges (between 82 km and 98 km) and different wind components (meridional and zonal).…”

Section: Discussionmentioning

confidence: 99%

A climatology of medium‐scale gravity wave activity in the midlatitude/low‐latitude daytime upper thermosphere as observed by CHAMP

et al. 2014

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We report on a detailed global climatology of medium-scale (150-600 km) thermospheric gravity wave (GW) activity using mass density observations onboard the CHAMP satellite from 2001 to 2010. Our study focuses mainly on daytime (09-18 h in local time) and midlatitude/low-latitude upper thermosphere between 300 km and 400 km altitudes. Midlatitude GW activity is strongest in the winter hemisphere. GW activity during June solstice adjacent to the Andes and Antarctic Peninsula is stronger than in any other season or location. GW activity in the low-latitude summer hemisphere is stronger above continents than above oceans: especially during December solstice and equinoxes. In terms of relative density variation, GW activity is stronger during solar minimum than solar maximum. These results agree well with the characteristics of stratospheric GWs, implying that the CHAMP GWs are mainly caused by GWs from tropospheric/stratospheric processes. Using mesosphere/lower thermosphere wind observations at a Korean Antarctic station, we investigated at which altitudes the upper thermospheric GW climatology becomes visible. While the correlation is insignificant at z = 82-88 km, it becomes significant for most cases at z = 90-98 km, suggesting that the upper thermospheric GW climatology may start to emerge at z ≥ 90 km.

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Section: Discussionmentioning

confidence: 99%

A climatology of medium‐scale gravity wave activity in the midlatitude/low‐latitude daytime upper thermosphere as observed by CHAMP

et al. 2014

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“…A VHF meteor radar has been in operation since March 2007 at KSS on the King George Island located about 150 km north of the Antarctic Peninsula. The radar system is composed of a cross‐folded dipole transmitter and five receivers arranged to minimize mutual antenna coupling (see Kim et al [] and Lee et al [] for further details). Since 2012, the peak transmitter power has been increased from 8 kW to 12 kW, resulting in increase in the number of received echoes [ Jee et al , ].…”

Section: Data and Analysis Methodsmentioning

confidence: 99%

“…Spectral analysis of these unevenly sampled data is achieved using the Lomb-Scargle (LS) periodogram method [Lomb, 1976;Scargle, 1982]. The LS periodogram method is equivalent to the least squares harmonic analysis (see Scargle [1982] for details) that has been used to extract tidal variations in previous observational studies [e.g., Mitchell et al, 2002;Lee et al, 2013;de Wit et al, 2014]. In the computation of the LS periodograms, missing values are differently distributed in time depending on height bins, and thus, the LS periodograms are obtained at different frequency bins depending on heights.…”

Section: General Characteristics Of Observed Large-scale Windsmentioning

confidence: 99%

“…Optical observational studies on GWs in the mesopause region have been carried out using airglow images [ Taylor and Hapgood , ; Kim et al , ; Nielsen et al , ; Kim et al , ; Suzuki et al , ] and noctilucent cloud (NLC) images [ Fritts et al , ; Chandran et al , ; Pautet et al , ]. GWs shown in airglow and NLC images are often found to have horizontal wavelengths of less than 100 km and ground‐based periods of less than 1 h. GW wind covariances (i.e., momentum fluxes) are crucial in estimating effects of interaction between GWs and mean flow, and they have been studied using radar instruments such as medium‐frequency (MF) Doppler radars [ Fritts and Vincent , ; Reid and Vincent , ; Thorsen et al , ] and meteor radars [ Hocking , ; Fritts et al , ; Lee et al , ; de Wit et al , ]. Similar to the cases of airglow images, GWs detected using MF radars are considered to have horizontal wavelengths of less than a couple of hundred kilometers and ground‐based frequencies of less than 1 h [ Reid and Vincent , ].…”

Section: Introductionmentioning

confidence: 99%

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Meteor radar observations of vertically propagating low‐frequency inertia‐gravity waves near the southern polar mesopause region

et al. 2017

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Vertically propagating low‐frequency inertia‐gravity waves (IGWs) are retrieved from meteor radar winds observed at King Sejong Station (KSS: 62.22°S, 58.78°W), Antarctica. IGW horizontal winds extracted from temporal band‐pass filtering in regular time‐height bins show the frequent occurrence of IGWs with the downward phase progression and the counterclockwise rotation of their horizontal wind vectors with time (i.e., upward energy propagation) near the mesopause region throughout the whole year of 2014. The vertical wavelengths of the observed IGWs roughly range from 14 km to more than 20 km, which is consistent with previous observational studies on the mesospheric IGWs over Antarctica. Stokes parameters and rotary spectra computed from the hodographs of the IGW horizontal wind components reveal that the intrinsic frequencies of the upward propagating IGWs are |f|−3|f| with seasonal variations of the relative predominance between |f|−2|f| and 2|f|−3|f|, where f is the Coriolis parameter at KSS. The hodograph analysis also indicates that the N‐S propagation is dominant in austral summer, while the NE‐SW propagation is pronounced in austral winter. The propagation direction is discussed in relation to the generation of IGWs due to dynamical imbalances occurring in the tropospheric and stratospheric jet flow systems. Ray tracing results indicate that the N‐S propagation in summer may be due to the jet flow systems roughly north of KSS and the NE‐SW propagation in winter may be either the SW propagation from the jet flow systems northeast of KSS or the NE propagation (around the South Pole) from the south of Australia and Southern Indian and Pacific Oceans.

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“…The complete details of KSS MR and its wind measuring capabilities can be found in Lee et al (2013). The hourly measured zonal winds of KSS MR during 2010 have been utilized in the present study.…”

Section: Databasementioning

confidence: 99%

Do minor sudden stratospheric warmings in the Southern Hemisphere (SH) impact coupling between stratosphere and mesosphere–lower thermosphere (MLT) like major warmings?

Eswaraiah

Kim

Liu

et al. 2017

Earth Planets Space

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We have investigated the coupling between the stratosphere and mesosphere-lower thermosphere (MLT) in the Southern Hemisphere (SH) during 2010 minor sudden stratospheric warmings (SSWs). Three episodic SSWs were noticed in 2010. Mesospheric zonal winds between 82 and 92 km obtained from King Sejong Station (62.22°S, 58.78°W) meteor radar showed the significant difference from usual trend. The zonal wind reversal in the mesosphere is noticed a week before the associated SSW similar to 2002 major SSW. The mesosphere wind reversal is also noticed in "Specified Dynamics" version of Whole Atmosphere Community Climate Model (SD-WACCM) and Ground-to-topside model of Atmosphere and Ionosphere for Aeronomy (GAIA) simulations. The similar zonal wind weakening/reversal in the lower thermosphere between 100 and 140 km is simulated by GAIA. Further, we observed the mesospheric cooling in consistency with SSWs using Microwave Limb Sounder data. However, the GAIA simulations showed warming between 130 and 140 km after few days of SSW. Thus, the observation and model simulation indicate for the first time that the 2010 minor SSW also affects dynamics of the MLT region over SH in a manner similar to 2002 major SSW.

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Seasonal variation of wave activities near the mesopause region observed at King Sejong Station (62.22°S, 58.78°W), Antarctica

Cited by 23 publications

References 43 publications

A climatology of medium‐scale gravity wave activity in the midlatitude/low‐latitude daytime upper thermosphere as observed by CHAMP

A climatology of medium‐scale gravity wave activity in the midlatitude/low‐latitude daytime upper thermosphere as observed by CHAMP

Meteor radar observations of vertically propagating low‐frequency inertia‐gravity waves near the southern polar mesopause region

Do minor sudden stratospheric warmings in the Southern Hemisphere (SH) impact coupling between stratosphere and mesosphere–lower thermosphere (MLT) like major warmings?

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