Height and time characteristics of seasonal and diurnal variations in PMWE based on 1 year observations by the PANSY radar (69.0°S, 39.6°E)

Nishiyama, Takanori; Sato, K.; Nakamura, Takuji; Tsutsumi, Masaki; Sato, Toru; Kohma, Masashi; Nishimura, Koji; Tomikawa, Yoshihiro; Ejiri, Mitsumu K.; Tsuda, Takuo T.

doi:10.1002/2015gl063349

Cited by 16 publications

(28 citation statements)

References 29 publications

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“…Summer echoes in December, January, and February are mostly confined to altitudes of 80−90 km and are rarely seen outside this region, which is a well-known feature of PMSEs (e.g., Sato et al 2014Sato et al , 2017. Non-summer echoes between mid-March and mid-November are seen mostly at altitudes of 55−80 km, which is in line with the reported features of PMWEs over Syowa (Nishiyama et al 2015). Note that there are transient periods from summer to winter in March, and also from winter to summer in October and November, in which echoes are observed in both PMSE and PMWE height regions.…”

Section: Resultssupporting

confidence: 74%

“…The PANSY echoes are observed from 55 km to nearly 80 km, mostly during the daytime, with a somewhat anti-symmetric structure about the local noon slightly shifted to post-sunset hours. These features are basically the same as the findings of Nishiyama et al (2015). Note that low-altitude MF echoes below approximately 70 km exhibit a similar time and height dependence, although the PANSY data demonstrates its much higher range resolution, showing fine wave structures propagating downward with time.…”

Section: Resultssupporting

confidence: 73%

“…PANSY echoes reproduced reported results by Sato et al (2014Sato et al ( , 2017 and Nishiyama et al (2015): summer echoes (PMSEs) were mostly confined to the height region of 80−90 km, and winter echoes (PMWEs) were mostly below 80 km during the daytime and for a few extended hours after sunset. This somewhat asymmetric structure about the local noon in winter was also depicted in the MAARSY observations in the Arctic (Latteck and Strelnikova 2015) although not explicitly mentioned.…”

Section: Discussionsupporting

confidence: 70%

“…Supplement 1 provides monthly mean composite days of winter MF echo acquisition rates to compare with those of the PANSY PMWEs by Nishiyama et al (2015). In supplement 2, possible height offsets of MF echoes caused by the large off-vertical AOAs seen in Figure 4 are discussed.…”

Section: Acknowledgementsmentioning

confidence: 99%

“…Nevertheless, extensive radar studies have proposed various generation mechanisms of PMWEs, such as strong turbulence (Lübken et al 2007), infrasound waves (Kirkwood et al 2006), and meteor smoke particles that increase the Sc (La Hoz and Havnes 2008). Nishiyama et al (2015) recently reported height, local time, and seasonal dependence of PMWEs using the PANSY radar at Syowa Station (69°S, 40°E) in the Antarctic. In addition to MST radars, Medium Frequency (MF) radars also have a long history and have greatly contributed to the understanding of the polar mesosphere and lower thermosphere (e.g., Vincent 1994;Murphy et al 2009).…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of Mesosphere Echoes over Antarctica Obtained Using PANSY and MF Radars

Tsutsumi

Sato

et al. 2017

SOLA

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We investigated characteristics of mesosphere echoes over Syowa Station (69S) in the Antarctic, which were detected by the Program of the Antarctic Syowa Mesosphere, Stratosphere and Troposphere/Incoherent Scatter (PANSY) radar (47 MHz) and Medium Frequency (MF) radar (2.4 MHz). Winter echoes from the PANSY radar and low altitude MF echoes below approximately 70−75 km mostly coexisted, appearing during the daytime as well as for a few hours post sunset. Summer echoes in the lower height region were absent in both radar observations, suggesting a close relationship in the generation mechanisms of these two radar echoes. High correlation between local K-index and the occurrence of winter echoes suggested that electron density enhancement due to ionized particle precipitation was one of the triggers of echo generation. Angles of arrival of the MF echoes were more isotropic in winter. Because gravity wave activity is much higher in winter over Syowa, higher turbulence energy caused by gravity wave breaking may also be responsible for the generation of the winter echoes and their isotropic behavior. The horizontal wind velocities of the two systems were further compared and agreed well throughout the height region of 60−90 km.

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Section: Resultssupporting

confidence: 74%

Section: Resultssupporting

confidence: 73%

Section: Discussionsupporting

confidence: 70%

Section: Acknowledgementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characteristics of Mesosphere Echoes over Antarctica Obtained Using PANSY and MF Radars

Tsutsumi

Sato

et al. 2017

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Remote sensing of mesospheric dust layers using active modulation of PMWE by high‐power radio waves

et al. 2017

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This paper presents the first study of the modulation of polar mesospheric winter echoes (PMWE) by artificial radio wave heating using computational modeling and experimental observation in different radar frequency bands. The temporal behavior of PMWE response to HF pump heating can be employed to diagnose the charged dust layer associated with mesospheric smoke particles. Specifically, the rise and fall time of radar echo strength as well as relaxation and recovery time after heater turn‐on and turnoff are distinct parameters that are a function of radar frequency. The variation of PMWE strength with PMWE source region parameters such as electron‐neutral collision frequency, photodetachment current, electron temperature enhancement ratio, dust density, and radius is considered. The comparison of recent PMWE measurements at 56 MHz and 224 MHz with computational results is discussed, and dust parameters in the PMWE generation regime are estimated. Predictions for HF PMWE modification and its connection to the dust charging process by free electrons is investigated. The possibility for remote sensing of dust and plasma parameters in artificially modified PMWE regions using simultaneous measurements in multiple frequency bands are discussed.

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Quasi-12 h Inertia-Gravity Waves in the Lower Mesosphere Observed by the PANSY Radar at Syowa Station (39.6 °E, 69.0 °S)

Shibuya¹

2020

Dynamical Characteristics of Inertia-Gravity Waves in the Antarctic Mesosphere

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The first observations made by a complete PANSY radar system (Program of the Antarctic Syowa MST/IS Radar) installed at Syowa Station (39.6 • E, 69.0 • S) were successfully performed from 16 to 24 March 2015. Over this period, quasi-half-day period (12 h) disturbances in the lower mesosphere at heights of 70 to 80 km were observed. Estimated vertical wavelengths, wave periods and vertical phase velocities of the disturbances were approximately 13.7 km, 12.3 h and −0.3 m s −1 , respectively. Under the working hypothesis that such disturbances are attributable to inertiagravity waves, wave parameters are estimated using a hodograph analysis. The estimated horizontal wavelengths are longer than 1100 km, and the wavenumber vectors tend to point northeastward or southwestward. Using the nonhydrostatic numerical model with a model top of 87 km, quasi-12 h disturbances in the mesosphere were successfully simulated. We show that quasi-12 h disturbances are due to wavelike disturbances with horizontal wavelengths longer than 1400 km and are not due to semidiurnal migrating tides. Wave parameters, such as horizontal wavelengths, vertical wavelengths and wave periods, simulated by the model agree well with those estimated by the PANSY radar observations under the abovementioned assumption. The parameters of the simulated waves are consistent with the dispersion relationship of the inertia-gravity wave. These results indicate that the quasi-12 h disturbances observed by the PANSY radar are attributable to large-scale inertia-gravity waves. By examining a residual of the nonlinear balance equation, it is inferred that the inertia-gravity waves are likely generated by the spontaneous radiation mechanism of two different jet streams. One is the midlatitude tropospheric jet around the tropopause while the other is the polar night jet. Large vertical fluxes of zonal and meridional momentum associated with large-scale inertia-gravity waves are distributed across a slanted region from the midlatitude lower stratosphere to the polar mesosphere in the meridional cross section. Moreover, the vertical flux of the zonal momentum has a strong negative peak in the mesosphere, suggesting that some large-scale inertia-gravity waves originate in the upper stratosphere. IntroductionGravity waves are atmospheric waves with a restoring force of buoyancy that can transport momentum upward from the troposphere to the middle atmosphere (e.g., Fritts and Alexander, 2003). Momentum deposition by gravity waves in the mesosphere is a major driving force for the summerto-winter pole material circulation in the mesosphere (e.g., Plumb, 2002). Adiabatic heating and cooling associated with vertical flow branches of the circulation maintain the thermal structure, which is considerably different from the radiative equilibrium state. Gravity waves also play an essential role in driving the quasi-biennial oscillation (QBO) and semiannual oscillation in the equatorial stratosphere Haynes, 1998;Baldwin et al., 2003). In addition, it has been shown that gravity ...

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Height and time characteristics of seasonal and diurnal variations in PMWE based on 1 year observations by the PANSY radar (69.0°S, 39.6°E)

Cited by 16 publications

References 29 publications

Characteristics of Mesosphere Echoes over Antarctica Obtained Using PANSY and MF Radars

Characteristics of Mesosphere Echoes over Antarctica Obtained Using PANSY and MF Radars

Remote sensing of mesospheric dust layers using active modulation of PMWE by high‐power radio waves

Quasi-12 h Inertia-Gravity Waves in the Lower Mesosphere Observed by the PANSY Radar at Syowa Station (39.6 °E, 69.0 °S)

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