Can VHF radars at polar latitudes measure mean vertical winds in the presence of PMSE?

Gudadze, Nikoloz; Stober, Gunter; Chau, Jorge L.

doi:10.5194/acp-19-4485-2019

Cited by 20 publications

(35 citation statements)

References 52 publications

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“…At midlatitudes and high latitudes, semidiurnal tides are the dominating tidal wave during the course of the year (Hagan and Forbes, 2002Forbes, , 2003. Figure 5 shows the vectoraveraged semidiurnal tidal amplitudes measured by all six meteor radars using again a 30 d median shifted by 1 d in analogy to the mean winds and diurnal tides.…”

Section: Semidiurnal Tidal Amplitudes and Phases Measured During 2019mentioning

confidence: 99%

Seasonal evolution of winds, atmospheric tides, and Reynolds stress components in the Southern Hemisphere mesosphere–lower thermosphere in 2019

et al. 2021

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Abstract. In this study we explore the seasonal variability of the mean winds and diurnal and semidiurnal tidal amplitude and phases, as well as the Reynolds stress components during 2019, utilizing meteor radars at six Southern Hemisphere locations ranging from midlatitudes to polar latitudes. These include Tierra del Fuego, King Edward Point on South Georgia island, King Sejong Station, Rothera, Davis, and McMurdo stations. The year 2019 was exceptional in the Southern Hemisphere, due to the occurrence of a rare minor stratospheric warming in September. Our results show a substantial longitudinal and latitudinal seasonal variability of mean winds and tides, pointing towards a wobbling and asymmetric polar vortex. Furthermore, the derived momentum fluxes and wind variances, utilizing a recently developed algorithm, reveal a characteristic seasonal pattern at each location included in this study. The longitudinal and latitudinal variability of vertical flux of zonal and meridional momentum is discussed in the context of polar vortex asymmetry, spatial and temporal variability, and the longitude and latitude dependence of the vertical propagation conditions of gravity waves. The horizontal momentum fluxes exhibit a rather consistent seasonal structure between the stations, while the wind variances indicate a clear seasonal behavior and altitude dependence, showing the largest values at higher altitudes during the hemispheric winter and two variance minima during the equinoxes. Also the hemispheric summer mesopause and the zonal wind reversal can be identified in the wind variances.

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Section: Semidiurnal Tidal Amplitudes and Phases Measured During 2019mentioning

confidence: 99%

Seasonal evolution of winds, atmospheric tides, and Reynolds stress components in the Southern Hemisphere mesosphere–lower thermosphere in 2019

et al. 2021

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“…According to these research results, it can be seen that the tidal amplitude in the vertical wind in the 65–85 km heights is smaller than that in higher altitudes (above 90 km) and may not exceed the mean vertical wind. Furthermore, Gudadze et al (2019) showed that there was no significant diurnal variation in the vertical wind observed with the PMSEs which exist all day in summer at high latitude. Eswaraiah et al (2011) stated that the effect of the diurnal and semidiurnal tidal amplitude is smaller at the mesospheric altitudes compared with those at higher altitudes (~85 km).…”

Section: Resultsmentioning

confidence: 96%

“…These correlations arise from the turbulence and gravity wave motion and can lead to the downward biases in the measured mean vertical velocity. Gudadze et al (2019) further studied these correlations with the long-term observations of the PMSEs by the MAARSY radar. However, they have found the contrary results, that is the negative correlation between the downward vertical wind and the velocity uncertainties.…”

Section: 1029/2020jd032776mentioning

confidence: 99%

“…6°N, 19.2°E), Hoppe and Fritts (1995) observed the vertical wind velocity under the Polar Mesopause Summer Echo (PMSE) conditions and noticed that the vertical motions exhibited the maximum amplitudes of~2 to 3 m/s. Recently, Gudadze et al (2019) used the MAARSY radar (69. 30°N, 16.04°E) to observe the MVWs with the PMSEs in two summer seasons, and the measured wind velocities were between ±1 m/s.…”

Section: Introductionmentioning

confidence: 99%

“…With the European Incoherent SCATter (EISCAT) VHF radar (69.6°N, 19.2°E), Hoppe and Fritts (1995) observed the vertical wind velocity under the Polar Mesopause Summer Echo (PMSE) conditions and noticed that the vertical motions exhibited the maximum amplitudes of ~2 to 3 m/s. Recently, Gudadze et al (2019) used the MAARSY radar (69.30°N, 16.04°E) to observe the MVWs with the PMSEs in two summer seasons, and the measured wind velocities were between ±1 m/s. They indicated that the mean vertical velocities are not dependent on both PMSE strength and local time, and showed the expected upward motion in the central region of the PMSE layer.…”

Section: Introductionmentioning

confidence: 99%

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Statistical Study of the Midlatitude Mesospheric Vertical Winds Observed by the Wuhan and Beijing MST Radars in China

et al. 2020

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Based on the long-term observations of the Wuhan and Beijing Mesosphere-Stratosphere-Troposphere (MST) radars, the statistic characteristics of the mesospheric vertical winds at midlatitudes are investigated for the first time. The vertical wind data come from the Wuhan MST radar (29.51°N, 114.13°E) during 2012-2017 and from the Beijing MST radar (39.75°N, 116.96°E) during 2012-2014. The subdaily, seasonal, and annual variations of the mesospheric vertical winds at Wuhan and Beijing are presented. No obvious subdaily and seasonal variations are found and the annual variations of the mean vertical winds are downward in most of time. The mean vertical winds at Wuhan become smaller in summer and turn to upward at some heights, while those of Beijing only become smaller in summer. The difference of summer vertical winds over Wuhan and Beijing is closely related to the gravity wave activity. The Wuhan MST radar is located to the east side of the Qinghai-Tibet plateau and also in the East Asian monsoon region, thus the mesospheric winds over Wuhan may experience more influence of gravity waves compared with those over Beijing. The possible bias sources in the vertical wind measurement of the two MST radars are carefully analyzed and the presented wind velocities are proved to be credible. The measured velocity magnitude is similar to other Very High Frequency radar observations, but much larger than that of the WACCM simulation. The Stokes drift, multicellular circulation structures, the wave influence on the radar echoes are raised as the potential sources for this discrepancy.

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Radar observation of extreme vertical drafts in the polar summer mesosphere

Chau

Marino

Feraco

et al. 2021

Preprint

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The polar summer mesosphere is the Earth's coldest region, allowing the formation of mesospheric ice clouds. These ice clouds produce strong polar mesospheric summer echoes (PMSE) that are used as tracers of mesospheric dynamics. Here, we report the first observations of extreme vertical drafts (50 1 ms  ) in the mesosphere obtained from PMSE, characterized by velocities more than five standard deviations larger than the observed vertical wind variability. Using aperture synthesis radar imaging, the observed PMSE morphology resembles a solitary wave in a varicose mode, narrow along propagation (3-4 km) and elongated ( 10 km) transverse to propagation direction, with a relatively large vertical extent (13 km). These spatial features are similar to previously observed mesospheric bores, but we observe only one crest with much larger vertical extent and higher vertical velocities.Plain Language Summary Extreme events are ubiquitous in geophysical flows. Examples of these events are tornadoes and rogue waves in the lower atmosphere and oceans, respectively. In the mesosphere, the boundary of Earth's atmosphere and outer space, extreme events can also occur, although this region is poorly observed. Here, we present the first observations of extreme vertical velocities (50 1 ms  ) in the mesosphere, that are more than five times their expected standard deviation. These observations are possible by tracking and imaging strong mesospheric radar echoes that occur in the summer at polar latitudes, with a radar used in a radio camera mode. The morphology of our observations resembles previously observed instabilities called bores or wave walls, but with much larger vertical velocities and vertical extents.

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Can VHF radars at polar latitudes measure mean vertical winds in the presence of PMSE?

Cited by 20 publications

References 52 publications

Seasonal evolution of winds, atmospheric tides, and Reynolds stress components in the Southern Hemisphere mesosphere–lower thermosphere in 2019

Seasonal evolution of winds, atmospheric tides, and Reynolds stress components in the Southern Hemisphere mesosphere–lower thermosphere in 2019

Statistical Study of the Midlatitude Mesospheric Vertical Winds Observed by the Wuhan and Beijing MST Radars in China

Radar observation of extreme vertical drafts in the polar summer mesosphere

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