Middle atmosphere dynamical studies at Resolute Bay over a full representative year: Mean winds, tides, and special oscillations

Hocking, W. K.

doi:10.1029/2000rs001003

Cited by 31 publications

(41 citation statements)

References 64 publications

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“…Again however, the strong wind shear towards the upper height gates >92 km evident in the MWR observations tends to be much larger than those of MF observations. For example, the zonal winds over Resolute Bay (Hocking, 2001) from the MWR reach values as large as 25 m s −1 and the MWR at Esrange, presented here, reaches wind speeds of >35 m s −1 . In contrast the zonal winds at the same height and time in the MF radar studies are generally in the range 5-10 m s −1 .…”

Section: Discussionmentioning

confidence: 57%

“…Studies of mean winds in the Arctic MLT include those of Portnyagin et al (1992Portnyagin et al ( , 1993Portnyagin et al ( , 2004Portnyagin et al ( , 2006, Hocking (2001), Dowdy et al (2001Dowdy et al ( , 2007a, Hall et al (2003), Kishore et al (2003). Again, we will not consider further the studies of Portnyagin et al (1992) because they used meteor radar without height finding capability.…”

Section: Discussionmentioning

confidence: 99%

“…Nevertheless, in the Arctic MF and Meteor radars have been used to establish a limited number of simple climatologies of the zonal and meridional mean winds. These include the MF radar studies of Portnyagin et al (1992Portnyagin et al ( , 1993Portnyagin et al ( , 2004; Dowdy et al (2001Dowdy et al ( , 2007a; Hall et al (2003); Kishore et al (2003) and the meteor radar studies of Hocking (2001); Mitchell et al (2002); Hall et al (2003).…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of the Antarctic and Arctic mesosphere and lower thermosphere – Part 1: Mean winds

et al. 2010

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Abstract. Zonal and meridional winds have been measured in the upper mesosphere and lower thermosphere at polar latitudes using two ground-based meteor radars. One radar is located at Rothera (68 • S, 68 • W) in the Antarctic and has been operational since February 2005. The second radar is located at Esrange (68 • N, 21 • E) in the Arctic and has been operational since October 1999. Both radars have produced relatively continuous measurements. Here we consider measurements made up to the end of 2009. Both radars are of similar design and at conjugate geographical latitudes, making the results directly comparable and thus allowing investigation of the differences in the mean winds of the Antarctic and Arctic regions. The data from each radar have been used to construct climatologies of monthly-mean zonal and meridional winds at heights between 80 and 100 km. Both Antarctic and Arctic data sets reveal seasonally varying zonal and meridional winds in which the broad pattern repeats from year to year. In particular, the zonal winds display a strong shear in summer associated with the upper part of the westward summertime zonal jet. The winds generally reverse to eastward flow at heights of ∼90 km. The zonal winds are eastward throughout the rest of the year. The meridional winds are generally equatorward over both sites, although brief episodes of poleward flow are often evident near the equinoxes and during winter. The strongest equatorward flows occur at heights of ∼90 km during summer.There are significant differences between the mean winds observed in the Antarctic and Arctic. In particular, the westward winds in summer are stronger and occur earlier in the season in the Antarctic compared with the Arctic. The eastward winds evident above the summertime zonal wind reversal are significantly stronger in the Arctic. The summertime equatorward flow in the Antarctic is slightly weaker, but occurs over a greater depth than is the case in the Arctic.Correspondence to: D. J. Sandford (d.j.sandford@bath.ac.uk) Comparisons of these observations with those of the URAP and HWM-07 empirical models reveal a number of significant differences. In particular, the zonal winds observed in the Antarctic during wintertime are significantly weaker than those of URAP. However, the URAP zonal winds are a good match to the observations of the Arctic. Significant differences are evident between the observations and HWM-07. In particular, the strong wintertime zonal winds of the Arctic in HWM-07 are not evident in the observations and the summertime zonal winds in HWM-07 are systematically stronger than observed. The agreement with meridional winds is generally poor.There is a significant amount of inter-annual variability in the observed zonal and meridional winds. Particularly high variability is observed in the Arctic zonal winds in spring and is probably associated with stratospheric warmings.

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Section: Discussionmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dynamics of the Antarctic and Arctic mesosphere and lower thermosphere – Part 1: Mean winds

et al. 2010

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“…Large meridional winds have been reported in the summertime MLT at polar-latitudes (e.g., Hocking, 2001;Sandford et al, 2010), mid-latitudes (e.g., Manson and Meek, 1987;Hall et al, 2008;Roper and Berkey, 2011) and equatoriallatitudes (e.g., Rajaram and Gurubaran, 1998;Kishore et al, 2000;Sharma et al, 2010).…”

Section: K a Day Et Al: Mean Winds Temperatures And The 16-and 5-dmentioning

confidence: 99%

Mean winds, temperatures and the 16- and 5-day planetary waves in the mesosphere and lower thermosphere over Bear Lake Observatory (42° N, 111° W)

2012

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Abstract. Atmospheric temperatures and winds in the mesosphere and lower thermosphere have been measured simultaneously using the Aura satellite and a meteor radar at Bear Lake Observatory (42 • N, 111 • W), respectively. The data presented in this study is from the interval March 2008 to July 2011.The mean winds observed in the summer-time over Bear Lake Observatory show the meridional winds to be equatorward at meteor heights during April-August and to reach monthly-mean velocities of −12 m s −1 . The mean winds are closely related to temperatures in this region of the atmosphere and in the summer the coldest mesospheric temperatures occur about the same time as the strongest equatorward meridional winds. The zonal winds are eastward through most of the year and in the summer strong eastward zonal wind shears of up to ∼4.5 m s −1 km −1 are present. However, westward winds are observed at the upper heights in winter and sometimes during the equinoxes. Considerable inter-annual variability is observed in the mean winds and temperatures.Comparisons of the observed winds with URAP and HWM-07 reveal some large differences. Our radar zonal wind observations are generally more eastward than predicted by the URAP model zonal winds. Considering the radar meridional winds, in comparison to HWM-07 our observations reveal equatorward flow at all meteor heights in the summer whereas HWM-07 suggests that only weakly equatorward, or even poleward flows occur at the lower heights. However, the zonal winds observed by the radar and modelled by HWM-07 are generally similar in structure and strength.Signatures of the 16-and 5-day planetary waves are clearly evident in both the radar-wind data and Aura-temperature data. Short-lived wave events can reach large amplitudes of up to ∼15 m s −1 and 8 K and 20 m s −1 and 10 K for the 16-and 5-day waves, respectively. A clear seasonal and shortterm variability are observed in the 16-and 5-day planetary wave amplitudes. The 16-day wave reaches largest amplitude in winter and is also present in summer, but with smaller amplitudes. The 5-day wave reaches largest amplitude in winter and in late summer. An inter-annual variability in the amplitude of the planetary waves is evident in the four years of observations. Some 41 episodes of large-amplitude wave occurrence are identified. Temperature and wind amplitudes for these episodes, A T and A W , that passed the Student T-test were found to be related by, A T = 0.34 A W and A T = 0.62 A W for the 16-and 5-day wave, respectively.

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“…The respective temporal and vertical resolutions of this radar are typically 60 min and 2-3 km. More details on the radar have been published elsewhere (Hocking, 1996(Hocking, , 2001Buriti et al, 2008).…”

Section: Meteor Radarmentioning

confidence: 99%

Determination of gravity wave parameters in the airglow combining photometer and imager data

et al. 2018

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Abstract. Mesospheric airglow measurements of two or three layers were used to characterize both vertical and horizontal parameters of gravity waves. The data set was acquired coincidentally from a multi-channel filter (Multi-3) photometer and an all-sky imager located at São João do Cariri (7.4 • S, 36.5 • W) in the equatorial region from 2001 to 2007. Using a least-square fitting and wavelet analysis technique, the phase and amplitude of each observed wave were determined, as well as the amplitude growth. Using the dispersion relation of gravity waves, the vertical and horizontal wavelengths were estimated and compared to the horizontal wavelength obtained from the keogram analysis of the images observed by an all-sky imager. The results show that both horizontal and vertical wavelengths, obtained from the dispersion relation and keogram analysis, agree very well for the waves observed on the nights of 14 October and 18 December 2006. The determined parameters showed that the observed wave on the night of 18 December 2006 had a period of ∼ 43.8 ± 2.19 min, with the horizontal wavelength of 235.66 ± 11.78 km having a downward phase propagation, whereas that of 14 October 2006 propagated with a period of ∼ 36.00 ± 1.80 min with a horizontal wavelength of ∼ 195 ± 9.80 km, and with an upward phase propagation. The observation of a wave taken by a photometer and an allsky imager allowed us to conclude that the same wave could be observed by both instruments, permitting the investigation of the two-dimensional wave parameter.

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Middle atmosphere dynamical studies at Resolute Bay over a full representative year: Mean winds, tides, and special oscillations

Cited by 31 publications

References 64 publications

Dynamics of the Antarctic and Arctic mesosphere and lower thermosphere – Part 1: Mean winds

Dynamics of the Antarctic and Arctic mesosphere and lower thermosphere – Part 1: Mean winds

Mean winds, temperatures and the 16- and 5-day planetary waves in the mesosphere and lower thermosphere over Bear Lake Observatory (42° N, 111° W)

Determination of gravity wave parameters in the airglow combining photometer and imager data

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