Seasonal variations in the horizontal wind structure from 0-100 km above Rothera station, Antarctica (67° S, 68° W)

Hibbins, R. E.; Shanklin, J. D.; Espy, P. J.; Jarvis, M. J.; Riggin, D. M.; Fritts, D. C.; Lübken, Franz‐Josef

doi:10.5194/acp-5-2973-2005

Cited by 23 publications

(25 citation statements)

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“…Studies of mean winds in the Antarctic MLT include those of Portnyagin et al (1992Portnyagin et al ( , 1993Portnyagin et al ( , 2006, Vincent (1994), Dowdy et al (2001Dowdy et al ( , 2007a, Kishore et al (2003), Hibbins et al (2005), Merzlyakov et al (2009). Here, we will not consider further the studies of Portnyagin et al (1992), Merzlyakov et al (2009) because they used meteor radars without height-finding capability and so reported winds that are averages across the meteor region, rather than revealing the vertical structure of the winds.…”

Section: Discussionmentioning

confidence: 99%

“…The possibility of discrepancies highlight the importance of the meteor radar technique in measuring MLT winds above 85-90 km. Hibbins et al (2005) used a combination of MF radar, falling sphere, radiosonde and model data to build up a climatology of zonal mean winds between 0 and 100 km above Rothera (67 • S, 68 • W). The MF radar is located at the same site as the MWR used here.…”

Section: Discussionmentioning

confidence: 99%

“…Here, we will not consider further the studies of Portnyagin et al (1992), Merzlyakov et al (2009) because they used meteor radars without height-finding capability and so reported winds that are averages across the meteor region, rather than revealing the vertical structure of the winds. Portnyagin et al (1993Portnyagin et al ( , 2006, Vincent (1994), Dowdy et al (2001Dowdy et al ( , 2007a, Kishore et al (2003), Hibbins et al (2005) used selections of MF and Meteor radars at: Syowa (69…”

Section: Discussionmentioning

confidence: 99%

“…This is largely because of the difficulty in operating ground-based radars for extended intervals in Antarctica. Despite these difficulties, MF and meteor radars have been used to measure the seasonal variability of MLT region mean winds in the Antarctic in a limited number of studies (e.g., Portnyagin et al, 1992Portnyagin et al, , 1993Vincent, 1994;Dowdy et al, 2001Dowdy et al, , 2007aKishore et al, 2003;Hibbins et al, 2005;Baumgaertner et al, 2005;Merzlyakov et al, 2009).…”

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: 99%

Section: Discussionmentioning

confidence: 99%

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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“…borne radiosondes provide detailed wind measurements in the troposphere and lower stratosphere (e.g. Hibbins et al, 2005). Rockets can deploy falling targets tracked by radar (Müllemann and Lübken, 2005), or chemical tracers (Chu et al, 2007), but such campaigns are expensive and unsuitable for long-term monitoring.…”

Section: Introductionmentioning

confidence: 99%

Simulation study for measurement of horizontal wind profiles in the polar stratosphere and mesosphere using ground-based observations of ozone and carbon monoxide lines in the 230–250 GHz region

Newnham¹,

Ford²,

Moffat‐Griffin³

et al. 2016

Atmos. Meas. Tech.

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Abstract. Meteorological and atmospheric models are being extended up to 80 km altitude but there are very few observing techniques that can measure stratospheric-mesospheric winds at altitudes between 20 and 80 km to verify model datasets. Here we demonstrate the feasibility of horizontal wind profile measurements using ground-based passive millimetre-wave spectroradiometric observations of ozone lines centred at 231.28, 249.79, and 249.96 GHz. Vertical profiles of horizontal winds are retrieved from forward and inverse modelling simulations of the line-of-sight Dopplershifted atmospheric emission lines above Halley station (75 • 37 S, 26 • 14 W), Antarctica. For a radiometer with a system temperature of 1400 K and 30 kHz spectral resolution observing the ozone 231.28 GHz line we estimate that 12 h zonal and meridional wind profiles could be determined over the altitude range 25-74 km in winter, and 28-66 km in summer. Height-dependent measurement uncertainties are in the range 3-8 m s −1 and vertical resolution ∼ 8-16 km. Under optimum observing conditions at Halley a temporal resolution of 1.5 h for measuring either zonal or meridional winds is possible, reducing to 0.5 h for a radiometer with a 700 K system temperature. Combining observations of the 231.28 GHz ozone line and the 230.54 GHz carbon monoxide line gives additional altitude coverage at 85 ± 12 km. The effects of clear-sky seasonal mean winter/summer conditions, zenith angle of the received atmospheric emission, and spectrometer frequency resolution on the altitude coverage, measurement uncertainty, and height and time resolution of the retrieved wind profiles have been determined.

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Observations of nitric oxide in the Antarctic middle atmosphere during recurrent geomagnetic storms

et al. 2013

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[1] We report ground-based measurements of the polar middle atmosphere made using a 230-250 GHz passive microwave radiometer deployed at Troll station (72°01′S 02°32′E, L shell of L = 4.8), Antarctica. Our observations show enhanced mesospheric nitric oxide (NO) volume mixing ratio (VMR) during a series of small recurrent geomagnetic storms in the 2008 austral winter, reaching 1.2 ppmv on day 200 (18 July). The Lomb normalized periodogram of the NO VMR time series averaged over 65-80 km for days 130 to 220 of 2008 (9 May to 7 August) shows a peak exceeding the 95% confidence limit at 25.8 days, close to the synodic rotation period for low-latitude solar coronal holes. The highest correlations between the radiometer NO VMR data and trapped and quasi-trapped electron count rates for L = 3.5-5.5 from the Polar Orbiting Environment Satellites 90°telescope are for the >30 keV (90e1) channel (r max = 0.56, lag time of 5.1 days) and >100 keV (90e2) channel (r max = 0.57, lag time of 4.4 days). Maximum correlation between NO VMR and the >700 keV (90P6) channel data is lower but lag times are close to zero. Superposed epoch analyses for the eight most significant geomagnetic storm periods and three Carrington rotations (2070)(2071)(2072) within the 90 day observation period indicate that significant NO abundance observed at 65-80 km in the Antarctic mesosphere may be produced directly by >200 keV electron precipitation or originate from a source at higher altitudes, e.g., production by >30 keV electrons followed by downward transport.

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Seasonal variations in the horizontal wind structure from 0-100 km above Rothera station, Antarctica (67° S, 68° W)

Cited by 23 publications

References 26 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

Simulation study for measurement of horizontal wind profiles in the polar stratosphere and mesosphere using ground-based observations of ozone and carbon monoxide lines in the 230–250 GHz region

Observations of nitric oxide in the Antarctic middle atmosphere during recurrent geomagnetic storms

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Seasonal variations in the horizontal wind structure from 0-100 km above Rothera station, Antarctica (67° S, 68° W)

Cited by 23 publications

References 26 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

Simulation study for measurement of horizontal wind profiles in the polar stratosphere and mesosphere using ground-based observations of ozone and carbon monoxide lines in the 230–250 GHz region

Observations of nitric oxide in the Antarctic middle atmosphere during recurrent geomagnetic storms

Contact Info

Product

Resources

About

Simulation study for measurement of horizontal wind profiles in the polar stratosphere and mesosphere using ground-based observations of ozone and carbon monoxide lines in the 230–250 GHz region