Large-scale planetary disturbances in stratospheric temperature at high-latitudes in the southern summer hemisphere

Shepherd, M. G.; Tsuda, Toshitaka

doi:10.5194/acp-8-7557-2008

Cited by 22 publications

(22 citation statements)

References 75 publications

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“…While, as usual, no SSWs occurred in the Southern Hemisphere during these years, significant interannual variability in wave activity is noted. In particular, a large amount of eastward wave activity is present during spring 2006, lasting until December, as previously reported by Shepherd and Tsuda (2008). This amount of travelling wave activity was not observed so late in the following two seasons, although the E1 waves were stronger earlier during the 2007 and 2008 springs.…”

Section: Southern Hemisphere Planetary Wave Activitysupporting

confidence: 83%

“…The launch of the Constellation Observing System for Meteorology, Ionosphere and Climate Global Positioning System Radio Occultation (COS-MIC GPS-RO) satellites in April 2006 has resulted in about 2000 profiles per day (Anthes et al, 2008) fully distributed about the globe in longitude and local time, making them ideal for global scale wave studies (Alexander et al, 2008b). COSMIC data were used to show large planetary wave activity in the 2006 Antarctic early summer, more consistent with winter-time activity (Shepherd and Tsuda, 2008). COSMIC data are also dense enough to quantify changes in gravity wave activity over short time scales (on the order of several days) and were used to study gravity wave activity associated with recent Arctic SSWs Wang and Alexander, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Planetary wave activity in the polar lower stratosphere

Alexander

Shepherd

2010

Atmos. Chem. Phys.

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Abstract. Temperature data from the COSMIC GPS-RO satellite constellation are used to study the distribution and variability of planetary wave activity in the low to midstratosphere (15-40 km) of the Arctic and Antarctic from September 2006 until March 2009. Stationary waves are separated from travelling waves and their amplitudes, periods and small-scale vertical distribution then examined. COS-MIC observed short lived (less than two weeks and less than 5 km vertically) but large enhancements in planetary wave amplitudes occurring regularly throughout all winters in both hemispheres. In contrast to recent Arctic winters, eastward wave activity during 2008-2009 was significantly reduced during the early part of the winter and immediately prior to the major SSW. The eastward waves which did exist had similar periods to the two preceding winters (∼ 16-20 days). A westward wave with zonal wavenumber two, with distinct peaks at 22 km and 35 km and period around 16-24 days, as well as a stationary wave two were associated with the 2009 major SSW. In the Southern Hemisphere, the height structure of planetary wave amplitudes also exhibited fluctuations on short time and vertical scales superimposed upon the broader seasonal cycle. Significant inter-annual variability in planetary wave amplitude and period are noticed, with the times of cessation of significant activity also varying.

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Section: Southern Hemisphere Planetary Wave Activitysupporting

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Planetary wave activity in the polar lower stratosphere

Alexander

Shepherd

2010

Atmos. Chem. Phys.

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“…[5] Observational studies of these waves can be separated into research which examines the characteristics of these motions using ground-based [Espy et al, 1997;Mitchell et al, 1999;Espy et al, 2005;Murphy et al, 2006;Hibbins et al, 2009] and satellite-based instruments [Wu et al, 1995;Limpasuvan et al, 2005;Shepherd and Tsuda, 2008;Limpasuvan and Wu, 2009]. A number of studies have also examined these waves in meteorological analyses and reanalyses data sets [Fedulina et al, 2004;Madden, 2007].…”

Section: Introductionmentioning

confidence: 99%

Properties of the quasi 16 day wave derived from EOS MLS observations

McDonald¹,

Hibbins²,

Jarvis³

2011

J. Geophys. Res.

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[1] This paper describes the use of EOS Microwave Limb Sounder (MLS) data to observe the field of traveling planetary waves with quasi 16 day periods. This study utilizes MLS v2.2 temperature and geopotential data between 1 January 2005 and 31 December 2008 in the range 316 hPa to 0.001 hPa (approximately 8 to 97 km) to examine these waves. Analysis demonstrates that the quasi 16 day wavefield is made up of a number of components with westward and eastward propagating s = 1 and s = 2 waves generally dominant. In the Northern Hemisphere the westward and eastward propagating s = 1 waves have similar magnitudes and are larger than the other modes, while in the Southern Hemisphere, the eastward propagating s = 1 and s = 2 waves are larger than the westward propagating wave modes. All of the modes examined display strong seasonal patterns in the temperature amplitude, significant variability in the wave activity from year to year, and the presence of strong pulse-like patterns in the activity. All of the modes also display large median temperature amplitudes poleward of 40 degrees in both hemispheres. Our analysis also demonstrates that the variability in winter from year to year is larger in the Northern Hemisphere than the Southern Hemisphere. Detailed study also suggests that the exclusion of waves from regions of negative refractive index squared likely forms much of the seasonal pattern observed. Thus, regions of strong westward wind speeds effectively exclude vertically propagating waves as expected from theory. The reflection and absorption of waves associated with critical lines is also likely to explain the frequent occurrence of standing wave patterns in the EOS MLS temperature observations. This study highlights the potential of MLS observations for observing waves from the upper troposphere to the lower mesosphere.

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“…A previous study from a southern hemispheric midlatitude station, Grahamstown (33.3 • S, 26.5 • W), Malinga and Poole (2002) reported strong QSDW activity in winter stratosphere due to a strong westerly jet. Using satellitebased observations, Shepherd and Tsuda (2008) reported a strong eastward 16-day wave coupling with the quasistationary waves of zonal wave number 1 and 2 at Antarctic latitudes.…”

Section: Discussionmentioning

confidence: 99%

Latitudinal variability of the quasi-16-day wave in the middle atmosphere over Brazilian stations

et al. 2016

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Abstract.A comparative study of the quasi-16-day wave (QSDW) in the middle atmosphere using meteor radar observations and reanalysis data from three Brazilian stations, Sao Joao do Cariri (7.4 • S, 36.5 • W) (CA), Cachoeira Paulista (22.7 • S, 45 • W) (CP), and Santa Maria (29.7 • S, 53.7 • W) (SM) has been carried out in the year 2005 to delineate its latitudinal variability characteristics. The broad spectral behavior around 16-day periodicity may indicate multiple modes of the concerned wave component. The wave amplitude shows a number of peaks over the year with the largest one in summer and winter in the case of mesosphere-lower thermosphere (MLT) and stratosphere, respectively. A potential coupling of the concerned wave with other short period planetary waves, especially at CA and CP is evinced. Although zonal propagation exhibits both eastward as well as westward waves there is a general preference of eastward waves at mid-latitude and westward waves at tropical latitudes. The prevailing westerly background wind in the middle atmosphere is conceived to favor the wave filtering of westward propagating Rossby waves at lower latitude.

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Large-scale planetary disturbances in stratospheric temperature at high-latitudes in the southern summer hemisphere

Cited by 22 publications

References 75 publications

Planetary wave activity in the polar lower stratosphere

Planetary wave activity in the polar lower stratosphere

Properties of the quasi 16 day wave derived from EOS MLS observations

Latitudinal variability of the quasi-16-day wave in the middle atmosphere over Brazilian stations

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