The wind regime of the mesosphere and lower thermosphere during the DYANA campaign—I. Prevailing winds

Singer, W.; Hoffmann, P.; Manson, A. H.; Meek, C. E.; Schminder, R.; Kürschner, D.; Kokin, G. A.; Knyazev, A. K.; Portnyagin, Yu. I.; Makarov, N. M.; Fakhrutdinova, A. N.; Сидоров, В. В.; Cevolani, G.; Müller, Heinz; Kazimirovsky, E. S.; Gaidukov, V. A.; Clark, Ronald; Chebotarev, R. P.; Karadjaev, Y.

doi:10.1016/0021-9169(94)90006-x

“…However, some stratospheric warming events occur similarly strong or even stronger at mid-than at high latitudes. During the DYANA campaign in 1990, for example, Cevolani (1991) and Singer et al (1994) found a strong perturbation of the zonal wind between the upper stratosphere and lower thermosphere at mid-latitudes which was in some cases similarly strong compared to higher latitudes (see Singer et al, 1994). A more current event was studied by Stober et al (2012) where a stronger wind reversal was observed at mid-than at high latitudes during the SSW event of 2010.…”

Section: Introductionmentioning

confidence: 96%

“…A large number of studies describe the individual response of SSWs on the middle atmosphere regarding the dynamical and thermal structure, especially of the record warming in 2009, e.g. Manney et al (2009), Kurihara et al (2010) and Shepherd et al (2009).…”

Section: Introductionmentioning

confidence: 99%

The impact of planetary waves on the latitudinal displacement of sudden stratospheric warmings

Matthias

¹

,

Hoffmann

²

,

Manson

³

et al. 2013

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The Northern Hemispheric winter is disturbed by large scale variability mainly caused by Planetary Waves (PWs), which interact with the mean flow and thus result in Sudden Stratospheric Warmings (SSWs). The effects of a SSW on the middle atmosphere are an increase of stratospheric and a simultaneous decrease of mesospheric temperature as well as a wind reversal to westward wind from the mesosphere to the stratosphere. In most cases these disturbances are strongest at polar latitudes, get weaker toward the south and vanish at mid-latitudes around 50° to 60° N as for example during the winter 2005/06. However, other events like in 2009, 2010 and 2012 show a similar or even stronger westward wind at mid- than at polar latitudes either in the mesosphere or in the stratosphere during the SSW. This study uses local meteor and MF-radar measurements, global satellite observations from the Microwave Limb Sounder (MLS) and assimilated model data from MERRA (Modern-ERA Retrospective analysis for research and Applications). We compare differences in the latitudinal structure of the zonal wind, temperature and PW activity between a "normal" event, where the event in 2006 was chosen representatively, and the latitudinal displaced events in 2009, 2010 and 2012. A continuous westward wind band between the pole and 20° N is observed during the displaced events. Furthermore, distinctive temperature differences at mid-latitudes occur before the displaced warmings compared to 2006 as well as a southward extended stratospheric warming afterwards. These differences between the normal SSW in 2006 and the displaced events in 2009, 2010 and 2012 are linked to an increased PW activity between 30° N and 50° N and the changed stationary wave flux in the stratosphere around the displaced events compared to 2006

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“…A similar connection with stratospheric processes was noted by Pancheva and Mukhtarov (1994), who related wave activity at MLT heights to the presence of a strongly ampli®ed planetary wave number 1 at the 30 hPa pressure level during the winter 1991/1992. Portnyagin et al (1994) also examined the DYANA campaign data used by Singer et al (1994) and concluded that the signi®cant di erences observed between monthly mean tidal parameters measured by the various radars could be explained by latitudinal and longitudinal structure in the tidal wind ®elds. In addition, well-de®ned¯uctuations in tidal parameters over periods of 2±3 weeks were found to be typical of all the observational sites.…”

Section: Introductionmentioning

confidence: 99%

A comparative study of winds and tidal variability in the mesosphere/lower-thermosphere region over Bulgaria and the UK

Pancheva

¹

,

Mukhtarov

²

,

Mitchell

³

et al. 2000

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Abstract. Meteor radars located in Bulgaria and the UK have been used to simultaneously measure winds in the mesosphere/lower-thermosphere region near 42.5°N, 26.6°E and 54.5°N, 3.9°W, respectively, over the period January 1991 to June 1992. The data have been used to investigate planetary waves and diurnal and semidiurnal tidal variability over the two sites. The tidal amplitudes at each site exhibit¯uctuations as large as 300% on time scales from a few days to the intra-seasonal, with most of the variability being at intra-seasonal scales. Spectral and cross-wavelet analysis reveals closely related tidal variability over the two sites, indicating that the variability occurs on spatial scales large compared to the spacing between the two radars. In some, but not all, cases, periodic variability of tidal amplitudes is associated with simultaneously present planetary waves of similar period, suggesting the variability is a consequence of non-linear interaction. Calculation of the zonal wave number of a number of large amplitude planetary waves suggests that during summer 1991 the 2-day wave had a zonal wave number of 3, but that during January±February 1991 it had a zonal wave number of 4.

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“…For example, Singer et al (1994) examined data from 14 radars recorded during the DYANA campaign of January 15 to March 15, 1990 and reported clear longitudinal di erences between the prevailing winds over Canada, Central Europe, Eastern Europe and Asia. These authors also noted a close connection between the circulation of the stratosphere and the observed longitudinal structure in the MLT-region response to stratospheric warming events.…”

Section: Introductionmentioning

confidence: 99%

A comparative study of winds and tidal variability in the mesosphere/lower-thermosphere region over Bulgaria and the UK

Pancheva

¹

,

Mukhtarov

²

,

Mitchell

³

et al. 2000

Annales Geophysicae

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Abstract. Meteor radars located in Bulgaria and the UK have been used to simultaneously measure winds in the mesosphere/lower-thermosphere region near 42.5°N, 26.6°E and 54.5°N, 3.9°W, respectively, over the period January 1991 to June 1992. The data have been used to investigate planetary waves and diurnal and semidiurnal tidal variability over the two sites. The tidal amplitudes at each site exhibit¯uctuations as large as 300% on time scales from a few days to the intra-seasonal, with most of the variability being at intra-seasonal scales. Spectral and cross-wavelet analysis reveals closely related tidal variability over the two sites, indicating that the variability occurs on spatial scales large compared to the spacing between the two radars. In some, but not all, cases, periodic variability of tidal amplitudes is associated with simultaneously present planetary waves of similar period, suggesting the variability is a consequence of non-linear interaction. Calculation of the zonal wave number of a number of large amplitude planetary waves suggests that during summer 1991 the 2-day wave had a zonal wave number of 3, but that during January±February 1991 it had a zonal wave number of 4.

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The wind regime of the mesosphere and lower thermosphere during the DYANA campaign—I. Prevailing winds

Cited by 28 publications

References 2 publications

The impact of planetary waves on the latitudinal displacement of sudden stratospheric warmings

The impact of planetary waves on the latitudinal displacement of sudden stratospheric warmings

A comparative study of winds and tidal variability in the mesosphere/lower-thermosphere region over Bulgaria and the UK

A comparative study of winds and tidal variability in the mesosphere/lower-thermosphere region over Bulgaria and the UK

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