Circulation changes in the stratosphere and mesosphere during the stratospheric sudden warming event in January 2009

Iida, C.; Hirooka, Toshihiko; Eguchi, Nawo

doi:10.1002/2013jd021252

Cited by 35 publications

(63 citation statements)

References 19 publications

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“…In a model study, Siskind et al (2010) discussed the possible in situ generation of SPWs in the mesosphere via a combination of forcing from below and in situ instability. The in situ generation of SPWs by instabilities in the lower mesosphere was confirmed by Iida et al (2014) using satellite observations.…”

Section: Introductionmentioning

confidence: 69%

“…This indicates in situ generation of SPWs by instabilities (Siskind et al, 2010). Furthermore, similarly to Iida et al (2014) the stratospheric PNJ and the mesospheric subtropical jet were intensified, conceivably bringing about instabilities in the mesosphere, and hence the possibility of the generation of SPWs in the mesosphere.…”

Section: Why Does the Spw 2 Dominate In Period Ii?mentioning

confidence: 83%

“…7b). Iida et al (2014) showed that instabilities forming SPWs might be brought about by an intensification of the PNJ in the strato- sphere and the subtropical westerly jet in the mesosphere, which is the case in Period I (cf. Fig.…”

Section: Why Does the Spw 2 Dominate In Period Ii?mentioning

confidence: 99%

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On the origin of the mesospheric quasi-stationary planetary waves in the unusual Arctic winter 2015/2016

Matthias

Ern²

2018

Atmos. Chem. Phys.

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Abstract. The midwinter 2015/2016 was characterized by an unusually strong polar night jet (PNJ) and extraordinarily large stationary planetary wave (SPW) amplitudes in the subtropical mesosphere. The aim of this study is, therefore, to find the origin of these mesospheric SPWs in the midwinter 2015/2016 study period. The study duration is split into two periods: the first period runs from late December 2015 until early January 2016 (Period I), and the second period from early January until mid-January 2016 (Period II). While the SPW 1 dominates in the subtropical mesosphere in Period I, it is the SPW 2 that dominates in Period II. There are three possibilities explaining how SPWs can occur in the mesosphere: (1) they propagate upward from the stratosphere, (2) they are generated in situ by longitudinally variable gravity wave (GW) drag, or (3) they are generated in situ by barotropic and/or baroclinic instabilities. Using global satellite observations from the Microwave Limb Sounder (MLS) and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) the origin of the mesospheric SPWs is investigated for both time periods. We find that due to the strong PNJ the SPWs were not able to propagate upward into the mesosphere northward of 50 • N but were deflected upward and equatorward into the subtropical mesosphere. We show that the SPWs observed in the subtropical mesosphere are the same SPWs as in the mid-latitudinal stratosphere. Simultaneously, we find evidence that the mesospheric SPWs in polar latitudes were generated in situ by longitudinally variable GW drag and that there is a mixture of in situ generation by longitudinally variable GW drag and by instabilities at mid-latitudes. Our results, based on observations, show that the abovementioned three mechanisms can act at the same time which confirms earlier model studies. Additionally, the possible contribution from, or impact of, unusually strong SPWs in the subtropical mesosphere to the disruption of the quasi-biennial oscillation (QBO) in the same winter is discussed.

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Section: Introductionmentioning

confidence: 69%

Section: Why Does the Spw 2 Dominate In Period Ii?mentioning

confidence: 83%

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On the origin of the mesospheric quasi-stationary planetary waves in the unusual Arctic winter 2015/2016

Matthias

Ern²

2018

Atmos. Chem. Phys.

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“…Iida et al (2014) showed instabilities forming SPWs might be brought about by an intensification of the PNJ in the stratosphere and the subtropical westerly jet in the mesosphere which is the case in Period I (cf. Fig.…”

mentioning

confidence: 95%

On the origin of the mesospheric quasi-stationary planetary waves in the unusual Arctic winter 2015/16

Matthias¹,

Ern²

2017

Preprint

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Abstract. The mid winter 2015/16 was characterized by an unusually strong polar night jet (PNJ) and by extraordinarily large stationary planetary wave (SPW) amplitudes in the subtropical mesosphere. The aim of this study is to find the origin of these mesospheric SPWs in mid winter 2015/16. The time period studied here is split into two periods. The first period runs from late December 2015 until early January 2016 and the second period from early January until mid January 2016.While the SPW 1 dominates in the subtropical mesosphere in Period I, it is the SPW 2 that dominates in Period II. There are 5 three possibilities how SPWs can occur in the mesosphere: 1) they propagate upward from the stratosphere, 2) they are in situ generated by longitudinally variable gravity wave (GW) drag, or 3) they are in situ generated by barotropic and/or baroclinic instabilities. Using global satellite observations from the Microwave Limb Sounder (MLS) and from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) the origin of the mesospheric SPWs is investigated for both time periods. We found that due to the strong PNJ the SPWs were not able to propagate upward into the mesosphere northward 10 of 50• N but were deflected upward and equatorward into the subtropical mesosphere. We show that the SPWs observed in the subtropical mesosphere are the same SPWs as in the mid-latitudinal stratosphere. At the same time we found evidence that the mesospheric SPWs in polar latitudes were in situ generated by longitudinally variable GW drag and that there is a mixture of in situ generation by longitudinally variable GW drag and by instabilities in mid latitudes. Our results based on observations show that every three mechanisms, upward propagating SPW and in situ generated SPWs by longitudinally variable GW drag 15 and instabilities can act at the same time which confirms earlier model studies. Additionally, a possible contribution or impact of the unusually strong SPWs in the subtropical mesosphere to the disruption of the QBO in the same winter is discussed.

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“…It has been suggested that the MASTJ, related to the solar cycle, modulates stratospheric mean meridional circulation, which further influences convective activity in the tropical troposphere (Kodera, 2004;Kodera and Shibata, 2006). On the other hand, it has been pointed out that the MASTJ may be important for the formation of a kind of dynamical instability in the extratropical mesosphere (Iida et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Stratospheric tropical warming event and its impact on the polar and tropical troposphere

et al. 2017

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Abstract. Stratosphere-troposphere coupling is investigated in relation to middle atmospheric subtropical jet (MASTJ) variations in boreal winter. An exceptional strengthening of the MASTJ occurred in association with a sudden equatorward shift of the stratospheric polar night jet (PNJ) in early December 2011. This abrupt transformation of the MASTJ and PNJ had no apparent relation to the upward propagation of planetary waves from the troposphere. The impact of this stratospheric event penetrated into the troposphere in two regions: in the northern polar region and the tropics. Due to the strong MASTJ, planetary waves at higher latitudes were deflected and trapped in the northern polar region. Trapping of the planetary waves resulted in amplification of zonal wave number 1 component, which appeared in the troposphere as the development of a trough over the Atlantic sector and a ridge over the Eurasian sector. A strong MASTJ also suppressed the equatorward propagation of planetary waves, which resulted in weaker tropical stratospheric upwelling and produced anomalous warming in the tropical stratosphere. In the tropical tropopause layer (TTL), however, sublimation of ice clouds kept the temperature change minor. In the troposphere, an abrupt termination of a Madden-Julian Oscillation (MJO) event occurred following the static stability increase in the TTL. This termination suggests that the stratospheric event affected the convective episode in the troposphere.

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Circulation changes in the stratosphere and mesosphere during the stratospheric sudden warming event in January 2009

Cited by 35 publications

References 19 publications

On the origin of the mesospheric quasi-stationary planetary waves in the unusual Arctic winter 2015/2016

On the origin of the mesospheric quasi-stationary planetary waves in the unusual Arctic winter 2015/2016

On the origin of the mesospheric quasi-stationary planetary waves in the unusual Arctic winter 2015/16

Stratospheric tropical warming event and its impact on the polar and tropical troposphere

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