Stratosphere-mesosphere coupling during stratospheric sudden warming events

Chandran, Amal; Collins, R. L.; Harvey, V. Lynn

doi:10.1016/j.asr.2014.02.005

Cited by 83 publications

(96 citation statements)

References 87 publications

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“…The GWPED per volume shows a decrease in both altitude regions during January and February. However, in the higher altitude region (40 to 50 km) the GWPED per volume increases from February to March while it decreases in the lower altitude region (30 Chandran et al (2014) to 40 km). This feature is also visible in the GWPED profiles presented in Fig.…”

Section: Resultsmentioning

confidence: 99%

Long-term lidar observations of wintertime gravity wave activity over northern Sweden

2014

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Abstract. This paper presents an analysis of gravity wave activity over northern Sweden as deduced from 18 years of wintertime lidar measurements at Esrange (68 • N, 21 • E). Gravity wave potential energy density (GWPED) was used to characterize the strength of gravity waves in the altitude regions 30-40 km and 40-50 km. The obtained values exceed previous observations reported in the literature. This is suggested to be due to Esrange's location downwind of the Scandinavian mountain range and due to differences in the various methods that are currently used to retrieve gravity wave parameters. The analysis method restricted the identification of the dominating vertical wavelengths to a range from 2 to 13 km. No preference was found for any wavelength in this window. Monthly mean values of GW-PED show that most of the gravity waves' energy dissipates well below the stratopause and that higher altitude regions show only small dissipation rates of GWPED. Our analysis does not reproduce the previously reported negative trend in gravity wave activity over Esrange. The observed interannual variability of GWPED is connected to the occurrence of stratospheric warmings with generally lower wintertime mean GWPED during years with major stratospheric warmings. A bimodal GWPED occurrence frequency indicates that gravity wave activity at Esrange is affected by both ubiquitous wave sources and orographic forcing.

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Section: Resultsmentioning

confidence: 99%

Long-term lidar observations of wintertime gravity wave activity over northern Sweden

2014

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“…However, because the winds only reversed above the 10 hPa level at 60 • N the criterion for a major warming is not matched (see, for example, Chandran et al, 2014), and the SSW in January 2012 is classified only as a minor SSW, even though after the warming a new elevated stratopause is formed in the mesosphere (Chandran et al, 2013). If an average over a wider latitude range of 60-80 • N is considered, like in Fig.…”

Section: Satellite Observations Of Gravity Wave Amplitudes Momentum mentioning

confidence: 99%

“…As a consequence, the zonal wind in the mesosphere/lower thermosphere (MLT), that is usually directed westward during winter, can change its sign to eastward (e.g., Holton, 1983). A recent review about coupling between stratosphere and mesosphere during SSWs is given by Chandran et al (2014).…”

Section: Effects Of Gravity Waves During Sswsmentioning

confidence: 99%

“…Further, it is noted by "ES" if an elevated new stratopause forms after the warming. A classification of SSWs can also be found in Chandran et al (2014), including their type. Of course, the classification of SSWs into major and minor SSWs somewhat depends on the data, as well as on the criterion used (e.g., Charlton and Polvani, 2007;Butler et al, 2015).…”

Section: Satellite Observations Of Gravity Wave Amplitudes Momentum mentioning

confidence: 99%

“…Often, the following classification is used: during a "minor warming", the temperature gradient in the stratosphere between 60 • latitude and pole, on zonal average, becomes positive over a certain altitude range at or below the 10 hPa level (about 32 km altitude). During a "major warming", additionally, the stratospheric zonal wind at 60 • latitude reverses from eastward to westward at or below the 10 hPa level (e.g., Chandran et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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Satellite observations of middle atmosphere gravity wave absolute momentum flux and of its vertical gradient during recent stratospheric warmings

Ern¹,

Trinh²,

Kaufmann³

et al. 2016

Atmos. Chem. Phys.

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Abstract. Sudden stratospheric warmings (SSWs) are circulation anomalies in the polar region during winter. They mostly occur in the Northern Hemisphere and affect also surface weather and climate. Both planetary waves and gravity waves contribute to the onset and evolution of SSWs. While the role of planetary waves for SSW evolution has been recognized, the effect of gravity waves is still not fully understood, and has not been comprehensively analyzed based on global observations. In particular, information on the gravity wave driving of the background winds during SSWs is still missing.

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Gravity wave activity during recent stratospheric sudden warming events from SOFIE temperature measurements

Thurairajah

Bailey

Cullens

et al. 2014

J. Geophys. Res. Atmos.

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Stratospheric Sudden Warmings (SSWs) followed by the formation of an elevated stratopause at 70-80 km occurred in four of the five recent Arctic winters (2009)(2010)(2011)(2012)(2013). We use global high-latitude temperature measurements from the Solar Occultation for Ice Experiment (SOFIE) to analyze the gravity wave (GW) activity in the upper stratosphere and mesosphere (30-90 km) during different phases of the SSW events. We characterize GW activity in terms of temperature fluctuations and the growth of GW potential energy with altitude. At both 40 and 60 km, compared to the non-SSW year of 2011, the GW activity in the SSW years of 2009, 2010, 2012, and 2013 was reduced after the warming, during the occurrence of an isothermal atmosphere and an elevated stratopause. In contrast, at 80 km the GW activity was highly variable between the individual stratospheric warming events. A case study of GW activity during the 2013 warming event and coincident SOFIE observations of water vapor (H 2 O) from~40 to 90 km indicate a correlation between increase in wave activity at each altitude and the time of descent of dry air. This study supports previous modeling studies' findings that enhanced GW activity is responsible for the downward transport of trace species from the mesosphere to the stratosphere following an SSW event.

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Stratosphere-mesosphere coupling during stratospheric sudden warming events

Cited by 83 publications

References 87 publications

Long-term lidar observations of wintertime gravity wave activity over northern Sweden

Long-term lidar observations of wintertime gravity wave activity over northern Sweden

Satellite observations of middle atmosphere gravity wave absolute momentum flux and of its vertical gradient during recent stratospheric warmings

Gravity wave activity during recent stratospheric sudden warming events from SOFIE temperature measurements

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