Variability of MLT winds and waves over mid-latitude during the 2000/2001 and 2009/2010 winter stratospheric sudden warming

Chen, X.; Hu, Xiong; Cunying, Xiao

doi:10.5194/angeo-30-991-2012

Cited by 14 publications

(10 citation statements)

References 28 publications

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“…Therefore, the events studied here are exceptional even if they occur in a temporally short interval. Our observations of a continuous westward wind band from the pole to the subtropics and an occasionally stronger westward wind at mid-than at polar latitudes are corroborated by case studies of the SSW in 2010 by Chen et al (2012) Orsolini et al (2010). The aim of their paper was to show that mesospheric H 2 O and temperature measurements from the Odin satellite allow to distinguish between the formation of an elevated stratopause and the descent of dry mesospheric air into the polar stratosphere.…”

Section: Discussionsupporting

confidence: 61%

“…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. This mid-latitudinal wind reversal in 2010 was also observed in MF radar winds by Chen et al (2012) over Langfang (39 • N,166 • E). Fritz and Soules (1970) were the first who found temperature anomalies in the tropical stratosphere during the SSW of 1970 with the help of global satellite data.…”

Section: Introductionsupporting

confidence: 65%

“…To address this question we compare the latitudinal and altitudinal variability of zonal wind reversal and temperature changes for different SSW events. Such an analysis was partly made by Chen et al (2012) for the SSW in 2010. These authors considered MLS gradient winds and investigated their latitudinal structure.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

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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Section: Discussionsupporting

confidence: 61%

Section: Introductionsupporting

confidence: 65%

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

et al. 2013

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“…Yuan et al (2012) found significant anomalies from climatological means with temperature anomalies as low as 30 K from climatological mean and zonal-mean wind turning eastward in the lower thermosphere in a reversal of climatological mean wind profile, which were directly attributed to the SSW. Chen et al (2012) reported changes in the wind structure during the SSW events of 2000over Wuhan (30 • N) and 2009 and found variability in wind responses at the two sites. also reported low and mid-latitude winds during the SSW events of 1998-1999, 2003-2004, and 2005-2006 found differences in the behavior of MLT winds at Tirunelveli (8.7 • N, 77.8 • E) and Collm (52 • N, 15 • E) and attributed the differences to variability in local gravity wave activity during the SSW events.…”

mentioning

confidence: 99%

Stratospheric sudden warming effects on winds and temperature in the middle atmosphere at middle and low latitudes: a study using WACCM

Chandran

Collins

2014

Ann. Geophys.

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Abstract.A stratospheric sudden warming (SSW) is a dynamical phenomenon of the wintertime stratosphere caused by the interaction between planetary Rossby waves propagating from the troposphere and the stratospheric zonal-mean flow. While the effects of SSW events are seen predominantly in high latitudes, they can also produce significant changes in middle and low latitude temperature and winds. In this study we quantify the middle and low latitude effects of SSW events on temperature and zonal-mean winds using a composite of SSW events between 1988 and 2010 simulated with the specified dynamics version of the Whole Atmosphere Community Climate Model (WACCM). The temperature and wind responses seen in the tropics also extend into the low latitudes in the other hemisphere. There is variability in observed zonal-mean winds and temperature depending on the observing location within the displaced or split polar vortex and propagation direction of the planetary waves. The propagation of planetary waves show that they originate in mid-high latitudes and propagate upward and equatorward into the mid-latitude middle atmosphere where they produce westward forcing reaching peak values of ∼ 60-70 m s −1 day −1 . These propagation paths in the lower latitude stratosphere appear to depend on the phase of the quasibiennial oscillation (QBO). During the easterly phase of the QBO, waves originating at high latitudes propagate across the equator, while in the westerly phase of the QBO, the planetary waves break at ∼ 20-25 • N and there is no propagation across the equator. The propagation of planetary waves across the equator during the easterly phase of the QBO reduces the tropical upwelling and poleward flow in the upper stratosphere.

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“…Note that the tracing is performed in time-varying background conditions, not using the average fields shown in Figures 3c and 3d. The SSW in 2015 was a minor warming and 2010 was weak, too (Zülicke et al, 2018), even though the latter could have also been classified as major (Chen et al, 2012;Peters et al, 2014). Nevertheless, results suggest that GWs are able to propagate substantial meridional and zonal distances.…”

Section: Resultsmentioning

confidence: 90%

Oblique Gravity Wave Propagation During Sudden Stratospheric Warmings

et al. 2020

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Gravity waves (GWs) are important for coupling the mesosphere to the lower atmosphere during sudden stratospheric warmings (SSWs). Here, a minor SSW is internally generated in a simulation with the upper-atmosphere configuration of the ICOsahedral Nonhydrostatic model. At a horizontal resolution of 20 km the simulation uses no GW drag parameterizations but resolves large fractions of the GW spectrum explicitly, including orographic and nonorographic sources. Consistent with previous studies, the simulated zonal-mean stratospheric warming is accompanied by zonal-mean mesospheric cooling. During the course of the SSW the mesospheric GW momentum flux (GWMF) turns from mainly westward to mainly eastward. Waves of large phase speed (40-80 m s −1 ) dominate the eastward GWMF during the peak phase of the warming. The GWMF is strongest along the polar night jet axis. Parameterizations of GWs usually assume straight upward propagation, but this assumption is often not satisfied. In the case studied here, a substantial amount of the GWMF is significantly displaced horizontally between the source region and the dissipation region, implying that the local impact of GWs on the mesosphere does not need to be above their local transmission through the stratosphere. The simulation produces significant vertically misaligned anomalies between the stratosphere and mesosphere. Observations by the Microwave Limb Sounder confirm the poleward tilt with height of the polar night jet and horizontal displacements between mesospheric cooling and stratospheric warming patterns. Thus, lateral GW propagation may be required to explain the middle-atmosphere temperature evolution in SSW events with significant zonally asymmetric anomalies.

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Variability of MLT winds and waves over mid-latitude during the 2000/2001 and 2009/2010 winter stratospheric sudden warming

Cited by 14 publications

References 28 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

Stratospheric sudden warming effects on winds and temperature in the middle atmosphere at middle and low latitudes: a study using WACCM

Oblique Gravity Wave Propagation During Sudden Stratospheric Warmings

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