Variabilities of mesospheric tides and equatorial electrojet strength during major stratospheric warming events

Sridharan, S.; Sathishkumar, Solomon; Gurubaran, S.

doi:10.5194/angeo-27-4125-2009

Cited by 98 publications

(110 citation statements)

References 26 publications

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“…The low-latitude ionospheric response to sudden stratospheric warmings (SSWs) has been an area of extreme interest in recent years [e.g., Vineeth et al, 2009;Chau et al, 2009Chau et al, , 2010Sridharan et al, 2009;Goncharenko et al, 2010a, b;Fejer et al, 2010Fejer et al, , 2011Yue et al, 2010;Rodrigues et al, 2011;Liu et al, 2011;Park et al, 2012;Yamazaki et al, 2012a, b]. These events are characterized by large-scale metereological changes in the winter polar atmosphere, driven by the rapid growth of upward propagating quasi-stationary planetary (Rossby) waves, rapid growth of waves from the polar troposphere, and their interaction with the mean circulation, that last for several days or even a few weeks [e.g., Matsuno, 1971;Andrews et al, 1987;Liu and Roble, 2002;Holton, 2004].…”

Section: Lunar Tidal Effects During Sudden Stratospheric Warmingsmentioning

confidence: 99%

“…The initial studies on arctic SSW effects on the equatorial upper atmosphere found large, multiday mesospheric wind changes and afternoon reversals of the equatorial electrojet [e.g., Stening et al, 1996;Vineeth et al, 2009;Sridharan et al, 2009]. Chau et al [2009] showed large daytime semidiurnal perturbations lasting for several days in the F-region vertical drift velocities over Jicamarca during the 2008 minor warming event.…”

Section: Lunar Tidal Effects During Sudden Stratospheric Warmingsmentioning

confidence: 99%

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Lunar tidal effects in the electrodynamics of the low latitude ionosphere

Fejer

Tracy

2013

Journal of Atmospheric and Solar-Terrestrial Physics

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respectively. The monthly and semimonthly amplitudes decrease from early morning to afternoon and evening to morning with moderate to large increases near dusk and dawn.We also examined these perturbation drifts during periods of sudden stratospheric warmings (SSWs). Our results show, for the first time, the enhancements of the lunar semimonthly tidal effects associated with SSWs to occur at night, as well as during the day. Our results also indicate during SSWs, monthly tidal effects are not enhanced as strongly as the semimonthly effects. We also examined these perturbation drifts during periods of sudden stratospheric warmings (SSWs), which is a meteorological event where the polar vortex is displaced or splits and which has been known to be associated with a large increase in planetary wave activity. Our results show, for the first time, the enhancements of the lunar semimonthly tidal effects associated with SSWs to occur at night, as well as during the day. Our results also indicate during SSWs monthly tidal effects are not enhanced as strongly as the semimonthly effects.vii ACKNOWLEDGMENTS

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Section: Lunar Tidal Effects During Sudden Stratospheric Warmingsmentioning

confidence: 99%

Section: Lunar Tidal Effects During Sudden Stratospheric Warmingsmentioning

confidence: 99%

Lunar tidal effects in the electrodynamics of the low latitude ionosphere

Fejer

Tracy

2013

Journal of Atmospheric and Solar-Terrestrial Physics

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“…Vineeth et al [2009] suggested that SSWs lead to higher occurrence of quasi 16 day periodicity of equatorial counterelectrojets and that stronger counterelectrojets are associated with more intense warmings. Sridharan et al [2009] used magnetic field and mesospheric wind measurements in the Indian region to show that major arctic SSW events affect the day-to-day variability of equatorial counterelectrojets through the enhancement of semidiurnal tides.…”

Section: Introductionmentioning

confidence: 99%

Lunar‐dependent equatorial ionospheric electrodynamic effects during sudden stratospheric warmings

et al. 2010

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[1] We have used plasma drift and magnetic field measurements during the [2001][2002][2003][2004][2005][2006][2007][2008][2009] December solstices to study, for the first time, the longitudinal dependence of equatorial ionospheric electrodynamic perturbations during sudden stratospheric warmings. Jicamarca radar measurements during these events show large dayside downward drift (westward electric field) perturbations followed by large morning upward and afternoon downward drifts that systematically shift to later local times. Ground-based magnetometer measurements in the American, Indian, and Pacific equatorial regions show strongly enhanced electrojet currents in the morning sector and large reversed currents (i.e., counterelectrojets) in the afternoon sector with onsets near new and full moons during northern winter warming periods. CHAMP satellite and ground-based magnetic field observations indicate that the onset of these equatorial afternoon counterelectrojets is longitude dependent. Our results indicate that these large electrodynamic perturbations during stratospheric warming periods are due to strongly enhanced semidiurnal lunar wave effects. The results of our study can be used for forecasting the occurrence and evolution of these electrodynamic perturbations during arctic winter warmings.Citation: Fejer, B. G., M. E. Olson, J. L. Chau, C. Stolle, H. Lühr, L. P. Goncharenko, K. Yumoto, and T. Nagatsuma (2010), Lunar-dependent equatorial ionospheric electrodynamic effects during sudden stratospheric warmings,

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“…The westward currents manifested during some instances of CEJs may be caused by reversal of the interplanetary magnetic field (IMF-Bz) component from south to north (Rastogi 1974;Sizova 2002;Francisca et al 2013) and or atmospheric tidal effects (Bhargava et al 1980;Somayajulu et al 1993;Sridharan et al 2002). Recent studies show that rise in atmospheric temperature connected with the phenomena of sudden stratospheric warming (SSW) exhibits positive correlation with occurrences of CEJs (Matsuno 1971;Liu and Roble 2002;Sridharan et al 2009). …”

Section: The Counter Electrojetmentioning

confidence: 99%

Evidence of short spatial variability of the equatorial electrojet at close longitudinal separation

2014

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The characteristics of longitudinal variability of equatorial electrojet (EEJ) and counter electrojet (CEJ), presented in this study, are based on concurrent observations from a hitherto unsampled region of the world to examine the (1) degree of correlation between hourly means and monthly averaged hourly means of ground observations with equatorial electrojet climatological model (EEJM-2.0), (2) day-to-day longitudinal variability of EEJ strength between the pairs of sites, and (3) At both longitudes, the overall correlation of monthly mean hourly values (i.e., from 05:00 to 19:00 LT) between the observed EEJ strength and modeled current density from EEJM-2.0 is good (r > 0.8). However, a significant lack of correlation is witnessed on day-to-day peak values (i.e., 12:00 LT) between the observed variations and the model at both sites. Further, a comparison of noontime peaks between the two sites shows a considerable day-to-day variability. A large number of CEJs (43 events) are recorded during the study: at CBY (15 events) and VEN (28 events). Analyses of the CEJ events highlight the variability of CEJ phenomena in terms of amplitude, dates, and time of occurrence over 15°l ongitude separation. The local nature of perturbations causing CEJ is evident; the possible factors are being non-migrating eastward and westward propagating diurnal tides and local meteorological phenomena associated with upper mesospheric temperature, wind, and density variations.

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Variabilities of mesospheric tides and equatorial electrojet strength during major stratospheric warming events

Cited by 98 publications

References 26 publications

Lunar tidal effects in the electrodynamics of the low latitude ionosphere

Lunar tidal effects in the electrodynamics of the low latitude ionosphere

Lunar‐dependent equatorial ionospheric electrodynamic effects during sudden stratospheric warmings

Evidence of short spatial variability of the equatorial electrojet at close longitudinal separation

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