Evidence of Polar Mesosphere Summer Echoes Observed by SuperDARN SANAE HF Radar in Antarctica

Ogunjobi, O.; Sivakumar, Venkataraman; Stephenson, J. A. E.; Sivla, W.T.

doi:10.3319/tao.2015.03.06.01(aa)

Cited by 6 publications

(10 citation statements)

References 38 publications

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“…In the prequel paper (Ogunjobi et al 2015), we found no significant correlations between SuperDARN-PMSE occurrence rate and absorption. Intuitively, we expect high Kp index to cause robust cosmic noise absorption (Ogunjobi et al 2014b); hence similar trend in the occurrence rate with Kp and absorption.…”

Section: Superdarn-pmse Occurrence In Relation Tomentioning

confidence: 79%

“…For completeness, therefore, we extend the meridional and zonal wind observations over SANAE IV in relation to mesospheric temperature variations, which we earlier provided on a short-term scale in Ogunjobi et al (2015). Present study has expanded on this for the purpose of clarity on the influence of solar activity.…”

Section: Mesospheric Temperature and Winds In Relation To Superdarn-pmsementioning

confidence: 99%

“…The trend of neutrals (neutral winds and neutral temperature) in relation to SuperDARN-PMSE season might be significant. Here, we have expanded temperatures observations based on our explanation since Ogunjobi et al (2015) (Fig. 8 of that paper).…”

Section: Mesospheric Temperature and Winds In Relation To Superdarn-pmsementioning

confidence: 99%

“…In the past few years, the PMSE have been closely linked to visible ice particles below 90 km altitude, known as Noctilucent Clouds (NLC) (Cho and Röt-tger 1997;Rapp and Lübken 2004;Smirnova et al 2010). Prequel to this paper, (Ogunjobi et al 2015), we describe how the NLC and PMSE arise from the ice particle growth in an extremely low Polar summer mesospheric temperature periods. Both NLC and PMSE are good indicators (or suspected indicators) of anthropogenic global warming.…”

Section: Introductionmentioning

confidence: 99%

“…This is particularly true for the southern hemisphere, which often lacks both space and ground based observational data. There is a growing effort to complement PMSE observations with coherent high frequency (HF) Super Dual Auroral Radar Network (SuperD-ARN) (e.g., Ogawa et al 2004;Hosokawa et al 2005;Liu et al 2013;Ogunjobi et al 2015). Using data from Syowa East HF radar in the Antarctic (during 1999/2000 and 2000/2001 summers) and Iceland HF radar in the Arctic (1999 and 2000 summers), Hosokawa et al (2005) observed a predominant diurnal PMSE variation, similar to Ogunjobi et al (2015) observations, and a weaker PMSE interhemispheric asymmetry occurrence than those earlier reported results.…”

Section: Introductionmentioning

confidence: 99%

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PMSE long term observations using SuperDARN SANAE HF radar measurements

Ogunjobi¹,

Sivakumar²,

Stephenson³

et al. 2017

Terr. Atmos. Ocean. Sci.

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It is known that the presence of nanometre-scale ice particles and neutral air turbulence in the Polar summer mesosphere modify the D-region plasma, resulting in strong backscatter. These strong backscatters are referred to as Polar Mesosphere Summer Echoes (PMSE). Although studies on PMSE have been ongoing for over three decades, aspects revealed by various instruments are still the subject of discussion. As a sequel to the paper by Ogunjobi et al. (2015), we report on the long term trends and variations in PMSE occurrence probability from Super Dual Auroral Radar Network (SuperDARN) high frequency (HF) radar measurements over the South African National Antarctic Expedition IV (SANAE IV). In this current paper, a simple multiple-filter technique is employed to obtain the occurrence probability rate for SuperDARN-PMSE during the summer periods for the years 1998 -2007. The SuperDARN-PMSE occurrence probability rate in relation to geomagnetic activity is examined. The mesospheric neutral winds and temperature trends during these periods, are further studied and presented in this paper. Both the monthly and diurnal variations in occurrence are consistent with previous reports, confirming the presence of PMSE from SuperDARN SANAE IV radar measurements and the influence of pole to pole mesospheric transport circulation. The special mesospheric mean flow observed prior to the year 2002 is ascribed to the influence of solar activity. The SuperDARN-PMSE occurrence probability peaks with lowered geomagnetic activity. These present results support the hypothesis that the particle precipitation also plays an important role in SuperDARN-PMSE occurrence.

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Section: Superdarn-pmse Occurrence In Relation Tomentioning

confidence: 79%

Section: Mesospheric Temperature and Winds In Relation To Superdarn-pmsementioning

confidence: 99%

Section: Mesospheric Temperature and Winds In Relation To Superdarn-pmsementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

PMSE long term observations using SuperDARN SANAE HF radar measurements

Ogunjobi¹,

Sivakumar²,

Stephenson³

et al. 2017

Terr. Atmos. Ocean. Sci.

Self Cite

View full text Add to dashboard Cite

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Algorithm for the estimation of ionosphere parameters from ground scatter echoes of SuperDARN

Huang

Liu

et al. 2018

Sci. China Technol. Sci.

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A comparison of outer electron radiation belt dropouts during solar wind stream interface and magnetic cloud driven storms

2017

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Energetic electrons are trapped in the Earth's radiation belts which occupy a toroidal region between 3 and 7 R E above the Earth's surface. Rapid loss of electrons from the radiation belts is known as dropouts. The source and loss mechanisms regulating the radiation belts population are not yet understood entirely, particularly during geomagnetic storm times. Nevertheless, the dominant loss mechanism may require an event based study to be better observed. Utilizing multiple data sources from the year 1997-2007, this study identifies radiation belt electron dropouts which are ultimately triggered when solar wind stream interfaces (SI) arrived at Earth, or when magnetic clouds (MC) arrived. Using superposed epoch analysis (SEA) technique, a synthesis of multiple observations is performed to reveal loss mechanism which might, perhaps, be a major contributor to radiation belt losses under SI and MC driven storms. Results show an abrupt slower decaying precipitation of electron peak (about 3000 counts/sec) on SI arrival within 5.05 < L < 6.05, which persist till 0.5 day before gradual recovery. This pattern is interpreted as an indication of depleted electrons from bounce lost cone via precipitating mechanism known as relativistic electron microburst. On the other hand, MC shows a pancake precipitating peak extending to lower L (Plasmapause); indicating a combination of electron cyclotron harmonic (ECH) and whistler mode waves as the contributing mechanisms.

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Evidence of Polar Mesosphere Summer Echoes Observed by SuperDARN SANAE HF Radar in Antarctica

Cited by 6 publications

References 38 publications

PMSE long term observations using SuperDARN SANAE HF radar measurements

PMSE long term observations using SuperDARN SANAE HF radar measurements

Algorithm for the estimation of ionosphere parameters from ground scatter echoes of SuperDARN

A comparison of outer electron radiation belt dropouts during solar wind stream interface and magnetic cloud driven storms

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