Is there a causal relationship between cosmic noise absorption and PMSE?

Morris, R. J.; Terkildsen, Michael; Holdsworth, David A.; Hyde, M.

doi:10.1029/2005gl024568

Cited by 14 publications

(12 citation statements)

References 17 publications

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“…Similar PMSE diurnal pattern variations were found by very high frequency (VHF) radar observations (Hoffmann et al 1999;Morris et al 2005;Latteck et al 2007;Nilsson et al 2008). Hosokawa et al (2005) observed similar diurnal results with Syowa and Iceland HF radar too.…”

Section: Diurnal Variationsupporting

confidence: 71%

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: Diurnal Variationsupporting

confidence: 71%

PMSE long term observations using SuperDARN SANAE HF radar measurements

Ogunjobi¹,

Sivakumar²,

Stephenson³

et al. 2017

Terr. Atmos. Ocean. Sci.

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“…where θ s is the effective HPHW of the combined two-way polar diagram (Hocking, 1987 Morris et al (2005) that PMSE are influenced by electron precipitation, which is more prevalent in the auroral oval region compared with inner region. The above concept was recently verified by using a new 51.0 MHz VHF radar at Eureka (80 • N, 86 • W) in northern Canada.…”

Section: Discussionmentioning

confidence: 99%

Radar efficiency and the calculation of decade-long PMSE backscatter cross-section for the Resolute Bay VHF radar

2009

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Abstract. The Resolute Bay VHF radar, located in Nunavut, Canada (75.0 • N, 95.0 • W) and operating at 51.5 MHz, has been used to investigate Polar Mesosphere Summer Echoes (PMSE) since 1997. PMSE are a unique form of strong coherent radar echoes, and their understanding has been a challenge to the scientific community since their discovery more than three decades ago. While other high latitude radars have recorded strong levels of PMSE activities, the Resolute Bay radar has observed relatively lower levels of PMSE strengths. In order to derive absolute measurements of PMSE strength at this site, a technique is developed to determine the radar efficiency using cosmic (sky) noise variations along with the help of a calibrated noise source. VHF radars are only rarely calibrated, but determination of efficiency is even less common. Here we emphasize the importance of efficiency for determination of cross-section measurements. The significant advantage of this method is that it can be directly applied to any MST radar system anywhere in the world as long as the sky noise variations are known. The radar efficiencies for two on-site radars at Resolute Bay are determined. PMSE backscatter cross-section is estimated, and decade-long PMSE strength variations at this location are investigated. It was noticed that the median of the backscatter cross-section distribution remains relatively unchanged, but over the years a great level of variability occurs in the high power tail of the distribution.

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“…A quantitative comparison of the PMSE intensity between Davis and Andenes (69°N, magnetic latitude 66.5°N) has been made which suggests that PMSE at Davis are weaker [Latteck et al, 2007]. Like the Arctic PMSE observation sites, Davis is located well inside the auroral zone and can be affected by energetic particle precipitation at any time of the day [Morris et al, 2005].…”

Section: Introductionmentioning

confidence: 99%