Are variations in PMSE intensity affected by energetic particle precipitation?

Barabash, Victoria; Kirkwood, S.; Chilson, Phillip B.

doi:10.5194/angeo-20-539-2002

Cited by 14 publications

(21 citation statements)

References 27 publications

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“…This result agrees with Barabash et al (2002) whereby there is no significant correlation between PMSE variations and cosmic noise absorption. However, Morris et al (2005) found a very weak correlation of PMSE, observed by VHF radar, and cosmic noise absorption.…”

Section: Superdarn-pmse Occurrence In Relation Tosupporting

confidence: 82%

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

Ogunjobi¹,

Sivakumar²,

Stephenson³

et al. 2015

Terr. Atmos. Ocean. Sci.

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We report on the polar mesosphere summer echoes (PMSE) occurrence probability over SANAE (South African National Antarctic Expedition) IV, for the first time. A matching coincidence method is described and implemented for PMSE extraction from SuperDARN (Super Dual Auroral Radar Network) HF radar. Several SuperDARN-PMSE characteristics are studied during the summer period from years 2005 -2007. The seasonal and interannual SuperDARN-PMSE variations in relation to the mesospheric neutral winds are studied and presented in this paper. The occurrence probability of SuperDARN-PMSE on the day-to-day scale show, predominantly, diurnal variation, with a broader peak between 12 -14 LT and distinct minimum of 22 LT. The SuperDARN-PMSE occurrence probability rate is high in the summer solstice. Seasonal variations show a connection between the SuperDARN-PMSE occurrence probability rate and mesospheric temperature from SABER (Sounding of the Atmosphere using Broadband Emission Radiometry). The seasonal trend for both meridional and zonal winds is very stable year-to-year. Analysis of the neutral wind variations indicates the importance of pole-to-pole circulations in SuperDARN-PMSE generation.

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Section: Superdarn-pmse Occurrence In Relation Tosupporting

confidence: 82%

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

Ogunjobi¹,

Sivakumar²,

Stephenson³

et al. 2015

Terr. Atmos. Ocean. Sci.

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“…Bremer et al, 1995;Rapp et al, 2002;Barabash et al, 2004). Analyses Bremer et al (2000Bremer et al ( , 2001 and Barabash et al (2002) concentrating mainly on the diurnal variation of the correlation between PMSE and geomagnetic activities. Other investigations estimate the correlation between monthly mean values of (P)MSE and geomagnetic indices .…”

Section: Introductionmentioning

confidence: 99%

The influence of geomagnetic activity on mesospheric summer echoes in middle and polar latitudes

Zeller

Bremer²

2009

Ann. Geophys.

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Abstract. The dependence of mesospheric VHF radar echoes during summer months on geomagnetic activity has been investigated with observation data of the OSWIN radar in Kühlungsborn (54 • N) and of the ALWIN radar in Andenes (69 • N). Using daily mean values of VHF radar echoes and of geomagnetic activity indices in superimposed epoch analyses, the comparison of both data sets shows in general stronger radar echoes on the day of the maximum geomagnetic activity, the maximum value one day after the geomagnetic disturbance, and enhanced radar echoes also on the following 2-3 days. This phenomenon is observed at middle and polar latitudes and can be explained by precipitating particle fluxes during the ionospheric post storm effect. At polar latitudes, the radar echoes decrease however during and one day after very strong geomagnetic disturbances. The possible reason of this surprising effect is discussed.

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“…Absorption intensity has also been shown to correlate well with the X-ray counting rate at ∼30 km (Brown and Barcus, 1963) and the magnetic disturbance level associated with the electrojet currents at 100-110 km measured by magnetometers (Brown and Campbell, 1962;Hargreaves, 1966;Kavanagh et al, 2004). Positive correlation has been reported between the CNA and Polar Mesospheric Summer Echo (PMSE) intensity (Czechowsky et al, 1989;Kirkwood et al, 1995;Klostermeyer, 1999;Barabash et al, 2002) as observed by VHF radars, although statistically the correlation appears to be rather weak (Czechowsky et al, 1989;Bremer et al, 2000;Barabash et al, 2002). In this paper we attempt to advance our knowledge of the processes leading to the enhanced cosmic noise absorption by exploring the relationship between the riometer absorption and backscatter power of auroral echoes detected by a VHF coherent radar.…”

Section: Introductionmentioning

confidence: 69%

“…Czechowsky et al, 1989;Kirkwood et al, 1995;Barabash et al, 2002). One should bear in mind, however, that the vast majority of the PMSE observations have been performed with vertical incidence VHF radars at frequencies near 50 MHz, while our measurements were carried out with an oblique-sounding 144-MHz radar, sensitive to fieldaligned irregularities in the E region.…”

Section: Discussionmentioning

confidence: 99%

Correlation between cosmic noise absorption and VHF coherent echo intensity

Makarevitch

Honary

2005

Ann. Geophys.

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Abstract.We present examples and statistical analysis of the events with statistically significant correlation between the cosmic noise absorption (CNA) and the signal-to-noise ratio (SNR) of the VHF coherent echo intensity in the area monitored simultaneously by an imaging riometer and two oblique-sounding coherent VHF radars in Northern Scandinavia. By only considering the observations from the narrow riometer beams comparable (in terms of the intersection with the ionosphere) with the VHF radar cells, we identify ∼200 one-hour high correlation periods (HCPs) for 2 years near the solar cycle maximum, 2000-2001. The HCP occurrence is maximized in the afternoon (12:00-17:00 UT, MLT ∼ =UT+3), with the secondary peak near the midnight (21:00-02:00 UT). Relative to the VHF echo occurrence, HCPs occur more frequently from 11:00 to 20:00 UT. The diurnal variation of HCP occurrence is similar to that of the 1-h intervals with the lowest mean absorption A<0.25 dB.The HCPs are observed more frequently during the winter months, which, combined with the fact that VHF echoes observed during HCPs exhibit features typical for field-aligned E-region irregularities, makes their association with the polar mesospheric echoes (for which some positive CNA/SNR correlation has been reported in the past) very unlikely. Instead, we attribute the high positive CNA/SNR correlation to the synchronous, to a first approximation, variation of the particle fluxes for two different but close sets of energies.By considering the dependence of the CNA/SNR correlation coefficients for both VHF radars (C A1 and C A2 ) upon the correlation between SNRs for two radars (C 12 ), we show that both coefficients, C A1 and C A2 , and the agreement between them decrease drastically with a C 12 decrease, which we interpreted through the progressively increasing role of the spatial inhomogeneity of the processes leading to the enhanced CNA and SNR. In this situation, a similarity between the radio signal collection areas should become important, and we demonstrate that the HCP occurrence and mean corCorrespondence to: R. A. Makarevitch (r.makarevitch@lancaster.ac.uk) relation coefficient decrease as the riometer beams and radar cells become less comparable in terms of mutual orientation and closeness between the points of maximum sensitivity.

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Are variations in PMSE intensity affected by energetic particle precipitation?

Cited by 14 publications

References 27 publications

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

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

The influence of geomagnetic activity on mesospheric summer echoes in middle and polar latitudes

Correlation between cosmic noise absorption and VHF coherent echo intensity

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