Quantitative relation between PMSE and ice mass density

Kirkwood, S.; Hervig, Mark E.; Belova, Evgenia; Osepian, A.

doi:10.5194/angeo-28-1333-2010

Cited by 8 publications

(11 citation statements)

References 30 publications

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“…Unlike SNR, the radar volume reflectivity is an intrinsic characteristics of PMSE strength which can be used for comparison of PMSE measured with different radars at different locations. An additional advantage of using η is in the fact that its value should be directly related to physical parameters such as electron and ice particle density, static stability and turbulence characteristics (Kirkwood et al, 2010b;Varney et al, 2010). Nowadays estimations of PMSE reflectivity have been made using a number of MesosphereStratosphere-Troposphere (MST) radars located both in the northern and southern polar regions (e.g.…”

Section: Introductionmentioning

confidence: 99%

Polar mesosphere summer echo strength in relation to solar variability and geomagnetic activity during 1997–2009

Smirnova

Belova²,

Kirkwood³

2011

Ann. Geophys.

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Abstract. This paper is based on measurements of Polar Mesosphere Summer Echoes (PMSE) with the 52 MHz radar ESRAD, located near Kiruna, in Northern Sweden, during the summers of 1997–2009. Here, a new independent calibration method allowing estimation of possible changes in antenna feed losses and transmitter output is described and implemented for accurate calculation of year-to-year variations of PMSE strength (expressed in absolute units – radar volume reflectivity η). The method is based on radar-radiosonde comparisons in the upper troposphere/lower stratosphere region simultaneously with PMSE observations. Inter-annual variations of PMSE volume reflectivity are found to be strongly positively correlated with the local geomagnetic K-index, both when averaged over all times of the day, and when considering 3-h UT intervals separately. Increased electron density due to energetic particle precipitation from the magnetosphere is suggested as one of the possible reasons for such a correlation. Enhanced ionospheric electric field may be another reason but this requires further study. Multi-regression analysis of inter-annual variations of PMSE η shows also an anti-correlation with solar 10.7 cm flux and the absence of any statistically significant trend in PMSE strength over the interval considered (13-years). Variations related to solar flux and K-index account for 86% of the year-to-year variations in radar volume reflectivity.

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Section: Introductionmentioning

confidence: 99%

Polar mesosphere summer echo strength in relation to solar variability and geomagnetic activity during 1997–2009

Smirnova

Belova²,

Kirkwood³

2011

Ann. Geophys.

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“…But the observed (weak) correlation is at least consistent with our hypothesis. Empirically it has been found that PMSE reflectivity increases roughly in proportion to electron density, at least for low levels of geomagnetic disturbance (K P < 3) at Wasa (Kirkwood et al, 2010b), and we can expect electron density due to ionisation of NO by solar Lyman-α to increase as [NO] 0.5 . Taking the comparison a step further, the black line in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Geophys., 31, 333-347, 2013 www.ann-geophys.net/31/333/2013/ twice as much ice mass in the 03:00-05:00 LT time sector compared to the 10:00-24:00 LT sector. However, according to the results of Kirkwood et al (2010b), relating ice-mass and electron densities to PMSE reflectivities, this should lead to a factor of only 2 difference between PMSE reflectivities between 03:00-05:00 LT and those at corresponding solar zenith angles in the afternoon (19:00-21:00 LT) if solar EUV is the only source of ionisation. Since the observed difference in reflectivities is an order of magnitude, it seems likely that this site is affected by energetic particle precipitation in the early morning even when K indices suggest that the situation is quiet.…”

Section: Pmse Response To Magnetic Disturbancementioning

confidence: 99%

“…As a result, observations from parts of Antarctica offer the possibility to study PMSE at high geographic latitude but relatively low geomagnetic latitude, reducing the effects of energetic particle precipitation. Observations from Antarctica have already been used to show that, during geomagnetically quiet conditions, PMSE reflectivities can, on average, be explained by ice-mass density together with electron densities produced by solar EUV radiation alone (Kirkwood et al, 2010b). In this study we particularly focus on how different responses to disturbance levels between a sub-auroral Antarctic site and an auroral Arctic site can indicate different mechanisms affecting PMSE strengths.…”

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confidence: 99%

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Response of polar mesosphere summer echoes to geomagnetic disturbances in the Southern and Northern Hemispheres: the importance of nitric oxide

et al. 2013

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The relationship between polar mesosphere summer echoes (PMSE) and geomagnetic disturbances (represented by magnetic <I>K</I> indices) is examined. Calibrated PMSE reflectivities for the period May 2006–February 2012 are used from two 52.0/54.5 MHz radars located in Arctic Sweden (68° N, geomagnetic latitude 65°) and at two different sites in Queen Maud Land, Antarctica (73°/72° S, geomagnetic latitudes 62°/63°). In both the Northern Hemisphere (NH) and the Southern Hemisphere (SH) there is a strong increase in mean PMSE reflectivity between quiet and disturbed geomagnetic conditions. Mean volume reflectivities are slightly lower at the SH locations compared to the NH, but the position of the peak in the lognormal distribution of PMSE reflectivities is close to the same at both NH and SH locations, and varies only slightly with magnetic disturbance level. Differences between the sites, and between geomagnetic disturbance levels, are primarily due to differences in the high-reflectivity tail of the distribution. PMSE occurrence rates are essentially the same at both NH and SH locations during most of the PMSE season when a sufficiently low detection threshold is used so that the peak in the lognormal distribution is included. When the local-time dependence of the PMSE response to geomagnetic disturbance level is considered, the response in the NH is found to be immediate at most local times, but delayed by several hours in the afternoon sector and absent in the early evening. At the SH sites, at lower magnetic latitude, there is a delayed response (by several hours) at almost all local times. At the NH (auroral zone) site, the dependence on magnetic disturbance is highest during evening-to-morning hours. At the SH (sub-auroral) sites the response to magnetic disturbance is weaker but persists throughout the day. While the immediate response to magnetic activity can be qualitatively explained by changes in electron density resulting from energetic particle precipitation, the delayed response can largely be explained by changes in nitric oxide concentrations. Observations of nitric oxide concentration at PMSE heights by the Odin satellite support this hypothesis. Sensitivity to geomagnetic disturbances, including nitric oxide produced during these disturbances, can explain previously reported differences between sites in the auroral zone and those at higher or lower magnetic latitudes. The several-day lifetime of nitric oxide can also explain earlier reported discrepancies between high correlations for average conditions (year-by-year PMSE reflectivities and <I>K</I> indices) and low correlations for minute-to-day timescales

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“…Some are associated with noctilucent clouds (NLCs), and it is widely accepted that PMSEs are a consequence of the existence of icy "dust" particles in the vicinity of the polar summer mesopause (e.g. Kirkwood et al, 2010). Havnes et al (1996) first reported the detection of charged PMSE dust particles with a rocket-borne probe launched in an effort to establish the relationship between the PMSE signals and the charge carried by dust.…”

Section: Introductionmentioning

confidence: 99%

Secondary charging effects due to icy dust particle impacts on rocket payloads

Kassa¹,

Rapp²,

Hartquist

et al. 2012

Ann. Geophys.

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Abstract. We report measurements of dust currents obtained with a small probe and a larger probe during the flight of the ECOMA-4 rocket through the summer polar mesosphere. The payload included two small dust probes behind a larger dust probe located centrally at the front. For certain phases of the payload rotation, the current registered by one of the small dust probes was up to 2 times the current measured with the larger probe, even though the effective collection area of the larger probe was 4 times that of the small one. We analyze the phase dependence of the currents and their difference with a model based on the assumption that the small probe was hit by charged dust fragments produced in collisions of mesospheric dust with the payload body. Our results confirm earlier findings that secondary charge production in the collision of a noctilucent cloud/Polar Summer Mesospheric Echo (NLC/PMSE) dust particle with the payload body must be several orders of magnitude larger than might be expected from laboratory studies of collisions of pure ice particles with a variety of clean surfaces. An important consequence is that for some payload configurations, one should not assume that the current measured with a detector used to study mesospheric dust is simply proportional to the number density of ambient dust particles. The higher secondary charge production may be due to the NLC/PMSE particles containing multiple meteoric smoke particles.

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Quantitative relation between PMSE and ice mass density

Cited by 8 publications

References 30 publications

Polar mesosphere summer echo strength in relation to solar variability and geomagnetic activity during 1997–2009

Polar mesosphere summer echo strength in relation to solar variability and geomagnetic activity during 1997–2009

Response of polar mesosphere summer echoes to geomagnetic disturbances in the Southern and Northern Hemispheres: the importance of nitric oxide

Secondary charging effects due to icy dust particle impacts on rocket payloads

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