Seasonal variation of meteor decay times observed at King Sejong Station (62.22°S, 58.78°W), Antarctica

Kim, Jeong‐Han; Kim, Yong Ha; Lee, Chang-Sup; Jee, Geonhwa

doi:10.1016/j.jastp.2010.05.003

Cited by 33 publications

(56 citation statements)

References 32 publications

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“…(The discrete nature of radar range measurements, 2 km steps, is responsible for the "pulses" in the contour.) Similar data presentations appear in Ballinger et al (2008) for a year's observations (all data combined) from the SKiYMET at Esrange, Sweden; Hall et al (2005) combined January to June, while Kim et al (2010) showed Antarctic data for 4 separate seasons. The equivalent MLS log 10 τ 1/2 has been calculated as follows: GPH-T profiles for each day were interpolated to get average daily log 10 P and T from 70 to 100 km in steps of 1 km.…”

Section: Measured Decay Times Compared With Mls-predicted Timessupporting

confidence: 83%

“…The potential dependence of decay time on dust and ice particles (Havnes and Sigernes, 2005;Ballinger et al, 2008;Kim et al, 2010) has been tested by looking for average τ 1/2 changes versus signal-to-noise (S/N) and month (over 6 years of data). More dust, and therefore a stronger effect, might be expected in summer because of the almost quadrupling of the meteor echo rate at Eureka then.…”

Section: Mls Log-decay Time Slopes Versus Various Meteor Optionsmentioning

confidence: 99%

“…This weak/strong effect has been found experimentally at Kiruna by Ballinger et al (2008) as a ∼ 10 % change in τ 1/2 near 83 km but negligible near 90 km. Kim et al (2010) have examined Antarctic meteor data for this effect; a careful examination of their Fig. 2 shows that there are negligible differences in all seasons at 90 km, but they can be significant above and below that height.…”

Section: Introductionmentioning

confidence: 99%

“…Kim et al (2010) have argued that chemistry in summer, through water cluster ions, could have a similar effect. Another weak/strong effect was proposed by Dyrud et al (2011), who modelled plasma turbulence created by the meteor itself and found a day (smaller) to night (larger) difference in generated turbulence.…”

Section: Introductionmentioning

confidence: 99%

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Eureka, 80° N, SKiYMET meteor radar temperatures compared with Aura MLS values

et al. 2013

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The meteor trail echo decay rates are analysed on-site to provide daily temperatures near 90 km. In order to get temperatures from trail decay times, either knowledge of the pressure or the background temperature height gradient near 90 km is required (Hocking, 1999). Hocking et al. (2004) have developed an empirical 90 km temperature gradient model depending only on latitude and time of year, which is used in the SKiYMET on-site meteor temperature analysis.

Here we look at the sensitivity of the resulting temperature to the assumed gradient and compare it and the temperatures with daily AuraMLS averages near Eureka. Generally there is good agreement between radar and satellite for winter temperatures and their short-term variations. However there is a major difference in mid-summer both in the temperatures and the gradients. Increased turbulence in summer, which may overwhelm the ambipolar diffusion even at 90 km, is likely a major factor.

These differences are investigated by generating ambipolar-controlled decay times from satellite pressure and temperature data at a range of heights and comparing with radar measurements. Our study suggests it may be possible to use these data to estimate eddy diffusion coefficients at heights below 90 km. Finally the simple temperature analysis (using satellite pressures), and a standard meteor wind analysis are used to compare mean diurnal variations of temperature (T) with those of zonal wind (U) and meridional wind (V) in composite multi-year monthly intervals

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Section: Measured Decay Times Compared With Mls-predicted Timessupporting

confidence: 83%

Section: Mls Log-decay Time Slopes Versus Various Meteor Optionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Eureka, 80° N, SKiYMET meteor radar temperatures compared with Aura MLS values

et al. 2013

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“…Recent advances in meteor radar performance have enabled the detection of meteors well below the peak detection height of about 90 km. Analysis of meteors in the lowest portion of the meteor ablation region, below about 85 km, indicates that there is significant deviation in meteor plasma behavior from theoretical predictions based only on ambipolar diffusion [Kim et al, 2010].…”

Section: Introductionmentioning

confidence: 81%

A method for estimating the height of a mesospheric density level using meteor radar

Younger

Vincent

Murphy

2015

Geophysical Research Letters

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A new technique for determining the height of a constant density surface at altitudes of 78–85 km is presented. The first results are derived from a decade of observations by a meteor radar located at Davis Station in Antarctica and are compared with observations from the Microwave Limb Sounder instrument aboard the Aura satellite. The density of the neutral atmosphere in the mesosphere/lower thermosphere region around 70–110 km is an essential parameter for interpreting airglow‐derived atmospheric temperatures, planning atmospheric entry maneuvers of returning spacecraft, and understanding the response of climate to different stimuli. This region is not well characterized, however, due to inaccessibility combined with a lack of consistent strong atmospheric radar scattering mechanisms. Recent advances in the analysis of detection records from high‐performance meteor radars provide new opportunities to obtain atmospheric density estimates at high time resolutions in the MLT region using the durations and heights of faint radar echoes from meteor trails. Previous studies have indicated that the expected increase in underdense meteor radar echo decay times with decreasing altitude is reversed in the lower part of the meteor ablation region due to the neutralization of meteor plasma. The height at which the gradient of meteor echo decay times reverses is found to occur at a fixed atmospheric density. Thus, the gradient reversal height of meteor radar diffusion coefficient profiles can be used to infer the height of a constant density level, enabling the observation of mesospheric density variations using meteor radar.

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The effects of deionization processes on meteor radar diffusion coefficients below 90 km

et al. 2014

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The decay times of VHF radar echoes from underdense meteor trails are reduced in the lower portions of the meteor region. This is a result of plasma neutralization initiated by the attachment of positive trail ions to neutral atmospheric molecules. Decreased echo decay times cause meteor radars to produce erroneously high estimates of the ambipolar diffusion coefficient at heights below 90 km, which affects temperature estimation techniques. Comparisons between colocated radars and satellite observations show that meteor radar estimates of diffusion coefficients are not consistent with estimates from the Aura Microwave Limb Sounder satellite instrument and that colocated radars operating at different frequencies estimate different values of the ambipolar diffusion coefficient for simultaneous detections of the same meteors. Loss of free electrons from meteor trails due to attachment to aerosols and chemical processes were numerically simulated and compared with observations to determine the specific mechanism responsible for low‐altitude meteor trail plasma neutralization. It is shown that three‐body attachment of positive metal ions significantly reduces meteor radar echo decay times at low altitudes compared to the case of diffusion only that atmospheric ozone plays little part in the evolution of low‐altitude underdense meteor trails and that the effect of three‐body attachment begins to exceed diffusion in echo decay times at a constant density surface.

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Seasonal variation of meteor decay times observed at King Sejong Station (62.22°S, 58.78°W), Antarctica

Cited by 33 publications

References 32 publications

Eureka, 80° N, SKiYMET meteor radar temperatures compared with Aura MLS values

Eureka, 80° N, SKiYMET meteor radar temperatures compared with Aura MLS values

A method for estimating the height of a mesospheric density level using meteor radar

The effects of deionization processes on meteor radar diffusion coefficients below 90 km

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