On the influence of background dust on radar scattering from meteor trails

Havnes, O.; Sigernes, F.

doi:10.1016/j.jastp.2004.12.009

Cited by 23 publications

(34 citation statements)

References 29 publications

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“…Ballinger et al (2008) report that meteor radars in general deliver reliable daily temperature estimates near the mesopause using the method outlined in this study, but emphasise that one should exercise caution when assuming that observed meteor echo fading times are primarily governed by ambipolar diffusion. They propose, after Havnes and Sigernes (2005), that electron-ion recombination can impact meteor echo decay times. This can especially affect the weaker echoes, hence this effect can lead to an underestimation of temperatures.…”

Section: Physical Explanations For Cooling and Comparison With Other mentioning

confidence: 99%

Neutral atmosphere temperature trends and variability at 90 km, 70 °N, 19 °E, 2003–2014

Holmen

Hall²,

Tsutsumi

2016

Atmos. Chem. Phys.

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Section: Physical Explanations For Cooling and Comparison With Other mentioning

confidence: 99%

Neutral atmosphere temperature trends and variability at 90 km, 70 °N, 19 °E, 2003–2014

Holmen

Hall²,

Tsutsumi

2016

Atmos. Chem. Phys.

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“…It has been proposed that processes other than ambipolar diffusion can have a detectable influence on meteor decay times throughout the mesopause region (e.g. Dyrud et al, 2001;Havnes and Sigernes, 2005;Dimant and Oppenheim, 2006a,b;Holdsworth et al, 2006). By ignoring these effects, one might inadvertently overestimate the ambipolar diffusion coefficient, which could have important consequences for temperature estimation, and thus deserves further investigation.…”

Section: Decay Times Within the Mesopause Regionmentioning

confidence: 99%

“…It has been suggested by Havnes and Sigernes (2005) that charged particles should have a more pronounced effect on meteor trails with relatively weak echo powers, compared to stronger ones. The term "charged particles" is used here to describe the charged species that are quasi-continually present in the mesopause region.…”

Section: Decay Times Within the Mesopause Regionmentioning

confidence: 99%

“…These particles arise from a variety of processes such as ionization from solar radiation, particle precipitation from the lower thermosphere, and the ablation of meteors (Brasseur and Solomon, 1986). The mechanism proposed by Havnes and Sigernes (2005) follows from an assumption that a given concentration of positive ions in the background environment is available for absorbing a certain number of electrons in a rapidly expanding and diffusing meteor trail. The number of electrons removed from the trail in this way is expected to be relatively independent of the initial density of electrons in the trail (i.e.…”

Section: Decay Times Within the Mesopause Regionmentioning

confidence: 99%

“…Each method of temperature estimation that uses ablating meteors requires the assumption that ambipolar diffusion alone governs the decay of the underdense meteor echoes. However, alternative mechanisms exist, which can also affect the decay rate (Dyrud et al, 2001;Havnes and Sigernes, 2005;Dimant and Oppenheim, 2006a,b;Holdsworth et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

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On the validity of the ambipolar diffusion assumption in the polar mesopause region

et al. 2008

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Abstract. The decay of underdense meteor trails in the polar mesopause region is thought to be predominantly due to ambipolar diffusion, a process governed by the ambient temperature and pressure. Hence, observations of meteor decay times have been used to indirectly measure the temperature of the mesopause region. Using meteor observations from a SKiYMET radar in northern Sweden during 2005, this study found that weaker meteor trails have shorter decay times (on average) than relatively stronger trails. This suggests that processes other than ambipolar diffusion can play a signicant role in trail diffusion. One particular mechanism, namely electron-ion recombination, is explored. This process is dependent on the initial electron density within the meteor trail, and can lead to a disproportionate reduction in decay time, depending on the strength of the meteor.

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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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On the influence of background dust on radar scattering from meteor trails

Cited by 23 publications

References 29 publications

Neutral atmosphere temperature trends and variability at 90 km, 70 °N, 19 °E, 2003–2014

Neutral atmosphere temperature trends and variability at 90 km, 70 °N, 19 °E, 2003–2014

On the validity of the ambipolar diffusion assumption in the polar mesopause region

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

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On the influence of background dust on radar scattering from meteor trails

Cited by 23 publications

References 29 publications

Neutral atmosphere temperature trends and variability at 90 km, 70 °N, 19 °E, 2003–2014

Neutral atmosphere temperature trends and variability at 90 km, 70 °N, 19 °E, 2003–2014

On the validity of the ambipolar diffusion assumption in the polar mesopause region

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

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Product

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Neutral atmosphere temperature trends and variability at 90 km, 70 °N, 19 °E, 2003–2014

Neutral atmosphere temperature trends and variability at 90 km, 70 °N, 19 °E, 2003–2014