Mesospheric anomalous diffusion during noctilucent clouds

• Main Authors: Laskar, Fazlul I., Stober, Gunter, Fiedler, Jens, Oppenheim, Meers M., Chau, Jorge L., Pallamraju, Duggirala, Pedatella, Nocholas M., Tsutsumi, Masaki, Renkwitz, Toralf
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus GmbH 2018
• Subjects: Meteorology & atmospheric sciences; Tides; Diffusion; Trails; Density profiles; Optical radar; Electron density; Lidar; Relative abundance; Diffusion rate; Radar; Noctilucent clouds; Meteor radar; Andenes
• Online Access: https://hdl.handle.net/2144/35757; https://doi.org/10.5194/acp-2018-1028

The Andenes specular meteor radar shows meteor-trail diffusion rates increasing on average by ~ 20% at times and locations where a lidar observes noctilucent clouds (NLCs). This high-latitude effect has been attributed to the presence of charged NLC but this study shows that such behaviors result predominantly from thermal tides. To make this claim, the current study evaluates data from three stations, at high-, mid-, and low-latitudes, for the years 2012 to 2016, comparing diffusion to show that thermal tides correlate strongly with the presence of NLCs. This data also shows that the connection between meteor-trail diffusion and thermal tide occurs at all altitudes in the mesosphere, while the NLC influence exists only at high-latitudes and at around peak of NLC layer. This paper discusses a number of possible explanations for changes in the regions with NLCs and leans towards the hypothesis that relative abundance of background electron density plays the leading role. A more accurate model of the meteor trail diffusion around NLC particles would help researchers determine mesospheric temperature and neutral density profiles from meteor radars. Public version