Ca+ ion layer observed by a resonance scattering lidar at Syowa in the Antarctic

• Main Authors: Ejiri, M., Nishiyama, T., Tsuda, T., Tsutsumi, M., Tsuno, K., Makoto, A., Takuya D, K., Ogawa, T., Satoshi, W., Nakamura, T.
• Format: Conference Object
• Language: English
• Published: 2023
• Subjects: Antarctic; The Antarctic; Antarc*; National Institute of Polar Research
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5021697

Layers of metal ions in the mesosphere and lower-thermosphere (MLT) are produced by meteoric ablation. The meteoric metal ions have relatively long chemical lifetime in the MLT region and behave as plasma affected by neutral atmosphere dynamics. Ca + is one of meteoric metal ion and only one ion, which can be measured its vertical profile from the ground by a lidar sounding. Ca + lidar observations have been conducted at the low and mid latitudes in the northern hemisphere only. A resonance scattering lidar developed by the National Institute of Polar Research (NIPR) was installed at Syowa (69S, 40E), Antarctic in 2017 and successfully obtained Ca + density profiles 6 nights in total in Spring of 2017 and 2018. The averaged Ca + layer observed at Syowa were with a FWHM of ~7 km, peak altitude of ~94 km, and peak density of ~10 cm -3 . The Ca + layers were observed in the main supply height region by meteor, however the layer was not always existing but sometimes disappeared. Temporal variation of Ca + density is compared with meteoric, geomagnetic, and gravity wave activities. In this presentation, we will discuss a main reason of Ca + layer disappearance with considering chemical lifetime of Ca + below 100 km.