First ground-based mesospheric measurements from central Himalayas

Abstract

First ground-based mesospheric temperature measurements from a central Himalayan station of India, Nainital (29.4°N and 79.5°E) have been carried out during January 2007 with the help of OH and O₂ airglow monitoring during night-time. The derived temperatures exhibit large amplitudes of ~3–6 h waves together with a longer period nocturnal tide-like feature with periodicity ~8–10 h. The observed temperatures are in agreement with the SABER derived temperatures, onboard the TIMED satellite and in less resemblance with MSIS-00 model data. The Krassovsky’s analysis shows the mean η values to be ~13.4 ± 2.5 and 10.05 ± 2.3; and ϕ values –23.8 ± 11° and –23.5 ± 11.5° for O₂ and OH data respectively, which are higher than the reported values in the literature. The deduced vertical wavelengths are found to be ~29.6 ± 11.1 km and 43 ± 21.5 km for O₂ and OH respectively, indicating the observed waves to be upward propagating.