Daytime upper mesospheric energetics over a tropical station, Trivandrum (8.5°N, 77°E): an investigation using the multiwavelength dayglow photometry

Abstract

This paper presents the first systematic measurements of "daytime" upper mesosphere temperatures over Trivandrum (8.5° N, 77° E), a near equatorial station in India. The measurements were made using a unique meridional scanning multiwavelength dayglow photometer. The first ever observation of the short-scale (within a day), seasonal (during a year), and spatiotemporal (spanning over a region of ~300 km centered at Trivandrum) variation of the daytime upper mesospheric temperature have been discussed. In general, the daytime mesospheric temperatures over this latitude exhibit large variability in their short scale seasonal, and spatiotemporal characteristics. The seasonal variation of temperature during the year 2005 exhibited a clear-cut semiannual oscillation pattern with minima around day numbers 75 and 250, which corroborate well with the earlier measurements of temperature over Thumba using the sounding rockets.