Lidar observations of middle atmosphere temperature variability over low latitude

Abstract

In this paper, 246 Rayleigh lidar observations covering the altitude range of stratosphere and mesosphere collected during the period March 1998 - December 2001 (37 months) using Indo-Japanese Lidar at National MST Radar Faculty (NMRF), Gadanki (13.8°N, 79.2°E), India. are presented. The atmospheric density profiles were derived. Using the limited database, a climatological structure of temperature over a tropical site giving seasonal variations of upper stratosphere and mesospheric region is also presented. It has been observed over Gadanki, that the stratopause is quite broad and occurred in the range of 43-58 km with the temperature maximum observed in winter and equinox periods. A semi-annual variation is seen clearly around 70 km with maxima at May/June and Dec/Jan. Mesospheric temperature shows strong inversion very often. The average climatology over 37 months period is found to compare well with a reference atmosphere model (MSISE 90). The observed temperature is, in general, colder throughout the year in the 30-45 km range and warmer in summer at 70-80 km as compared to the model derived values. The present study suggests that the 45-55 km region is less affected by temperature variability, which is well suited for the detection of possible temperature trends.