Study of thermal structure differences from coordinated lidar observations over Mt. Abu (24.5° N, 72.7° E) and Gadanki (13.5° N, 79.2° E)

Som Sharma,S Lal,H Gadhavi,Y B Acharya,H Chandra,S Sridharan,S Chandra,A Jayaraman

doi:10.1186/s40623-015-0258-3

Abstract

Rayleigh lidars at Gadanki (13.5° N, 79.2° E), a tropical site, and at Mt. Abu (24.5° N, 72.7° E), a subtropical site, in India were operated simultaneously during the months of March, April, and May 2004. Significant differences are found in the temperatures over both the locations. Higher temperature, ~10–20 K, in the altitude region of 40–65 km is found during March 2004 over Mt. Abu. The mean stratopause temperature during March 2004 is found ~284 K at an altitude of 48 km over Mt. Abu, which is 18 K higher than the observed stratopause temperature of ~266 K over Gadanki. During April and May 2004, the temperatures over Mt. Abu are higher in the entire altitude range of 30–70 km than over Gadanki. Lidar-observed temperatures, over both the locations, are compared with the temperatures observed by SABER (Sounding of the Atmosphere using Broadband Emission Radiometry; onboard TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics)) and HALOE (Halogen Occultation Experiment; onboard UARS (Upper Atmosphere Research Satellite)). It is found that the lidar-observed temperatures are in qualitative agreement with the temperature observed by satellites, though quantitatively there are significant differences. Wave types of fluctuations have been noted in the upper stratosphere and in the lower mesosphere over both the locations.

Highlights

The middle atmosphere is an important region of the Earth’s atmosphere and plays very important role in deciphering atmospheric dynamics
Several studies have been made in the past for studying atmospheric temperature using a Rayleigh lidar, at mid- and high-latitude stations (e.g., Hauchecorne and Chanin 1980; Shibata et al 1986; Jenkins et al 1987; Whiteway and Carswell 1994)
Lidar probing of the Earth’s atmosphere was initiated at the Physical Research Laboratory (PRL) during the early 1990s, and initially lidar was operated over Ahmedabad, a subtropical location, for the study of stratospheric temperature and aerosols (Jayaraman et al 1995, 1996)

Summary

Introduction

The middle atmosphere is an important region of the Earth’s atmosphere and plays very important role in deciphering atmospheric dynamics. Temperature is an important physical entity to understand the chemical and dynamical features of this region (Singh et al 1996). A Rayleigh lidar provides vertically well-resolved density and temperature profiles in the middle atmosphere above the altitude of 30 km. Several studies have been made in the past for studying atmospheric temperature using a Rayleigh lidar, at mid- and high-latitude stations (e.g., Hauchecorne and Chanin 1980; Shibata et al 1986; Jenkins et al 1987; Whiteway and Carswell 1994). There have been a number of studies of the temperature structure at low latitudes

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Discussion

Conclusion