Observations on Stratospheric-Mesospheric-Thermospheric temperatures using Indian MST radar and co-located LIDAR during Leonid Meteor Shower (LMS)

R Selvamurugan,R Sridharan,C Raghava Reddi,C V Devasia,P B Rao,A R Jain

doi:10.5194/angeo-20-1869-2002

R Selvamurugan, R Sridharan + Show 4 more

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https://doi.org/10.5194/angeo-20-1869-2002

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Abstract

Abstract. The temporal and height statistics of the occurrence of meteor trails during the Leonid meteor shower revealed the capability of the Indian MST radar to record large numbers of meteor trails. The distribution of radio meteor trails due to a Leonid meteor shower in space and time provided a unique opportunity to construct the height profiles of lower thermospheric temperatures and winds, with good time and height resolution. There was a four-fold increase in the meteor trails observed during the LMS compared to a typical non-shower day. The temperatures were found to be in excellent continuity with the temperature profiles below the radio meteor region derived from the co-located Nd-Yag LIDAR and the maximum height of the temperature profile was extended from the LIDAR to ~110 km. There are, how-ever, some significant differences between the observed profiles and the CIRA-86 model profiles. The first results on the meteor statistics and neutral temperature are presented and discussed below. Key words. Atmospheric composition and structure (pres-sure, density, and temperature) History of geophysics (at-mospheric sciences) Meteorology and atmospheric dynamics (middle atmosphere dynamics)

Highlights

The Leonid Meteor Stream (LMS), having its origin from the Leo constellation located at 17◦ north declination and 11◦ right ascension of the celestial sphere, exhibits substantial increase of meteor fluxes in the Earth’s atmosphere at intervals of about 33 years
Since the estimated temperature using the meteor trail agrees well with independent estimates from a LIDAR providing continuity, the results shown in Fig. 7 are believed to prove the validity of the method of retrieval of temperature profiles using meteor trails, and this could be a valuable means of extending the maximum height of the temperature profiles at least up to 110 km
The main results obtained from the LMS observations can be summarized as follows: 1. There was a four-fold increase in the hourly meteor flux due to the Leonid meteor stream that occurred during 16–20 November 1999

Summary

Introduction

The Leonid Meteor Stream (LMS), having its origin from the Leo constellation located at 17◦ north declination and 11◦ right ascension of the celestial sphere, exhibits substantial increase of meteor fluxes in the Earth’s atmosphere at intervals of about 33 years. The co-located LIDAR, operating at 532 nm, has been used to make measurements of atmospheric temperature in the height range of 30–80 km region from the photon count, which is proportional to the molecular density, presuming that the atmosphere is in hydrostatic equilibrium. The exponential decay rate of the meteor echoes give the ambipolar diffusion coefficient, which, in turn, can be interpreted in terms of temperature of the atmosphere in the height range of 80–110 km, where sufficient number of meteor trails are observed. This paper presents the temporal and altitude distribution of Leonid’s meteor occurrences obtained during the LMS period, as well as the method of deriving a diffusion coefficient and of estimating the Mesospheric temperature. Simultaneous measurements of LIDAR and Indian MST radar are used to obtain the atmospheric temperature in the Mesospheric and Lower Thermospheric (MLT) region during this period

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