Latitudinal variation in vertical distribution of meteor decay time and its relation with mesospheric Ozone in the altitude range of 80-90 km

Abstract

Investigations on meteor trail decay time and its evolution in the mesosphere and lower thermosphere are very important to estimate the temperature in this region. The present study focuses on the vertical distribution of meteor decay times at three different latitudes to understand the mechanism responsible for the deviation of meteor decay time from the theoretical estimations below 90 km of altitude. The present study is based on measurements from three identical meteor radars located at equatorial (Kototabang: 0.2° S, 100.3° E), low (Thumba: 8.5° N, 76.9° E) and polar latitudes (Eureka: 80.0° N, 85.8° W). The results reveal a pronounced seasonal variation of vertical distribution of meteor decay time turning altitude (inflection point) over polar latitudes as compared to that over equatorial and low latitudes. Apart from direct estimations from meteor radar observations, the meteor decay time is estimated using temperature and pressure measurements from the SABER/TIMED. Above 90 km of altitude, decay times estimated from both methods are in good agreement. However, below 90 km of altitude, these estimations start deviating and it has been noted that the deviation increases with decreasing altitude. Further, observed meteor decay times correlated with ozone concentration at three representative altitude bins. The correlation analysis reveals a significant negative correlation at 80 - 90 km of altitude over the three latitudes indicating that an increase in ozone concentration results in decrease in meteor decay time. The significance of the present results lies in analyzing the vertical distribution of meteor decay time simultaneously from three radar locations representing equatorial, low and polar latitudes and evaluating the relation between ozone concentration and meteor decay time, quantitatively.