Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8139685 | Journal of Atmospheric and Solar-Terrestrial Physics | 2018 | 33 Pages |
Abstract
Medium Frequency (MF) radar located at Kolhapur (16.8°N, 74.2°E) has been upgraded in August 2013. Since then continuous measurements of zonal and meridional winds are obtained covering larger altitudes from the Mesosphere and Lower Thermosphere (MLT) region. Diurnal, monthly and seasonal variation of these mean winds is presented in this study using four years (2013-2017) of observations. The percentage occurrence of radar echoes show maximum between 80 and 105â¯km. The mean meridional wind shows Annual Oscillation (AO) between 80 and 90â¯km altitudes with pole-ward motion during December solstice and equatorial motion during June solstice. Quasi-biennial oscillation (QBO) with weaker amplitudes are also observed between 90 and 104â¯km. Zonal winds show semi-annual oscillation (SAO) with westward winds during equinoxes and eastward winds during solstices between 80 and 90â¯km. AO with eastward winds during December solstice and westward wind in the June solstice is also observed in the mean zonal wind between 100 and 110â¯km. These results match well with that reported from other latitudes within Indian region between 80 and 90â¯km. However, above 90â¯km the results presented here provide true mean background winds for the first time over Indian low latitude region as the present station is away from equatorial electro-jet and are not contaminated by ionospheric processes. Further, the results presented earlier with an old version of this radar are found contaminated due to unknown reasons and are corrected in the present work. This upgraded MF radar together with other MLT radars in the Indian region forms unique network to investigate the vertical and lateral coupling.
Keywords
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geophysics
Authors
A.K. Sharma, H.P. Gaikwad, M. Venkat Ratnam, O.B. Gurav, L. Ramanjaneyulu, G.A. Chavan, S. Sathishkumar,