Solar cycle dependence of thermospheric neutral winds at Arecibo, Puerto Rico

Abstract

The 12-month running averages of the meridional wind velocities obtained at Arecibo Observatory, Puerto Rico, using a Fabry-Perot interferometer, shoed transitions during the night which were of different natures during sunspot cycle maximum and minimum. The meridional component at 18-21 AST (Atlantic Standard Time) shifted from large southward at sunspot maximum to small northward at sunspot minimum. The meridional and zonal components at other local times showed small variations. The F-layer height obtained from incohered scatter radar measurements decreased from about 400 km to about 300 km from sunspot maximum to sunspot minimum in a manner compatible with the variations of neutral wind.