Seasonal and local solar time variation of the meridional wind at 95km from observations of the 11.072-GHz ozone line and the 557.7-nm oxygen line

Ground-based spectrometers have been deployed to measure the concentration, velocity, and temperature of ozone in the mesosphere and lower thermosphere (MLT), using low-cost satellite television electronics to observe the 11.072-GHz line of ozone. The ozone line was observed at an altitude near 95 km at 38°N, 71°W using three spectrometers located at the Massachusetts Institute of Technology's Haystack Observatory (Westford, Massachusetts), Chelmsford High School (Chelmsford, Massachusetts), and Union College (Schenectady, New York), each pointed south at 88 elevation. Observations from 2009 through 2014 were used to derive the nightly averaged seasonal variation of the 95-km altitudemeridionalwind velocity, as well as the seasonally averaged variation of the meridional wind with local solar time. The results indicate a seasonal trend in which the winds at 95km are directed southward at about 10ms^-1 in the summer of the Northern Hemisphere and northward at about 10ms^-1 in the winter. Nighttime data from 25 to 15 local solar time show a gradual transition of the meridional wind velocity from about 220 to 20ms^-1. These variations correlate well with nighttime wind measurements using 557.7-nm optical airglowobservations fromtheMillstone Hill high-resolution Fábry-Perot interferometer (FPI) inWestford.