Geomagnetic quiet-time behavior of the thermospheric meridional winds and temperature at Albany, New York

Abstract

High resolution Fabry-Perot interferometer data were used to deduce the thermospheric temperatures and meridional winds at a mid-latitude station, Albany (42.7°N, 73.8°W), New York, during 6 geomagnetically quiet nights in the year 1981. The meridional wind velocities are generally equatorward and they increase from less than 100ms −1 shortly after sunset, to a maximum value of around 170ms −1 before local midnight, and then decrease to small values toward early morning hours and become poleward by morning twilight. The neutral temperature varied between 890 and 1450 K and a detailed comparison was made with the predictions from the empirical models of MSIS-83 and MSIS-86. The observed variations in the thermospheric neutral temperatures are in qualitative accord with the computed structure based on the MSIS models. In general, the MSIS-86 model gave temperatures smaller than the observed values by nearly 42 K compared to the 106 K difference obtained between the MSIS-83 model values and the experimental temperatures. In summary, the results of this study show a good agreement between the observed temperature structure and the MSIS model values for quite-time geomagnetic conditions. The mean meridional wind is essentially equatorward in agreement with the thermospheric circulation theory and is also in general accord with other mid-latitude optical wind observations.