HIWIND Balloon and Antarctica Jang Bogo FPI High Latitude Conjugate Thermospheric Wind Observations and Simulations

Abstract

Using the High attitude Interferometer WIND observation balloon and Antarctic Jang Bogo station high latitude conjugate observations of the thermospheric winds we investigate the seasonal and hemispheric differences between the northern and southern hemispheres in June 2018. We found that the summer (northern) hemisphere dayside meridional winds have a double-hump feature, whereas in the winter (southern) hemisphere the dayside meridional winds have a single hump feature. We attribute that to stronger summer, perhaps, northern hemisphere cusp heating. We also compared the observation with NCAR Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) model. The TIEGCM reproduced the double-hump feature because of added cusp heating. The summer hemisphere has stronger anti-sunward winds. This is the first time we have very high latitude conjugate thermospheric wind observations. Using balloon instrument in the northern hemisphere and ground based instrument in the southern hemisphere, we study the conjugacy of the thermospheric winds of high latitudes. We found that the more summer hemispheric heating alters the thermospheric winds and resulted in a double-hump feature on the dayside meridional winds. We also used model with cusp heating to simulate the winds and were able to reproduce the double-hump feature. The stronger summer (northern) hemispheric power could be the cause of double hump in the dayside meridional winds Thermosphere Ionosphere Electrodynamics General Circulation Model (TIEGCM) was able to reproduce the double-hump features seen by the High attitude Interferometer WIND observation, and single hump in the winter hemisphere observed at Jang Bogo station TIEGCM overestimates the poleward wind on the dayside and equatorward wind on the nightside in the summer hemisphere