First simultaneous multistation observations of the polar cap thermospheric winds

Abstract

Based on two northern (Eureka 80.0N, 85.9W, MLAT 88, and Resolute, 74.7N, 94.8W, MLAT 83) and one southern (Jang Bogo, 74.7S, 164.2E, MLAT 77) polar cap stations, simultaneous thermospheric wind data during the northern (December) and southern (June) winter month were obtained and compared with the NCAR TIEGCM model simulations driven by the Weimer ion convection model. The TIEGCM simulation overestimates the thermospheric wind by 30 to 60 %. The thermospheric winds at Eureka were larger than those at Resolute probably because Eureka is at high geomagnetic latitude. The observed ion drifts observed by RISR-N (Resolute Incoherent Scatter Radar North face) at Resolute also show the Weimer ion convection model overestimate the ion drift. The observation and simulation also appear to suggest the ion convection pattern in the Weimer model may be too large. The observed thermospheric winds at Jang Bogo are smaller than the TIEGCM but mostly in the zonal component. That the thermospheric winds are smaller at Jang Bogo than the two northern stations is likely due to its lower magnetic latitude. The results indicate the presence of internal structure in the thermospheric winds inside the polar cap and call for more observations in the polar cap to be undertaken.