First daytime thermospheric wind observation from a balloon-borne Fabry-Perot interferometer over Kiruna (68N)

HIWIND (High altitude Interferometer WIND Observation) is the first balloon Fabry-Perot interferometer (FPI) to achieve successful thermospheric wind measurement for both day and night. By flying at ̃40 km altitude, HIWIND avoids the high solar scattering background and enables daytime remote sensing of Doppler shift in airglow for thermospheric wind observation. During its first flight in June 2011 from Kiruna, (68N, 65 MLAT), HIWIND observed persistent equatorward winds, while the NCAR TIEGCM model predicted poleward winds on the dayside. Combined with simultaneous EISCAT incoherent scatter radar observation, HIWIND yielded a daytime Burnside factor value of 0.85. HIWIND data appear to suggest that upward vertical winds near the auroral oval may be the cause for large differences between the FPI measured and radar derived winds near midnight.