ARE POLAR-CAP GRAVITY-WAVES A HEAT-SOURCE FOR THE HIGH-LATITUDE THERMOSPHERE

Ground based measurements of thermospheric temperatures from Mawson, A ntarctica, often show a marked spatial gradient, with data taken polew ard of the discrete auroral oval up to 200 K or more warmer than measu rements taken in or equatorward of the oval. This region of increased temperature is identified as the polar cap. We suggest a possible cont ribution to polar cap heating may be from thermospheric gravity waves.