VALIDATION OF THE CUTLASS HF RADAR GRAVITY-WAVE OBSERVING CAPABILITY USING EISCAT CP-1 DATA

Quasi-periodic fluctuations in the returned ground-scatter power from the SuperDARN HF radars have been linked to the passage of medium-scal e gravity waves. We have applied a technique that extracts the first r adar range returns from the F-region to study the spatial extent and c haracteristics of these waves in the CUTLASS field-of-view. Some ray t racing was carried out to test the applicability of this method. The E ISCAT radar facility at Tromso is well within the CUTTLASS field-of-vi ew for these waves and provides a unique opportunity to assess indepen dently the ability of the HF radars to derive gravity wave information . Results from Ist March, 1995, where the EISCAT UHF radar was operati ng in its CP-1 mode, demonstrate that the radars were in good agreemen t, especially if one selects the electron density variations measured by EISCAT at around 235 km. CUTLASS and EISCAT gravity wave observatio ns complement each other, the former extends the spatial held of view considerably, whilst the latter provides detailed vertical information about a range of ionospheric parameters.