Mesospheric observations with the EISCAT UHF radar during polar cap absorption events: 3. Comparison with simultaneous EISCAT VHF measurements

HAL CCSD European Geosciences Union (EGU)

EISCAT Scientific Association ; EISCAT Scientific Association
Collis, P. N.
Rietveld, M. T.

International audience
Mesospheric observations were obtained by the EISCAT UHF and VHF radars during the solar proton event of March 1990. We present the first comparison of incoherent-scatter spectral measurements from the middle mesosphere using simultaneous, co-located observations by the two radars. VHF spectra observed with a vertical antenna were found to be significantly narrower than model predictions, in agreement with earlier UHF results. For antenna pointing directions that were significantly away from the vertical, the wider VHF radar beam gave rise to broadening of the observed spectra due to vertical shears in the horizontal wind. In this configuration, UHF spectral measurements were found to be more suitable for aeronomical applications. Both radar systems provide consistent and reliable estimates of the neutral wind. Spectral results using both the multipulse and pulse-to-pulse schemes were intercompared and their suitability for application to combined mesosphere ? lower thermosphere studies investigated.

[SDU.OCEAN] Sciences of the Universe/Ocean, Atmosphere; [SDU.STU] Sciences of the Universe/Earth Sciences; Journal articles

Annales Geophysicae
English

RNQ oai:HAL:hal-00316459v1
hal-00316459
893027412

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