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On 30 October 2004 during a strong solar proton event, layers of enhanced\udbackscatter from altitudes between 55 and 75km have been observed by both\udESRAD (52MHz) and the EISCAT VHF (224MHz) radars. These echoes have\udearlier been termed Polar Mesosphere Winter Echoes, PMWE. After considering\udthe morphology of the layers and their relation to observed atmospheric\udwaves, we conclude that the radars have likely seen the same phenomenon even\udthough the radars' scattering volumes are located about 220km apart and\udthat the most long-lasting layer is likely associated with wind-shear in an\udinertio-gravity wave. An ion-chemistry model is used to determine parameters\udnecessary to relate wind-shear induced turbulent energy dissipation rates to\udradar backscatter. The model is verified by comparison with electron density\udprofiles measured by the EISCAT VHF radar. Observed radar signal strengths\udare found to be 2-3 orders of magnitude stronger than the maximum which can\udbe expected from neutral turbulence alone, assuming that previously\udpublished results relating radar signal scatter to turbulence parameters,\udand turbulence parameters to wind shear, are correct. The possibility\udremains that some additional or alternative mechanism may be involved in\udproducing PMWE, such as layers of charged dust/smoke particles or large\udcluster ions

The dynamical background of polar mesosphere winter echoes from simultaneous EISCAT and ESRAD observations