Abstract
Abstract. An all-sky VHF meteor radar (MR) has been continuously operated at Collm (51.3° N, 13° E) since summer 2004. The radar measures meteor parameters, diffusion coefficients, and horizontal winds in the mesopause region. There exists a temporal overlap of the MR wind measurements with co-located low-frequency (LF) ionospheric drift measurements until 2007. Comparison of MR and LF semidiurnal tidal phases allows to empirically determine the virtual height overestimation of LF reflection heights due to the group retardation of LF waves. LF reference heights have to be reduced by up to 20 km to match real heights. Correction of LF heights for group retardation allows to determine the wind underestimation by the LF method compared with meteor radar measurements and opens the possibility to continue long-term trend analysis using mesosphere/lower thermosphere winds.
Highlights
As background information for linear models, for validation purposes, and for estimation of further derived parameters there is a need for empirical models of wind parameters such as prevailing winds and tidal parameters in the mesosphere/lower thermosphere (MLT) region
While the former is the usual method for meteor radars (MR), the latter has been used for the conventional analysis of medium frequency (MF) radars as well as for the low-frequency (LF) method applied, e.g., with earlier measurements over Collm, Germany
Jacobi et al (2009) compared LF, MR and MF winds of one year, and found that MF and LF winds are smaller than MR ones and the differences increase with height
Summary
As background information for linear models, for validation purposes, and for estimation of further derived parameters there is a need for empirical models of wind parameters such as prevailing winds and tidal parameters in the mesosphere/lower thermosphere (MLT) region. Operational radars used for MLT wind measurements in general either use the Doppler shift of the reflected radio wave, or apply the spaced receiver (D1) method. While the former is the usual method for meteor radars (MR), the latter has been used for the conventional analysis of medium frequency (MF) radars as well as for the low-frequency (LF) method applied, e.g., with earlier measurements over Collm, Germany. In 2004, these measurements have been replaced by a VHF meteor radar, with some years of overlapping data This opens the possibility to analyse MR winds together with LF winds in nearly the same volume during the years 2005–2007.
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