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Boundary‐layer mean dynamic characteristics of cold fronts over Brittany
Author(s) -
Lefloch Claire,
AmoryMazaudier Christine
Publication year - 1998
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49712454710
Subject(s) - sodar , mesoscale meteorology , cold front , boundary layer , front (military) , radiosonde , meteorology , geology , atmospheric sciences , climatology , planetary boundary layer , mechanics , oceanography , geography , physics
The European Mesoscale Frontal Dynamic Project/Fronts 87 lasted from 18 October 1987 to 13 January 1988. Its aim was to study the dynamics of activ cold fronts observed over the area centred on the English Channel between England and France. In this paper the mean dynamic characteristics derived from the five intensive observation phases during which the acoustic sodar at Brest was operating are presented. Observations of wind at ground level, sodar wind in the surface and the boundary layers, sodar friction velocity, and radiosonde wind measurements are combined to determine the dynamics of a ‘mean cold front’ in the boundary layer. In spite of the important variability of the frontal phenomena, ‘mean’ frontal characteristics (over Brittany, in autumn) can be identified. The analysis shows that for all the cases, except for the dry cold front, the variations of the dynamical parameters at the frontal passage are closely related. Variations of the friction velocity and the horizontal wind in the surface and the boundary layers are linearly related.