Occurrence of Kelvin-Helmholtz Billows in Sea-breeze Circulations |
| |
Authors: | R S Plant G J Keith |
| |
Institution: | (1) Joint Centre for Mesoscale Meteorology, University of Reading, Earley Gate, Reading, RG6 6BB, UK;(2) Environment Agency, Rivers House, Higher Shaftesbury Road, Blandford Forum, Dorset, DT11 8ST, UK |
| |
Abstract: | Centred at the interface between the sea-breeze and the return flow aloft, Kelvin-Helmholtz billows (KHB) are an important
feature of the turbulent structure of some sea-breeze circulations (SBCs). In other SBCs, there are no prominent KHBs observed.
Factors governing the appearance of billows are determined from a database of 139 sea breezes, constructed from two years
of summertime surface observations at a site on the south coast of England. Post-frontal oscillations occur in the surface
data for some SBCs and are interpreted as indicating possible KHBs aloft. The SBCs are formed under a wide range of synoptic
conditions, enabling various measures of possible billow occurrence to be related to properties of the large-scale, ambient
flow. Consistent with laboratory experiments of density currents, KHBs are suppressed for propagation into a head wind and
enhanced with a tail wind. They are also found to be enhanced for stronger ambient wind speeds, while large-scale coast-parallel
flow is effective in suppressing the billows. |
| |
Keywords: | Kelvin-Helmholtz billows Post-frontal oscillations Sea breeze Surface observations |
本文献已被 SpringerLink 等数据库收录! |
|