Sodar observations of the stable boundary layer height in relation to the nocturnal low-level jet

Abstract

Two different patterns of the time evolution of the stable boundary layer height under clear conditions can be typically observed with acoustic sounders in midlatitudes: a steady ("parabolic") growth during the whole night (type I) or an increase during the first hours followed by a marked decrease towards the end of the night (type II). Analysing the height evolution and wind field for ten nights of each type it is concluded that the second pattern seems to be an indicator for the presence of a nocturnal low-level jet, a fact that might be used as a diagnostic tool to identify the nocturnal inertial oscillation solely from a sodar facsimile record.

Keywords

• sodar observations
• parabolic
• boundary layer
• sodar-beobachtungen
• parabolisch
• grenzschicht