Print Email Facebook Twitter Local characteristics of the nocturnal boundary layer in response to external pressure forcing Title Local characteristics of the nocturnal boundary layer in response to external pressure forcing Author van der Linden, S.J.A. (TU Delft Atmospheric Remote Sensing) Baas, P. (TU Delft Atmospheric Remote Sensing) van Hooft, J.A. (TU Delft Atmospheric Remote Sensing) van Hooijdonk, I.G.S. (Eindhoven University of Technology) Bosveld, Fred C. (Royal Netherlands Meteorological Institute (KNMI)) van de Wiel, B.J.H. (TU Delft Atmospheric Remote Sensing) Date 2017-11-01 Abstract Geostrophic wind speed data, derived from pressure observations, are used in combination with tower measurements to investigate the nocturnal stable boundary layer at Cabauw, the Netherlands. Since the geostrophic wind speed is not directly influenced by local nocturnal stability, it may be regarded as an external forcing parameter of the nocturnal stable boundary layer. This is in contrast to local parameters such as in situ wind speed, the Monin-Obukhov stability parameter (z/L), or the local Richardson number. To characterize the stable boundary layer, ensemble averages of clear-sky nights with similar geostrophic wind speeds are formed. In this manner, the mean dynamical behavior of near-surface turbulent characteristics and composite profiles of wind and temperature are systematically investigated. The classification is found to result in a gradual ordering of the diagnosed variables in terms of the geostrophic wind speed. In an ensemble sense the transition from the weakly stable to very stable boundary layer is more gradual than expected. Interestingly, for very weak geostrophic winds, turbulent activity is found to be negligibly small while the resulting boundary cooling stays finite. Realistic numerical simulations for those cases should therefore have a comprehensive description of other thermodynamic processes such as soil heat conduction and radiative transfer. Subject Boundary layerClimatology To reference this document use: http://resolver.tudelft.nl/uuid:9977ba4d-5e96-472c-b51d-f36ca5d40ca7 DOI https://doi.org/10.1175/JAMC-D-17-0011.1 ISSN 1558-8424 Source Journal of Applied Meteorology and Climatology, 56 (11), 3035-3047 Part of collection Institutional Repository Document type journal article Rights © 2017 S.J.A. van der Linden, P. Baas, J.A. van Hooft, I.G.S. van Hooijdonk, Fred C. Bosveld, B.J.H. van de Wiel Files PDF doi_10.1175JAMC_D_17_0011.1.pdf 1.34 MB Close viewer /islandora/object/uuid:9977ba4d-5e96-472c-b51d-f36ca5d40ca7/datastream/OBJ/view