edu.ucar.opensky::articles:24321 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T06:40:26.501000 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7wd440h Marine boundary layers above heterogeneous SST: Across-front winds 2020-12-01T00:00:00Z publication https://n2t.org/ark:/85065/d7wd440h https://doi.org/10.1175/JAS-D-20-0062.1 Sullivan, Peter P. author McWilliams, J. C. author Weil, Jeffrey author Patton, Edward G. author Fernando, H. J. S. author UCAR/NCAR - Library publisher Turbulent flow in a weakly convective marine atmospheric boundary layer (MABL) driven by geostrophic winds U-g = 10 m s(-1) and heterogeneous sea surface temperature (SST) is examined using fine-mesh large-eddy simulation (LES). The imposed SST heterogeneity is a single-sided warm or cold front with temperature jumps Delta theta = (2, -1.5) K varying over a horizontal distance between <b>[0.1 , -6] km characteristic of an upper-ocean mesoscale or submesoscale regime. A Fourier-fringe technique is implemented in the LES to overcome the assumptions of horizontally homogeneous periodic flow. Grid meshes of 22 x 10(9) points with fine-resolution (horizontal, vertical) spacing (delta x = delta y, delta z) = (4.4, 2) m are used. Geostrophic winds blowing across SST isotherms generate secondary circulations that vary with the sign of the front. Warm fronts feature overshoots in the temperature field, nonlinear temperature and momentum fluxes, a local maximum in the vertical velocity variance, and an extended spatial evolution of the boundary layer with increasing distance from the SST front. Cold fronts collapse the incoming turbulence but leave behind residual motions above the boundary layer. In the case of a warm front, the internal boundary layer grows with downstream distance conveying the surface changes aloft and downwind. SST fronts modify entrainment fluxes and generate persistent horizontal advection at large distances from the front. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright 2020 American Meteorological Society (AMS). None eng geoscientificInformation