Dense Filaments, Turbulence, and Frontogenesis in the holds a Ph.D. in tropical meteorology, M.Tech. Degree in Atmospheric Science and M.S. Degree in Meteorology. Hurricane Weather Research and Forecast (HWRF) modeling system. Dense Filaments, Turbulence, and Frontogenesis in the Ocean Surface Boundary Layer The spatial and temporal state of the upper ocean boundary layer is determined by a set of poorly understood complex interactions between submesoscale turbulence, (e.g., fronts, dense filaments and coherent vortices) and small-scale boundary-layer turbulence. Of particular interest here is the life-cycle of a cold dense filament undergoing frontogenesis in the presence of wind-wave generated Langmuir turbulence. Cold filaments generate secondary circulations that are frontogenetic with super-exponential sharpening of the cross-filament buoyancy and horizontal velocity gradients.  Within less than a day, the frontogenesis is arrested at a very small width, < 100 m, primarily by boundary layer turbulence, with a subsequent slow decay by further turbulent mixing. This phenomenon is examined in Large-Eddy Simulations (LESs) with resolved turbulent motions in large-horizontal domains using 10^9 gridpoints. Winds and waves are oriented in directions both perpendicular and parallel to the cold filaments in the LES. The LES solutions show that the boundary layer turbulence is strikingly inhomogeneous in relation to the submesoscale filamentary currents and density stratification. Also, the spatial and temporal evolution of frontogenesis is dependent on the orientation of the winds and waves, and for some wind-wave combinations the sharp filament exhibits an unexpected submesoscale lateral shear instability that facilitates the frontogenetic arrest. Tuesday, November 15, 2016 11:00-12:15 PM 216 DeBartolo Hall Dr. Peter Sullivan Senior Research Scientist National Center for Atmospheric Research (NCAR) Boulder, CO If you interested in meeting individually with Dr . Sullivan, please contact Debbie at 631-1083 Peter Sullivan is a Senior Scientist in the Mesoscale and Microscale Laboratory at the National Center for Atmospheric Research. His research interests include: simulations and measurements of geophysical turbulence, subgrid-scale modeling, air-sea interaction, effects of surface gravity waves on marine boundary layers, impacts of stratification, and numerical methods.  He uses large-eddy and direct numerical simulations to investigate turbulent processes in both the atmospheric boundary layer and the ocean mixed layer.  He has participated in and planned several field campaigns focused on the measurement of subgrid scale variables in the atmosphere.  Prior to coming to NCAR, Peter worked for six years as a Senior Specialist Engineer in Aerodynamics Research at the Boeing Company.