National Weather Center Colloquium

Small-Scale Turbulent Mixing at the Top of the Planetary Boundary Layer

Dr. Juan Pedro Mellado
Max Planck Institute for Meteorology
Hamburg, Germany

09 December 2014, 4:00 PM

National Weather Center, Room 1313
120 David L. Boren Blvd.
University of Oklahoma
Norman, OK

This Colloquium talk will present new insights into small-scale turbulent mixing at the boundary-layer top gained by means of direct numerical simulation (DNS). First it will be shown that, under cloud-free conditions, the entrainment zone is better characterized by two length scales rather than one. This duplicity of scales explains the observed dependence of entrainment-zone properties on weak and strong tropospheric stratification regimes. Second, for the stratocumulus-topped boundary layer, it will be demonstrated that mixing enhancement by wind shear can render evaporative cooling as important as provided by other sources of turbulence at the cloud top. This result implies that, even though its effect is indirect, wind shear must be taken into account for a correct representation of entrainment at the cloud top.

Speaker bio

For accommodations based on disability, or more details, please call 325-6561. All visitors without NOAA or University of Oklahoma identification must register at the registration desk on arrival. Visitor parking is available for all University visitors. However, faculty/staff/students must have a current multi-purpose parking permit. Additional parking is available at the Lloyd Noble Center (LNC) for those individuals who do not have a parking permit. You do not need a permit to park in one of 1,200 spaces reserved for CART bus riders, although you must ride the CART shuttle to park in the reserved area. This area is on the north central side of the Lloyd Noble Center. Elsewhere at the LNC, permits are required.

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National Weather Center Colloquium Seminar Series website