Crew/People :: Professor Carl A. Friehe

The research I am conducting centers mainly on turbulence in the atmosphere, particularly that responsible for energy exchanges between the earth's land and ocean surfaces and the overlying atmosphere. The transfer rates per unit area (fluxes) of sensible heat, water vapor and momentum are important to the overall energy balance of the earth's climate system, as well as in the dynamics and thermodynamics of the atmospheric boundary layer. Recently, there has also been interest in fluxes of trace gases such as CO2 between the atmosphere and land and ocean.

The flow of air over the land or sea is usually turbulent, so the fluxes are obtained in the statistical sense of averaged covariances of vertical turbulent velocity and the appropriate quantity being transferred: horizontal momentum (wind), temperature (sensible heat) and water vapor (latent heat). The study of turbulence is important in fluid mechanics, both in the ocean and atmosphere (geophysical turbulence) and in engineering flows. Geophysical turbulence measurements are often sought because the high Reynolds number of the flow, for which asymptotic theories apply. High fidelity measurements of these variables are required, and large amounts of data are collected for statistical convergence. The measurements, in conjunction with mean wind, temperature, humidity, pressure, etc., are used to parameterize the fluxes for use in numerical models and other studies and to study the physics of the boundary layer in a wide variety of weather situations.

The measurements are usually obtained from specialized instrumentation on research aircraft, towers over land or unique sea-going platforms such as the Scripps Institution of Oceanography's FLIP, a large spar buoy that provides a stable platform on the open ocean. Often, the turbulence measurements are part of larger multi-disciplinary experiments involving many platforms and investigators. Generally, one field experiment occurs per year. In the past, these have ranged from wind-driven coastal upwelling near the Northern California coast, boundary- layer cloud formation in the Atlantic Ocean, and energy exchange studies in the Western Pacific.

Some instrumentation is provided, especially on the research aircraft which are operated by national facilities such as NCAR or NOAA. Some is purchased (sonic anemometers, data systems) and some is built in-house (fine-scale temperature and humidity sensors). Data analysis is performed with high-capacity work stations at UCI. Access to national super computer facilities is obtained when required. Detailed modeling of some of the sensors is also done.

Funding for students and the research is obtained from the National Science Foundation Divisions of Atmospheric Sciences and Ocean Sciences, and the Office of Naval Research. Typically, one student is added per year. The research group also has undergraduate students and post-doctoral fellows. Collaboration is maintained with fellow researchers at Scripps, Woods Hole Oceanographic Institution, and other universities throughout the world.

 

:: Address and Contact Info. ::
University of California, Irvine Irvine, CA 92697-3975 USA
Carl A. Friehe
cfriehe@uci.edu
(949) 824-6159
Djamal Khelif
jamal@wave.eng.uci.edu
(949) 824-7437
Fax: (949)824-2249/8585

 

Carl A. Friehe

E-mail: cfriehe@uci.edu
Office: Engineering Gateway E1114
Phone: (949) 824-6159
FAX: (949) 824-2249

 

 

 

 

 

 

 

Department of Mechanical and Aerospace Engineering University of California at Irvine Irvine, CA, 92697-3975
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