Professor Carl A. Friehe

Department of Mechanical and Aerospace Engineering

University of California, Irvine

Irvine, CA 92697

E-mail: cfriehe@uci.edu
Office: REC 202
Phone: (949) 824-6159
FAX: (949) 824-4229

 

 

 

 

 

General Information

Research Projects

Courses

Recent Publications

Links0

 

General

Projects

Courses

Publications

Links

 

 

 

 

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.

 

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Research Projects

 

  • MARINE BOUNDARY LAYERS EXPERIMENT
    The unique research platform R/P FLIP was used for 30 days in April-May off of Monterey, California, to study the interactions of the wind and upper ocean in the Marine Boundary Layer (MBL) experiment, Phase II. The physics of the energy exchanges between the air and ocean are not well understood and require specific experiments to obtain parameterizations of the complex processes for use in computer models of weather forecasting, climate studies, ocean wave prediction and upper-ocean thermal structure.

  • TOGA COARE/CEPEX
    The UCI group processed the NOAA/AOC WP-3D Aircraft data gathered during the Tropical Ocean Global Atmosphere Coupled Ocean Response Experiment (TOGA COARE) and the Central Equatorial Pacific Experiment (CEPEX). These pages are intended to provide the users with information about the data processing and to serve as a means for data transfer.

Courses

    MAE 281

    Fundamentals of Digital Signal Analysis (3)

    Fall '97

    MAE 162

    Engineering Meteorology (4) (Same as EARTHSS 162, LEC A)

    Winter '98

 

 

Recent Publications

  • MBL Experiment Publications
  1. C. A. Friehe et al., Wind and turbulence profiles in the surface layer over the ocean. 12th AMS Symposium on Boundary Layers and Turbulence, UBC, Vancouver, BC, Canada, July 1997.
  2. C. A. Friehe et al., Wind and turbulence profiles in the surface layer over ocean waves. Wind-Over-Wave Couplings: Perspectives and Prospects, Salford University, England, April, 1997.
  3. C. A. Friehe et al., Structure in the atmospheric surface layer over open ocean waves: representation in terms of phase averages.
  4. C. A. Friehe et al., Structure of the atmospheric surface layer over the ocean waves---phase averaging via the Hilbert Transform. 12th AMS Symposium on Boundary Layers and Turbulence, UBC, Vancouver, BC, Canada, July 1997.
  5. Song, X., and Friehe, C.A. (1997) Surface Air-sea Fluxes and Upper Ocean Heat Budget at 156E, 4S During TOGA COARE, Journal of Geophysical Research.
  6. Song, X., Friehe, C.A. and D. Hu (1996) Ship-board Measurements and Estimations of Air-Sea Fluxes in the Western Tropical Pacific Ocean, Boundary-Layer Meteorology.
  7. Oncley, S. P., Friehe, C. A., LaRue, J. C., Businger, J. A., Itsweire, E. C. and S. Chang, ``Surface Layer Fluxes, Profiles and Turbulence Measurements over Uniform Terrain under Near-Neutral Conditions,'' J. Atmos. Sci., 53, No. 7, 1029-1044 (1996).

  • TOGA COARE and CEPEX Publications
  1. Friehe, C. A., S. P. Burns, D. Khelif and X. Song, (1996), Meteorological and Flux Measurements from the NOAA WP3D Aircraft in TOGA COARE , American Meteorological Society, pp. J42-J45.
  2. Song, X., Friehe, C.A. and D. Hu, (1996), Ship-board Measurements and Estimations of Air-Sea Fluxes in the Western Tropical Pacific Ocean, submitted to Boundary-Layer Meteorology.
  3. Song, X., and Friehe, C.A., Surface Air-sea Fluxes and Upper Ocean Heat Budget at 156E, 4S During TOGA COARE, submitted to Journal of Geophysical Research.
  4. Khelif, D., C. A. Friehe and S. P. Burns, 1997: ``Boundary-Layer and Turbulent Flux Measurements From the TOGA COARE Aircraft,'' 22nd Conference on Hurricanes & Tropical Meteorology, American Meteorological Society, 254-255.
  5. Khelif, D., S. P. Burns and C. A. Friehe, 1998: ``Meteorological and Turbulence Measurements on the NOAA WP-3D Aircraft,'' submitted to J. Atmos. and Oceanic Tech.

 

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Last updated: December 12, 1997.