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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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Recent
Publications
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- MBL Experiment Publications
- 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.
- 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.
- C. A. Friehe et al., Structure in the
atmospheric surface layer over open ocean waves:
representation in terms of phase averages.
- 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.
- 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.
- 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.
- 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).
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- TOGA COARE and CEPEX Publications
- 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.
- 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.
- 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.
- 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.
- 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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