Hartmut
Peters
hpeters@rsmas.miami.edu
RSMAS/MPO Fax:
+305 421-4696
University of
Miami Telephone:
+305
421-4032
4600 Rickenbacker Causeway
Miami, FL 33149, USA
Education:
Johannes-Brahms Gymnasium, Pinneberg, Germany: Abitur, 1966
University of Kiel, Germany, Oceanography: B.S. (Vordiplom), 1971; M.S. (Diplom), 1974; Ph.D. (Dr.rer.nat.), 1981
Experience:
University of Miami: Research Associate Professor, 1996-Present
State University of New York at Stony Brook: Assistant Professor, 1989-1996
University of Washington: Oceanographer, 1987-1989; Oceanographer/Postdoctoral Research Associate , 1984-1987
University of Kiel, Germany: Assistant Professor, 1983-1984; Research Associate, 1981-1983, 1974-1979
Publications
Click here
for a list of selected publications or
here for a nearly complete list of publications. The list contains
links for downloading the actual PDF files of the papers, even old ones.
Relevant Research Links
MPO
Experimental Physical Oceanography, Ocean Technology and
Instrumentation
Teaching
In the fall semester 2006 I taught Atmosphere Ocean Turbulence (MPO 664).
The syllabus of Geophysical Fluid Dynamics II (MPO 611) from spring 2006, can be found here. For a list of classes taught over the years click here.
Projects
There is a continuing need to parameterize turbulent mixing in numerical circulation models. A rational means of treating low-Richardson number shear-driven turbulence is through two-equation turbulence closures of "q-l" kind (e.g. Mellor & Yamada) or "k-e" kind. Dr. Helmut Baumert of IAMARIS, Hamburg, Germany, and I have been working on making physical and mathematical sense of closure models. This theoretical work begun with Baumert and Peters (2000) and Baumert and Peters (2004). Numerical simulations of dissipation rates and turbulent length scales are compared with observation in Peters et al. (2005, Chapter 39 in "Marine Turbulence" - Baumert, Simpson and Sündermann, eds., Cambridge Univ. Press. Since April 2004 the work has been continuing with NSF funding with the participation of Tamay Özgökmen and Mehmet Ilicak.
There are multiple strands to our work. Mehmet Ilicak, our Ph.D. student, is examining turbulence closures in partially turbulence-resolving VLES models and also in conventional, comparatively low-resolution, hydrostatic 3D circulation models, the latter in a study of the outflow from the Red Sea into the Gulf of Aden. Peters and Baumert (2007) have completed the work begun in Peters et al. (2005, see above) in validating a simple, rational k-e closure against estuarine turbulence measurements. Maybe not incidentally, this closure works well in the 3D simulations of the Red Sea outflow. This closure stays within the conventional bounds of turbulence closure in assuming that there is turbulence and mean shear, which provides all the energy input into the turbulence.
As stratified flows support internal waves, and as these are ubiquitous and generate turbulence, the usual two-component Reynolds decomposition into mean and turbulence is wrong - and a true mother of all problems. Under the lead of our theoretician Helmut Baumert we are working toward closures which explicitly account for the energy interchange between waves, turbulence, and mean flow.
Latest results:
Part of the past activity has been within CARTUM - Comparative Analysis and Rationalization of Second-Moment Turbulence Models, a "brainstorming" initiative of 1999-2001 which was sponsored by the European Commission. It attempted to critically review turbulence modeling with special respect to closure models. Its findings appeared in 2005 as the book Marine Turbulence: Theories, Observations and Models, H. Z. Baumert, J. H. Simpson and J. Sündermann, editors, Cambridge University Press.
New Microstructure Profiler
We have acquired a new microstructure profiler with funds provided by the Office of Naval Research through the DURIP Program. The profiler was designed and built by RGL Consulting and Rockland Oceanographic in Victoria, B.C. We tested the almost completed profiler in Saanich Inlet and the Sansum Narrows in the Vancouver Island area on Oct. 15, 2004.
Climate Process Team Gravity
Currents
It is the depths of world ocean that hold the bulk of the heat capacity
of the atmosphere-ocean system. Hence the vertical overturning
circulation of the oceans is a crucial factor in climate and climate
change on longer time scales. NSF is funding a team of modelers
and observationalists charged with the task of improving the
representation of gravity currents in climate models. Gravity
currents are one process in the downward branch of the vertical
overturning. They transport to depth waters formed near the
surface in marginal seas such as the Mediterranean Sea, the Arctic
Seas, the Red Sea, and Antarctic waters. CPT Gravity Currents Home Page. Results
have been published or submitted in
Chang et al. (2005)
and Xu et al. (2005).
The "Red Sea Outflow Experiment" (REDSOX) is to investigate the saline outflow from the Red Sea in the Gulf of Aden over a wide range of scales from small-scale turbulence to the pathways of Red Sea water on its way into the Indian Ocean. Principal investigators are Bill Johns and Hartmut Peters (RSMAS/UM) and Amy Bower and Dave Fratantoni (WHOI). The first cruise one the R/V "Knorr" took place from February 5 to March 15, 2001. Our operations were very successful as detailed in the REDSOX-1 Cruise Report. The second cruise on the R/V "Maurice Ewing" lasted from August 19 to September 12, 2001, the day after the terror attack on the United States of Sept. 11, 2001. Prior to this event, we had our own experience with political volatility in parts of the world as reported in Nature of 13-Sep-01. (The "Ewing" was attacked presumably by militiamen from northern Somalia.) The REDSOX-2 cruise report details our observations. My focus within REDSOX is on the turbulent mixing in the descending Red Sea plume. We have repeatedly deployed a five-head acoustic Doppler current profiler on the sea floor in order to measure the Reynolds stress at 5-40 m above the bottom. The entrainment on the upper edge of the plume can be estimated by observing the overturning in the water column, i.e. by measuring smallscale instabilities in the density profile. The interfacial mixing turned out to be unexpectedly energetic with 20-m overturns and eddy diffusivities of the order of 10^-2 m^2/s, very large values for oceanic settings. The turbulence studies are embedded in investigations of the momentum and mass budgets of the descending plume and of the general spreading of Red Sea water in the Gulf of Aden. For published results see the bibliography. Funded by the National Science Foundation with continuing support for the further analysis.
The Office of Naval Research funded an extensive suite of observations in
the Adriatic Sea. Part of this is the experiment "Dynamics of Localized
Currents and Eddy Variability in the Adriatic" (DOLCEVITA).
Participants come from the USA, Italy, Croatia and Austria. In close
collaboration with Craig Lee of the Applied Physics Lab, University of
Washington, I contributed a component of turbulence observations with focus
on measuring turbulence during wintertime convection in the northern
Adriatic. The DOLCEVITA-1 cruise on the Knorr took place from
31-Jan-03 to 24-Feb. The cruise
report gives a first impression of the observations. We wanted
wind, bora events, and we got it. Winds speeds exceeded 45 knots at times,
but sea states remained modest owing to short fetch. We directly
observed convection and turbulence, and intriguing, energetic small-scale
horizontal current variability as well as extremely narrow fronts.
Results from the Knorr cruise have been
published in J. Geophys. Res.. A paper on the microstructure observations from the May 2003 cruise on the R/V G. Dallaporta
appeared
in Geofizika.
In May 2001, we returned to the Hudson River in the New York City area to explore the spatial variability of turbulent mixing. Working from the R/V "Lionel A. Walford" of the New Jersey Marine Sciences Consortium, we took sections with the "Shallow Water Microstructure Profiler" (SWAMP) and an ADCP mounted over the side. We focused on the vicinity of the George Washington Bridge where varying channel cross section and curvature appear to give rise to hydraulic control. The last 2 days of our operations were coordinated with a dye release experiment done by Bob Chant, Rocky Geyer and Bob Houghton (Rutgers, Woods Hole, Lamont, respectively). It appears to be the first time ever that turbulent mixing in an estuary was simultaneously observed through dye dispersion and microstructure measurements. For more detail see the cruise report. Scientific results are reported in Peters (2003). Funded by the Hudson River Foundation.
"Four Dimensional Current Experiment" in the Florida Current off Ft. Lauderdale
This experiment observed surface and subsurface currents and stratification with an ocean surface current Doppler radar (OSCR), with autonomous underwater vehicles equipped with upward and downward looking acoustic Doppler current profilers and a CTD, with shipborne ADCP and CTD, and with moored current meters and CTDs. Field measurements from July-August 1999 provide an unprecendented view of energetic variability at small spatial sales (order of kilometers) and temporal scales (order of hours) in the coastal ocean. The setting is unsual in that the shelf is very narrow, ca. 5 km wide, and that the area on the shelf is affected by the adjacent Florida Current, the root of the Gulf Stream. I took the lead in analyzing the highly energetic "10-h signal." The 4D Experiment was funded by the Office of Naval Research.
RESOURCES: functions related to ocean and atmosphere thermodynamics
Seawater functions in Fortran 77
Seawater functions in matlab, alternate
See also Siedler and Peters (1986).
