Pathfinder data sets take advantage of currently archived earth science data. Where necessary, sensors have been intercalibrated, algorithms improved, and processing procedures revised in order to produce long time-series, global measurements of ocean, land, and atmospheric properties essential for climate research. These data of the Earth's system are available to researchers now, nearly a decade before the advent of EOS, so they may become familiar with the handling of enormous volumes of the satellite data they will routinely analyze in just a few years. The lessons learned from the pathfinder programs will pave the way for the processing and management of terabytes of EOS data.
The National Environmental Satellite and Data Information Service (NESDIS) of NOAA has been producing estimates of SST operationally for more than a decade using high-resolution, multispectral infrared data from space-borne instruments. The primary sensor, flown on NOAA polar orbiting satellites, is the Advanced Very High Resolution Radiometer (AVHRR). Multichannel SST (MCSST) algorithms developed by NOAA/NESDIS produced the longest global record of satellite-derived SST we know (McClain et al., J. Geophys. Res., 90(C6), 11,587-11,601, 1985). However, because of known biases in the MCSST data, their utility for climate and global change research is questionable (Bates, Adv. Space Res., 14. 3, (3)5-(3)14, 1994), especially during episodes of high volcanic aerosol concentration in the troposphere and stratosphere.
The NOAA/NASA Pathfinder AVHRR SST project is providing an important new collection of AVHRR-derived SST data suitable for global change research. Daily (both day and night), global SST fields at 9 kilometer spatial resolution are being produced at the Jet Propulsion Laboratory. A joint effort between NOAA and NASA has resulted in an improved calibration of the AVHRR sensors and a better SST retrieval algorithm. Technological advances in computing in the past decade make it possible to process more and more data very efficiently. This, in turn, enables more sophisticated cloud detection and quality assurance methods to be applied, which results in a dramatic increase in believable SST retrievals for the Pathfinder SST data relative to its predecessor, MCSST. Preliminary analyses show that the Pathfinder SST data preserve more of the spatial and temporal variability found in the surface thermal expression of the oceans than does the MCSST data.
With a grant from NASA's Pathfinder Program office, ELIZABETH SMITH, research associate, has begun to assess the quality and validity of the Pathfinder SST data set. Are these estimates of SST more accurate than previous satellite-derived SSTs, or are there simply more data? According to data archivists at NASA and NOAA, the MCSST data have been used by hundreds of researchers since the early 1980's. This level of use of MCSST suggests the practicality of a thorough analysis of the spatial and temporal differences between the Pathfinder SST and the MCSST data. Preliminary analysis shows, in addition to the dramatic increase in the number of retrievals (see figure), that the MCSST data are about 1 warmer than the Pathfinder data (for weekly averaged data for 1987 and 1988). Future work will concentrate on comparisons between the satellite-derived SSTs and in situ measurements with known errors.
To obtain Pathfinder Sea Surface Temperature data, contact the Jet Propulsion Laboratory Physical Oceanography DAAC at podaac@podaac.jpl.nasa.gov, (818) 354-9890, or visit JPL's WWW site at http://sst-www.jpl.nasa.gov.
FIGURE CAPTION: The weekly average data coverage as a percent of the total number of oceanic pixels is shown for 1987 Pathfinder SST data (red) and MCSST data (blue) for both daytime and nighttime retrievals. Pathfinder SST data coverage is improved dramatically compared to MCSST data coverage due to better cloud detection algorithms and increased computing efficiency.
I believe the funding agencies should consider some demonstration uses of remote sensing in coastal waters. Innovative uses of the AVHRR visible bands would be especially interesting.
Larry P. Atkinson The four primary objectives of the workshop were: (1) to urge
international cooperation among Argentine, Brazilian, and Uruguayan
oceanographers, with additional cooperation by U.S. and European
scientists, for developing an observational and modeling program concerned
with the physical oceanography of the marginal and open ocean regimes of the
western South Atlantic; (2) to assess recent and ongoing programs by the
participating countries and other nations in the southwestern Atlantic; (3)
to develop an overview of the outstanding scientific issues not presently
being addressed but which can be addressed by the international forum; and
(4) to recommend future field and laboratory research.
JERRY MILLER was an invited participant in the workshop and gave a talk
entitled, ``Modeling of Santos Bight with the Princeton Ocean Model.''
Jerry also chaired the working group on ``Shelf and Western Boundary Current
Dynamics'' and is a co-author of the workshop proceedings which will be
published in early 1995. The proceedings are available on-line via Jerry's
home page at URL http://www.ccpo.odu.edu/~jerry/.
At CCPO, GLEN WHELESS fascinated the students with a Virtual Reality
demonstration consisting of a trip through the Chesapeake Bay without ever
leaving CCPO's computer room. The journey was a computer-based
flythrough simulation using a graphics program developed by Glen,
ARNOLDO VALLE-LEVINSON, and Bill Herman, a computer scientist at the
National Center for Supercomputer Applications. The virtual Chesapeake Bay
environment consisted of a 3D graphical representation of a Chesapeake Bay
bathymetry dataset which was colored according to depth and upon which
transparent 3D isosurfaces of salinity derived from numerical modeling
results were overlaid. The students were able to get hands-on experience
working in a virtual environment as each had a chance to take the controls
and fly through the Bay. Students were shown the main shipping channels of
the Bay and the abrupt topographic variations. Glen explained the concepts
of estuarine circulation and rotationally controlled flow, and he also
explained the Bay's seasonal salinity cycle, demonstrated by the animated
salinity fields.
LIZ SMITH talked with students about using satellites to study the
oceans. With the students ``at the helm'' of a MacIntosh computer,
Liz and the students explored two important ocean variables measured
from space, sea surface temperature and color/pigments. Together,
they examined the temperature and pigments of various parts of the
world's oceans in different seasons, and they talked about the
strengths and limitations of using satellites to study ocean
phenomena. Students were impressed by the varied amount of
oceanographic information available from studying satellite images.
To top off CCPO's demonstration, LARRY ATKINSON showed students all
of the amazing things available to the students on the Internet World
Wide Web.
Picture Caption: Liz Smith guides a student in the use of a
MacIntosh computer to examine the oceans' temperature and color.
In 1991, Cathy decided to combine her computer and science
background and enrolled in the physical oceanography program at ODU
under Eileen Hofmann. Her dissertation topic is entitled,
``Distribution and dynamics of Antarctic krill, Euphausia superba, in
relation to environmental variability.'' Cathy's research involves
analysis of a multi-disciplinary data set collected in the region west
of the Antarctic Peninsula and the development of time- and
space-dependent models of krill growth. As part of her dissertation
research, Cathy participated in two cruises to the Antarctic Peninsula
region. After graduation, Cathy plans to continue pursuing her
primary research interests in the capacity of a postdoctoral
associate.
G. V. R. K. VITTAL received his B.S. in mechanical engineering from
the Osmania University, Hyderabad, India. His M.S., from IISc,
Bangalore, India, is in mechanical engineering, specializing in fluid
mechanics applied to turbomachines. He worked as a scientific officer
at IISc for one year carrying out experiments to measure 3D boundary
layers using hot wire anemometry. Vittal enrolled in the Ph.D.
program at ODU in the fall of 1991 under the direction of
G. T. Csanady.
Vittal's dissertation work focuses on circulation in an isopycnal
layer of the subtropical thermocline driven at the surface outcrops.
Density surfaces which outcrop towards higher latitudes are the
potential regions where the surface processes influence the interior
thermocline layers. These processes are parameterized in terms of
potential vorticity fluxes which forces the interior circulation in
the present study. To elucidate the above form forcing, a constant
layer depth and nonlinear, quasigeostrophic model is studied for
simplicity and forced on the northern boundary by the PV gradient
flux. The results obtained reflect, to a certain extent, the features
in the eastern boundary currents, such as in the Azores frontal area.
Upon completion of Vittal's Ph.D. work, he intends to obtain a
postdoctoral position for a few years before returning to India. His
main interests focus on large-scale circulation problems and coupled
ocean-atmosphere models.
In brief, a paradigm shift seems to be taking place in
environmental science. This will involve unprecedented collaboration
between applied mathematicians and scientists. These developments
also may be signaling a new direction for interdisciplinary studies.
A core technology (in this case, dynamical systems) emerges and
applications are made to several disciplines. No one individual
masters all aspects of the problem; rather, people with different
expertise join together.
As a result of this paradigm shift, four professors, with aid from the
College of Sciences and the Center for Coastal Physical Oceanography
at Old Dominion University, came together to develop a pilot course
for students. The professors involved in this effort are John Adam,
Mathematics Department; CHET GROSCH, Computer Science Department and
CCPO; A. D. KIRWAN, JR., CCPO and Oceanography Department; and, JOHN
KROLL, Mathematics Department and CCPO.
The theme of the course is chaos vs. stochasticity and application
of nonlinear methods to time series. It emphasizes application of
methods from dynamical systems to practical problems drawn mostly
from, but not restricted to, the environment. The course lectures are
presented by those who have been leaders in both developing the
techniques and in the applications. The first distinguished lecturers
for the spring 1995 semester are: Eric S. Posmentier, South Hampton
College, Long Island University; Chris Jones, Brown University; Steve
Wiggins, Cal Tech; Barry Saltzman, Yale University; and Al Osborne,
University of Torino, Italy.
Photo Caption: Eric S. Posmentier: one of the distinguished
lecturers of the Chaos and the Environment course.
Two interns, CARRIE LEONARD, a Ph.D. student at the University of
Maryland, and TONYA CLAYTON, a Ph.D. student at the University of
South Florida, worked closely with EILEEN HOFMANN on a NASA funded
project that is concerned with the use of satellite observations in
circulation and biological models, a joint venture between scientists
at NASA/Goddard Space Flight Center, the Virginia Institute of Marine
Sciences, and CCPO. While at CCPO, Carrie and Tonya took a course in
mathematical modeling of marine ecosystems and participated in other
Center activities. A primary outcome of the time Carrie and Tonya
spent was the development of longer term collaborative research
projects.
A third intern, MICHELLE (Shelly) PARASO, an undergraduate at
Southampton College, worked primarily with ARNOLDO VALLE-LEVINSON on
the processing of wind, temperature, barometric pressure, and tide
gauge data sets from the lower Chesapeake Bay. She also analyzed some
of the features (i.e., extreme events) and trends (i.e., correlations)
in the various data sets. The results of that effort have been
described in a draft manuscript. In addition, Shelly assisted in the
production of data reports that present hydrographic measurements made
in the lower Chesapeake Bay. These reports will be published as part
of the CCPO technical report series, available upon request. In
addition, Shelly participated in two oceanographic cruises to collect
hydrographic data in the lower Chesapeake Bay.
One classic example of the application of the theorem in oceanography
is waves. Deep water waves can be described by four parameters:
gravity, [eq]; wave number, [eq]; density, [eq]; and velocity, [eq].
Since there are three fundamental parameters, the theorem implies a
single nondimensional relation between the four wave parameters. This
is easily found to be
[check hardcopy for equation to go here].
Most will recognize this as the dispersion relation for deep water
ocean waves.
L. A. CODISPOTI, ``A Numerical Modeling Study of the
Circulation and Transport in the Kara Sea,'' 9,160, ONR.
G. T. CSANADY, ``Air-Sea Coupling in the North Atlantic,''
63,400, NOAA.
E. E. HOFMANN, ``Long-term Ecological Research on the
Antarctic Marine Ecosystem: An Ice-dominated Environment,'' 64,765, NSF.
G. H. WHELESS and J. M. KLINCK, ``Effects of External Forcing and
Turbulent Mixing on the Dynamics of an Estuarine Plume,'' 170,000,
NSF.
G. H. WHELESS and A. VALLE-LEVINSON, ``Ballast Exchange Study:
Consideration of Near-Coastal Backup Exchange Zones and the
Environmental Effects of Open Ocean Ballast Exchange,'' 100,000,
Mystic Seaport.
C. E. GROSCH, ``Absolute Instability in a Quasigeostrophic
Current-Undercurrent System,'' Fluid Dynamics Division, American
Physical Society, Atlanta, GA, November 21, 1994.
E. E. HOFMANN, ``Examples of Assimilation of Biological Data,''
Modeling the Southern Ocean Ecosystem Workshop, Skamania Lodge, WA,
January 17-19, 1995.
A. D. KIRWAN, JR., ``Modons: The Inside Story on Ocean Eddies,''
Brown University, September 26, 1994.
A. D. KIRWAN, JR., ``Hydrodynamic Aspects of Oceanographic
Research,'' Department of Aerospace and Mechanical Engineering, Old
Dominion University, October 14, 1994.
A. D. KIRWAN, JR., ``The Inside Story on Ocean Eddies,'' Alumni
Research Symposium, Department of Marine Science, University of South
Florida, St. Petersburg, FL, October 27, 1994.
J. M. KLINCK, ``Modeling the Southern Ocean Ecosystem: Overview of
Physical Processes,'' Modeling the Southern Ocean Ecosystem Workshop,
Skamania Lodge, WA, January 17-19, 1995.
A. KUMAR, ``Satellite Observations of Shelfwater Overrun in the
Southern Middle Atlantic Bight,'' the 1994 Fall American Geophysical
Union Meeting, San Francisco, CA, December 5-9, 1994.
J. L. MILLER, ``Modeling the Santos Bight with the Princeton Ocean
Model,'' invited talk at the Physical Oceanography of the Southwest
Atlantic Ocean workshop, Sao Paulo, Brazil, November 26-December 4,
1994.
J. L. MILLER, ``Interactions of the Delaware and Chesapeake Bay
Plumes,'' the 1994 Fall American Geophysical Union Meeting, San
Francisco, CA, December 5-9, 1994.
E. A. SMITH and M. Hamilton, J. Vazquez, and A. Tran, all three of
NASA/Jet Propulsion Laboratory, ``A Global, Statistical Comparison of
Multichannel Sea Surface Temperature and NOAA/NASA Pathfinder Sea
Surface Temperature Data,'' the 1994 Fall American Geophysical Union
Meeting, San Francisco, CA, December 5-9, 1994.
G. V. R. K. VITTAL and G. T. Csanady, ``Nonlinear Model of the
Subduction Driven Thermocline Circulation,'' the 1994 Fall American
Geophysical Union Meeting, San Francisco, CA, December 5-9, 1994.
J. W. Murray, University of Washington, L. A. CODISPOTI, and
G. E. Friederich, Monterey Bay Aquarium Research Institute,
``Oxidation-Reduction Environments: The Suboxic Zone in the Black
Sea,'' Aquatic Chemistry: Interfacial and Interspecies Processes,
developed from a symposium sponsored by the Division of Environmental
Chemistry, Inc., at the 203rd National Meeting of the American
Chemical Society, San Francisco, CA, April 5--10, 1992,
Eds. C. P. Huang, C. R. O'Melia, and J. J. Morgan, The American
Chemical Societys, 1994.
M. A. M. FRIEDRICHS and M. S. McCartney and M. M. Hall,
both of Woods Hole Oceanographic Institution,
``Hemispheric Asymmetry of Deep Water Transport Modes in the Western
Atlantic,'' Journal of Geophysical Research, Vol. 99(C12), December 1994.
A. Dubey and M. Zubair, both of Computer Science Department, Old
Dominion University, and C. E. GROSCH, ``A General Purpose Subroutine
for Fast Fourier Transform on a Distributed Memory Parallel Machine,''
Parallel Computing, 20(1994), 1,697-1,710.
A. A. Tsonis and G. N. Triantafyllou, both of the University of
Wisconsin-Milwaukee, J. B. Elsner, Florida State University, and
J. HOLDZKOM II and A. D. KIRWAN, JR., ``An Investigation of the
Ability of Nonlinear Methods to Infer Dynamics of Observables,''
Bull. Am. Meteorol. Soc., 1,623-1,633, September 1994.
A. D. KIRWAN, JR., B. L. LIPPHARDT, JR., and K. L. GREGORY,
``Nonlinear Ocean Dynamics,'' Chapter Three, The Oceans:
Physical-Chemical Dynamics and Human Impact, Eds. S. K. Majumdar,
E. W. Miller, G. S. Forbes, R. F. Schmatz, and Assad A. Panah, The
Pennsylvania Academy of Sciences, 1994.
L. M. Ivanov, Marine Hydrophysical Institute of the Ukrainian,
Sevastopol, Ukraine, A. D. KIRWAN, JR., and D. V. Melnichenko, Marine
Hydrophysical Institute of the Ukrainian, Sevastopol, Ukraine,
``Prediction of the Stochastic Behavior of Nonlinear Systems by
Deterministic Models as a Classical Time-Passage Probanbilistic
Problem,'' Non. Proc. Geophys., 1, 4, 224-233, 1994.
SANG-KI LEE and G. T. CSANADY, ``Instability Waves in
the Gulf Stream Front and Its Thermocline Layer,'' Journal of Marine
Research, Vol. 52, 837-863, 1994.
CCPO CIRCULATION is published quarterly.
Director, Center for Coastal Physical OceanographyPhysical Oceanography of the Southwestern Atlantic
A multinational group of 21 oceanographers with expertise in the South
Atlantic and/or western boundary currents recently convened a workshop on
the physical oceanography of the southwestern Atlantic, the western Brazil
and Argentine Basins between the origin of the Brazil Current near 10[degrees]S,
and the northern Antarctic Circumpolar Current near 50[degrees]S. This
region is marked at all depths by circulation patterns and exchange
processes that are centrally important to the regional marine resources and
local economies and to the global distributions of heat and dissolved
substances. The workshop was hosted by the Oceanographic Institute of the
University of Sao Paulo, Brazil, from November 28--December 1, 1994.
Community Outreach
On October 22, 1995, the Department of Mechanical Engineering of ODU,
hosted a demonstration for the Institute for Young PhD's (Persons
having Dreams) In Science and Engineering with the cooperation of
CHROME (Corporating Hampton Roads Organizations for Minorities in
Engineering). CHROME is an organization for underrepresented
minorities (including women) to pursue non-traditional technical
career fields. Dr. Gregory Selby, associate professor of mechanical
engineering, is responsible for initiating the Institute for Young
PhD's In Science and Engineering program at ODU, and he was
fundamental in coordinating demonstrations for approximately 40 CHROME
students (grades 6--8) to participate in hands-on demonstrations on
engineering design/computers, robotics, and oceanography at CCPO.
Student Profiles
CATHY MEYER LASCARA received her B.S. in marine biology from Florida
Institute of Technology in 1978 and her M.S. in marine science from
the College of William and Mary in 1982. She then worked for two years
as a research associate for McNeese State University, investigating
the impact of high salinity brine discharge on zooplankton in the
north central Gulf of Mexico. In 1983, Cathy shifted careers and took
a job as a computer programmer for The Jonathan Corporation in
Norfolk, VA. After progressing from programmer to application
designer, she became the software development manager and was
responsible for several marketed software products including a design
and drafting CAD package and a graphical user interface management
system.
Chaos and the Environment
In popular jargon, ``chaos'' refers to a class of nonlinear processes that
describe erratic behavior of a system. Chaotic systems have many of the
visual attributes of stochastic or random systems but in fact are produced
by deterministic nonlinear processes. The field has achieved an
exceptionally high level of popular awareness and public allure, partly from
flamboyant claims made by early practitioners. In fact, dynamical systems
(the correct title for this area) has produced substantial advances in some
branches of mathematics, physics, and engineering. However, its record in
the environmental sciences has not been nearly so successful, as the
problems are much harder and the simple techniques so successful with small
degrees of freedom problems generally are not adequate for most realistic
environmental problems. After a decade of hard work, however, there is
evidence that this situation is changing due to the large number of
national/international conferences and workshops and by the recent increase
in the number of papers on
application of dynamical systems in standard environmental journals. In
addition, a new journal was started by the European Geophysical Society
entitled, Nonlinear Processes in Geophysics.
Student Internships
During the 1994 fall semester, CCPO was pleased to have three
student interns. The intern program is a new effort at CCPO
designed to foster exchanges with graduate and undergraduate programs at
other universities. The program provides the opportunity for the students
to participate in ongoing research projects at CCPO. It is anticipated that
the intern program will continue at a level of one to three students per
academic year.
Visiting Scientist Lecture Series
During the academic year, CCPO invites several distinguished
scientists to present seminars on topics related to coastal
oceanography. The lectures take place in Room 109, Crittenton Hall,
Old Dominion University, on Mondays at 3:30 p.m. EILEEN HOFMANN,
associate professor of oceanography, coordinates the lecture series
with the assistance of BEVERLY SCOTT. Below is a schedule of lectures
for the spring semester 1995. Please contact Beverly at (804)
683-4945 for more information or if you would like to be included on
the mailing list for lecture announcements. Specific lecture topics
are announced one week prior to each lecture.
January 23
Glen Gawarkiewicz
Woods Hole Oceanographic Institute
January 30
Gustav Paffenh["o]fer
Skidaway Institute of Oceanography
February 6
Hugh Ducklow
Virginia Institute of Marine Science
February 13
David Basco
Old Dominion University
February 20
Percy Donaghay
University of Rhode Island
February 27
Ray Alden
Old Dominion University
March 13
Larry Atkinson
Center Coastal Physical Oceanography
March 20
Leonard Walstad
Horn Point Environmental Laboratory
March 27
Igor Belkin
National Oceanic Data Center/NOAA
April 3
James Carlton
Williams College
April 10
Louis Codispoti
Center Coastal Physical Oceanography
April 17
Leonard Johnson
Texas AM University
ADK'S Words of Wisdom
Buckingham Theorem (Phys. Rev. 4, 345, 1914) determines the
number of independent nondimensional parameters which can be formed
from the dimensional parameters of a problem. Except for singular
cases, the number of independent parameters is the total number of
parameters less the number of fundamental dimensions (mass, length,
and time for most oceanographic problems).
Just the Facts...
Grants/Contracts Awarded
L. P. ATKINSON, ``Characterization of Water Circulation Over
the Sandbridge Study Area Using Remote Sensing,'' 8,500, VIMS.
Presentations
P. BECKER and G. Bjork, University of Goteborg, ``Residence Times in
the Upper Arctic Ocean,'' World Climate Research Program, Arctic
Climate System Study (ACSYS), Scientific Conference on the Dynamics of
the Arctic Climate System, Goteborg, Sweden, November 7-10, 1994.
Book Reviews
E. E. HOFMANN and C. M. LASCARA, Review of Book: ``Towards a Model of
Ocean Biogeochemical Processes,'' Limnology and Oceanography,
39, 1,780-1,781, 1994.
Publications
G.A. Paffenhofer, Skidaway Institute of Oceanography, L.
P. ATKINSON, T. N. Lee, Rosenstiel School of Marine and Atmospheric
Science, and P. G. Verity and L. R. Bulluck, III, both of Skidaway
Institute of Oceanography, ``Distribution and Abundance of Thaliaceans and
Copepods off the Southeastern U.S.A. During Winter,'' Continental Shelf
Research, Vol. 15(2/3), 255-280, 1995.
Contact Carole E. Blett, editor, for more information, (804) 683-4945.
Editor ........................Carole E. Blett
Technical Editor ..............Julie R. Morgan
Design Editor .................Karal L. Gregory
Distribution Manager ..........Beverly S. Mitchell
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