The Taiwanese/U.S. “Sea Soar” team on the
fantail of the research vessel Ocean
Researcher #1. The team used the towed vehicle to measure ocean properties
and identify water from the Kuroshio Current over the continental shelf.
A bottom-mounted instrument package is being
deployed from the R/V Tioga on a calm
day in December 2008. Wasque nature reserve, on the southeast corner of
Martha’s Vineyard, is visible in the background.
(Photo by Richard Limeburner, Woods Hole Oceanographic Institution)
Due to the ice
conditions, Will Ostrom brings the recovered top float of a BGOS (Beaufort Gyre
Observing System) mooring onboard upside down, with the “upward looking sonar”
that measures ice thickness, now pointed down! Four BGOS moorings were
recovered for the 5th straight year and three were redeployed to obtain another
year of oceanic data beneath the Arctic ice pack.
(Photo by Gerty Ward)
After deploying an Ice-Tethered Profiler,
Canadian Coast Guard crew member Gary Morgan attaches the helicopter sing to a
winch for transport back to the icebreaker. The surface buoy will drift with
the sea ice in all seasons and broadcast data from the subsurface instruments
in real time to WHOI, which will make the data available on the ITP Web site within hours of
(Photo by Rick Krishfield, Woods Hole Oceanographic Institution)
Scientist Fiamma Straneo and Kyle Covert,
Boatswain of the R/V Knorr, put
together the upper part of a mooring designed to measure the transport of fresh
water through the Hudson Strait. The long tube containing a CTD recorder
resides in the upper part of the water column, where collisions with icebergs
and sea ice could occur.
(Photo by Dave Sutherland, Woods Hole Oceanographic Institution)
Joe Pedlosky, delivering the Haurwitz Lecture at
the January 2009 meeting of the American Meteorological Society.
(Woods Hole Oceanographic Institution)
On a calm day,
ocean waters may look featureless and smooth at the surface. Beneath, currents
and variations in the water’s temperature, salinity, density and other features
create structure within the ocean that affects sea, land, and atmosphere. Researchers
in the Physical Oceanography (PO) Department seek to describe and understand
the physical structure and variability of the ocean and the processes that create
that structure and variability.
investigate physical properties of the ocean using laboratory experiments,
analytical and numerical modeling (creating mathematical descriptions and
computer simulations of the ocean to test against real-world observations), analysis
and synthesis of existing data, and new observations at sea. A strong heritage
and expertise in observing the ocean and in developing new observational
methods plays a defining role in work done by members of the PO Department, in
2008 as in other years.
Here, we highlight some of the year’s accomplishments.
—Robert Weller, Department Chair
Gawarkiewicz, Frank Bahr, and Craig Marquette participated in an international
experiment to study oceanographic processes that contribute to uncertainty in
predictions of ocean currents and how sound travels in the East China Sea.
In September 2008, these scientists conducted a pilot experiment for this
project, jointly with scientists from National Central University, National
Taiwan University, and National Taiwan Ocean University.
- In this pilot
project northeast of Taiwan, WHOI and National Taiwan University team members
used a “SeaSoar”—a towed vehicle that undulates up and down through the water,
measuring water properties as it moves forward— to identify water from the
strong Kuroshio Current forcefully intruding over the continental shelf. The
Kuroshio is the northward-flowing current that is the Pacific counterpart to
the Gulf Stream in the western north Atlantic. The main fieldwork for this
international project will take place in August and September 2009, with four
different ships measuring ocean currents, temperature, salt content, and
density, as well as how sound propagates in an oceanographically complex
- Closer to home Richard Limeburner, Bob Beardsley, and Will Ostrom deployed an
array of three moorings from the R/V
Tioga to measure and record temperature, salinity, and currents at the
three main openings to Nantucket Sound – between Woods Hole and Martha’s
Vineyard, between Martha’s Vineyard and Nantucket, and between Nantucket and
Monomoy Island on Cape Cod. The moorings were recovered in November 2008, refurbished
and re-deployed December, and their final recovery will be in June 2009.
- The moorings
collected measurements will be used to improve computer models of ocean
circulation for the waters around Cape Cod and the larger-scale coastal ocean
in this region. One of these is the Northeast Coastal Ocean Forecast System
(NECOFS) – a coupled atmosphere/ocean model for the New England and Gulf of
Maine region, recently developed by PO’s Bob Beardsley and Changsheng Chen of
the University of Massachusetts Dartmouth.
- Work at high
latitudes continues as a research focus. In August-September 2008, a WHOI PO Department
team led by Richard Krishfield (see www.whoi.edu/beaufortgyre for
details) returned to the Beaufort Gyre in the Canadian Arctic Ocean, to make
field observations, re-deploy moorings, and install instrument systems
including Ice-Tethered Profilers (ITPs), Ice Mass Balance Buoys (IMBs)) and
Autonomous Ocean Flux Buoys (AOSBs) – all designed to measure properties of the
ice-covered ocean. Scientists will observe variability over years to decades, observe changes in fresh water and heat
content, and aim to understand processes involved in Arctic climate change.
Since 2004, 31 of these systems—developed and constructed at WHOI, placed by
WHOI and by international teams of scientists—have operated throughout the
Arctic Ocean in all seasons, recording conditions from the seafloor to just
below the ice cover (approximately 7 to 760 meters.)
- Fiamma Straneo continued
fieldwork in Canada’s Hudson Strait, to quantify the transport of freshwater southward
through the strait, part of the overall export of freshwater from the polar
region, a process that markedly affects ocean circulation. Straneo also began
doing innovative measurements from a small local vessel in a glacial fjord in
East Greenland, that showed a thick layer of warm, salty subtropical waters rapidly
intruding deep into the fjord, which may contribute to the acceleration of
Greenland's outlet glaciers (and loss of ice) that researchers observe.
- PO Department
members continue to do research in the Red Sea under a research partnership
with KAUST (
Abdullah University of Science and Technology) highlighted elsewhere in this
annual report. Planning for the National Science Foundation’s Ocean Observatory
Initiative (OOI) advanced this year as well.
- Terry Joyce
and many in the Department have been studying the formation of a persistent
layer of constant-temperature seawater in the north Atlantic [link here] called
“18oC mode water” that may influence climate – part of a project
called CLIMODE (“CLIVAR Mode Water Dynamics Experiment.”) Shipboard research
for this project finished in 2007, and scientists are following up this year
with data analysis and publication.
- Members of
the Department continue making long-term observations of the ocean – both with
long-term “Ocean Reference Station” moorings (off northern Chile, north of
Hawaii, and in the North Atlantic trade winds region) and with ongoing
deployments of ARGO profiling floats that drift throughout the global ocean
automatically measuring temperature and salinity from the surface to great
Cenedese is interested in improving our understanding of how buoyant (less-dense)
waters in the ocean transport pollution and sediments along coastlines,
particularly when multiple buoyant sources are present. Using a combination of
analytical calculations and laboratory simulations, she is studying the
interaction and stability of two buoyant coastal currents having different
densities. Using calculations, she predicted different scenarios for where the
currents would be, along the coastline. Then, doing laboratory experiments with
a rotating tank designed to mimic Earth’s rotation, she confirmed her
analytical predictions. Furthermore, she discovered that the two current fronts
(edges) became unstable, as shown in the
accompanying image. This result – the two currents’
coupled frontal instability – is different from previous results on the instability
of a single current, a difference that is unexpected and interesting, and could
yield insight into real-ocean situations.
- Members of
the PO Department also continued numerical and analytical modeling and
theoretical studies through 2008. Joe Pedlosky’s contributions were
acknowledged when he was invited to deliver the Haurwitz Lecture at the January
2009 American Meteorological Society annual meeting, presenting a talk entitled
“Kelvin's Theorem, the Tunneling of Rossby Waves and the Circulation around
Planetary Islands.” And Senior Scientist
Ray Schmitt participated in a large study on climate change by the National
Academy of Sciences, serving on a panel on the science of climate change.
Last updated: August 10, 2009