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Whale
Acoustics: Whale, dolphins, and porpoises
have the ability to transmit and receive underwater sound for communication
or hunting purposes. Visual and acoustic monitoring of vocalizing marine
mammals provides information on their seasonal and geographic (time-space)
presence and insight to their behavioral characteristics. We are conducting
studies of vocalizing baleen and odonotcete (toothed) whale presence off
Southern California, Alaska, Hawaii, and Antarctica using various passive
acoustic recording tools and ship-based visual techniques.
Our primary acoustic
tools, acoustic recording packages (ARPs), are autonomous, stationary
seafloor instruments that can continuously record underwater sound at
rates up to 1 kHz for durations over one-year. Developed by our lab,
ARPs have been used worldwide for multi-year studies of baleen whale
presence. Currently, we are developing another more capable autonomous
bottom-mounted instrument, high-frequency acoustic recording package
(HARP), for recording odonotocetes at frequencies over 100 kHz.
We are also developing an acoustic-structural
finite element model (FEM) of a beaked whale from CT, MRI and tissue
property data to understand how these animals transmit and receive sound.
Recent stranding events of beaked whales have been linked to concurrent,
nearby sonar activity. Our modeling efforts are focused on understanding
the relationship between the strandings and the acoustic events. Full
Website >>
Coastal Observatory Development: The
San Diego Coastal Ocean Observing System provides a gateway for up-to-date
oceanographic, weather, and water quality data for the San Diego coastal
region. Funded under the California Clean Beaches Initiative, the system
merges a number of emerging technologies used for oceanographic and
environmental sensing into a regional sensor network to provide a heightened
awareness of the coastal environment. Partnerships established with
this program has enabled a direct link between the information generated
by this observing system, Scripps oceanographers, and a wide audience
of end-users including local and regional agencies, policy makers, and
the public at large. At present, the system is focused on the use of
an array of HF radars deployed in the San Diego region to map ocean
surface currents to examine the coastal transport issues and their relation
to local water quality. Full
Website
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Whole Sky Imager: The Atmospheric
Optics Group has specialized for many years in the development of
Whole Sky Imagers and related systems designed to characterize the cloud
and radiance field. These systems acquire images of the sky, from which
the cloud fraction over the whole sky may be determined, as well as
distributions of radiance. Some of the WSI systems are 24-hour systems
capable of acquiring high quality data all day and all night, while
others are more specialized systems designed for handling day only,
or for looking down from an aircraft. Full
Website
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Observations of Waves and Currents Nearshore:
The goal is to understand the forms and dynamics
of the flows near shore. These flows are forced by a combination of
wave breaking, winds, pressure gradients, and topographic effects (Coriolis
is of secondary importance, but its role increases moving offshore).
Of particular interest here is the occurrence, form, and dynamics of
rip currents. (Here, rip currents are loosely defined as narrow, offshore-directed
flows extending some distance seaward from the shore through the surf
zone.) Given the forcing and topography, we wish to predict the flow
regime, in terms of the occurrence and strength of instabilities and
rip currents, and the net effect on horizontal mixing and diffusion.
Full
Website >>
Time Reversal Mirror in the Ocean:
A series of four ocean acoustic experiments in the ocean in which a
time reversal mirror (TRM) was implemented in coastal water of the order
of 100 meter depth were conducted. Two frequency regimes were studied:
450 Hz and 3500 Hz. We have studied both the basic physics of the time
reversal (phase conjugation in the frequency domain) process and the
application of the TRM to sonar and underwater communications. In the
case of the latter, we have found that the TRM process is sufficiently
robust as to reproduce ultrasonic laboratory results to the extent that
we measured diffraction limited focusing in the ocean out to 30 km.
We have also investigated an assortment of potential sonar applications
including bistatic sonar configurations as well as binary and higher
order phase shift keying (M-PSK) TRM-based undersea acoustic communications.
Full
Website >>
Air-Sea Interaction Research:
The group, led by Ken
Melville, is affiliated with the Marine Physical Laboratory and
the Physical Oceanography Research Division of Scripps. The primary
area of research includes the topics of surface wave dynamics, air-sea
fluxes, upper ocean turbulence, including Langmuir circulations, and
the remote sensing of ocean surface phenomena using electromagnetic
and acoustic techniques. Many of these processes and phenomena are influenced
directly by surface wave breaking.
A combination of laboratory experiments, field measurements, theoretical
analysis and numerical modeling to improve our understanding of air-sea
interaction and ocean surface processes. Laboratory experiments are
carried out in the Hydraulics Laboratory of SIO. Field measurements
use moored or drifting instrument systems, airborne instruments, and
sometimes fixed platforms on the continental shelf. Field experiments
have been conducted in the North Atlantic, the North Pacific, the North
Sea, the Gulf of Mexico and Bass Strait, off the coast of Australia.
Experiments in the laboratory use modern optical, electromagnetic, and
acoustical instrumentation to measure the evolution of velocity, temperature,
surface-displacement and bubble concentration fields under wind-driven
surface waves and mechanically generated breaking waves.
Full
Website >>
Optical and Ancillary
Measurements at High Latitudes in Support of the MODIS Ocean Validation
Program: As part of NASA's "Satellite
Remote Sensing Measurement Accuracy, Variability, and Validation Studies"
optical and ancillary measurements were taken by Dr.
Dariusz Stramski in the north polar waters of the Atlantic in support
of the MODIS ocean color validation program. The major goal of our project
was to characterize errors for the ocean color data products and develop
an understanding of these errors, in order to improve performance of
bio-optical algorithms at high latitudes of the north Atlantic. Full
Website
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Reference
Materials for Oceanic Carbon Dioxide Measurements:
Dr. Andrew Dickson and his
group have successfully developed seawater based reference materials
certified for total dissolved inorganic carbon and for total alkalinity
(pH and d13C of the inorganic carbon will be available in the future).
These reference materials are now used throughout the world to provide
quality control for oceanic carbon dioxide measurements resulting in
a substantial improvement in the internal consistency of the resulting
data sets. Full
Website
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