truth data from the FRF proved
accurate data to date and has the
conducted at the FRF. In 1995,
extremely useful in verifying syn-
added advantage of requiring only a
NDBC, in cooperation with the FRF,
thetic aperture radar images sent
single operator to drive the CRAB
added a permanent Coastal-Marine
from the satellite. The Atlantic
and collect the data. By combining
Automated Network (C-MAN)
Remote Sensing Land and Ocean
the RTK GPS system with a digital
weather station to the end of the
Experiment (ARSLOE) followed in
echosounder and using the LARC
pier as part of a new Ocean Sensor
October l980, and included 3l U.S.
as a platform, the surveys can now
Test Facility for the long-term testing
participants and four foreign
be extended into deeper water while
of oceanographic sensors deployed
researchers. In addition to evaluat-
maintaining nearly the same
by the Corps or on NDBC's ocean
ing remote sensing techniques,
accuracy.
buoys (Woody et al. 1997).
wave transformation theories were
The surveys are not frequent
Equally important to the FRF
tested and directional wave measur-
enough to capture the dynamic
measurement responsibilities is the
ing systems evaluated (Baer and
nature of the beach and inner sand
surveying program using the CRAB
Vincent 1983).
bar zone (changes in the foreshore
to obtain centimeter-accurate mea-
In the fall of l98l, A Shoreface
profile of up to 0.8 m have been
surements through the breaker zone
EXperiment (ASEX) brought several
observed over a single tidal cycle,
and across the inner shoreface.
investigators to the FRF to deter-
Holland and Puleo (in preparation)).
Four profile lines extending seaward
mine the spatial and temporal vari-
This region is monitored remotely
to the 9-m (30-ft) depth contour are
ability in sediment characteristics,
with video cameras mounted on the
surveyed biweekly, and a region 1
and to relate changes in these char-
observation tower using techniques
km by 1 km centered on the pier is
acteristics to hydrodynamic pro-
originally developed by Dr. Robert
surveyed monthly. The program has
cesses. This was the first experi-
Holman of Oregon State University.
benefited from advances in survey-
ment to make extensive use of the
Daily images from a single camera
ing technology through the evolution
CRAB both to survey several
began to be collected in 1986.
of four different systems. Early sur-
cross-shore profiles and to collect a
Today the images from eight cam-
veys used a surveying level to read
unique series of cross-shore
eras are obtained hourly and used
a large stadia board mounted on the
vibracores. Though ASEX included
to create rectified mosaic images,
back of the CRAB. Handwritten
only limited monitoring of morphol-
equivalent to a vertical aerial photo-
notes, weather, biting flies, and
ogy and surf zone dynamics, the
graph, for a 2-km (1.2-mile) stretch
reading errors made these data
observations foreshadowed the
of coastline, centered on the
error prone. The level was soon
focus of the following experiments:
research pier.
replaced with a Zeiss Elta-2s elec-
the complex interaction between
tronic surveying system, (Birkemeier
Experiments
hydrodynamics and sediment related
and Mason 1984). With the Elta-2s,
processes including morphology
a typical survey of 50 points could
To fully utilize the unique poten-
change. ASEX was the first of many
be conducted in about 45 min with
tial of the facility and to obtain as
Duck experiments that Dr. Asbury
an accuracy of 3 cm horizontally and
many benefits to the Corps and the
Sallenger (U.S. Geological Survey)
vertically.
nation as possible, non-Corps use of
participated in. ASEX was unique in
In 1990, the Elta-2s was replaced
the facility and its data has always
being the only experiment held
with a Geodimeter 140-T
been encouraged. This policy has
south of the pier.
self-tracking total station capable of
led to one of the most productive
It was during ASEX that plans
following the CRAB as it moved and
accomplishments of the FRF, serv-
developed for DUCK82 held in the
acquiring data every second. For the
ing as a site for cooperative experi-
fall of l982 (Mason et al. 1985). FRF
first time, sufficient data points were
ments where resources (funds,
scientists and researchers from the
obtained to fully define the curves
labor, instruments, and data) are
U.S. Geological Survey, and Oregon
and shapes of the nearshore. In
pooled to investigate complex
State University conducted a com-
fact, some of the earliest evidence
coastal processes. A sequence of
prehensive month-long study of
of mega-ripples was observed even
such studies has been conducted at
nearshore processes and morpho-
with the large wheel size of the
the FRF resulting in a wealth of new
logical change to test models of
CRAB. Because the Zeiss and
coastal knowledge. In addition,
crescentic sandbar generation
Geodimeter instruments are both
these experiments have also created
(Bowen and Inman 1971). Movie
range-azimuth systems, their accu-
a core group of sponsors (U.S. Army
cameras, current meters and wave
racy decreases with distance from
Corps of Engineers, Office of Naval
gauges on the pier, a
the instrument, and they are there-
Research, and the U.S. Geological
mobile-instrumented sled and the
fore least accurate at the offshore
Survey) and researchers who have
CRAB were used to collect wave,
extent of the surveys, where
helped to establish the FRF as a
current, and bathymetric data. It was
changes are typically small but can
premier research facility.
during DUCK82 that Dr. Robert
be significant. This problem was
In l978, DUCK-X brought together
Holman from Oregon State Univer-
resolved in 1996 with the adoption
24 participants to evaluate the use
sity began his long relationship with
of a Real-Time Kinematic (RTK)
of remote sensing for coastal stud-
the FRF, bringing his remote
GPS system. This system has pro-
ies, particularly the capabilities of
duced the most consistently
the SEASAT-A satellite. Ground
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