| Adverse Weather Experiment 2000
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| This page describes RSMAS participation in the 2000 Adverse
Weather Experiment at the South Florida Ocean Measurement Center.
Principal
investigators are:
RSMAS participants include:
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| Goal:
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The goal of the proposed study is to understand the role of adverse weather
on small-scale surface processes and the upper ocean including turbulent
mixing. Using observations of microscale turbulence from the FAU Autonomous
Underwater Vehicle (AUV) technology with the UM Ocean Surface Current Radar
(OSCR), the proposed research seeks to evaluate upper ocean structural
response from AUV-based measurements during atmospheric frontal passages in
regions of oceanic features. We seek to characterize the subsurface
turbulent mixing in the wind and wave-forced upper layer in an adaptive
sample strategy using OSCR over a month time series.
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| Objectives:
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Specific objectives are:
- Relate OSCR-derived surface currents in selected cells to
high-resolution subsurface turbulence microstructure measurements from an
AUV at several levels during adverse weather;
- Examine current sections for
coherent structures and relate them to forcing mechanisms; and,
- Estimate surface wave-induced orbital velocities (based on significant
wave height from Doppler spectra) to upper ocean measurements from the AUV
and the significant wave heights and winds from the UM/RSMAS ASIS surface mooring.
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| Work Plan:
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Over a period of about six weeks ( 15 March 30
April 00), the experiment will involve OSCR (VHF Mode) to map surface
currents (250 m resolution) at 700 cells over a 6 km x 9 km area overseeing
the UM/RSMAS ASIS buoy, and Autonomous Underwater
Vehicles (AUV) turbulence measurements from FAU acquired within the US Navy's
South Florida Testing Facility range under the auspices of the South Florida
Ocean Measurements Center range. Two radar sites will be used at John U.
Lloyd State Park and Hollywood Beach over the same domain as in the ONR 4-D
Ocean Current Experiments. OSCR maps will be made available for an adaptive
sampling strategy in deploying the AUV.
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| Experiment:
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During adverse weather conditions, AUVs will be deployed to map
upper ocean turbulent microstructure over an approximate 1000 m x 500 m box
(6-9 OSCR grid Cells). The AUV will acquire measurements at several levels
to insure profiler measurements will be acquired that also includes a CTD.
For a 6-12 hr period, the AUVs will measure the structure with cross-shelf
transects separated by 50-100 m, with a positional accuracies of 25-50 m.
The intent is to acquire measurements under pre-event, event and post-event
conditions to examine the oceanic response and turbulent mixing processes at
very high 3-dimensional sampling embedded within an OSCR grid. The research
plan requires at least two sequences of these missions over the 6-week
deployment period during weather events. Here events are defined as winds of
up to 10 m s-1 and significant waves of 2 m or less that would include
turbulence measurements on the AUV. During
the AUV-based measurements, spectra will be collected and archived from the
OSCR measurements for subsequent processing and analysis.
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| SFOMC Facility:
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The well instrumented facility extends offshore of Ft.
Lauderdale on the east coast of Florida over a region nearly 7.5 km along
shore and over 33 km across shelf, with constant north-south depth contours
ranging from 6m - 600m. Details are given at http://www.sfomc.org.
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