| MMS ENVIRONMENTAL STUDIES PROGRAM: ONGOING STUDIES | ||||||
| MMS OCS Region: | Alaska | |||||
| Title: | Drifter Testing and Evaluation for Oil-Spill Trajectory Modeling in Cook Inlet and Shelikof Strait (AK-02-13) | |||||
| Total Cost: | $740-$1,100 | Period of Performance: | FY 2002 - 2003 | |||
| Conducting Organization: | ||||||
| MMS Contact: | ||||||
| Description: | ||||||
| Background Over the past eight years, MMS
has deployed several hundreds of satellite-tracked drifters for the purpose of measuring
the surface currents and simulating oil spills in the Gulf of Mexico. The purpose of these
activities was the testing, evaluation, and improvement of MMS's Oil Spill Risk Analysis
(OSRA) model applied to the Gulf. However, no such evaluation study has been performed yet
in Alaskan waters. Given the considerable differences in the physical oceanographic
setting of these two regions, it is necessary to perform the same kind of evaluation of
the OSRA model applied to Alaskan waters. A few modest Lagrangian surface current studies have been performed in the Cook Inlet/Shelikof Strait. Burbank (1977) released drifters in and near Kachemak Bay; Muench, Schumacher, and Pearson (1981) released drifters from lower Cook Inlet; and Reed and Stabeno (1989) released drifters in the lower Shelikof Strait. The latter study released a small number of oil-spill-simulating drifters for the purpose of testing how well these drifters would follow an actual oil spill, in this case the Exxon Valdez spill. While useful, these past studies provide too little information for a comprehensive evaluation of MMS's oil-spill modeling in this area. Also, there have been no Lagrangian current measurements in the middle and upper Cook Inlet. The study outlined herein emulates the excellent drifter studies performed in the Gulf of Mexico and will help MMS improve its OSRA conducted in support of lease sales in the Alaska Region. The budget figures above represent 50 percent of the cost of the study and assume 50 percent cost participation by other interested agencies. |
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| Objectives The objective is the acquisition of a one-year-long, synoptic, Lagrangian realization of the mesoscale and tidal currents in the Cook Inlet and Shelikof Strait and concurrent meteorological observations, and oil-spill simulations numerous enough for a statistical evaluation of MMS's OSRA model applied to Alaskan waters. | ||||||
| Methods The surface currents will be
observed by aircraft-deployed drifters as done in the SCULP and NEGOM projects in the Gulf
of Mexico. Ten water-following (SCULP-type) drifters will be deployed every two weeks
along the inlet and strait from a chartered aircraft for a total of 260 drifters. In each
deployment cycle, two drifters will be deployed in each of the upper and middle of Cook
Inlet and Shelikof Strait, and four drifters will be deployed in a rectangular array in
the lower Cook Inlet. This deployment scheme may be adjusted later in the project if the
earlier deployed drifter tracks suggest a better sampling scheme. The drifters will be tracked by the ARGOS system employing "multi-satellite" service in order to resolve the strong tidal signal in the currents better. The drifters will transmit for 30 days and then automatically shut off. The choice of 30 days is based on summer salt balance and the potential persistence of emulsified oil. At selected locations and/or locations of practicality, five oil-following "ARGOSPHERE-type" drifters will be deployed in Cook Inlet and in the Shelikof Strait. They will also be tracked for 30 days using Service ARGOS' multi-satellite service. The shipboard drifter deployments will be made from chartered fishing boats or volunteer fishermen if any can be recruited. Deployments will be concurrent with SCULP drifter deployments. Finally, NOMAD-type meteorological buoys will be deployed in the area for the one year of drifter observations. The National Data Buoy Center (NDBC) will install the buoys and provide MMS with the digital data. One mooring will be deployed in each of lower Cook Inlet and the Shelikof Strait. Middle Cook Inlet may use an oil-platform based meteorology station and upper Cook Inlet a land-based meteorology station to avoid the seasonal ice pack. Although the tides are the dominate currents most of the time, the locally forced, wind-generated currents will be important too, especially for the oil-spill simulating drifters. |
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| Importance to MMS The surface currents will be observed by aircraft-deployed drifters as done in the SCULP and NEGOM projects in the Gulf of Mexico. Ten water-following (SCULP-type) drifters will be deployed every two weeks along the inlet and strait from a chartered aircraft for a total of 260 drifters. In each deployment cycle, two drifters will be deployed in each of the upper and middle of Cook Inlet and Shelikof Strait, and four drifters will be deployed in a rectangular array in the lower Cook Inlet. This deployment scheme may be adjusted later in the project if the earlier deployed drifter tracks suggest a better sampling scheme | ||||||
| Current Status: | ||||||
| Final Report Due: | ||||||
| Publications: | ||||||
| Affiliated WWW Sites: | ||||||
| Revised date: | March 2002 | |||||
| ESPIS |
ESPIS - All completed
ESP Studies: |
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