ACCESS NUMBER: 74261

STUDY TITLE: CODAR in Alaska

REPORT TITLE: CODAR in Alaska

CONTRACT NUMBER: 1435-01-02-CA 85294 TO 74261

SPONSORING OCS REGION: Alaska

APPLICABLE PLANNING AREA: Cook Inlet; Beaufort Sea

FISCAL YEARS OF PROJECT FUNDING: 2003

COMPLETION DATE OF REPORT: June 2006

COST: FY 2003: $59,361

CUMULATIVE PROJECT COST: $59,361

PROJECT MANAGER: Dave Musgrave

AFFILIATION: University of Alaska Fairbanks

ADDRESS: Institute of Marine Science, University of Alaska Fairbanks, Fairbanks, AK 99775-7220

PRINCIPAL INVESTIGATOR*: Dave Musgrave

KEY WORDS: High-frequency Radar, CODAR, Cook Inlet, surface current mapping, physical

oceanography, circulation

BACKGROUND:

Electromagnetic remote sensing of ocean currents provides a complete mapping capability that has

become a cost-effective solution for coastal current mapping. Over the past 25 years, oceanographic

radar techniques have been developed and improved so that detailed, gridded, two-dimensional maps of

surface circulation can be provided and recorded in real time. Currents play a critical role in the transport

and fate of spilled oil, but there is a paucity of direct circulation measurements in some areas of Cook

Inlet. Current meters provide data at only a few specific points and not at the water surface, where the oil

would be found. HF radar techniques provide a measured equivalent of a gridded circulation model and

can be used as input and validation for oil spill trajectory models.

OBJECTIVES:

Our goals were to: 1) Interpret CODAR radar data for possible use in Alaska. 2) Compare the CODAR

data from Cook Inlet with satellite-tracked drifter data and tidal model results. 3) Participate in MMS HF

Radar Workshop including presentation of Cook Inlet CODAR results.

DESCRIPTION:

Surface currents were measured and analyzed near the mouth of the Kenai River in upper Cook Inlet

from December 2002 through June 2003 by utilizing High Frequency (HF) radar systems.

SIGNIFICANT CONCLUSIONS:

Tidal currents dominate the flows in Cook Inlet, accounting for about 70 - 90% of the total variance. All

variability (tidal and subtidal) is polarized along the axis of the inlet. Patterns of mean surface currents

show across inlet variability with (generally) southward flow in the west, a reversal of flow in mid inlet and

southward flow in the east, although winds can affect this pattern.
ACCESS NUMBER: 74261

STUDY RESULTS:

Tidal currents accounted for about 90% of the total current variance, and tidal ellipses for all tidal

components were polarized along the axis of the inlet The dominant component was the lunar

semidiurnal (M2), with major axis magnitudes ranging from 30-200 cm s1. Mean subtidal currents were

as great as 25 cm s1, and the current patterns were related to the wind direction. Particle excursions due

to tides are between 4-32 km in this section of Cook Inlet, and predicted tidal current ellipses agree

quite well in magnitude and phase with the tidal model of Foreman et al. (2000). Comparison of surface

velocities from the HF radar with drifters drogued at 7 m gave root-mean-square (rms) differences in the

range of 40 100 cm s1. The large differences are probably due to large vertical shear in the upper 7 m

of the water column.

STUDY PRODUCTS:

Musgrave, 0. and H. Statscewich. 2006. CODAR in Alaska. Final Report. OCS Study MMS 2006-032.

Coastal Marine Institute, University of Alaska Fairbanks and USD01, MMS, Alaska OCS Region.

Fairbanks: AK

Musgrave, D. L. CODAR in Alaska [abstract]. 2004 University of Alaska, Coastal Marine Institute Annual

Report No. 10, OCS Study MMS 2004-002, p. 110. Fairbanks, AK, University of Alaska, CMI and

United States 001, MMS, Alaska OCS Region.

Musgrave, 0. L. 2004. Power, Data Transmission, and Site Suitability associated with the Beaufort Sea

and Cook Inlet. In 0. L. Musg rave [ed.] Proceedings of a Workshop on Research Sponsorship on

the Mapping of Surface Currents from High Frequency Radar in the Cook Inlet and Beaufort Sea,

OCS Study MMS 2004-045, pp. 13-15. Anchorage, AK, Prepared by MBC Applied Environmental

Sciences for United States DOt, MMS, Alaska OCS Region.

Musgrave, D. L. [ad.]. 2004. Proceedings of a Workshop on Research Sponsorship on the Mapping of

Surface Currents from High Frequency Radar in the Cook Inlet and Beaufort Sea. OCS Study MMS

2004-045. Anchorage, AK, Prepared by MBC Applied Environmental Sciences for United States

DOl, MMS, Alaska OCS Region.

Statscewich, H. and Musgrave, D. L. 2005. CODAR in Alaska [Abstract]. University of Alaska Coastal

Marine Institute. Annual Report No.11, OCS Study MMS 2005-055, p. 10. Fairbanks, AK, University

of Alaska, Coastal Marine Institute and USD01, MMS, Alaska OCS Region.

*pls affiliation may be different than that listed for Project Manager(s).
Cook Inlet Focus area for "CODAR in Alaska"

ACCESS NUMBER: 74261

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BEAUFORT SEA

ACCESS NUMBER: 74261

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