Itinerary:

Depart Kodiak, Alaska 5/10/99
Arrive Dutch Harbor, AK 5/19/99

Participating Organizations:

NOAA, Pacific Marine Environmental Laboratory (PMEL)

Cruise Description and Objectives:

The objectives for this cruise are:

1. To recover five and deploy four sub-surface Bottom Pressure Recorders (BPRs) in the North Pacific Ocean off the Alaskan Peninsula in support of the Pacific Tsunami Observational Program (PacTOP) (See Attachment 1 for BPR sites). PacTOP is a research program designed to obtain quality tsunami data in order to resolve theoretical and modeling tsunami issues. The goal of PacTOP is to acquire high quality tsunami measurements during the generation and deep ocean propagation of one or more tsunami events.
2. Recover and redeploy one sub-surface mooring in Pavlof bay in support of the Fisheries-Oceanography Coordinated Investigation (FOCI) program.
3. Conduct four Acoustic Doppler Current Profiler (ADCP) transects, time and weather permitting.

Keith Roberts  (206) 526-6556
Hugh Milburn  (206) 526-6169
LCDR Michele Bullock  (206) 526-4485
7600 Sand Point Way NE
Seattle, WA 98115

1.0 PERSONNEL

1.1 Chief Scientist: Keith Roberts PMEL

1.2 Participating Scientist:

Name, Sex, Nationality, Affiliation
Carrie Hadden, F, USA, NOAA/PMEL
Kevin Kinsey, M, USA, NOAA/PMEL

2.0 OPERATIONS

2.1 Loading

The following Mooring items will be loaded on WECOMA prior to departure from Newport, OR

Item, Item Weight, Number, Total Weight
BPR, 110 lbs, 4, 440 lbs.
Stand, Anchor, Release, 600 lbs, 4, 2,400 lbs.
69X35" 7 pack flotation, 330 lbs, 1, 330 lbs.
Hardware boxes, 50 lbs, 2, 100 lbs.

Total = 3,270 lbs.

Operations will consist of mooring recoveries and deployments and ADCP transects (time permitting). (See attachments 1 & 2)
Coordinates of the five BPR Stations:

BPR, Station Latitude (N), Longitude (W), Depth [m]
AK158, 54° 17.46', 158° 33.11', 1707
AK157N, 53° 25.47', 157° 16.58', 4643
AK158SW, 52° 02.28', 158° 45.02', 4754
AK155SE, 52° 01.20', 155° 43.55', 4683
D157-1, 52° 31.7’, 157° 15.0’, 4596

Coordinates for the Pavlof bay mooring:

Station Latitude (N), Longitude (W), Depth [m]
Pavlof, 55° 10.94’, 161° 41.09’, 101

Coordinates and speed for the ADCP transect lines:

ADCP Line, Latitude, Longitude, Speed
1 Start, 53° 55.00'N, 158° 00.00'W, 10Kts
1 End, 54° 36.00'N, 158° 40.00'W, 10Kts
2 Start, 55° 15.00'N, 156° 56.00'W, 10Kts
2 End, 54° 22.00'N, 156° 04.00'W, 10Kts
3 Start, 54° 27.00'N, 154° 37.80'W, 10Kts
3 End, 55° 24.40'N, 155° 40.00'W, 10Kts
4 Start, 55° 57.00'N, 154° 58.00'W, 10Kts
4 End, 54° 36.00'N, 153° 21.00'W, 10Kts

2.3 Equipment Loading/ Off-loading

All mooring equipment and instrumentation will be loaded on the ship prior to the ship’s departure from Newport, OR. All equipment and instrumentation will be off-loaded in Seattle, WA when the ship returns, on or about 15 June 1999.

2.4 BPR Mooring Descriptions

The Tsunami Bottom Pressure Recorder (BPR) mooring configuration (Attachment 3) consists of an expendable steel plate anchor attached to a combination aluminum tripod and platform. Mounted on the platform are an acoustic release, the BPR pressure case, a Paroscientific pressure sensor, and a Miniature Temperature Recorder (MTR). Flotation is provided by seven Benthos glass spheres with yellow propylene hardhats fastened to a seven-pack holder. An orange signal flag, transmitter, and strobe light are attached, to aid in locating and recovering the moorings when they are at the surface.

2.5 BPR Recovery/Deployment Procedures

The EG&G Ocean Products Model 8011 deck unit will be used for both the recovery and deployment operations. During recovery operations the ship will heave to and attempt recovery using a transducer lowered over the side. The ship should remain DIW with the screws secured (to prevent noise interference) for this operation. The acoustic release will then be interrogated and the anchor released, allowing the BPR to float to the surface (which takes approximately one hour). Once the unit is on the surface it can be recovered using a grappling hook or a small boat, if weather permits. The float-ring is equipped with a strobe and a transmitter (which broadcasts on Ch. 70, or 156.525 MHz) to assist in locating the mooring when on the surface.

During deployment, the acoustic release’s transducer is used to provide ranging information and track the mooring’s descent. The ship should remain DIW with the screws secured until the unit's position on the bottom is verified. When the instrument is determined to be on the bottom, a code is sent to disable the release.

2.6 PROCEDURES FOR ADCP OPERATIONS:

The following FOCI operations are to be conducted on this cruise on a not-to-interfere basis.

Vessel-mounted acoustic Doppler current profiler (VM-ADCP) observations will be collected with the 150 kHz RDI ADCP on NOAA/PMEL cruises using Version 2.48 of RDI’s DAS software running with user exit UE4.EXE on the dedicated DOS computer. Data are usually logged on 3.5-inch floppy diskettes that are brought back for processing. One or more DAS configuration files specifying the system settings will usually be provided. One configuration file may be used in deep water (> 500 m, but dependent upon weather conditions) where bottom tracking is not possible, and another with bottom tracking enabled may be used in shallow water. When operating plans call for the ship repeatedly to cross this depth horizon or for operations to be only incidentally in shallow water, the no-bottom-tracking configuration is usually used.

The ADCP system should be configured to use the ship’s gyrocompass for heading, a P-code encrypted GPS receiver for positioning and the Ashtech 3DF attitude determination unit to provide supplementary heading information to DAS via user exit 4. If the P-code GPS fails, a differential GPS receiver should be substituted. Normally the ADCP is set up with an 8 m transmit pulse and bin size, a 4 m blank after transmit, 1 s pulse cycle time, and a 5 minute sampling interval.

2.6.1 Station Information: