Expected Datasets from the HLY-03-03 Bering Strait Cruise

MOORING PROGRAMS

(UAF: Dave Leech, Tom Weingartner, (Rob Palomaroes, Dan Schuller for NAS); UW: Jim Johnson, Rebecca Woodgate, Knut Aagaard; WHOI: John Kemp, Ryan Schrawder, Dan Torres, Marshall Swartz, Sarah Zimmermann; SIO: Lisa Munger)

The main objective of the cruise was to recover and redeploy the UAF/UW and WHOI moorings serving the SBI project. Additional mooring work was also performed for the Whale Acoustic group of SIO/NOAA (1 recovery, 3 deployments) and the Chinese Arctic and Antarctic Administration, CAAA (1 recovery).

CTD Operations

(Bob Pickart, Sarah Zimmermann, Rob Palomares, Marshall Swartz, Dan Torres, Christina Courcier, Jeremy Kasper, Marther Delaney, Lisa Munger)

A total of 321 CTD casts were taken, as per the map above. The data will be quality controlled, post-calibrated and archived by Pickart, WHOI and the SBI Service Team.

LOWERED ACOUSTIC DOPPLER CURRENT PROFILER (LADCP) WORK

(Dan Torres)

LADCP (Lowered Acoustic Doppler Current Profiler) data were collected at selected CTD casts to yield a full water column profile of absolute velocity.

VIDEO PLANKTON RECORDER (VPR) PROGRAM

(Carin Ashjian and Sarah Zimmermann)

The primary purpose of the VPR study was to obtain a description of the distribution of plankton and particles across the Beaufort Shelf and Slope at high horizontal (2.5 km) and vertical (<1m) resolution. Coupled with velocity estimates from the acoustic Doppler current profiler, these data will elucidate what is in the water exchanged between shelf and basin and how this exchange may impact the transfer of biogenic material at this dynamic boundary.

NET TOW PROGRAM

(Carin Ashjian)

Net tows were conducted next to each Beaufort mooring that was equipped with an ADCP (i.e. BS1, BS2, BS3, BS4, BS5 and BS6). The purpose of the net tows was to collect animals to use in ground-truthing the ADCP backscatter intensity from the adjacent moored instrument. Eleven tows were conducted in total, ten along the mooring line and 1 on the Chukchi Shelf to the west of Barrow Canyon as a test tow. Tows were conducted using a 1 m2, ring net equipped with 150 µm mesh nets. The

samples will be analyzed for size-specific taxonomic composition upon return to the laboratory. This information will be used with sound scattering models to predict the backscatter that should have resulted from insonification of that portion of the water column. This predicted backscatter will then be compared to actual backscatter from the ADCPs.

XBT WORK

(Rebecca Woodgate)

A total of 63 XBT casts were taken during the cruise. The first three of these were taken at the start of the cruise to obtain sound speed corrections for the SeaBeam data. The remaining 60 were thrown on two lines in the Chukchi slope region, as part of a large-scale survey to assess the number of warm core eddies in the region.

SHIP’S ADCP DATA

(Andreas Muenchow)

(Detailed technical cruise reports on both the 75kHz and the 153kHz system are to be found at http://newark.cms.udel.edu/~muenchow/HEALY-2003. Preliminary copies of these reports are included in the appendices to this cruise report.)

The USCGC Healy contains two separate and independent hull-mounted acoustic Doppler current profiler systems. The systems are a 75 kHz phased array (Ocean Surveyor) and a regular 4-beam 153 kHz transducer (BroadBand).

SEABEAM DATA

(Val Schmidt, Dale Chayes, Larry Mayer)

(A detailed technical cruise report on the SeaBeam system is available from Val Schmidt, LDEO. A preliminary copy of this report is included in the appendices to this cruise report.) The SeaBeam 2112 sonar was operated continuously during the cruise. Only one dedicated SeaBeam expert (Val Schmidt, LDEO) was present on the ship, so monitoring the system was performed by Schmidt and by the MSTs at least every 6 hours and more usually every 3 hours.

WHALE ACOUSTICS PROGRAM

(Lisa Munger, John Hildebrand, Sue Moore)

The objectives of marine mammal acoustics onboard SBI-03-03 were twofold:

1) to turnaround one Acoustic Recording Package (ARP) and deploy an additional two for a total of three ARPs in the Beaufort Sea, near the WHOI physical mooring array, and 2) to visually and acoustically observe marine mammals in real time while aboard the Healy. The three Acoustic Recording Packages (ARPs) were successfully activated and then deployed at the following locations: 71-39.327 N, 151-48.001 W (ARP North=ARPN); 71-28.277 N.

UNDERWAY SYSTEMS

(MSTs)

Whilst the SeaBeam and ADCP systems were tended primarily by members of the science party (see above), the remaining underway systems of the Healy were maintained and recorded by the MSTs as per standard operating procedures of the ship and logged by the SCS system.

Bottom depth data was taken using the SeaBeam system and both the Bathy and Knudsen systems. The latter two cannot be run simultaneously since they share the same transducers. There was frequent switching between Bathy and Knudsen echosounders. In addition, the WHOI group attached their mooring acoustic equipment to the Bathy/Knudsen transducers resulting in further occasional downtime of the system. Both Bathy and Knudsen data are corrected for transducer depth and assume a standard sound speed of 1500 m/s. SeaBeam data is corrected for sound speed during collection.

Underway systems were logged to the SCS and are available as part of the data archive for the cruise. Terascan Satellite images were recorded when good. These data are also archived separately from the cruise data under an agreement between USCG and Dan Lubin, UCSD.