This cruise and preliminary data report was prepared by Richard Limeburner. We thank the officers and crew of the R/V Oceanus Cruise 345 for their skill and superb assistance that made possible the recovery of 8 moorings and completion of the hydrographic survey. Special thanks to Wil Ostrom for leading the successful mooring deployment operation and George Tupper for maintaining and operating the shipboard scientific equipment and coordinating this instrumentation with the needs of the scientific party.

The GLOBEC research effort is sponsored by the National Science Foundation and the National Oceanic and Atmospheric Administration. Support for Frontal Exchange Processes over Eastern Georges Bank Program as part of the U.S. GLOBEC Northwest Atlantic/Georges Bank Study was provided by NSF research grant OCE-98-06379. All data and results in this report are to be considered preliminary.

Cruise Report


Table of Contents

Table of Contents 2

Purpose and Accomplishment Summary 3

Cruise Results 4

1. Frontal Study Moorings 4

1.1 North Flank Shallow – Mooring site NFS 4

1.2 Eastern Flank – Mooring site EF 4

1.3 North Flank Deep – Mooring site NFD 4

2. Hydrography 5

2.1 Calibration 5

2.2 Hydrographic Station Locations 6

2.3 Near-surface Temperature and Salinity Profiles 6 2.4 T/S plot of all stations 8

Cruise Event Log 9

Cruise Personnel 11

Chief Scientist’s Log of Daily Events 11

Appendix 1 – CTD station profile data 14

Lists of Figures

Figure 1. R/V Oceanus OC345 Cruise Track and Mooring Locations.

Figure 2. CTD Conductivity Sensor calibration

Figure 3. Oceanus 345 CTD station locations

Figure 4. Surface temperature and Salinity, August 1-6, 1999

Figure 5. T/S plot of all CTD stations.

Figures 6-22. CTD profile data

Preliminary Cruise Report


US State Department Cruise No. 99-013

Woods Hole to Georges Bank to Woods Hole

August 1-6, 1999


The primary purpose of OC345 was to recover instrumented moorings at several sites on the northern and eastern flank of Georges Bank and to conduct CTD and ADCP surveys over the eastern half of the Bank. This NSF program, Frontal Exchange Processes Over Eastern Georges Bank, was designed to focus on frontal processes, which occur over eastern Georges Bank in winter through spring. In particular we want to examine (a) the flow of water and biota onto the Bank along the northeastern flank driven by the strong local semidiurnal tidal currents (which can reach 1.5 m/s during spring tide), winter storms, and the seasonally-evolving density field, and (b) the advection of Scotian shelf water across the Northeast Channel onto the Bank associated with the shelf/slope front and episodic events such as winds and buoyancy pulses.

Accomplishment Summary

The cruise successfully recovered 8 moorings at 3 sites over the north and east flanks of Georges Bank. The ship’s track, mooring locations, and CTD station locations are shown in Figure 1. A total of 33 CTD stations were made during the cruise.

Figure 1. OC345 cruise track, CTD station and mooring locations.

Cruise Results:

  1. Frontal Study Moorings – Dick Limeburner and Charlie Flagg

1.1 North Flank Shallow - Mooring Site NFS

The ship arrived at the NFS mooring site at 1800Z on 8/2/99 and we immediately made a CTD cast. Preparation for recovery of NFS guard buoy C began after the CTD cast and the recovery was completed at 1910Z. There was a large knot of chain near the anchor and about 78 m of chain were measured between this chain knot and the mooring swivel. NFS guard buoy A was recovered at 2058 Z and again there was a large chain knot near the anchor located about 72 m below the wire rope. The NFS subsurface mooring was recovered at 2218Z and all the subsurface instrumentation appeared in good condition. A GPS drifter with drogue centered at 10 m was deployed near the NFS site at 2255Z and we then began making CTD stations along a north/south line passing through the NFS and NFD sites.

At 1020 Z on August 31, 1999 we began recovering the NFS discus mooring. Large tensions were apparent during the recovery and we believe the NFS discus ground chain was also wrapped in a knot near the 5000 lb anchors. We disconnected the mooring below the lowest instrument and steamed to the EF mooring site

    1. Eastern Flank - Mooring Site EF

The guard buoy at the EF mooring site was recovered on August 2, 1999 at 1429Z along with a small fisherman’s buoy. We then began recovering the EF discus mooring at 1658Z. A piece of polypropylene fishnet was caught in the discus bridle and needed to be cut away in order to disconnect the EF discus from the rest of the mooring. We disconnected the mooring below the lowest instrument and began an east/west CTD section during the evening.

1.3 North Flank Deep – Mooring Site NFD

At sunrise on August 3, 1999 we released the anchor on the ADCP frame, but the instrument package remained on the bottom at the NFD site. We decided to recover the NFD discus and then begin dragging operations for the bottom mounted ADCP. The NFD discus was on the deck at 1233Z. Fish line was attached to the discus bridle as well as a collapsed polyform buoy. We disconnected the mooring below the lowest instrument and began the dragging operation for the ADCP. At 1824Z the ADCP surfaced after one hour of dragging and at 1851Z the ADCP was on the deck. Table 1 summarizes the mooring recoveries.

Time UTC
Latitude N

Longitude W

Depth m

North Flank Shallow Guard




42° 04.80’

66° 42.00’


North Flank Shallow Guard




42° 04.71’

66° 42.27’


North Flank Shallow SubSurf.




42° 04.60’

66° 41.93’


North Flank Shallow Discus




42° 04.49’

66° 42.04’


East Flank Guard




41° 44.29’

66° 06.78’


East Flank Discus




41° 44.31’

66° 06.53’


North Flank Deep Discus




42° 09.79’

66° 42.19’


North Flank Deep ADCP




42° 10. 25’

66° 42.57’


Table 1. OC345 mooring recovery times and positions.

2. HYDROGRAPHY – Dick Limeburner

2.1 Calibration

Standard CTD data was collected during Oceanus 345 with a Sea Bird Electronics SBE-911 profiling CTD measuring pressure, conductivity, temperature, light transmission, fluorescence, turbidity and irradiance. At least one seawater sample was collected at each station for calibration of the conductivity sensor on the SBE-911 CTD. Figure 2 below summarizes the comparison between the conductivity measured by the CTD and the in situ conductivity calculated from the water sample bottle salinity using a Guildline Salinometer. The RMS conductivity difference was 0.0032 s/cm and this offset was not applied to the data.

Figure 2. Differences between the CTD conductivity and the seawater sample conductivity during the cruise.

2.2 Hydrographic Station Locations

A total of 33 CTD stations were completed during the cruise along 3 sections radiating outward from the center of the eastern flank of Georges Bank. The locations of the CTD stations are shown in Figure 3.

Figure 3. CTD station locations during OC345.

2.3 Surface Temperature and Salinity and Profiles

Near-surface temperature and salinity over the eastern flank of Georges Bank during OC333 are shown in Figure 7.

Figure 4. Surface temperature and salinity.

2.4 T/S Plot of all stations.

Figure 5. T/S plot of all the stations on OC345.

Oceanus 345 Cruise Event Log

EventInstrumentCast #StationYearMonthDayHr:mnS/EN. LatW. LonCastWaterCommentsUTCDepth mDepth m1SBE-9111NFS1999821814S420 04.57'660 42.60'6974Bottle V1E2NFS GuardNFSC1999821910S420 04.80'660 42.00'74Recover mooringE3NFS GuardNFSO1999822104S420 04.71'660 42.27'74Recover mooringE4NFS SSNFSSS1999822223S420 04.60'660 41.93'72Recover mooringE5SBE-9112NF11999830119S420 19.2004'660 42.0026'295299Bottle V2E6SBE-9113NF21999830210S420 14.2647'660 41.9509'241245Bottle V3E7SBE-9114NF31999830246S420 12.2532'660 42.0248'211216Bottl3 V4 E 8SBE-9115NF41999830314S420 11.0061'660 41.9803'197203Bottle V5 E 9SBE-9116NF51999830342S420 09.5222'660 42.0207'123133Bottle V6 E10SBE-9117NF61999830406S420 08.3969'660 42.0367’9699Bottle V7E11SBE-9118NF71999830431E420 07.0475'660 42.0226'6975Bottle V812SBE-9119NF81999830503S420 04.8200'660 42.0378'6672Bottle V9E13SBE-91110NF91999830555E410 59.5403'660 39.5159'7075Bottle V1014SBE-91111NF101999830642E410 54.7969'660 37.0508'7175Bottle V1115SBE-91112NF121999830727S410 49.7380'660 34.7605'7277Bottle V12 E 16NFS Discus NFS1999831021S420 04.49'660 42.04' 76Recovered E 17SBE-91113EF1999831406S410 44.1840'660 06.7385'8893Bottle V13 E 18EF Guard EF1999831433S410 44.1840'660 06.7385'8893Recovered E19EF Discus EF1999831658S410 44.31'660 06.53'8893Recovered E20SBE-91114EF1999832031S410 48.1349'650 38.4337'9951050Bottle V14 E 21SBE-91115EF1999832205S410 47.2637'650 45.2522155160Bottle V15 E 22SBE-91116EF1999832239S420 46.7000'650 52.8328'121125Bottle V16 E 23SBE-91117EF1999840020S410 46.1242'650 58.9482100103Bottle V17 E 24SBE-91118EF1999840109S410 45.6255'660 05.7546'9093Bottle V18 E 25SBE-91119EF1999840153S410 45.1591'660 12.2679'8589Bottle V19 E 26SBE-91120EF1999840236E410 44.750'660 18.1362'7884Bottle V2027SBE-91121EF1999840314S410 43.2305'660 41.6853'7376NFS site,Bot AJ18@73m E 28SBE-91122NEP1999840354E410 43.6548’660 32.3612'6873Bottle V2229NFD Discus NFD1999841233S420 09.79’660 42.19’160Recovered E 30NFD ADCP NFD1999841851S420 10.25’660 42.57'160 Recovered E 31SBE-91123NEC1999842235S420 18.0691’650 50.1784210215Bottle V23 E 32SBE-91124NE1999842324S420 14.1636’650 53.1036’235240Bottle V24 E 33SBE-91125NE1999850019S420 10.2168'650 58.3961222224Bottle V25 E 34SBE-91126NE1999850101S420 08.0081’660 01.3598’212220Bottle V26 E 35SBE-91127NE1999850138E420 05.4109'660 04.5258’123128Bottle V2736SBE-91128NE1999850215E420 01.9473’660 08.9290’8993Bottle V2837SBE-91129NE1999850249E410 58.2042’660 13.1959’7983Bottle E138SBE-91130NE1999850325E410 54.6725’660 18.0566’7783Bottle E239SBE-91131NE1999850356S410 51.1255’660 22.4207'7580Bottle E3 E 40SBE-91132NE 1999850433S410 37.3297660 26.7083’7378Bottle E4 E 41SBE-91133NE 1999850513S410 44.2765’660 31.8416’6973Bottle E5 E Cruise Personnel

Scientific Crew

Richard Limeburner, Chief Scientist

Charles Flagg, Scientist

Wil Ostrom, Senior Engineer

Larry Costello, Engineer

Jim Dunn, Engineer

Claudia Cenedese, Post doc

Natasha Grey, NSF Biology

Rochelle Ugstad, Electonic Engineer

Erica Rude, Electronic Engineer

Kristin France, Student

Rachael Stanley, Student

Andrew Thompson, Student

Alex Walsh, EPaint representative

Ship’s Crew

Lawrence Bearse, Captain

Richard Chase, Chief Mate

Emily Sheasley, 2nd Mate

Horace Madeiros, Boatswain

James Ryder, AB

Peter Liarikos, OS

Patrick Pike, AB

Richard Morris, Chief Engineer

Alberto Collasius, Jr. Engineer

John Kay, Jr. Engineer

Torii Corbett, Steward

Benjamin Malarkey, Mess Attendant

Chief Scientist’s Daily Log

Sunday – August 1, 1999


1600 – Depart WHOI dock

1630 – Fire and boast drill

1700 – Science meeting

Monday – August 2, 1999


0830 – Wil gave class on deck work

1400 – Arrive at mooring location NSF

1415 – CTD 1 at NFS

1510 – Recovered NFS Guard C

1658 – Recovered NFS Guard O

1818 – Recovered NFS Subsurface

1855 – Deployed GPS drifter 24947

2119 – CTD 2 – Begin north section CTD line

2210 – CTD 3

2246 – CTD 4

2314 – CTD 5

2342 – CTD 6

Tuesday – August 3, 1999


0006 – CTD 7

0031 – CTD 8

0103 – CTD 9

0155 – CTD 10

0242 – CTD 11

0327 – CTD 12

0620 – Recovered NFS Discus

1006 – CTD 13

1029 – Recovered EF Guard

1258 – Recovered EF Discus

1631 - CTD 14

1805 – CTD 15

1839 – CTD 16

2020 – CTD 17

2109 – CTD 18

2153 – CTD 19

2236 – CTD 20

2314 – CTD 21

2354 – CTD 22

Wednesday – August 4, 1999


0833 – Recovered NFD Discus

1105 – 1424 - Dragged for ADCP

1451 – Recovered ADCP

1835 – CTD 23

1924 – CTD 24

2019 – CTD 25

2101 – CTD 26

2138 – CTD 27

2215 – CTD 28

2249 – CTD 29

2325 – CTD 30

2356 – CTD 31

Thursday – August 5, 1999


0033 – CTD 32

0113 – CTD 33

Friday – August 5, 1999


0000 – 0400 – Steamed along cross-shelf line for Paula Fratantoni

0845 – Tied up at WHOI dock

Appendix 1. CTD Station Profile Data