HAFRANNSÓKNASTOFNUNIN

Marine Research Institute

Reykjavík, Iceland

VEINS@ICES HAFRÓ MAIN










CRUISE REPORT

CRUISE NUMBER: B02 - 98
(February-March 1998)


















SCIENTIFIC OBJECTIVES

The B02-98 cruise was carried out by the Marine Research Institute (MRI) on the RV Bjarni Sæmundsson with the following aims:

  1. To carry out long-term hydrographic investigations on standard sections in the waters all around Iceland. The work included CTD-casts together with sampling for nutrient and oxygen-analysis. Included in the observation work is MRI's role in VEINS, a program with the objective of measuring and modeling the variability of fluxes between the Arctic Ocean and the Atlantic with view on implementing a longer term system of measurements needed to understand the high-latitude oceans steering role in decadal climate variability. Funding is provided by the EU MAST-III programme and the participants in the project. The work on this cruise was part of the following tasks:

    1. Measuring the Denmark Strait Overflow. (Task 1.4.1)
    2. Determining the water mass properties of the Denmark Strait Overflow. (Task 1.4.2)
    3. Improving estimation of the freshwater flux to the North Atlantic via the East Greenland Current and East Icelandic Current. (Task 1.4.3)
    4. Measuring the inflow of Atlantic Water to the Iceland Sea. (Task 1.4.4)

  2. Deploy 10 standard SVP - Woce drifters in a program on "Satellite-tracked buoys in SW Icelandic waters", which is a joint project of the MRI, supported by the Icelandic Research Council, and Scripps Institute of Oceanography, USA.

  3. Deploy a VEINS ADCP mooring in the Denmark Strait Overflow Water (UK1, VEINS task 1.4.1).

  4. Collect water samples for the determination of pCO2, total carbonate, delta-C13, oxygen, nutrients, iodine-129 and the sulfur hexafluoride (SF6) tracer, as part of the ESOP-2 program.

  5. Collect water samples for determination of total carbonate, oxygen and nutrients as part of the ESOP-2 program. These samples are for time series which are intended to show variability with time and carbon-nutrient relationships.

  6. Collect continuous surface data on temperature, salinity and pCO2, for the ESOP-2 program to complement data from the occupied stations.

  7. Capelin survey NW and N of Iceland, 1-3 group.

  8. Collect samples for analysis of Cesium-137 (Icelandic Radiation Protection Institute).


CRUISE NARRATIVE

The RV Bjarni Sæmundsson left Reykjavík harbor at 2000 hours on the 9th of February 1998 for the B02-98 cruise.

The vessel headed for Faxaflói section towards East Greenland, where a bottom mounted ADCP mooring was deployed on behalf of the British VEINS group (Robert R. Dickson, Lowestoft). From there the vessel headed to the Northwest Peninsula of Iceland, and to the town of Ísafjörður due to weather conditions. From there the ship headed for the Látrabjarg section and for capelin investigations in the Denmark Strait area as well as north of Iceland along with hydrographic sections - Kögur section, Hornbjarg section and a Mooring section IS8. Due to bad weather conditions and severe icing the ship had to go to shelter or ports three times - Ísafjörður and Siglufjörður. The Siglunes section was carried out in bits, and at last the ship stayed for 4 days in the capital of northern Iceland, Akureyri, still due to very unusual weather conditions for such a long time, i.e. northerly storms and icing (up to ÷14°C at sea and ÷30 to ÷20°C ashore). From Akureyri the ship went eastwards to the Langanes NE and Langanes E sections, both incomplete due to weather conditions.

From here the ship went to port at Neskaupsstaður, East Iceland, for 24 hours, where the scientific and ship crew gave information to undergraduate students on the tasks of the cruise, including the VEINS and ESOP2 programmes.

After Neskaupsstaður, the vessel continued eastwards into the Norwegian Sea (the Krossanes section) and from there to south Icelandic waters (Stokksnes and Ingólfshöfði sections). Coming to Selvogsbanki section again the weather hampered the cruise, this time with more southerly gales, and the ship headed for Reykjavík and arrived there at 0900 hours on the 9th of March having sailed 3773 nm. Thus a planned cruise of around 20 days lasted for 30 days.

Sections confined to VEINS are those of Faxaflói, Látrabjarg, Kögur, Langanes NE and Krossanes. Locations where surface drifters were deployed (indicated by o) are shown in Figure 1 as well as the location of an ADCP moorings (indicated by m (UK1)) in VEINS task 1.4.1.

HYDROGRAPHY

The hydrographic work was carried out with two independent CTD-water sampling units both equipped with Seabird Inc. SBE 911plus CTD's. The first unit, a MRI made rosette equipped with 12 modified Hydro-Bios 1.7 liter water bottles and a General Oceanics underwater unit, was used for all standard CTD stations. The other unit (referred to as Unit B) comprised of SBE 32 rosette equipped with 12 Go-Flo 8 liter water samplers was used for chemical sampling on ESOP-2 stations. A Sea-Tec transmissometer was attached to the MRI unit. Both units were equipped with newly calibrated temperature and conductivity sensors and water samples were collected at deepest sampling level on all stations for calibration purposes.

CTD (SBE 911plus CTD System) Sensor Status.

	    Temp. Calibr.  Cond. Calibr.
	   sensor date    sensor date

Unit A       2021 22-01-98  1643 16-01-98
Unit B       1428 17-01-98  1162 16-01-98

CHEMISTRY

Samples for oxygen measurements were collected in 60 ml bottles, and Winkler reagents added. Samples were then placed in a dark cold storage until the time of analysis. Oxygen concentration was determined using a modified Winkler method.
Samples for nutrient analysis, nitrate, phosphate and silicate, were collected on selected stations, in 250 ml polyethylene bottles. Samples were freezed, for later analysis in land on a ChemLab auto-analyzer.
Samples for pCO2 and total carbonate were collected on 6 stations in 500 and 250 ml bottles, preserved with mercury chloride and placed in cold storage.
Samples for delta carbon-13 were collected from the surface at 5 stations and a full profile was collected from 1 station. The samples were preserved with mercury chloride.
Samples for sulfur-hexafluoride (SF6) were collected at 5 stations in 500 ml bottles supplied by the Gothenburg University and placed in cold storage.
Samples for iodine-129 profile were collected at 1 station in 1 liter polyethylene bottles supplied by Centre de Spectrometrie Nucleaire et de Specrometrie de Masse.

MOORINGS

During the B02-98 cruise the following current meter mooring was deployed (VEINS task 1.4.1).

St.id.	     Position       Water Instr. Type           Serial  Date    Notes
	Lat.	  Lon.	    depth depth			no.
UK1     63 32.25N 36 28.64W 1777  botm   ADCP                   120298  VEINS deployment

RESULTS

As seen from the cruise narrative above not quite all goals of the cruise were achieved due to weather conditions (see list of stations and cruise track-Figure 1), but though most of the VEINS plans except the northern most stations of the Kögur and Langanes NE sections were carried out. The Kögur section was incomplete due to drift-ice conditions in the Denmark Strait area.

Click your way through the cruise track , i.e. by clicking in the left or right part of the section name you will get potential temperature or salinity sections of the section respectively.

The main result of the hydrographic observations in Icelandic waters in February-March 1998 were the following (see e.g. Fig. 14a , Fig. 14b , Fig. 15a , and Fig. 15b ):

The Atlantic Water (Irminger Current) south and west of Iceland showed relatively high temperatures (6-8°C) and salinities (35.00-35.20), the high salinities being in accordance with those of 1997 which were higher than during the years before or even since the sixties-seventies. In the Denmark Strait area cold and low-saline Polar Water and drift-ice was found to be relatively near to the NW peninsula of Iceland, but farther eastwards in North and East Icelandic waters indication of Atlantic water from the Irminger Current were found with relatively high temperatures (2-3.5°C) and salinities (~34.8), revealing North Icelandic Winter Water in the shelf area. The boundaries to the cold water from north (<0°C) were found to be quite northerly and the cold tongue of the East Icelandic Current northeast and east of Iceland was relatively far off as in November-December 1997. The boundary between the cold and warm water off the southeast coast seemed to be relatively northerly ( Fig. 14a and Fig. 15a ) and high saline Atlantic water along the south coast was found into the near coastal areas with only slight indications of low-saline coastal water (run-off)( Fig. 14b and Fig. 15b ). Thus the hydrographic conditions in Icelandic waters were quite favorable in February-March 1998 except in the Denmark Strait area.

The overall results of interest for the VEINS project are those conditions in the Denmark Strait area and a relatively weak transport of fresh water from the north within the East Icelandic Current, but on the other hand the general strong input of Atlantic water from the south was quite pronounced. The cold "overflow" along the East Greenland continental slope ( Fig. 3a ) showed potential temperatures below 2°C in a wider depth range (1200m - 2500m, Faxaflói section) than during previous VEINS investigations ( May-June and November-December 1997) as well as indications of "low" saline water (Polar Intermediate Water) above 1400m depth.

At last it may be noted that during the cruise frequently and very persistent northerly gales together with cold outbreaks from the Arctic (less than ÷10°C at sea and less than ÷25°C in land) hampered the cruise, not least due to heavy icing conditions.

Preliminary TS-diagrams from the Faxaflói , Látrabjarg , Kögur , Siglunes , Langanes NE , Langanes E , Krossanes and Stokksnes sections show the results above. In addition are preliminary potential temperature and salinity sections shown for Faxaflói (Fig. 3a and Fig. 3b), Látrabjarg (Fig. 4a and Fig. 4b), Kögur (Fig. 5a and Fig. 5b), Siglunes (Fig. 6a and Fig. 6b), Langanes NE (Fig. 7a and Fig. 7b), Langanes E (Fig. 8a and Fig. 8b), Krossanes (Fig. 9a and Fig. 9b), and Stokksnes (Fig. 10a and Fig. 10b) sections respectively, of which Figure 3, 4, 5, 7 and 9 are part of the VEINS programme.

Three other potential temperature and salinity sections have been included in this report showing: Mooring Section IS8 (Fig. 11a and Fig. 11b), including the location of the current meters, Hornbjarg section (Fig. 12a and Fig. 12b), and Húnaflói Section (Fig. 13a and Fig. 13b). For location of these sections see Figure 1 and the station numbers.


CONTACT

In case of further information contact:

Dr. Svend-Aage Malmberg Email: svam@hafro.is
Mr. Jóhannes Briem Email: briem@hafro.is
Mr. Héðinn Valdimarsson Email: hv@hafro.is
Dr. John Mortensen Email: johnm@hafro.is

or by mail:

Att. name
Hafrannsóknastofnunin
(Marine Research Institute)
P.O. Box 1390
Skúlagata 4
121 Reykjavík
Iceland

or

Tel. (+354) 55 20240
Fax. (+354) 56 23790




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