CRUISE REPORT

Vessel: RV Árni Friðriksson

Departure: Reykjavík, Iceland, August 4th 1999

Arrival: Reykjavík, Iceland, August 29th 1999

PARTICIPANTS:

Sveinn Sveinbjörnsson, Chief scientist

Héðinn Valdimarsson, Physical oceanography

Steingrímur Jónsson, Physical oceanography

Sigurður Jónsson, Physical oceanography, 0-group

Björn Sigurðarsson, Physical oceanography, 0-group

Þorgrímur Baldursson, 0-group

Albert Stefánsson, 0-group

Gísli Ólafsson, 0-group

Páll Svavarsson, 0-group

Eydís Cartwright, 0-group

Gerður Pálsdóttir, 0-group

SCIENTIFIC OBJECTIVES

The A10-99 cruise was carried out by the Marine Research Institute (MRI) on the RV Árni Friðriksson with the following aims:

1. To carry out long-term hydrographic investigations on standard sections in the waters all around Iceland along with the yearly 0-group investigations. The oceanographic investigations were performed by CTD-casts. Included in the observation work is MRI's role in VEINS, a program with the objective of measuring and modelling 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 VEINS tasks:
   1. Determining the water mass properties of the Denmark Strait Overflow. (Task 1.4.2)
   2. Improving estimation of the freshwater flux to the North Atlantic via the East Greenland Current and East Icelandic Current. (Task 1.4.3)
   3. Measuring the inflow of Atlantic Water to the Iceland Sea. (Task 1.4.4)

CRUISE NARRATIVE

The RV Árni Friðriksson left Reykjavík harbor at 1400 hours on the 4th of August 1999 for the A10-99 cruise.

The vessel headed for the Faxaflói section ( Figure 1) occupying the first nine stations. From there the ship headed for the Denmark Strait NW of Iceland (Látrabjarg and Kögur sections) and eastwards into North Icelandic waters (Húnaflói, Siglunes, Slétta, and Langanes NE sections). After occupying North Icelandic waters the vessel continued eastwards into East Icelandic waters (Langanes E and Krossanes sections) and to South Icelandic waters (Stokksnes, Ingólfshöfði and Selvogsbanki sections). The RV arrived to Reykjavik at 1000 hour on the 29th of August.

Sections confined to VEINS are those of Faxaflói, Látrabjarg, Kögur, Langanes NE and Krossanes. Locations of hydrographic sections and CTD stations are shown in Figure 1.

HYDROGRAPHY

The hydrographic work was carried out with a CTD-water sampling units equipped with a Seabird Inc. SBE 911plus CTD. The unit, a MRI made rosette equipped with 12 modified Hydro-Bios 1.7 liter water bottles and a General Oceanics underwater unit, was used on all CTD stations. The CTD was 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        868 20-07-99   549 20-07-99

RESULTS

All of the goals of the cruise were achieved (see list of stations and cruise track-Figure 1)

In August 1999 the main features of the hydrographic conditions in Icelandic waters were as follows:

South and west of Iceland temperatures were relatively high with a strong seasonal warming of the surface layer. The salinity of the Atlantic water in this area was high as it has been since 1997 (35.1-35.2).

The flow of Atlantic water into the area north of Iceland was pronounced and spread further eastwards than in the previous 3 years. A slight cold intrusion from the north was observed in the surface layer in the northwestern part of the survey area.

Temperatures of the surface layer in the northeastern and eastern part were in general 1 to 2°C higher and the thermocline was deeper than in August 1998. In the surface layer as well as in deeper layers northeast and east of Iceland the cold East Icelandic Current was further out than in August 1997 and August 1998. The surface layer was in general more saline this year than previous years.

It is concluded that in summer 1999 hydrographic conditions in Icelandic waters were observed as quite favorable as regards temperature and salinity. To the south and west temperature and salinity were similar to what has been observed the last two years but higher to the north and east.

The overall results of interest for the VEINS project from the investigation in August 1999 are that high salinities are still found in the Irminger Current west of Iceland further expressed with a widespread inflow of warm Atlantic water into North Icelandic waters. The fresh water component of the East Icelandic Current was relatively weak and far off the coast. The near-bottom overflow just south of the sill in the Denmark Strait (Látrabjarg section) had values of -0.5°C and 34.89 referring to intermediate water from the north (Iceland Sea).

Preliminary TS-diagrams from the Faxaflói , Látrabjarg , Kögur , Siglunes , Langanes NE , Langanes E , Krossanes , Stokksnes and Selvogsbanki 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), Húnaflói (Fig. 6a and Fig. 6b), Siglunes (Fig. 7a and Fig. 7b), Slétta (Fig. 8a and Fig. 8b), Langanes NE (Fig. 9a and Fig. 9b), Langanes E (Fig. 10a and Fig. 10b), Krossanes (Fig. 11a and Fig. 11b), Stokksnes (Fig. 12a and Fig. 12b) and Selvogsbanki (Fig. 13a and Fig. 13b) sections respectively, of which Figures 3, 4, 5, 9 and 11 are part of the VEINS programme. For location of the above sections see Figure 1 and the station numbers.

CONTACT

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