KV Svalbard cruise 19. March - 31.March 2007

The cruise started in Longyearbyen and ended in Tromsø.



We had about 10 days in the sea-ice south-east of Svalbard.
We did three ice-stations with ~24 h duration.
Ice conditions were quite strange this year, with thin fast ice
and only very thin ice, or grease/frazil between Svalbard and
Bjørn Øya.

There were two other groups joining the cruise (DNV and SINTEF).
Sea ice thickness measurements were made by Andreas Pfaffling and are available here.

Andreas now has his own company called Pfaffling Geophysics.

The efforts was along the lines of BIAC 'sea ice' with many processes being relevant,
the CO2 etc. "Bipolar Atlantic thermohaline Circulation"

The process studies that was worked on are listed below, for more on the
different sensors we operate have a look at our Fieldwork page.
The cruise narrative can be found here.


A) Atmospheric/flux measurements

Jochen Reuder (joachim.reuder@gfi.uib.no) and Anna Sjøblom (anna.sjoblom@unis.no)
Tor DeLange (GFI technitian) and Charlotta Petterson (UNIS student)


Atmospheric fluxes of momentum, heat,
moisture and CO2 by one eddy
correlation system (Campbel CSAT3, Licor 7500)
measured on the ice stations.

Measurements with the inertial dissipation
method were done from the bow of KV Svalbard.
A sonic anemometer was placed approximately
9 meters above the water pointing
in the ships travel direction.
The measurements were done semi-continuously
during the whole cruise, but intense measuring
periods with the ship at rest
in the wind were done especially in
Storfjorden but also other places along
the cruise track. The purpose is to evaluate
the momentum and sensible heat
fluxes over the air-ice-sea interface.










Micrometeorological profiles at two locations with two measurement heights

1m: temperature, humidity, pressure, wind speed
5m: temperature, humidity, wind speed, wind direction

These measurements will be done by our Aanderaa system. Therefore no special
logistics concerning power supply are necessary for this. We intend to fix
the masts by ice screws.


B)
Oceanic Microstructure Profiles

Ilker Fer (BBCR)
Help from Anna, Lars, Ragnheid along the way.

Full report here (under construction)

In addition to the eddy-correlation turbulence
measurements conducted by Miles McPhee (see C),
microstructure profiles were collected covering
the full depth at three ice stations:
Station 1 in Van mijenfjorden fast-ice;
Station 2 near Freemansundet fast-ice; and
Station 3 from drifting ice east of
Freemansundet in western Barents Sea.
An MSS90L loosely tethered free-fall
profiler was used with a noise level for
dissipation of about 3x10^-9 W/kg.
Ice deployments were made from a
hydrohole in the ice, within
30 m from TIC location and at least
150 m away from the research vessel.
Background currents in the upper 30-60 m
(depending on the scatterer strength)
were monitored by acoustic Doppler profiler
Aanderaa RDCP600 at Stations 1 & 2
and Sontek at Station 3, suspended from ice
looking downwards. Additional
microstructure profiles were collected from K.V.
Svalbard along a section in the Storfjorden
polynya and at several stations in the vicinity of the
Storfjorden sill.







Station 1: Fast-ice station in Van mijenfjorden was occupied at 77deg
48.6075min N, 015deg 56.9013minE at water depth of about 65 m and ice
thickness of 35-40 cm. In total, 63 casts were made between 200307
1926 – 210307 0914 UTC at an average sampling interval of 13 minutes
between profiles.

Station 2: Fast-ice station in Freemansundet was occupied at 78deg 08.634min N,
020deg 52.009minE at water depth of about 46 m and ice thickness of 80 cm.
In total, 5 casts were made between 220307 2309 – 230307 0008 UTC. Working
conditions were difficult and the shear probes and microstructure sensors
were vulnerable to slush continuously forming or advecting from below at
the hydrohole. Time series were terminated after a mechanical failure of
the MSS-winch system which was repaired on board K.V. Svalbard.

Station 3: Drift-ice station was occupied on a large ice floe with variable
ice thickness (15 cm to 120 cm). At the MSS measurement site ice was about
30 cm thick and during the first cast position was approximately 78degN,
025deg 26minE at about 150 m water depth. 58 profiles were collected
between 270307 1147 – 280307 0400 UTC.


C) Turbulence and supercooling of the ocean boundary layer
Full report here


During the cruise aboard the Norwegian Coast Guard icebreaker K/V
Svalbard
, we had the opportunity to deploy two turbulence instrument
clusters (TICs) during three short on-ice stations at different locations in or
near the Svalbard archipelago. The second station was situated near the edge of
fast ice approximately 45 cm thick in the northern end of Stor Fjord (between
Spitsbergen and Edge Islands), near the mouth of Freeman Sound. We measured
there at two lev­els, 1 and 3 m below the ice/water interface, for about 20
hours, or slightly more than 11/2 tidal cycles. This is an area of much interest
because the combination of strong tidal action and cold northerly winds often
forms a polynya capable of producing exceptionally dense water that is both
highly saline and cold. In winter the water is nearly always near its freezing
temperature, and may become supercooled. In the measurements we made during our
brief station in Freeman Sound, we observed what appear to be supercooled conditions,
but also noticed a response of the SBE 04 conductivity meters in those conditions
that may bear on other discussions of supercool­ing observed in polar waters,
based on measurements made with Sea-Bird and similar conductivi­ty measuring instrumentation.





Miles McPhee (Washington)
Cooperative US-Norway project.
Some help from Ragnheid Skogseth and Lars H. Smedsrud to set up the mast etc.

D) Sea ice / grease properties

Lars H. Smedsrud
Johan Wåhlin (Nansen Centre, Master student)

The sea ice program included taking cores and measuring temperature, salinity, and
ice thickness, as well as snow depths and floe size.
Measurements were also planned to include new sea ice bulk salinity,
grease and congelation ice samples.

The warm temperatures during the cruise resulted in almost no mesurements of
frazil ice and thin ice, so the main results were the measurements of the
fast ice in Freemansundet, and of the floe from wich we were working east
of Edge Øya in the Barents Sea.

A detailed report is available here.



Johan Wåhlin (Nansen Centre, supervised by Stein Sandveen)
doing manual ice coring on the fast ice in Freemansundet. He also did
snow measurements for validation of satellite data.


E) CTD profiles from the vessel
Full report here (PDF)

Skogseth, Ragnheid, UNIS, E-mail: Ragnheid.Skogseth@unis.no
Smedsrud, Lars H., GFI, E-mail: larsh@gfi.uib.no
Wåhlin, Anna, University of Gothenburg, E-mail: anna@gu.se
Fer, Ilker, BCCR, E-mail: ilker.fer@gfi.uib.no

The aim was to sample concurrent atmospheric and water properties in the area of open water in Storfjorden that is termed a polynya. Such a polynya forms due to winds, and partly currents, that transport sea ice away from land or fast ice areas.
In order to enter the polynya area we were lucky to utilize the large and powerful icebreaker, K/V Svalbard. During the first days of the cruise the weather conditions were favourable for polynya activity, with strong north-easterly winds pushing the pack ice out of Storfjorden. Unfortunately, the wind became strong southerly when we left Van Mijenfjorden and entered Storfjorden and the polynya area. This gradually closed the polynya with thin ice and pack ice from south. Warmer and less saline water was measured to enter the shallow polynya area from south, while dense brine water formed on the shallow polynya area during the frazil ice polynya event, prior to the cruise, was measured along the bottom towards the deeper basin in Storfjorden.

 
Above a densely spaced section across the western side of the sill in
Storfjorden is shown as an example of the data measured. See the full report
for calibrated data and further derails.