NACLIM Deliverable D21.21
Deliverable title
Daily time series data of mass, heat and freshwater transports across the GreenlandScotland-Ridge-1st Batch
This deliverable consists of time series of mass, heat and freshwater transport across the GSR
calculated on the first year of observations.
WP No.
2.1
Lead beneficiary:
WP title
Exchanges across the Greenland-Scotland-Ridge
Work duration1) 18
UIB, Kjetil Våge
Due delivery deadline: 30 April 2014
Actual delivery
date:
30 April 2014
R= report
P= prototype
Nature of the
deliverable
D= demonstrator
X
O= Other
PU = public
X
Dissemination
level
PP= restricted to other programme participants, including the Commission services
RE= restricted to a group specified by the consortium, including the Commission
services
CO= confidential, only for members of the consortium, including the Commission
services
1) Work duration = project month
Lead beneficiary:
Other contributing
partners:
UIB
Kjetil Våge
UHAM
Unires
SAMS
HAV
Detlef Quadfasel, Kerstin Jochumsen
Svein Østerhus
Stuart Cunningham, Clare Johnson
Karin M. H. Larsen, Bogi Hansen
Hedinn Valdimarsson, Steingrimur Jonsson,
Bee Berx
Laura de Steur
MRI
MSS (Marlab)
NIOZ
NACLIM project is financed by the European Commission
through the 7th Framework Programme for Research
Theme 6 Environment
Grant Agreement 308299
Page 1
Index
1. Executive summary ....................................................................................................................................... 3
2. Project objectives .......................................................................................................................................... 4
3. Detailed report on the deliverable .................................................................................................................. 5
4. References .................................................................................................................................................. 13
5. Dissemination and uptake ........................................................................................................................... 14
5.1 Dissemination ............................................................................................................................................. 14
5.2 Uptake by the targeted audience ............................................................................................................... 16
6. The delivery is delayed:  Yes  No ....................................................................................................... 16
7. Changes made and difficulties encountered, if any ...................................................................................... 16
8. Efforts for this deliverable ............................................................................................................................ 16
9. Sustainability ............................................................................................................................................... 17
10. Dissemination activities ................................................................................ Error! Bookmark not defined.
Page 2
1. Executive summary
The meridional exchange across the Greenland-Scotland Ridge is of key importance for the North Atlantic
climate system. Warm, saline Gulf Stream-origin waters flow northward across the ridge into the Nordic seas
(red arrows in Figure 1), release heat to the atmosphere, and are transformed into dense overflow waters.
These waters return southward by flowing through gaps in the ridge as overflow plumes (purple arrows in
Figure 1), which form the lower limb of the Atlantic Meridional Overturning Circulation. As part of the horizontal
circulation, fresh surface waters from the Arctic Ocean are advected southward by the East Greenland Current
along the western boundary of the Nordic seas and across the ridge (green arrows in Figure 1).
Figure 1: The map presents a schematic of the exchange across the Greenland-Scotland Ridge. The red arrows show the three
branches of the Atlantic inflow into the Nordic seas, the purple arrows indicate the locations of the main deep overflows across the
ridge, and the green arrows show the two branches of the fresh outflow in the East Greenland Current system north of the Denmark
Strait. The yellow squares and lines mark the locations of moorings and hydrographic sections used to calculate the properties and
transports of the various branches of the exchange. The acronyms are: FBC = Faroe Bank Channel; WTR = Wyville Thomson Ridge.
Most of the warm Atlantic inflow into the Nordic seas (approximately 90% of the total) takes place to the east of
Iceland. The Faroe and Shetland branches of the inflow transport waters that passed across the ridge between
Iceland and the Faroe Islands and flowed northward through the Faroe Shetland Channel, respectively. Farther
downstream the Atlantic Water carried by these two branches progresses northward in the eastern Norwegian
Sea and form the Norwegian Atlantic Current. The two branches are monitored on sections extending
northward from the Faroe Islands and across the Faroe Shetland Channel, and are, according to long-term
measurements, of comparable magnitude. The flow of Atlantic Water northward through the Denmark Strait
constitutes the Iceland branch. This branch, monitored using moorings deployed north of Iceland, is weaker
and highly variable, but of great importance to the regional marine climate and ecosystem.
Page 3
The transport of overflow water is evenly divided east and west of Iceland. The Denmark Strait overflow is the
largest of the overflow plumes and is the densest source of water to the lower limb of the Atlantic Meridional
Overturning Circulation. East of Iceland the bathymetry is more complex. The Faroe Bank Channel overflow,
which passes through the deepest gap in the Greenland-Scotland Ridge, provides the dominant contribution to
the eastern overflows. Smaller contributions come from overflows across the Iceland-Faroe Ridge (not
observed by the NACLIM project) and the Wyville Thomson Ridge. The overflow plumes are monitored by
moorings near the sills of the deepest passages through the Greenland-Scotland Ridge (Fig. 1).
The final component in the exchange across the Greenland-Scotland Ridge is the outflow of cold, fresh surface
waters transported by the East Greenland Current from the Arctic Ocean. Due to the presence of sea ice and
icebergs during large parts of the year, it is very challenging to obtain moored estimates of freshwater transport
in the East Greenland Current. Using an array of moorings deployed on the Greenland continental shelf and
slope north of the Denmark Strait, a first estimate of freshwater flux through the strait is presented here.
Relative to previous results, the most recent measurements from summer 2012 to summer 2013 do not show
any substantial changes in the various components of the exchange across the Greenland-Scotland Ridge.
The transports of Atlantic Water in all of the inflow branches were marginally below the long-term mean. Both
of the two major overflow plumes, the Denmark Strait and Faroe Bank Channel overflows, also had a transport
slightly below the long-term mean, but there is no indication of a persistent weakening.
2. Project objectives
With this deliverable, the project has contributed to the achievement of the following objectives (see DOW
Section B.1.1):
No.
Objective
Assessing the predictability and quantifying the uncertainty in forecasts of the North
Atlantic/Arctic Ocean surface state
2. Assessing the atmospheric predictability related to the North Atlantic/Arctic Ocean
surface state
3. Monitoring of volume, heat and fresh water transports across key sections in the
North Atlantic
4. Quantifying the benefit of the different ocean observing system components for the
initialization of decadal climate predictions
5. Establishing the impact of an Arctic initialization on the forecast skill in the North
Atlantic/European sector
6. Quantifying the impact of predicted North Atlantic upper ocean state changes on the
oceanic ecosystem
7. Quantifying the impact of predicted North Atlantic upper ocean state changes on
socioeconomic systems in European urban societies
8. Providing recommendations for observational and prediction systems
9. Providing recommendations for predictions of the oceanic ecosystem
10. Disseminating the key results to the climate service community and relevant
endusers/stakeholders
11. Constructing a dataset for sea surface and sea ice surface temperatures in the Arctic
Yes
1.
Page 4
No
X
X
X
X
X
X
X
X
X
X
X
3. Detailed report on the deliverable
Atlantic inflows
The Faroe branch
The inflow of Atlantic Water between Iceland and the Faroe Islands is monitored on a section north of the
Faroes (Fig. 2, left panel). Hydrographic sections have been obtained as planned three times in 2012 and
again in 2013. Three Acoustic Doppler Current Profiler (ADCP) moorings are deployed along the section, but
only two moorings were recovered in May 2013. It was not possible to establish contact with the third mooring,
and its deep location prevents any other recovery of the mooring.
A complete ADCP mooring was planned to be funded through NACLIM. This mooring has been purchased and
was deployed on the section in June 2013 together with the two recovered moorings (i.e. a total of three
moorings). These three moorings are planned to be recovered in May 2014 and redeployed in June 2014.
Figure 2: Locations where the Faroe (IF-inflow) and Shetland (FSC-inflow) branches of the Atlantic inflow as well as the Faroe Bank
Channel (FBC) overflow are monitored (left panel).The system for bottom temperature logging consists of a temperature recorder
connected to an underwater modem. Both of these are powered by an external battery pack with Lithium D-cells (right panel).
In an effort to make the section more sustainable, a bottom temperature observing system is being developed.
This work is in progress and the components for the first system have been ordered (Fig. 2, right panel).
Preliminary tests will be carried out in summer 2014. If the system performs to satisfaction, the remaining units
for the section north of the Faroes are planned to be acquired and deployed in autumn 2014.
The conductivity-temperature-depth (CTD) data have been processed and calibrated and the properties of the
Atlantic Water core have been calculated (Larsen et al, 2012). Generally, temperatures and salinities have
Page 5
been high in recent years, but both properties decreased during 2012 and 2013 to a level close to the levels of
the early 2000s (not shown).
The ADCP data have undergone standard quality control, but since only two moorings were recovered in 2013,
changes were needed in the calculations of volume transports compared to pre-NACLIM calculations (Hansen
et al, 2003).
As described in more detail in a technical report (Hansen et al., 2014a), it was found that by combining the
data from the two recovered moorings with satellite altimetry data, it was possible to generate an algorithm that
could explain 78% (R2) of the variance in the weekly averaged volume transport time series from 2000 to 2012.
Using this algorithm, weekly averaged volume transport values were determined for the 2012 – 2013
deployment period (Fig. 3). The mean volume transport for the June 2012 – May 2013 period is 3.3 Sv.
Within NACLIM, it is planned to redesign the monitoring system north of the Faroes, reducing the number of
expensive moorings while including data from the bottom temperature loggers (Figure 2, right panel) and from
altimetry. This process will involve a thorough re-analysis of all the hydrographic and ADCP data and will
presumably lead to a new transport time series for the whole period from 1997. The present transport values
for 2012 – 2013 should therefore be considered preliminary.
Figure 3: Weekly averaged volume transport of Atlantic Water through a section along 6°05'W north of the Faroes from summer 1997 to
summer 2013. The blue curve indicates transport calculated by the traditional method (Hansen et al., 2003). The red curve indicates
transport calculated by a regression algorithm using only two ADCP moorings and satellite altimetry. The configuration of the mooring
array was changed in 2000, which explains the superior consistency after that time.
Page 6
The Shetland branch
The monitoring of the Atlantic inflow through the Faroe Shetland Channel (FSC) is a joint effort between MSS
and HAV, with support from UiB and UHAM. During 2011-2012, an experiment was carried out as part of both
the THOR project (2008-2013 funded by FP7), which investigated the potential of monitoring the transport of
Atlantic Water through the FSC at a different location from the traditional Munken – Fair Isle Section. The
results of this experiment were recently published by Hansen et al. (2013). The two main recommendations
from this report were (1) that higher resolution in situ velocity observations could improve the current
methodology, and (2) that additional hydrographic data from gliders and moorings could reduce uncertainty in
the current transport estimates. Both these recommendations will be incorporated into the planned NACLIM
fieldwork in 2014-2015.
ADCP moorings were deployed on both the NWZ-line (from South Faroes to Cape Wrath) and on the NWSline (from Munken to Fair Isle) between May 2011 and May 2012; on only the NWS-line between May 2012
and May 2013; and on only the NWZ-line between May 2013 and May 2014. From April-May 2014, the
monitoring will focus on the Scottish edge of the FSC along the NWS-line, to tie in with two other research
projects: the Brahan project (a high frequency radar array measuring surface currents around the Shetland and
Orkney Islands) and FASTNEt (a study on ocean-shelf exchange with mooring and glider deployments in the
FSC during summer 2014).
The current methodology for calculating the transport of Atlantic Water through the FSC (as outlined by Berx et
al., 2013) results in a time series of monthly mean volume transport based on the altimetry and ADCP records.
The quality assurance and processing of the moored current meters is experiencing some delay, but meantime
the transport based on altimetry has been updated to July 2013 (the latest available SLA data from AVISO).
The net volume transport based on altimetry observations averaged 2.4 Sv ± 0.9 Sv (mean ± standard
deviaton) in the period from August 2012 to July 2013. This is somewhat lower than the long-term mean
observed on the section (2.7 Sv ± 0.5 Sv; Berx et al., 2013).
Currently, the time series are provided as monthly estimates, but the planned fieldwork may provide a basis to
extend this to weekly or even daily estimates including heat and salt fluxes.
The Iceland branch
All four moorings, (HB1 – HB4, Fig. 4), that were deployed in August 2012 along the Hornbanki section north of
Iceland (Fig. 4) were recovered in August 2013 except for mooring HB1, which came loose at the end of May
2013 and drifted ashore, but recorded data until then. The current meters at the mooring HB2 stopped
operating in early June 2013, presumably due to battery failure. Moorings HB3 and HB4 delivered full data sets
for the entire period. Hydrographic data from the standard CTD stations LB6 on the Latrabjarg section and
KG6 on the Kögur section along with temperature data from current meters on the Hornbanki section were
used to determine the proportion of Polar and Atlantic water masses. This was then multiplied with the current
Page 7
measured by the current meters in boxes covering the Hornbanki section from 66°20´N to 67°20´N to get the
flux of Atlantic Water through the section following the procedure of Jónsson and Valdimarsson (2012).
Figure 4: Location of hydrographic sections and current meter moorings used for producing the deliverable.
Figure 5: Time series of heat (top panel) and mass (bottom panel) transports in the Iceland branch.
Page 8
Dense overflows
The Denmark Strait overflow
The mooring array at Denmark Strait is designed to monitor the Denmark Strait overflow plume as it enters the
North Atlantic Ocean at the sill of Denmark Strait. The distance between the two moorings is only 10 km; one
mooring is at the deepest point of the passage (approximately 650 m depth) and the other is located at 570 m
on the Greenland side of the strait (Fig. 7). Each consists of an ADCP in a floatation buoy, a SeaBird
MicroCAT SBE-37SM (recording temperature, conductivity and pressure) and an IXSEA OCEANO release.
Quality control of current data includes the rejection of data measured during times of extreme mooring
movement (large pitch and roll), when not under water and while the mooring was descending or ascending.
The temperature and salinity measurements were calibrated using CTD station data. Transports were
calculated following Jochumsen et al. (2012). The calculation of heat and freshwater transports was
rescheduled to autumn 2014, since the telemetry data of the Pressure Inverted Echo Sounder (PIES) deployed
close to the mooring positions proved to be too intermittent to obtain a time series of temperature and salinity
profiles. The recovery of the PIES is planned for July 2014, at which time the full data set will be available for
the calculations.
Figure 6: Volume transport time series of the Denmark Strait overflow in Sverdrup (Sv). The blue lines show estimates based on data
from two ADCPs, the magenta/grey lines show transports calculated using data from one ADCP only. The thin lines are daily transports
and the thick lines depict the 20 day low-pass filtered transports. Updated from Jochumsen et al. (2012) using the same methods.
Page 9
Figure 7: Locations of moorings near the Denmark Strait sill.
The Faroe Bank Channel overflow
The Faroe Bank Channel (FBC) overflow has since 1995 been monitored by regular hydrographic sections
across the channel and by 1-2 BroadBand ADCP moorings at the sill (Fig. 2). Three hydrographic sections
were obtained in each of the years 2012 and 2013 as planned. In June 2012 only one ADCP was deployed at
the sill, but due to an accident upon deployment it was not recoverable. Therefore, a Long Ranger ADCP was
borrowed from UHAM and deployed in September 2012. This mooring was recovered in May 2013 and two
BroadBand ADCPs redeployed in June 2013.
In late autumn 2013 it became clear that RDI Long Ranger ADCPs may produce faulty current velocities close
to the instrument when deployed close to the bottom in strong flows as in the FBC and Denmark Strait (pers.
comm., Nuno Nunes). When the Long Ranger ADCP was recovered it turned out that the data suffered from
this error. Fortunately, the velocity profiles in the FBC are well described by previous observations and seem to
follow a consistent pattern.
Therefore an attempt has been made to adjust the good velocity data further away from the instrument to
“standard profiles” and the procedure is described in Hansen et al., (2014b). The resulting monthly averaged
kinematic overflow transport is shown in Figure 8 along with the 1995 – 2012 Broadband time series. The
frequency distribution of the daily (not shown), monthly and annually averaged transport in this period is quite
similar to that based on the Broadband ADCPs. This indicates that the volume transport based on adjusted
Long Ranger profiles is realistic. The mean volume transport for the September 2012 – May 2013 period is 2.1
Sv, similar to the long-term average.
Page 10
Figure 8. Monthly averaged kinematic overflow volume transport through the Faroe Bank Channel based on Broadband ADCPs (blue)
and adjusted Long Ranger ADCP measurements (red) plotted against time (left) and against month (right).
The Wyville Thomson Ridge overflow
The dense flow over the Wyville Thomson Ridge has been monitored since 2003 with a single ADCP mooring
south of the ridge crest. However, the exact position of the mooring has changed over time as new discoveries
of the pathways of the overflow water were discovered (Sherwin et al., 2008). The data have undergone basic
quality checking and daily volume transports have been calculated (up to August 2013) using the method
detailed in Sherwin et al. (2008). Whilst the transports at sites two and three (blue and red, Fig. 9) are
comparable, the transports calculated from site 1 (green, Fig. 9) are much lower. This is because site 1 does
not capture flow through the Faroe Bank Canyon, a relatively recently discovered important conduit for Wyville
Thomson Ridge Overflow Water (Sherwin et al., 2008). The mean volume transport at site 1 for water with a
temperature less than 0 °C is 0.09 ± 0.05 Sv, for 13 months of data between September 2003 and May 2006.
The mean volume transport for sites 2 and 3 combined, again for water with a temperature below 0 °C, is 0.21
± 0.10 Sv. This estimate uses 61 months of data between May 2006 and August 2013. Although the overall
transport is relatively small, there are sometimes large overflow events with associated transports up to 1.76
Sv (Fig. 9). There does not appear to be any overall trend with time. We cannot reliably calculate salt and heat
fluxes due to the lack of suitable temperature and salinity data.
Page 11
Transport < 0 °C (Sv)
Figure 9. Volume transport (Sv) of Wyville Thomson Ridge Overflow Water with a temperature less than 0 °C. Green: Site 1 (60.24 °N,
8.87 °W); blue: Site 2 (60.25 °N, 8.92 °W); red: site 3 (60.25 °N, 9.01 °W). Thick black line: monthly mean. Data gap between June
2009 and May 2011 due to instrument loss.
The Wyville Thomson Ridge mooring will be re-deployed in July 2014 in the western Rockall Trough. A
pathway of Wyville Thomson Ridge Overflow Water has been shown to exist here (Johnson et al., 2010). The
mooring instrumentation will also be expanded by the inclusion of a further two current meters, with added
value gained from two nearby moorings operated by the recently-funded Overturning in the Subpolar North
Atlantic Project (OSNAP). Additionally the re-located mooring will also lie on a hydrographic line (the Ellett
Line) that has been occupied at least annually since 1975.
Fresh outflow
The East Greenland Current
Here, the first time series of freshwater flux (FWF) in the East Greenland Current (EGC) is presented, which
was determined based on existing mooring data from the Kögur array between June 2011- June 2012. There
are no earlier estimates from moored arrays of current meters at this location. These data were used to obtain
a preliminary estimate of the FWF in the EGC before a refinement of the flux can be determined by 1)
improving upper ocean salinity and velocity fields (i.e. interpolation schemes, dealing with data gaps) and 2)
when including newly obtained data on the shallow shelf east of the shelfbreak EGC.
The mooring positions used to calculate the FWF are shown in Figure 10 (right panel). The first estimate of the
11-month mean FWF is 69 mSv (± 43 mSv standard deviation) to the southwest (Fig. 10, left panel). The flux is
determined relative to a reference salinity of 34.9. We expect this estimate to increase when improving the
stratification of upper ocean salinity and velocity in the interpolation scheme.
Different instrumentation (SBE Microcats, RDI ADCPs, AADI RCMs and an RDCP, and Nortek Aquadopps)
were used for the FWF calculation. They were placed at 100 m, 200 m, 300/350 m and 450/500 and 650 m
Page 12
depth. On the shelf there was only data from 300 m depth. The instruments delivered data every 15 minutes or
hourly of velocity and hydrography. The data were detided with a 40-hour low-pass filter. The data were then
interpolated in the vertical on 5-m grid spacing in the upper 150 m and on bottom-following contours below that
with grid spacing up to ~70 m in the deepest part of the strait. In the horizontal the grid spacing was typically
one km. On locations where there were no instruments, but where for interpolation purposes data was needed
to capture the structure of the EGC, artificial time series were 'constructed' through a regression with a
neighbouring instrumentation or with hydrographic data This was done in order to obtain a more realistic
vertical stratification in the upper 100 m or to improve the vertical velocity profile on moorings where
instrumentation was lost or had not initially been placed. Finally the FWF was determined as
∫∫vxz.(Sref-Sxz)/Sref dzdx
integrated down to isohaline Sref, which is chosen to be 34.9 here.
Figure
Fi
Figure 10: Time series of freshwater flux (left) and mooring locations (right).
4. References
Berx, B., Hansen, B., Østerhus, S., Larsen, K. M., Sherwin, T., and Jochumsen, K. (2013). Combining in situ
measurements and altimetry to estimate volume, heat and salt transport variability through the Faroe–Shetland
Channel, Ocean Science, 9: 639-654, doi:10.5194/os-9-639-2013.
Jochumsen, K., Quadfasel, D., Valdimarsson, H., and Jónsson, S. (2012). Variability of the Denmark Strait
overflow:
Moored
time
series
from
1996-2011,
Journal
of
Geophysical
Research,
117,
doi:10.1029/2012JC008244.
Johnson, C., Sherwin, T., Smythe-Wright, D., Shimmield T., and Turrell, W. (2010). Wyville Thomson Ridge
Overflow Water: Spatial and temporal distribution in the Rockall Trough, Deep-Sea Research I, 57, 1153-1162.
Page 13
Jónsson, S., and Valdimarsson, H. (2012). Water mass transport variability to the North Icelandic shelf, 1994–
2010, ICES Journal of Marine Science, doi:10.1093/icesjms/fss024.
Hansen, B., Hátún, H., Larsen, K.M.H., Kristiansen, R., Mortensen, E, Østerhus, S. (2014). Atlantic water flow
between Iceland and Faroes 2012 – 2013. Havstovan nr. 14-02, Technical report.
Hansen, B., Larsen, K.M.H., Hátún, H., Kristiansen, R., Mortensen, E., Berx, B., Sherwin, T., Østerhus, S.,
Quadfasel, D., and Jochumsen, K. (2013). Monitoring the flow of Atlantic Water through the Faroe-Shetland
Channel. Havstovan Technical Report 13-13, pp. 22.
Hansen, B., Larsen, K.M.H., Kristiansen, R., Mortensen, E, Østerhus, S. (2014). Faroe Bank Channel overflow
2012 – 2013. Havstovan nr. 14-01, Technical report.
Hansen, B., Østerhus, S., Hátún, H., Kristiansen, R., and Larsen, K.M.H. (2003). The Iceland-Faroe inflow of
Atlantic water to the Nordic Seas, Progress in Oceanography, 59, 443-474.
Larsen, K.M.H., Hátún, H., Hansen, B. and Kristiansen, R. (2012). Atlantic water in the Faroe area: sources
and variability, ICES Journal of Marine Science, 69(5), 802–808. doi:10.1093/icesjms/fss028
Sherwin, T., Griffiths, C., Inall, M., and Turrell, W. (2008). Quantifying the overflow across the Wyville Thomson
Ridge into the Rockall Trough, Deep-Sea Research I, 55, 396-404.
5. Dissemination and uptake
5.1 Dissemination
Add the new publications (starting from December 2011) related to this deliverable.
Fill in the table below.
Peer reviewed articles:
Title
Authors
Combining in situ
measurements and
altimetry to
estimate volume,
heat and salt
transport variability
through the FaroeShetland Channel
Berx, B.,
Hansen,
B.,
Østerhus,
S.,Larsen,
K. M.,
Sherwin,
T. and
Jochumse
n, K.
Title of
the
periodic
al or the
series
Ocean
Science
Number,
date or
frequency
Publishe
r
Volume 9
Coperni
cus
GmbH
www.oc
eansci.net
Page 14
Plac
e of
publ
icati
on
Year of
publica
tion
Permanent
identifiers[1
] DOI
2013
doi:10.519
4/os-9-6392013
Is/Will open
access[2]
provided to
this
publication?
Yes
Atlantic water in the
Faroe area:
sources and
variability
The hydrography
and circulation of
the Faroe-Shetland
Channel
Water mass
transport variability
to the North
Icelandic shelf,
1994–2010.
Larsen,
K.M.,
Hátún, H.,
Hansen,
B. And
Kristianse
n, R.
Berx, B.
ICES
Journal
of
Marine
Science
Volume
69 (5)
ICES
2012
Ocean
Challen
ge
19: 15-29
2012
Jónsson,
S., and H.
Valdimars
son,
ICES
Journal
of
Marine
Science
Volume
69
The
Challen
ger
Society
for
Marine
Science
Oxford
Universi
ty Press
2012
doi:
10.1093/ice
sjms/fss02
8
No
doi:10.109
3/icesjms/f
ss024
No
Plan for future publication:
In
preparation
OR
submitted?
Title
Main author
All authors
Title of the
periodical or the
series
Is/Will open
access[2] provided
to this publication?
In
preparation
Arctic Mediterranean
Exchanges
Østerhus, S., Hansen, B., Olsen,
S. et al.
Unknown
Yes
In
preparation
Iceland-Faroe Ridge
overflow
Olsen, S., Hansen, B., Østerhus,
S., et al.
Unknown
Yes
In
preparation
Convective mixing in
the Faroe Bank
Channel overflow
Hansen, B., Østerhus, S., et al.
Unknown
Yes
In
preparation
The retroflection of
the Faroe Current
into the FaroeShetland Channel
Larsen, K.M.H., Hátún, H.,
Hansen, B., et al.
Unknown
Yes
In
preparation
Recent changes in
the freshwater
composition in
the East Greenland
Current
Freshwater flux in the
East Greenland
Current north
of Denmark Strait results from the
Kögur array 20112012
de Steur, L., et al.
Unknown
Yes
de Steur, L., Våge, K., Østerhus,
S., et al.
Unknown
Yes
In
preparation
Page 15
5.2 Uptake by the targeted audience
The general public (PU)
X
The project partners, including the Commission services (PU)
A group specified by the consortium, including the Commission services (RE)
This reports is confidential, only for members of the consortium, including the Commission services (CO)
The time series and the report are published on the NACLIM website.
6. The delivery is delayed:
 Yes
 No
7. Changes made and difficulties encountered, if any
The delivery of the ADCP-based transport of Atlantic Water in the Shetland branch of the inflow has incurred a
minor delay. At the start of NACLIM, MSS and HAV planned to align the quality assurance procedures applied
to the collected data. This has yet to occur. As meantime monthly transport estimates based on the altimetry
observations continue to be provided, this is estimated to carry a low risk to the project.
The Faroe branch: One of three ADCP moorings is presumably lost. Calculations of Atlantic Water volume
transport for the 2012 – 2013 period is changed, so that it is based on two ADCP moorings and satellite
altimetry data.
The Iceland branch: The current meters at the mooring HB2 stopped operating in early June 2013, presumably
due to battery failure. The current meter at the mooring HB1 stopped operating at the end of May 2013.
Faroe Bank Channel overflow: The RDI LongRanger ADCP that was deployed in the channel in September
2012, was affected by errors in the 200 meter layer close to the bottom. A method was developed that allowed
daily transport values to be estimated from the non-affected part of the velocity profiles and information from
previous measurements.
The Wyville Thomson Ridge mooring was not redeployed in August 2013. However, it will be redeployed in
July 2014 (with additional current meters) in the western Rockall Trough. There will therefore be no data
between August 2013 and July 2014.
8. Efforts for this deliverable
Partner
Person-months
UIB
UHAM
Unires
SAMS
HAV
9
3
1
2
4
Period covered
November 2012-April 2014
November 2012-April 2014
November 2012-April 2014
November 2012-April 2014
November 2012-April 2014
Page 16
MRI
MSS (Marlab)
NIOZ
Total
6
2
1
28
November 2012-April 2014
November 2012-April 2014
November 2012-April 2014
Total estimated effort for this deliverable (DOW) was 28 person-months.
9. Sustainability
The two main Atlantic inflow branches have been monitored by mooring arrays that are expensive to maintain
and sensitive to instrument loss. Attempts to integrate satellite altimetry into the monitoring systems for both
branches have been encouraging and the development of cheap bottom mounted systems (Figure 2, right
panel) is on track. Thus, the development of a more sustainable monitoring system for oceanic heat transport
towards the Arctic within NACLIM is progressing according to plan.
There was a delay in the purchase/delivery of Microcats to put on the moorings monitoring the Iceland branch
of the inflow in 2013, which will increase the quality of data. The plan is to improve the moorings with these
instruments in 2014.
The Wyville Thomson Ridge mooring will be re-deployed in July 2014 in the western Rockall Trough, where a
pathway of Wyville Thomson Ridge Overflow Water has been shown to exist. The mooring instrumentation will
be expanded by the inclusion of a further two current meters, with added value gained from two nearby
moorings operated by the recently-funded Overturning in the Subpolar North Atlantic Project (OSNAP).
Additionally the re-located mooring will also lie on a hydrographic line (the Extended Ellett Line) that has been
occupied at least annually since 1975.
10. Dissemination activities
The complete list of dissemination activitites is available on the NACLIM website
http://naclim.zmaw.de/Dissemination.2509.0.html and on the ECAS portal, section “List of Dissemination
Activities”.
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