Polar Front Process Cruise 2022

The cruise KB2022625 (28. September 2022, Tromsø to 13. October 2022, Tromsø) aboard the Research Vessel Kristine Bonnevie is a Polar Front process studies cruise of the Nansen LEGACY project.
The study region covered the steep topographic slope southeast of Bjørnøya and the Polar Front region between Hopen and Storebanken, all-in-all spreading 73.5°- 78°N and 19.5°-34.5°E. The objectives are to study frontal mixing processes using microstructure profilers, to deploy and recover a short-term mooring at the Polar Front and to deploy and recover an underwater glider equipped with turbulence sensors. The overarching goal is to collect data allowing for the analysis of physical processes at the Polar Front on sub-tidal to synoptic timescales. Combined with data from previous cruises, the timescales of investigation may be expanded to seasonal and inter-annual periods.
During the cruise, we collected measurements of ocean stratification, currents, and microstructure from the vessel as well as from transects using an ocean glider. From the vessel we obtained 267 microstructure profiles down to 0-20 m above seabed, 62 CTD/LADCP profiles down to 5 m above seabed (all with salinity calibration samples taken at the deepest point), and 14 days of underway current profiles. From the glider we obtained 207 profiles (7 days) including using microstructure sensors in the Polar Front region between Hopen and Storebanken. 


Summary
The cruise KB2022625 (28. September 2022, Tromsø to 13. October 2022, Tromsø) aboard the Research Vessel Kristine Bonnevie is a Polar Front process studies cruise of the Nansen LEGACY project.
The study region covered the steep topographic slope southeast of Bjørnøya and the Polar Front region between Hopen and Storebanken, all-in-all spreading 73.5°-78°N and 19.5°-34.5°E.The objectives are to study frontal mixing processes using microstructure profilers, to deploy and recover a short-term mooring at the Polar Front and to deploy and recover an underwater glider equipped with turbulence sensors.The overarching goal is to collect data allowing for the analysis of physical processes at the Polar Front on sub-tidal to synoptic timescales.Combined with data from previous cruises, the timescales of investigation may be expanded to seasonal and inter-annual periods.

Background
The cruise KB2022625 aboard the Research Vessel Kristine Bonnevie is a process studies cruise of the Nansen LEGACY project.LEGACY aims to establish a holistic understanding of a changing Arctic Ocean and ecosystem and will provide the observation-based scientific knowledge needed for future sustainable resource management in the Barents Sea and the adjacent Arctic Basin.KB2022625 is a physical oceanography cruise with the objective to investigate processes associated with the position and variability of the Barents Sea Polar Front separating warm and salty Atlantic Water (AW) in the southwest from colder and fresher Polar Water (PW) in the north.The front is especially pronounced on the sill between Hopen and Storebanken but extends to a degree all along AW inflow pathways.The region around Bjørnøya is known for vigorous tidal currents; in conjunction with steep topography, these currents may cause substantial mixing between the inflowing AW and surrounding waters.To test this hypothesis, we conduct hydrographic sections across the continental slope south of Bjørnøya.Along this section, we perform two separate 24-h stations of repeat microstructure casts, to capture the temporal change of mixing over complete tidal cycles.
At the Polar Front on the sill spanning between Hopen and Storebanken, we investigate temporal variability up to synoptic time scales using short-term (~1 week long) mooring and glider deployments.These observations are complemented by shipbased hydrographic transects and ocean mixing measurements.
The cruise contributes to tasks T1-1 on the Atlantic Water inflow to the northern Barents Sea at key gateways, T1-2 on processes that control sea ice and stratification in the northern Barents Sea.More specifically, the cruise contributes to deliverables associated with subtasks: T1-1.2 Ocean and sea ice fluxes into the northern Barents Sea T1-2.1, Oceanic processes T2-1.1.Current variability and drivers of ocean acidification This report provides an overview of the methods employed and the data collected.

Activity reports
We collected measurements of ocean stratification, currents, and microstructure from the vessel as well as from transects using ocean gliders.From the vessel we obtained 267 microstructure profiles down to 0-20 m above seabed: 62 CTD/LADCP profiles down to 5 m above seabed, and 14 days of underway current profiles.From gliders we obtained 207 profiles (7 days) including using microstructure sensors in the Polar Front region.

Hydrography
The hydrographic work was carried out using a CTD-water sampling package from SeaBird Inc., acquiring data during both down and upcast.The package consisted of a SBE 911plus CTD (SN: 09P0510) with sensors listed below.An altimeter allowed profiling close to the bottom.The CTD was equipped with a 12 position SBE 32 Carousel (SN 32-1109).The rosette was fitted with one 10-litre bottle for collecting water samples for salinity calibration at all stations.Because temperature and salinity profiles are also obtained from the MSS microstructure casts, we performed somewhat fewer CTD-casts (usually every other station on the sections).In total 62 CTD-stations were taken, recorded in files sta1121 to sta1182.Their locations are listed in Appendix I. Station positions are shown in Figure 1.At all stations, water samples for salinity calibration were collected at the deepest sampling level.Raw data (pressure, temperature and conductivity from dual sensors) are converted to physical units using calibration files modified for air pressure and conductivity slope factor (DATCNV).Outliers, differing more than 2 and 20 standard deviations for the first and second pass, respectively, from the mean of 100 scan windows are flagged and excluded from analysis (WILDEDIT).WILDEDIT flags only the bad data point of each parameter and does not flag the entire scan.The thermal mass effects in the conductivity cell are corrected for (CELLTM, with parameters alpha = 0.03 and 1/beta = 7.0).Pressure is low-pass filtered with a time constant of 0.15 s.Following the SBE recommendation, the conductivity or temperature signals were low-pass filtered.Auxiliary sensors (oxygen, flC, Trans) were filtered using a time constant of 0.03 s.Scans when the CTD package moved less than the set minimum fall rate of 0.25 m s - 1 are flagged to remove pressure reversals due to ship heave (LOOPEDIT).Data are then averaged (BINAVG) into 1-dbar vertical bins and 1-s temporal bins (the latter is for the LADCP data processing).

Comparison of the sensor sets 1 and 2
The CTD package was equipped with two sets of temperature and conductivity sensors.Below figures show a comparison of the records from the temperature (Figure 2) and the conductivity (Figure 3, as derived salinity) sensors, as the difference of the sensor pairs, its histogram, and the RMS value of the difference for each profile throughout the cruise.Temperature measurements agree very well, with profile-averaged RMS values to within 0.016°C.Apart from two outliers, the profile-average RMS differences for salinity are less than 0.012.However, investigation of profiles showed that the conductivity probe of CTD 2 was less noisy than the probe of CTD 1. CTD 2 is thus used for scientific analyses.

Conductivity correction form salinity bottle samples
A total of 62 salinity bottle samples are analyzed at IMR with a Guildline Portasal 8410 salinometer.Salinity and conductivity values measured by the Portasal for each sample are compared with the corresponding CTD data.The histogram of ΔC = CCTD -CBot, difference of conductivity measured by CTD and inferred from the Portasal, is already nearly normally distributed (Figure 5).Following the recommendations given by Seabird Electronics, the conductivity values are corrected by the formula, Cnew = m Cold, where m is the slope calculated by Here ai and bi are the CTD conductivity and the bottle conductivity, respectively and n is the total number of bottles.The results from the selected samples are shown in the following two figures.
A slope correction of 0.99987 is obtained, which reduced the RMS salinity difference from 0.00943 to 0.00774.An alternative correction is a constant salinity offset with 0.00538 practical units, which also reduced the RMS salinity difference to 0.00775.

Lowered-ADCP (LADCP)
Two LADCP-profilers (RD Instruments) were mounted on the CTD rosette in order to obtain current profiles.The ADCPs are 6000-m rated, 300 kHz Sentinel Workhorses.Each unit contained an internal battery pack (we did not have an external battery canister).Both units are installed on the rosette in a balanced distribution to ensure minimum tilt.
Each ADCP has the L-ADCP option installed.The ADCPs were configured to sample in master/slave mode to ensure synchronization.The master ADCP pointed downward (SN 10012) and the slave ADCP pointed upward (SN 10151).The compass of each instrument was calibrated on land (in Bergen) in their respective orientation prior to the cruise and the resulting compass errors were <5°.Batteries were not replaced during the cruise (i.e., a compass re-calibration was not necessary).In total 62 profiles were collected using the LADCP.Communication with the instruments, start & stop of data acquisition and data download were done using the BBTalk software.PC time (UTC) was transferred to each instrument before each cast.The vertical bin size (and pulse length) was set to 8 m for each ADCP.Single ping data were recorded in narrow bandwidth (to increase range), in beam coordinates, with blank distance set to zero.
The data from the first bin are discarded during post processing.In order to mitigate a possible influence of previous pinging, especially close to steep slopes, staggered pinging with alternating sampling intervals of 0.8 s and 1.2 s were used.The altimeter worked reliably and no sign of degradation of LADCP data quality was observed.
The LADCP data are processed using the LDEO software version IX-13 based on Visbeck (2002).For each master/slave profile data, synchronized time series of CTD and navigation is used.The NMEA GPS stream is automatically stored in the CTD *.hex files with each scan and are post-processed as 1-s bin averages, same as the ADCP ping rate.LADCP-relevant processing of the CTD data included the identical steps in the SBE-Data Processing software.5-minute time averaged profiles from the SADCP are included for additional constraint on the inversion of the LADCP data.

Shipboard-ADCP (SADCP)
Kristine Bonnevie has a 150KHz "Ocean Surveyor" ADCP made by Teledyne R.D.Instruments mounted in the hull of the ship.The ADCP measures with 4 beams at a 30° beam angle and reaches up to 250m depth.The ADCP is set to measure in Narrow Band (NB) mode and 50 bins of 8-m vertical thickness.Bottom tracking was disabled.The transducer alignment angle was determined to be 45.5°.Raw data (single-ping data) from the ADCP is collected and automatically processed by the ship software that is based on the UHDAS routine generating short-term and long-term averages.Data below the bottom and interference with other acoustic instruments is automatically removed.Preliminary post-processing of the NB data was applied using the UHDAS software available at https://currents.soest.hawaii.edu.The postprocessing includes small corrections in the heading and amplitude calibrations, as well as manual removal of bad data close to the surface, below the bottom and in the ocean interior.The manual removal is based on outliers, the bottom topography and low values of "percent good" of the measurements.Typical final processed horizontal velocity uncertainty is 1-2 cm s -1 .

Microstructure profiling
Ocean microstructure measurements were made using the Microstructure Sensor Profiler (MSS, Sea&Sun Technology, Germany).We used the long version, MSS90L (SN 047).It is a loosely tethered free-fall instrument equipped with two airfoil probes aligned parallel to each other, a fast-tip thermistor (FP07), an acceleration sensor and conventional CTD sensors for precision measurements.The shear probes used were SN067 (sensitivity 4.63e-04, SHE1) and SN068 (sensitivity 4.60e-4, SHE2).The same sensors were used throughout the cruise.The MSS probe was serviced and calibrated in May 2021.
The sensors point downward when the instrument profiles vertically, and all sample at 1024 Hz.The instrument is ballasted for a typical fall speed of 0.6-0.7 m s -1 and is decoupled from operation induced tension by paying out cable at sufficient speed to keep it slack.Data are transmitted in real time to a ship-board data acquisition system.In total 267 casts were made down to about 5-15 m height above bottom.The profiler is equipped with a sensor protection guard at the leading end, and occasionally the profiler landed on the bottom.A full list of MSS casts is given in Appendix I.The deployment of the MSS from the ship was done from the starboard side of the ship, on the main deck.A motor-driven winch was mounted on the railing of the ship and an arm was used to keep the cable clear of the ship's side.The profiler was lowered in the water and brought back on board by hand, lifting it by the data transmission cable.Usually, one cast was performed at each station.
To avoid the instrument or cable coming under the ship during the cast, the ship is generally oriented with the starboard side into the wind, so that it drifts away from the free-falling profiler using a minimal amount of thruster power.This procedure also requires a decoupling of the ship's main propeller.This was done during the first 87 casts.Due to the captain's concerns about the wear and tear on the clutch during the recoupling of the main propeller after each cast, at cast 88, we started to use the DP system of the ship to drift at a speed of about 0.2-0.5 kn away from the profiler.This alleviated the need to decouple (and crucially, recouple) the propeller at every cast.As this practice was both challenging for the operator (the MSS cable was sucked under the ship several times) and likely detrimental to the data quality in the upper ocean, we reverted to free drift at cast 120.However, now the rpm of the engine was lowered from 600 to 400 rpm, allowing for smoother clutching.After cast 185, the transmission cable was reterminated at its connection to the MSS (this is a common maintenance procedure).
For the 24h stations DS1 and DS2 (DS2 was cut shorter to 21h because of bad weather conditions) the ship was anchored from the stern via the trawl winch to avoid having to relocate (and thereby clutching) frequently.This worked quite well.The processing of the data and the format of this data set follows the recommendations and guidelines of the SCOR Working Group 160, ATOMIX (https://wiki.uib.no/atomix).
The conversion from the native binary files to physical units were done using own routines.Processing of the obtained time series was based on the standard Matlab routines provided by Rockland Scientific, which were adjusted for the ATOMIX recommendations.Spectra are obtained using 2-s fft length.Dissipation estimates are obtained over 6 s segments, overlapping by 3 s (50% overlap), from the cleaned shear spectra using the Goodman coherent-noise reduction algorithm.We used the record from the one-axis body vibration sensor of the MSS for cleaning the shear spectra.
Resulting values from both probes were quality screened following the recommendations of ATOMIX.A dissipation estimate is flagged when for the analyzed segment the figure of merit of spectrum is larger than 1.15, when the despike fraction is larger than 5%, when the estimate is anomalously large relative to a second probe, or when data transmission error fraction is more than 20%.A final dissipation rate estimate is obtained by averaging the estimates from the two probes when they agree within 95% confidence intervals following Lueck (2022) , or the minimum estimate if they do not.Noise level of the dissipation rate measured by the MSS is about 10 -9 W kg -1 .Dissipation measurements from the upper 12 m were excluded because of the disturbance from the ship's keel, and the profiler's adjustment to free fall.The practical salinity and temperature obtained from the MSS is compared against the shipboard SBE-911plus CTD system from stations collected within 1.5 h and 1.5 km.
The ship CTD was calibrated against salinity water samples.10-m averaged values in quasi-mixed layers agreed to within 1e-3 for salinity and 4e-3 C for temperature, and no correction was applied.The pressure sensor was replaced before this mission.Since the pressure sensor used was the one from sg563 (a rev E glider) and sg564 is a rev B glider, the calibration coefficients of the pressure sensor were wrong in the beginning of the mission and were updated on dive 204.The compass was not calibrated before this problem was solved either as the glider was exposed to strong currents on the shelf/slope of Bjørnøya.Compass calibration dives were 217-219.We received pitch retries/errors throughout the entire mission, but this has not affected the glider dives and data, as the retries and errors happens during the surface maneuver when the battery pitch all the way forward.

Slocum glider
One Teledyne Webb Research 1000m electric glider (Slocum G3) was deployed on 2 October 2022, 10:25 UTC, during the cruise.All pre-deployment tests were made by the onshore pilot Ailin Brakstad at the Geophysical Institute, Bergen.(No free-wave communication was set up for this deployment and recovery.)After the start piloting and trimming by Brakstad, further piloting was carried out by Anna-Marie Strehl at the Geophysical Institute, Bergen.
The Slocum G3's are buoyancy-driven autonomous underwater vehicles that provide high-resolution surveys of the physical properties of the water column.Our Slocum G3, named Odin, (SN775) was equipped with a pumped Seabird conductivity-temperature sensor (CTD41CP, SN9545) and an integrated RSI MicroRider (MR-1000, SN324) with two shear probes (S1=M2033, S2=M2034) and two thermistors (T1=T2060, T2=T1107) for measuring turbulence microstructure.CTD was sampled during the dives and climbs.Final profiles have an average horizontal along-track resolution of 0.5 km and vertical bins of 1 m.The MicroRider was configured to sample on dive and climb.To minimize vibration noise in the vehicle and achieve the desired science goals the glider mission was configured as follows: -"Fixed mode" battery position was used to control the trim of the glider, which prevented the pitch motor from running during the glide.The fixed position was determined from test dives to 180 m and implemented from 3 October 2022.
-Auto ballast control determined pump volumes for diving and climbing to keep the profiles symmetrical while maintaining a minimum vehicle speed of 0.1 m/s.The pump volume was set to fixed values and adjusted manually from 5 October to avoid adjustments during the flight.A minimum of auto ballast control was maintained for optimizing the flight.Flight data did not indicate adjustments that should impact the measurements.
-To capture the complete water column, particularly the top few meters, the glider carried out one dive-climb profile per segment.The "climb to" depth was set to 0 m to avoid noise contamination from the air bladder and ballast bump that automatically switch on when the glider reaches surface.We were aware that this could cause the glider to sit on the surface un-commanded if the pressure sensor were offset when it reached surface, and thus it was monitored throughout the mission.
-The glider dived to 30 m above ground.From the 6 October, it dived to 22m above ground.
Odin ran the transect along the "B" section once, starting from the northern end.The MicroRider and the SBE-CT sampled without any issues.The glider was retrieved on 9 October 12:30 UTC using the same net as for the Seaglider.There was no apparent damage on the turbulence sensors during recovery.
A Teledyne Webb Research 1000m electric glider was deployed during the cruise.The Slocum G3 is a buoyancy-driven autonomous underwater vehicle that provides highresolution surveys of the physical properties of the water column.Odin (SN775) was equipped with a Seabird conductivity-temperature-depth sensor (CTD41CP, SN9545) and an integrated RSI MicroRider (MR-1000, SN324) with two shear probes (S1=M2031, S2=M2032) and two thermistors (T1=T1849, T2=T1851) for measuring turbulence microstructure.The CTD was sampled during the dive, climb, inflection and surfacing at 0.25Hz (as fast as possible).
Quality control procedures from the Balearic Islands Coastal Observing and Forecasting System (SOCIB) data processing toolbox was used for data (Troupin et al., 2015) and include salinity corrections for the thermal lag error for the un-pumped CTD data (Garau et al., 2011).Final profiles have an average horizontal along-track resolution of 0.5 km and vertical bins of 1 m.The MicroRider was configured to sample on dive, climb and inflection.The glider initiated MicroRider sampling by sending the following odasir message: odas5ir -f setup.cfg-l 3000 -D Care was taken to minimize vibration noise in the vehicle and achieve the desired science goals, using the glider mission UIB01AMR.MI.The MicroRider and CTD sampling behaviors were defined separately.Sampling science sensors individually reduces the number of science oddities occurring and allows for more control of individual sensors.'Fixed mode' battery position was used to control the trim of the glider, this prevented the pitch motor from running during the glide.Autoballast control was used to command pump volumes for diving and climbing in order to the keep the profiles symmetrical while maintaining a minimum vehicle speed of 0.1m/s.We targeted a vertical velocity of .15m/sbut set the minimum as 0.1m/s to the account for slower velocities during AB adjustments and avoid aborts.After testing altimeter functionality, the glider was configured to inflect 15m above the seabed.In order to capture the complete water column, particularly the top few meters, the glider carried out one yo per segment.The 'climb to' depth was set to 0m to avoid noise contamination from the air bladder and ballast bump that are automatically switched on when the glider is instructed to surface.We were aware that this may cause the glider to sit on the surface un-commanded if the pressure sensor was offset when it reached the surface and this was monitored throughout the mission.

Mooring
To supplement the snapshot-type measurements obtained from hydrographic sections, a short-term mooring was deployed at the Polar Front location.The goal was to measure hydrographic properties throughout the water column for as long as possible during the cruise.The mooring was designed to be deployed in 195 m water depth and was extensively equipped with temperature loggers, CTDs and ADCPs (see Appendix II.Mooring).
At the planned position, a CTD cast (#1126) showed both Polar Water and Atlantic Water in the water column, indicating the presence of the front.The ship went ~1.5 miles Northwest of this location to begin with the deployment.The mooring was deployed buoy-first over the stern via the Starboard main winch and A-frame while slow steaming towards the mooring location (towing at 1.5kn for ~1h).The anchor drop was 08:39 UTC on 2 October at 77° 22.212' N, 30° 04.418'E.
Recovery took place on October 9.It was released at an acoustic range of 280 m at 10:28 UTC.The mooring came up very tangled and was taken on board effectively all at once.
A calibration dip for all temperature loggers and CTDs that were at the mooring was performed on 10 October at 12:30 UTC, by fixing all instruments to the CTD rosette.The calibration cast (CTD cast #1177) included 3-minute calibration stops on the up-cast at depths of 200 m, 150 m, 58 m and 17 m.

Wave buoys
Two OpenMetBuoys (v2021a) were provided by the Norwegian Meteorological Service to measure frequency spectra of sea surface elevation.Their design follows Rabault et al. (2022).They were deployed on October 4 at 12:40 UTC and on October 6 at 4:40 UTC, respectively.

Argo floats
On behalf of the Finnish Meteorological Institute, two ice-tolerant APEX Argo floats were deployed at the northernmost point of the cruise (see Figure 1) on October 3 at 14:55 UTC, with about 200 m between them.Their status and data is openly accessible at https://fleetmonitoring.euro-argo.eu/float/5906973 and https://fleetmonitoring.euroargo.eu/float/6990507.Figure 12: Cross-sectional velocities measured by the ship-ADCP for repeat transects of the B-section.

Figure 1 :
Figure 1: Map of the study area with shading indicating topography (IBCAOv4, darker (lighter) indicates deeper (shallower)).The 200 m isobath is drawn in blue.The cruise track is given as red lines.MSS microstructure profiler stations are shown as red dots and CTD/LADCP profiles as blue circles.The deployment sites of the F1_st (short-term) mooring and Argo floats are indicated.

Figure 2 :
Figure 2: Comparison of temperature measurements from the two SBE units.Profiles of difference between the two sensors, its histogram, and RMS temperature difference for each profile throughout the cruise.

Figure 3 :
Figure 3: As in Figure 2, but for comparison of the salinity measurements from the two SBE units.

Figure 5 :
Figure 5: (Left) Histogram of CTD-derived and bottle conductivity differences.Red curve is the normaldistribution fit for the sample mean and standard deviation.(Right) ∆C in chronological order with 95% confidence intervals on the mean indicated (black envelopes).
One Seaglider was recovered during the cruise.Sg564 was recovered on 09 October 2022 08:15 UTC near the Barents Sea Polar Front (77˚24.815N,29˚38.536E),after 61 days in the water.The sea state was calming but yet challenging after approximately 3 m waves and 15 m/s winds for one day, and we made the recovery using a net.The net was attached to a hexagonal frame, which we lowered under the glider.A CTD cast (sta1174) was conducted upon recovery.The Sg564 is 1000 m depth-rated and was equipped with Paine strain-gauge pressure sensors, SBE CT Sail, Aanderaa dissolved oxygen sensors and WetLabs ECOpuck sensor and operated between the surface and about 10 m above seabed (mission depths were shallower than 1,000 m).CTD, oxygen, fluorescence and backscatter were sampled on both dives and climbs.CTD was sampled approximately every 1 m in the upper 400 m while oxygen, fluorescence, and backscatter were sampled at every 2 m between 0-100m depth, every 3m between 100-200m depth, and approximately every 5m below 200m.The vertical velocity was about 10 cm s −1 .For each dive, a depth-averaged current (DAC) was estimated based on the deviation between expected surfacing location deduced from the flight model, and the actual surfacing location.

Figure 6 :
Figure 6: Full track of the Seaglider sg564, from deployment south of Bear Island to recovery near the Barents Sea Polar Front.Surface fixes (circles) and the depth-averaged currents (sticks) are shown, as displayed in the Norgliders portal (https://gp.gfi.uib.no).

Figure 7 :
Figure 7: Odin's track as displayed on the Slocum Fleet Mission Control dashboard, showing the surface fixes (yellow circles) and the depth-averaged currents (red sticks).The deployment was on the northern end of the transect.Odin completed one southward transect across the front, turned northward and it was recovered as it approached the front once more.

Figure 9 :
Figure 9: As above, but for section T.

Figure 11 :
Figure 11: Map showing vertically averaged currents at the main sections measured from the ship-ADCP.

Figure 13 :
Figure 13: Measurements of dissipation rate (left), temperature (middle) and salinity (right) for section T, repeat 1. Black lines are isopycnals, the white line is the 0°C isotherm.

Figure 14 :
Figure 14: As above, but for section T, repeat 2.

Figure 15 :
Figure 15: As above, but for section B, repeat 1.

Figure 16 :
Figure 16: As above, but for section B, repeat 2.

Figure 17 :
Figure 17: As above, but for section B, repeat 3.

Figure 18 :
Figure 18: As above, but for section B, repeat 4.

Figure 19 :
Figure 19:As above, but for section A/F.

Figure 20 :
Figure 20: As above, but for section D.

Figure 21 :Figure 22 :
Figure 21: As above, but for section I.

Figure 23 :
Figure 23: As above, but for the 24-h station DS2.

Figure 24 :
Figure 24: As above, but for the 24-h station DS3.

Figure 25 :
Figure 25: Group photo of the cruise participants.
will conduct 15 scientifi c cruises and spend more than 350 days in the northern Barents Sea and adjacent Arctic Ocean between 2018 and 2022.Most of these cruises are conducted on the new Norwegian research icebreaker RV Kronprins Haakon.The Nansen Legacy includes scientists from the fi elds of biology, chemistry, climate research, ecosystem modelling, ecotoxicology, geology, ice physics, meteorology, observational technology, and physical oceanography.The Nansen Legacy has a total budget of 740 million NOK.Half the budget comes from the consortiums' own funding, while the other half is provided by the Research Council of Norway and the Ministry of Education and Research.280peopleThere are about 230 researchers working with the Nansen Legacy, of which 73 are early career scientists.In addition, 50 persons are involved as technicians, project coordinators, communication advisers and board members.The Nansen Legacy is a six-year project, running from 2018 to 2023.The Nansen Legacy investigates the physical and biological environment of the northern Barents Sea and adjacent Arctic Ocean.The Nansen Legacy unites the complimentary scientifi c expertise of ten Norwegian institutions dedicated to Arctic research.

Table 1 :
Sensors installed on the CTD rosette

Table 2 :
Meta data of glider missions

Table 6 :
List of planned datasets