Gridded fields of salinity for 50 N - 67 N, 41,5 W - 61,5 W geographic region (yearly, 2000 - 2016), 29 standard depths

Two ice mass balance instruments (part of IAOOS7 and IAOOS8 platforms) deployed near 83°N on the same ice floe, documented the evolution of snow and ice conditions in the Arctic Ocean north of Svalbard in Jan-Mar 2015. Frequent profiles of temperature (every 3 hours) and temperature change after 30s and 120s heating (once a day) were recorded. The ratio of the temperature changes after heating provides a proxy for thermal diffusivity. Both instruments documented flooding and snow-ice formation. Flooding was clearly detectable in the simultaneous changes in thermal diffusivity proxy, increased temperature, and heat propagation through the underlying ice. Slush then progressively transformed into snow-ice. Flooding resulted from two different processes; i) after storm-induced break-up of snow-loaded floes for IAOOS8 and ii) after loss of buoyancy due to basal ice melt for IAOOS7. The instrument on IAOOS7 documented basal sea-ice melt over warm Atlantic waters and ocean-to-ice heat flux peaked at up to 400 Wm-2 in winter. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

We report continuous observations in the high Arctic (north of 84°N) over the full 2013 summer season at two nearby sites with distinct initial snow depth, ice thickness and altitude with respect to the local ice topography. The two sites subject to similar atmospheric conditions that did not favor strong ice melt showed a contrasted evolution. One site, with an initial thin sea ice (1.40 m) at a low location of the floe, witnessed the formation of a spectacular 1.20 m-deep melt pond, a pond-enhanced erosion of the ice surface and a sudden pond drainage into the ocean. Then, the outpoured fresh water rapidly froze, heated the old ice from below and also acted as a temporary shield from the ocean heat flux while it was progressively ablated through dissolution. Eventually, the site almost recovered its initial ice thickness. In contrast, the other site, with an initial thicker sea ice (1.75 m) at a high location of the floe, did not support any significant melt water and underwent over 0.5 m of continuous basal ablation. The two sites witnessed formation of superimposed and interposed ice. Sea-ice survived summer melt at the two sites which entered the refreezing season with similar snow and ice thicknesses. For the first time, processes associated with the formation of a deep melt pond and subsequent false bottom evolution are continuously documented with ice mass balance instruments.  Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

The mooring was deployed on 25 July 2007 from the R/V Haakon Mosby at 80.601°N, 7.119°E (depth of 745 m) in the Yermak Pass over the Yermak Plateau north of Svalbard. It comprised an upward-looking RDI 75kHz Long Ranger Acoustic Doppler Current Profiler (ADCP) at 585 m with 16 m vertical resolution and a 1hour sampling time, and an ocean profiler on a taut cable between 130 and 530 m. The mooring was recovered on 23 September 2008 by the K/V Svalbard. The dataset is composed of the raw data from the ADCP, after declination correction. A white shaded zone is visible in the data between 380 and 500 m depth throughout the time series. It corresponds to the reflection of the acoustic bins on the profiler stuck on the cable.

The cruise HM 2015617 onboard the Research Vessel Håkon Mosby is the second and last research cruise of the project ”On Thin Ice (NICE): Role of Ocean Heat Flux in Sea Ice Melt”. NICE is led at the Geophysical Institute, University of Bergen (PI: Ilker Fer) and is funded by the Research Council of Norway (project number 229786) for the period 01.01.2014-31.12.2017

We defined the interfaces between the air/snow, snow/ice, and ice/ocean and calculated the ocean heat flux for two SIMBA recordings (SIMBA2015a and SIMBA_2015f) of repeated temperature profiles at 6h interval and 2cm vertical resolution, during N-ICE 2015 experiment floe1. The snow/ice interface is derived from the sharp contrast in the diffusivity proxy values between both media. The snow/ice interface does not change except for slush formation associated with flooding events. The air/snow interface is calculated using simultaneous information from the vertical gradient of the temperature and the standard deviation over 24, 48, and 72 h period. Snow accumulation of more than 10 centimeters happened at different time for the 2 SIMBA. The ice/ocean interface is estimated from temperature profiles alone since the winter sea-ice remains colder than the ocean. The ocean just below the ice is at or just above the freezing temperature (estimated from a near surface conductivity-temperature-depth (CTD) sensor see Koenig et al. [2016]). The method detects (1) the first sensor, downward of the snow/ice interface, with a temperature above the ocean freezing temperature and (2) the last sensor in the ice with a temperature below the mean ocean temperature by at least twice the ocean temperature standard deviation in that profile. The ice/ocean interface is then defined as half way between the last sensor in the ice and the first sensor in the ocean. Note it take 3-4 days for the deployment hole to refreeze. Then the ice thickness remains constant up to 20 February when floe1 breaks. Simba_2015f stops working and SIMBA_2015a features basal melt events corresponding to temperature changes in the ocean. The consistency of the 3 interfaces estimate is validated with the thermal diffusivity proxy and the vertical and temporal derivatives of temperature. The ocean heat flux is derived from the latent heat flux which is directly proportional to the change in time of the ice/ocean interface depth and the conductive heat flux in the lower portion of the ice estimated 6 cm above the ice/ocean interface. The ocean heat flux values for SIMBA_2015a and SIMBA2015f range from -50 to 350 W/m2, and -50 to 150 W/m2 respectively, while the basal melt events associated with ocean temperature increase stand out in SIMBA_2015a.   The SIMBA data are available through the Norwegian Polar Institute’s data center (https://data.npolar.no/dataset/6ed9a8ca-95b0-43be-bedf-8176bf56da80) and the method of interface detection is thoroughly described in Provost et al. (2017). Note that all time series have been smoothed with a 36-h running mean.   Provost, C., N. Sennechael, J. Miguet, P. Itkin, A. Rosel, Z. Koenig, N. Villacieros-Robineau, and M. A. Granskog (2017), Observations of flooding and snow-ice formation in a thinner Arctic sea-ice regime during the N-ICE2015 campaign: Influence of basal ice melt and storms, J. Geophys. Res. Oceans, 122, 7115–7134, doi:10.1002/2016JC012011. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

A mooring, equipped with a CTD sensor (SBE37) at 350 m depth, was deployed in the Yermak Pass on the 24 September 2017 from the R/V Lance. The mooring was recovered in summer 2020 from K/V Svalbard. The present dataset provides 10-day smoothed time series of daily conservative temperature (CT, °C), absolute salinity (SA, g/kg) and pressure (db) recorded by the SBE37 sensor, from the 24 September 2017 to the 31 May 2020. The mooring was located at 80.63°N, 6.88°E. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

We gathered ocean profiles during the first two floes of the N-ICE2015 ice camp north of Svalbard with IAOOS ocean profilers. Between January and March 2015, four ocean profilers were deployed: two below a full IAOOS platform (500 m long cable) during floe 1, two on an 800 m long instrumented line in a tent-covered testing-hole during floe1 and floe 2. The ocean profilers, from French manufacturer NKE (PROVOR SPI), carried a Seabird SBE41CP CTD (Conductivity, Temperature, Depth) with an Aanderaa 4330 optode for dissolved oxygen (DO). The profilers were set to perform two profiles a day from 500 m upward (800 m from testing hole) starting at 6 am and 6 pm. They provided the first winter data in the region with a total of 138 profiles during floe 1 (January 15- February 21) with 62, 50, and 26 profiles for IAOOS7, IAOOS8, and IAOOS 9, respectively and 16 profiles during floe 2 (February 24 - March 19- IAOOS 11 from testing hole). Following quality control, we retain all the temperature profiles and remove 1% of the salinity profiles. Finally, the accuracy is estimated to be 0.002°C in temperature, and 0.02 g/kg in salinity. Several profiles are missing or incomplete because of high drift speeds (> 0.4 m s-1) impeding the ascent of the profiler. There are no bottle DO measurements during Floe 1 to calibrate the DO data. DO accuracy is estimated comparing the deep values of DO concentration (rather stable at 500m) between the three profilers. A difference of 3 µmol L-1 is observed between IAOOS 8 and 9, and IAOOS 7. An offset of 3 µmol L-1 is then applied to the oxygen data from IAOOS7 and the accuracy of the data is estimated to be at ±3 µmol L-1. The vertical resolution of the processed CTD data is 1 dbar in the upper 400 dbars, 5 dbars from 400 to 550 dbars and 10 dbars from 550 to 850 dbars. The vertical resolution in dissolved oxygen is 2 dbars over all depths. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

ADCP data was collected at EMEC (Orkney, UK) full scale tidal site at Fall of Warness. No structures were present around the instrument at the time of the deployment. ADCP was mounted on a seabed frame. Resolution of data [s]: 1200; Sample period (s): 1200; Number of data records: 1005; Bin count: 59; Pings per Ens: 50; Time per Ping [s]: 24; 1st Bin [m]: 1.86; Bin size [m]: 0.75; Mode: Earth; Processing Software: IMPAQCT; QC process: SOP134; Data quality comments: No QC applied to the data. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

In April 2017, two Ice Atmosphere Arctic Ocean Observing System platforms (IAOOS 23 and IAOOS 24) were deployed near the North Pole. Over the next 8 months, they meandered southwards with the ice in the Transpolar Drift, collecting measurements in the upper 250 m of Amundsen Basin, Nansen Basin and Fram Strait. The ocean profilers are PROVOR SPI (from French manufacturer NKE), which includes a Seabird SBE41 CTD (Conductivity, Temperature, Depth) and a dissolved oxygen (DO) Aandera 4330 optode. IAOOS 23 also featured a bio-optics sensor suite and a submersible ultraviolet nitrate analyzer (SUNA, Satlantic-Seabird Inc.). The bio-optics sensor suite (called Pack Rem A) combines a three-optical-sensor instrument (ECO Triplet, WET Labs Inc.) and a multispectral radiometer (OCR-504, Satlantic Inc.). The present dataset is composed of chlorophyll-a fluorescence, backscatter, irradiances (at 412, 490 and 555 nm), photosynthetically active radiation (PAR), nitrate and colored-dissolved organic matter data from the IAOOS 23 platform, as well as composites of absolute salinity, conservative temperature and apparent oxygen utilization data from both profilers. The profilers were set to perform two upward profiles a day from 250 m starting at approximately 6 am and 6 pm. In this dataset, chlorophyll-a, PAR and irradiances were corrected with a shift to set dark values to zero. Nitrate was interpolated vertically every 5 m, and all other parameters were interpolated vertically every 0.5 m. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.