ALBERT

Description: This dataset contains geographical features representing selected infrastructures (houses, roads, airfield, pipelines etc.) in the town Longyearbyen on Svalbard. Each feature has attributes listing relevant classifiers, such as: - the type of infrastructure (residential building, road, pipeline, etc.) - the shape of the feature (flat, sloped, pitched, domed, barrel-shaped) - the type of surface material (wood, concrete, asphalt, etc.) - the background setting (rock, sediments, sea, etc.) - its current status as actively used or inactive infrastructure. -- All feature locations and attributes have been validated either by on-site inspection, or by Google Street View imagery (validation method indicated in feature attributes). -- Photos are provided for most of the features that were field validated.

Description: First- and second-year sea-ice thickness, draft, salinity, temperature, and density were measured during two ice stations on 24 October 2022 and 30 October 2022 during leg 1 of the GoNorth 2022 expedition. The ice cores were extracted with 7.25-cm (Mark III) internal diameter ice corers (Kovacs Enterprise, US). During each ice station, ice temperature was measured in situ from a separate temperature core, using Ebro TFX 410 Thermometer thermometers in drill holes with a length of half-core-diameter at 5 cm vertical resolution. Ice bulk practical salinity was measured from melted core sections at 5 cm resolution using a Mettler Toledo SevenGo conductivity meter. Sea ice density was measured using the hydrostatic weighing method (Pustogvar and Kulyakhtin, 2016) from several density cores in the freezer laboratory onboard RV Kronprins Haakon at the temperature from –10°C to –14°C. Relative volumes of brine and gas were estimated from ice salinity, temperature, and density using Cox and Weeks (1983) for cold ice and Leppäranta and Manninen (1988) for ice warmer than –2°C. This sea ice physics data was collected during leg 1 of the GoNorth 2022 scientific expedition on 14 October – 3 November 2022 (cruise number 2022713) on the RV Kronprins Haakon. The ice cores were collected at two ice stations (Station 6 and Super Station 14) located at 82°13.56' N and 26°41.43' E for the first and 82°31.05' N and 17°30.04' E for the second sea ice station in the area north of Svalbard. The data contains the event label (1), station (2), time (3), global coordinates (4,5) of each coring measurement, ice type (11), and sample ID (12). Each core has its manually measured ice thickness (6), ice draft (7), snow height (8), and local coordinates for each ice station (7,8). Each core section has the total length of its top (13) and bottom (14) measured in situ. Each core section has the value of its practical salinity (15), each core section of a temperature core has the value of its in situ temperature (16), and each core section of density cores has the value of its ice density (18). Each core section also has laboratory temperature (17), an estimate of brine volume fraction (19), and gas volume fraction (20).

Description: We present sea ice temperature and salinity data from first-year ice (FYI) and second-year ice (SYI) relevant to the temporal development of sea ice permeability and brine drainage efficiency from the early growth phase in October 2019 to the onset of spring warming in May 2020. Our dataset was collected in the central Arctic Ocean during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) Expedition in 2019 to 2020. MOSAiC was an international transpolar drift expedition in which the German icebreaker RV Polarstern anchored into an ice floe to gain new insights into Arctic climate over a full annual cycle. In October 2019, RV Polarstern moored to an ice floe in the Siberian sector of the Arctic at 85 degrees north and 137 degrees east to begin the drift towards the North Pole and the Fram Strait via the Transpolar Drift Stream. The data presented here were collected during the first three legs of the expedition, so all the coring activities took place on the same floe. The end dates of legs 1, 2, and 3 were 13 December, 24 February, and 4 June, respectively. The dataset contributed to a baseline study entitled, Deciphering the properties of different Arctic ice types during the growth phase of the MOSAiC floes: Implications for future studies. The study highlights downward directed gas pathways in FYI and SYI by inferring sea ice permeability and potential brine release from several time series of temperature and salinity measurements. The physical properties presented in this paper lay the foundation for subsequent analyses on actual gas contents measured in the ice cores, as well as air-ice and ice-ocean gas fluxes. Sea ice cores were collected with a Kovacs Mark II 9 cm diameter corer. To measure ice temperatures, about 4.5 cm deep holes were drilled into the core (intervals varied by site and leg) . The temperatures were measured by a digital thermometer within minutes after the cores were retrieved. The ice cores were placed into pre-labelled plastic sleeves sealed at the bottom end. The ice cores were transported to RV Polarstern and stored in a -20 degrees Celsius freezer. Each of the cores was sub-sampled, melted at room temperature, and processed for salinity within one or two days. The practical salinity was estimated by measuring the electrical conductivity and temperature of the melted samples using a WTW Cond 3151 salinometer equipped with a Tetra-Con 325 four-electrode conductivity cell. The practical salinity represents the the salinity estimated from the electrical conductivity of the solution. The dataset also contains derived variables, including sea ice density, brine volume fraction, and the Rayleigh number.

Description: First-year sea-ice thickness, draft, salinity, temperature, and density were measured during near-weekly surveys at the main first-year ice coring site (MCS-FYI) during the MOSAiC expedition (legs 1 to 4). The ice cores were extracted either with a 9-cm (Mark II) or 7.25-cm (Mark III) internal diameter ice corers (Kovacs Enterprise, US). This data set includes data from 23 coring site visits and were performed from 28 October 2019 to 29 July 2020 at coring locations within 130 m to each other in the MOSAiC Central Observatory. During each coring event, ice temperature was measured in situ from a separate temperature core, using Testo 720 thermometers in drill holes with a length of half-core-diameter at 5-cm vertical resolution. Ice bulk practical salinity was measured from melted core sections at 5-cm resolution using a YSI 30 conductivity meter. Ice density was measured using the hydrostatic weighing method (Pustogvar and Kulyakhtin, 2016) from a density core in the freezer laboratory onboard Polarstern at the temperature of –15°C. Relative volumes of brine and gas were estimated from ice salinity, temperature and density using Cox and Weeks (1983) for cold ice and Leppäranta and Manninen (1988) for ice warmer than –2°C. The data contains the event label (1), time (2), and global coordinates (3,4) of each coring measurement and sample IDs (13, 15). Each salinity core has its manually measured ice thickness (5), ice draft (6), core length (7), and mean snow height (22). Each core section has the total length of its top (8) and bottom (9) measured in situ, as well estimated depth of section top (10), bottom (11), and middle (12). The depth estimates assume that the total length of all core sections is equal to the measured ice thickness. Each core section has the value of its practical salinity (14), isotopic values (16, 17, 18) (Meyer et al., 2000), as well as sea ice temperature (19) and ice density (20) interpolated to the depth of salinity measurements. The global coordinates of coring sites were measured directly. When it was not possible, coordinates of the nearby temperature buoy 2019T66 were used. Ice mass balance buoy 2019T66 installation is described in doi:10.1594/PANGAEA.938134. Brine volume (21) fraction estimates are presented only for fraction values from 0 to 30%. Each core section also has comments (23) describing if the sample is from a false bottom, from rafted ice or has any other special characteristics. Macronutrients from the salinity core, and more isotope data will be published in a subsequent version of this data set.

Description: Temperature and heating-induced temperature differences were measured along a chain of thermistors. SIMBA 2020T60 (a.k.a. HAVOC 0101) is an autonomous instrument that was installed on drifting sea ice in the Arctic Ocean during the 2nd leg of MOSAiC in February 2020. The thermistor chain was 10m long and included 250 sensors with a regular spacing of 4cm. The resulting time series describes the evolution of temperature and temperature differences after two heating cycles of 30 and 120 s as a function of place, depth and time between 08 Jan 2020 and 22 Apr 2020 in sample intervals of 6 hours for temperature and 24 hours for temperature differences. The buoy was installed on the ridge crest known as SIRO. In addition to temperature, geographic position, barometric pressure, air temperature measured 1m over the ice level, tilt and compass were measured. The data set has been processed as follows: obvious inconsistencies (missing values) have been removed and unrealistic values in position have been replaced by NaN (Not a Number). This instrument was deployed as part of the project "Ridges - Safe HAVens for ice-associated Flora and Fauna in a Seasonally ice-covered Arctic OCean" (HAVOC), funded by the Research Council of Norway, project number: 280292, "Coordinated Arctic Acoustic Thermometry Experiment" (CAATEX), funded by Norwegian Research Council, project number: 280531 and "Arctic Ocean ecosystems - Applied technology, Biological interactions and Consequences in an era of abrupt climate change" (Arctic ABC Development, Research Council of Norway, project number: 245923).

Description: Oxygen (dO18) and hydrogen (dH) isotope ratio data from snow samples taken during MOSAiC leg 4 (PS122.4). Snow samples were taken from several locations around the central observatory (main ice floe. They were collected using a metal density cutter, placed in plastic cups with lids and melted at room temperature. Once completely melted, ~20 ml sub-samples were poured into 20 ml glass or plastic vials with lids and sealed with parafilm tape for isotope analyses. These samples were stored at +4°C. After the sub-samples were taken, bulk salinity was measured on the remaining water sample using a calibrated YSI 30 conductivity meter (practical salinity scale, unitless). The stable oxygen isotopic compositions of the melted snow samples (δ18O) were determined in the central laboratory of the Swiss Federal Institute for Forest, Snow and Landscape, Birmensdorf, Switzerland with an Isotopic Water Analyzer IWA-45-ER (ABB - Los Gatos Research Inc., US). Measurement uncertainty for δ18O is ±1‰, the precision ± 0.5‰. All samples were measured in duplicate and averaged. 169 The quality control was conducted with three standards for δ18O at 0.00‰, -12.34‰ and -55.50‰ and are presented as per mil difference relative to VSMOW (‰, Vienna Standard Mean Ocean Water).

Description: Oxygen (dO18) and hydrogen (dH) isotope ratio data from sea ice samples taken during MOSAiC leg 4 (PS122/4). Sea ice samples were taken from Jaride and Alli's Ridge. Sea ice cores were extracted f 139 rom the ridges using a 9 cm inner diameter ice corer (Kovacs Enterprise Mark II coring system) powered by a cordless electric drill. Salinity/isotope ice cores were stored in sterile U-Lines bags (sections 〈 1 m), immediately placed in Styrofoam boxes and transported back to the ship within 2 hours of sampling. Ice cores were stored in a -20°C walk-in freezer until processing. The ice cores were cut into ~5 cm sections using a stainless steel, electric butcher band saw. To ensure we captured potential transition zones within the sea ice (i.e., rapid transitions in salinity), we only cut to the top or bottom of natural breaks in the ice cores (i.e., some sections were thicker or thinner than 5 cm but all in the range of 2-7 cm). The samples were placed in plastic cups with lids and melted at room temperature. Once completely melted, ~20 ml sub-samples were poured into 20 ml glass or plastic vials with lids and sealed with parafilm tape for isotope analyses. These samples were stored at +4°C. After the sub-samples were taken, bulk salinity was measured on the remaining water sample using a calibrated YSI 30 conductivity meter (practical salinity scale, unitless). The stable oxygen isotopic compositions of the melted ice samples (δ18O) were determined in the central laboratory of the Swiss Federal Institute for Forest, Snow and Landscape, Birmensdorf, Switzerland with an Isotopic Water Analyzer IWA-45-ER (ABB - Los Gatos Research Inc., US). Measurement uncertainty for δ18O is ±1‰, the precision ± 0.5‰. All samples were measured in duplicate and averaged. 169 The quality control was conducted with three standards for δ18O at 0.00‰, -12.34‰ and -55.50‰ and are presented as per mil difference relative to VSMOW (‰, Vienna Standard Mean Ocean Water).