The data set presents keyed and translated from Norwegian daily observations of sea ice and icebergs conducted onboard research vessel “Norvegia” (D/S Norvegia) during its navigation around Antarctica in the austral summer of 1930-1931. The data covers the period of 20.10.1930 to 09.02.1931.

The file contains an inventory of the archive of slides with fossil marine planktic diatoms from a network of sediment cores and surface sediment samples, including core tops. The collection of slides was prepared in NPI over the period from 1980s to 2019. The slides are packed in 83 diatom slide boxes and placed in 2 larger cardboard boxes (flytteeske) and 2 smaller cardboard boxes. The inventory file for each sediment core/surface sample provides the information on the sample ID, sample position (depth) in a sediment core, number of slides prepared from this sample, solution concentration and the slide location in the archive. Metadata also lists coordinates for some of the cores and the respective publications where the data were used.

Incident and transmitted spectral irradiance from transects on ponded first year ice during the ICE12 expedition with RV Lance in 2012. Under ice irradiance was measured approximately every 1m along three different transects, incident surface irradiance was measured concurrently at a fixed location near the start of the transect. After irradiance measurements, ice thickness, freeboard and pond depth was measured every 1m along the transect.

We performed measurements of carbon dioxide fugacity (fCO2) in the surface water under 8 Arctic sea ice from January to June 2015 during the Norwegian young sea ICE (N-ICE2015) expedition. Over 9 this period, the ship drifted with four different ice floes and covered the deep Nansen Basin, the slopes 10 north of Svalbard, and the Yermak Plateau. This unique winter-to-spring data set includes the first 11 winter-time under-ice water fCO2 observations in this region. The observed under-ice fCO2 ranged between 12 315 matm in winter and 153 matm in spring, hence was undersaturated relative to the atmospheric fCO2. 13 Although the sea ice partly prevented direct CO2 exchange between ocean and atmosphere, frequently 14 occurring leads and breakup of the ice sheet promoted sea-air CO2 fluxes. The CO2 sink varied between 0.3 15 and 86 mmol C m22 d21, depending strongly on the open-water fractions (OW) and storm events. The 16 maximum sea-air CO2 fluxes occurred during storm events in February and June. In winter, the main drivers 17 of the change in under-ice water fCO2 were dissolution of CaCO3 (ikaite) and vertical mixing. In June, in 18 addition to these processes, primary production and sea-air CO2 fluxes were important. The cumulative loss 19 due to CaCO3 dissolution of 0.7 mol C m22 in the upper 10 m played a major role in sustaining the 20 undersaturation of fCO2 during the entire study. The relative effects of the total fCO2 change due to CaCO3 21 dissolution was 38%, primary production 26%, vertical mixing 16%, sea-air CO2 fluxes 16%, and temperature 22 and salinity insignificant.

This table present the carbon and nitrogen isotopic ratios measured plasma and whole blood samples from Antarctic fur seals (Arctocephalus gazella) from Bouvetøya. Corrected δ13C values were estimated using normalization equations and applied only to plasma samples (details are in the manuscript).

Sea ice, snow depth, freeboard, and total thickness (ice + snow) measurements from 2" drillholes or ice core holes during the N-ICE2015 expedition. EM31 conductivity value for EM31 calibration are included where available.

This dataset contains results from seawater column samples collected in Rijpfjorden (80°N, 22°30’E) and northern coast of Svalbard during three years in July 2012-2014 using R/V Lance. Measured variables include seawater total alkalinity (AT), total dissolved inorganic carbon (DIC), salinity, and temperature.

This dataset contains results from seawater column samples collected in Kongsfjorden (between 78°50' and 79°04'N and 11°20' and 12°30'E) and West-Spitsbergen shelf (Svalbard) during three years in July 2012-2014 using R/V Lance. Measured variables include seawater total alkalinity (AT), total dissolved inorganic carbon (DIC), salinity, and temperature.

In the period between the austral summers of 1982/83 to 1997/98, iceberg observations were recorded by most research vessels cruising Antarctic waters, under an international programme for systematic collection of Antarctic iceberg data initiated by The Norwegian Polar Institute (NPI) in 1981 with the endorsement of the Scientific Committee on Antarctic Research (SCAR). The resulting database contains records of 323 520 iceberg positions from 26 634 individual observations. Of these, 262 007 icebergs have been classified by size into five different length categories: 10-50, 50-200, 200-500, 500-1000 and ˃1000 m. The database also includes 8061 additional iceberg observations collected by the Australian National Antarctic Research Expeditions ships from 1984 (AAD), operating in the 50-150° E longitude sector. Some of these have been classified by slightly different size categories. For this reason, the complete database has been packaged in three separate csv files: - one file containing the entire NPI database, including AAD observations 1978-1984 - one file containing the 8061 additional AAD observations 1984-2010 - one file containing 970 AAD observations 1978-1984, also included in the NPI data file The dataset is described in detail in the attached data report, with an overview of the contents of the database and their potential use, the data quality and quality control process, and some concluding remarks on iceberg occurrence and distribution around Antarctica; drift patterns, dissolution rates, calving rates and their contribution to the mass balance of Antarctica. During the three decades of observations, most of the ocean around Antarctica has been observed, but there are large differences in data density, primarily because nearly all ship tracks follow repeated routes to the various research stations, and these are not evenly located around the continent.  Figure 1: The 34 695 individual observations in the SCAR database shown as blue dots for the NPI data collection scheme with 5 classes and red for the AAD data with 7 classes (described in subsequent sections). The red dots overprint and hide many blue dots.

EN: This dataset shows the extent of areas with at least 15 percent frequency of sea ice occurrence in April in the Arctic Ocean. The ice frequency, i.e. the percentage of days with observed ice coverage during the given month, has been calculated from 30 years of satellite observations, from 1988 to 2017. The dataset is available in the ESRI shapefile format, as iso lines and polygons.