Particle number flux of airborne snow particles was measured near-continuously at 1-min resolution above the sea ice surface from October 2019 to July 2020 during the year-round MOSAiC expedition. Sensors where mounted at 0.08 m and 10 m on the mast in MetCity on the MOSAiC ice floe drifting during the measurement period within an area of 79.2 N to 88.6 N and 2.7 W to 133.6 E. The SPC measurements were part of the BAS measurement suite during MOSAiC to quantify sea salt aerosol production from blowing snow above sea ice and potential impacts on clouds and climate. Instrument and data quality checks during the year-round campaign were carried out by BAS scientists and the MOSAiC ATMOS team. Funding was provided by UKRI Natural Environment Research Council (NERC) project "Sea Salt Aerosol above Arctic Sea Ice - sources, processes and climate impacts" (SSAASI-CLIM) grant NE/S00257X/1. The project was part of the international Multi-disciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) with the tag MOSAiC20192020.

Salinity profiles of sea ice and snow on sea ice were measured in the Arctic Ocean during the Norwegian Young Sea Ice cruise in 2015 (https://www.npolar.no/en/projects/n-ice2015/), an international sea ice drift expedition led by the Norwegian Polar Institute. Salinity is a key parameter for a range of processes related to biology, photochemistry and physics of sea ice, snow on sea ice as well as atmospheric aerosol. Sea ice cores and snow samples were collected during the sea ice drift expedition from the ice floe and transferred to the ship's laboratory. The aqueous conductivity of melted sea ice core and snow samples was measured and converted into practical salinity units. Funding was provided by the NERC grant NE/M005852/1, Japan Society for the Promotion of Science (15K16135, 24-4175) and the Centre of Ice, Climate and Ecosystems (ICE) at the Norwegian Polar Institute through the N-ICE project

This dataset provides daily, 8-day, and monthly Arctic melt pond fractions and binary classification, from 2000-06-01 to 2020-08-31. Level-2 MODerate resolution Imaging Spectroradiometer (MODIS) top-of-the-atmosphere (TOA) reflectances for bands 1-4 were obtained, to which two machine learning algorithms such as multi-layer neural networks and logistic regression were applied to map melt pond fraction and binary melt pond/ice classification. This work was funded by NERC standard grant NE/R017123/1.

Morphometric data were collected for 417 Calanus finmarchicus copepods (stage CV), swimming activity data were collected using locomotor activity monitors for 469 Calanus finmarchicus copepods (stage CV) and oxygen consumption activity data were collected using a Loligo microplate respirometry system for 40 Calanus finmarchicus copepods (stage CV). All data were collected in the Fram Strait, Arctic Ocean, from two stations (F7 and D6) in August 2019, coinciding with the timing of early diapause in this species. Photographs were taken and experiments were conducted onboard RRS James Clark Ross. The data are reported in detail in Grigor et al., Torpidity as an indicator of overwintering diapause in Calanus finmarchicus. Funding was provided by the CHASE project (NE/R012733/1), part of the Changing Arctic Ocean (CAO) programme, jointly funded by the UKRI Natural Environment Research Council (NERC) and the German Federal Ministry of Education and Research (BMBF). Sampling and experiments were performed on the DIAPOD cruise to the Fram Strait in August 2019.

This dataset provides daily, 8-day, and monthly Arctic melt pond fractions and binary classification, from 2021-05-01 to 2022-08-31. Level-2 MODerate resolution Imaging Spectroradiometer (MODIS) top-of-the-atmosphere (TOA) reflectances for bands 1-4 were obtained, to which two machine learning algorithms such as multi-layer neural networks and logistic regression were applied to map melt pond fraction and binary melt pond/ice classification. This work was funded by NERC standard grant NE/R017123/1.

This data product comprises 5 files, containing marine sediment pore water and solid phase leachate silicon (Si) isotopic and element concentration data, as well as benthic silica flux magnitudes derived from core incubation experiments and sediment biogenic silica contents. Samples were collected over three cruises of the Changing Arctic Ocean Seafloor (ChAOS) project summer sampling campaigns in the Barents Sea between 2017 and 2019 aboard the RRS James Clark Ross (cruises JR16006, JR17007 and JR18006). The aim of this study was to improve our mechanistic understanding of the cycling of Si within the Arctic Ocean seafloor through measurement of stable Si isotopes in the dissolved Si pool and the solid phase sources. This project was part of the Changing Arctic Ocean programme, funded by the Natural Environment Research Council (NERC) (grant no. NE/P005942/1).