ALBERT

Description: The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Rabe, B., Heuze, C., Regnery, J., Aksenov, Y., Allerholt, J., Athanase, M., Bai, Y., Basque, C., Bauch, D., Baumann, T. M., Chen, D., Cole, S. T., Craw, L., Davies, A., Damm, E., Dethloff, K., Divine, D., Doglioni, F., Ebert, F., Fang, Y-C., Fer, I., Fong, A. A., Gradinger, R., Granskog, M. A., Graupner, R., Haas, C., He, H., He, Y., Hoppmann, M., Janout, M., Kadko, D., Kanzow, T., Karam, S., Kawaguchi, Y., Koenig, Z., Kong, B., Krishfield, R. A., Krumpen, T., Kuhlmey, D., Kuznetsov, I., Lan, M., Laukert, G., Lei, R., Li, T., Torres-Valdés, S., Lin, L,. Lin, L., Liu, H., Liu, N., Loose, B., Ma, X., MacKay, R., Mallet, M., Mallett, R. D. C., Maslowski, W., Mertens, C., Mohrholz, V., Muilwijk, M., Nicolaus, M., O’Brien, J. K., Perovich, D., Ren, J., Rex, M., Ribeiro, N., Rinke, A., Schaffer, J., Schuffenhauer, I., Schulz, K., Shupe, M. D., Shaw, W., Sokolov, V., Sommerfeld, A., Spreen, G., Stanton, T., Stephens, M., Su, J., Sukhikh, N., Sundfjord, A., Thomisch, K., Tippenhauer, S., Toole, J. M., Vredenborg, M., Walter, M., Wang, H., Wang, L., Wang, Y., Wendisch, M., Zhao, J., Zhou, M., & Zhu, J. Overview of the MOSAiC expedition: physical oceanography. Elementa: Science of the Anthropocene, 10(1), (2022): 1, https://doi.org/10.1525/elementa.2021.00062.

Description: Arctic Ocean properties and processes are highly relevant to the regional and global coupled climate system, yet still scarcely observed, especially in winter. Team OCEAN conducted a full year of physical oceanography observations as part of the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC), a drift with the Arctic sea ice from October 2019 to September 2020. An international team designed and implemented the program to characterize the Arctic Ocean system in unprecedented detail, from the seafloor to the air-sea ice-ocean interface, from sub-mesoscales to pan-Arctic. The oceanographic measurements were coordinated with the other teams to explore the ocean physics and linkages to the climate and ecosystem. This paper introduces the major components of the physical oceanography program and complements the other team overviews of the MOSAiC observational program. Team OCEAN’s sampling strategy was designed around hydrographic ship-, ice- and autonomous platform-based measurements to improve the understanding of regional circulation and mixing processes. Measurements were carried out both routinely, with a regular schedule, and in response to storms or opening leads. Here we present along-drift time series of hydrographic properties, allowing insights into the seasonal and regional evolution of the water column from winter in the Laptev Sea to early summer in Fram Strait: freshening of the surface, deepening of the mixed layer, increase in temperature and salinity of the Atlantic Water. We also highlight the presence of Canada Basin deep water intrusions and a surface meltwater layer in leads. MOSAiC most likely was the most comprehensive program ever conducted over the ice-covered Arctic Ocean. While data analysis and interpretation are ongoing, the acquired datasets will support a wide range of physical oceanography and multi-disciplinary research. They will provide a significant foundation for assessing and advancing modeling capabilities in the Arctic Ocean.

Description: The following projects and funding agencies contributed to this work: Why is the deep Arctic Ocean Warming is funded by the Swedish Research Council, project number 2018-03859, and berth fees for this project were covered by the Swedish Polar Research Secretariat; The Changing Arctic Ocean (CAO) program, jointly funded by the United Kingdom Research and Innovation (UKRI) Natural Environment Research Council (NERC) and the Bundesministerium für Bildung und Forschung (BMBF), in particular, the CAO projects Advective Pathways of nutrients and key Ecological substances in the ARctic (APEAR) grants NE/R012865/1, NE/R012865/2, and #03V01461, and the project Primary productivity driven by Escalating Arctic NUTrient fluxeS grant #03F0804A; The Research Council of Norway (AROMA, grant no 294396; HAVOC, grant no 280292; and CAATEX, grant no 280531); Collaborative Research: Thermodynamics and Dynamic Drivers of the Arctic Sea Ice Mass Budget at Multidisciplinary drifting Observatory for the Study of the Arctic Climate; National Science Foundation (NSF) projects 1723400, Stanton; OPP-1724551, Shupe; The Helmholtz society strategic investment Frontiers in Arctic Marine monitoring (FRAM); Deutsche Forschungsgemeinschaft (German Research Foundation) through the Transregional Collaborative Research Centre TRR 172 “ArctiC Amplification: Climate Relevant Atmospheric and SurfaCe Processes, and Feedback Mechanisms (AC)3” (grant 268020496); The Japan Society for the Promotion of Science (grant numbers JP18H03745, JP18KK0292, and JP17KK0083) and the COLE grant of U. Tokyo; National Key Research and Development Plan Sub-Project of Ministry of Science and Technology of China (2016YFA0601804), “Simulation, Prediction and Regional Climate Response of Global Warming Hiatus”, 2016/07-2021/06; National Science Foundation grant number OPP-1756100 which funded two of the Ice-Tethered Profilers and all the Ice-Tethered Profiler deployments; Chinese Polar Environmental Comprehensive Investigation and Assessment Programs, funded by the Chinese Arctic and Antarctic Administration; Marine Science and Technology Fund of Shandong Province for Qingdao National Laboratory for Marine Science and Technology (Grant: 2018SDKJ0104-1) and Chinese Natural Science Foundation (Grant: 41941012); UK NERC Long-term Science Multiple Centre National Capability Programme “North Atlantic Climate System Integrated Study (ACSIS)”, grant NE/N018044/1; The London NERC Doctoral Training Partnership grant (NE/L002485/1) which funded RDCM; NSF grant number OPP-1753423, which funded the 7Be tracer –measurements; and The Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung (AWI) through its projects: AWI_OCEAN, AWI_ROV, AWI_ICE, AWI_SNOW, AWI_ECO, AWI_ATMO, and AWI_BGC.

Description: 44 Southtek Iridium GPS drifters of types Offshore NOMAD-T V3 (33) and Offshore NOMAD V2 (11) were deployed in the marginal ice zone northwest of Svalbard as part of RV Polarstern expedition PS131 (ATWAICE) in July-August 2022. In addition to GPS position and time, the 33 NOMAD-T buoys also measured sea-surface temperatures. The 44 buoys were used for a total of 48 individual deployments, including 4 redeployments of recovered instruments, to either mark and track non-iridium instruments (6), to mark important sites (2), to track individual ice floes (1), or to elucidate the surface ocean currents as a complement to measurements obtained by the towed Triaxus system (31) or the ship-based CTD (8). The buoys were either thrown over board into open water, placed on sea ice, or attached to instruments. The measurement and transmission intervals were between 1 hour and 15 minutes, and were also partly reconfigured during operation. The drifter data were downloaded directly on board and displayed in the ship's Mapviewer software in near-real time, to facilitate navigation and to support the scientific program in decision-making. The attached .zip archive contains the original data files obtained from the Southtek server, which were partially modified to account for the 4 redeployments (indicated by "redeployed" in the filename), and to fill a data gap caused by an iridium data provider issue (indicated by "merged" in the filename). The files still include the deck test data, which needs to be removed according to the attached table with deployment metadata (including deployment time and position).

Description: During Polarstern expedition PS131 (ATWAICE: ATlantic WAter pathways to the ICE), a large number of autonomous instruments were installed on three representative ice floes across the marginal ice zone northwest of Svalbard in July 2022. The aim was to investigate sea ice summer melt processes, with a focus on the contribution of the Atlantic water inflow into the region. The attached .zip file includes raw data files obtained from all instruments deployed on the southernmost floe, also referred to as Floe South. Depending on the instrument, the data were transmitted via satellite, collected on internal memory, or both. The instruments were installed on Floe South on 14 July 2022, revisited for maintenance on 21 July 2022, and partially recovered on 31 July 2022. The sensors included 1 ADCP to measure ocean currents, a CTD buoy (SIT) with 5 SBE37IMP, a SIMBA- and a SIMB-type ice mass balance buoy to determine ice surface and bottom melt, an OpenMetBuoy (OMB) and iridium IMU logger for wave detection, two GPS drifters, and 2 timelapse cameras to document surface changes. All instruments performed as expected. All instruments except one OpenMetBuoy were recovered before leaving the study area on 31 July. The processed data will be provided and linked to when available.

Description: During Polarstern expedition PS131 (ATWAICE: ATlantic WAter pathways to the ICE), a large number of autonomous instruments were installed on three representative ice floes across the marginal ice zone northwest of Svalbard in July 2022. The aim was to investigate sea ice summer melt processes, with a focus on the contribution of the Atlantic water inflow into the region. The attached .zip file includes raw data files obtained from all instruments deployed on Floe Middle, located between Floe North and Floe South. Depending on the instrument, the data were transmitted via satellite, collected on internal memory, or both. The instruments were installed on Floe Middle on 15 July 2022, revisited for maintenance on 22 July 2022, and partially recovered on 31 July 2022. The sensors included 1 ADCP to measure ocean currents, a CTD buoy (SIT) with 5 SBE37IMP and 3 SBE56, a SIMBA-type ice mass balance buoy to determine ice surface and bottom melt, an OpenMetBuoy (OMB) and IMU logger for wave detection, one GPS drifter to mark the ADCP, and 3 timelapse cameras to document surface changes. All instruments performed as expected. All instruments except one OpenMetBuoy were recovered before leaving the study area on 31 July. The processed data will be provided and linked to when available.

Description: The MacArtney Triaxus extended version is a remotely operated towed vehicle (ROTV). It is towed behind the ship between 2 and 10 knots and can undulate in a saw tooth pattern between a few meters below the surface and 350m depth. The umbilical provides power and a fiber optic link to sensors that are mounted on the Triaxus (see SensorWeb). The data collected by the sensors were recorded on separate computers, one computer per sensor (including the flight information from the Triaxus itself). Thus, there are 7 separate data streams saved in separate folders plus a folder with metadata information about the different dives. During long Triaxus operations, new data files would be started approximately every 4 hours, because some of the employed software programs do not allow for backing up of the files while they are still being written to. A heavy weight (depressor) was employed directly behind the ship to pull the umbilical below the water line before sea ice can close in behind the ship. In addition to a few test dives, three transects across the marginal ice zone north of Svalbard (Yermak Plateau) were collected on PS131 in July/August 2022.

Description: During Polarstern expedition PS131 (ATWAICE: ATlantic WAter pathways to the ICE), a large number of autonomous instruments were installed on three representative ice floes across the marginal ice zone northwest of Svalbard in July 2022. The aim was to investigate sea ice summer melt processes, with a focus on the contribution of the Atlantic water inflow into the region. The attached .zip file includes raw data files obtained from all instruments deployed on the northernmost floe, also referred to as Floe North. Depending on the instrument, the data were transmitted via satellite, collected on internal memory, or both. The instruments were installed on Floe North on 13 July 2022, revisited for maintenance on 20 July 2022, and partially recovered on 30 July 2022. The sensors included 3 ADCPs in different configurations to measure ocean currents, a CTD buoy (SIT) with 6 SBE37IMP and an ECO Triplet fluorometer, a HOBO under-ice conductivity chain, 3 ice mass balance buoys (IMBs) of different types to determine ice surface and bottom melt, a radiation station equipped with 3 TriOS RAMSES radiometers to measure albedo and the under-ice light field, a Campbell Scientific weather station for atmospheric conditions, an OpenMetBuoy (OMB) and IMU logger for wave detection, a handful of GPS drifters to mark instruments, and 4 timelapse cameras to document surface changes. All instruments performed as expected, except one S1000 ADCP that failed due to power issues. All but three instruments (one OpenMetBuoy, one SVP, and one IMB) were recovered before leaving the study area on 30 July. The processed data will be provided and linked to when available.

Description: Time-series data of physical & biological oceanography, ocean current velocities, nutrient biogeochemistry, molecular biology and carbon/particle export were obtained from mooring HG-EGC-7 in the Fram Strait from June 2021 to July 2022 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV POLARSTERN expedition PS126 and recovered during PS131. The attached archive contains raw data files of three Seabird SBE37 MicroCATs (nominal depths: 38m, 232m, 484m; sampling interval 1h), three AADI RCM11 current meters (nominal depths: 45m, 239m, 487m; sampling interval 1h), one AADI Seaguard current meter (nominal depth: 993m, sampling interval 1h), one Wetlabs ECO PAR sensor (nominal depth: 38m; sampling interval 1h), one Wetlabs ECO Triplet fluorometer (nominal depth: 38m; sampling interval 2h), two Satlantics SUNA nitrate sensors (nominal depths: 38m, 232m; sampling interval 4h), two Sunburst SAMI-pCO2 sensors (nominal depths: 38m, 232m; sampling interval 1h) and two Sunburst SAMI-pH sensors (nominal depths: 38m, 232m; sampling interval 3h). The mooring also included two McLane RAS water samplers (nominal depths: 38m, 232m; data archived elsewhere), one sediment trap (nominal depth: 480m; data archived elsewhere), and four PE samplers (nominal depths: 51m, 239m, 482m, 893m; data archived elsewhere). Auxiliary information such as sensor calibration sheets, mooring diagrams, and schedule files are also provided, if applicable. The pH sensor at 38 m, the ECO Triplet at 38 m and the SUNA at 232m had issues and did not record any valid data.

Description: Time-series data of physical oceanography and ocean current velocities were obtained from mooring F3-19 in the Fram Strait from July 2020 to July 2022 as part of the Helmholtz infrastructure program Frontiers in Arctic Marine Monitoring (FRAM) and the long-term monitoring program at AWI HAUSGARTEN. The mooring was deployed during RV MARIA S. MERIAN expedition MSM93 and recovered during RV POLARSTERN expedition PS131. The attached archive contains raw data files of three Seabird SBE37 MicroCATs (nominal depths: 49m, 245m, 764m; sampling interval 30m/1h), one RDI Longranger ADCP (nominal depth: 406m; sampling interval 2h) and two Nortek Aquadopp current meter (nominal depths: 763m, 1070m; sampling interval 1h). Auxiliary information such as sensor calibration sheets, mooring diagrams, and schedule files are also provided, if applicable.