Deliverable 3.11 Final implementation and data: North of Svalbard

This document, Deliverable 3.11 Final implementation of the observing system: Data delivery and report on results of the observing systems north of Svalbard, provides an overview of platforms, sensors, and samplers which were implemented north of Svalbard for various periods in 2017-2020, describes multidisciplinary data collected by different instruments, and addresses the performance of the employed systems and their applicability for a future sustained observing system.

The main goal of Task 3.2 is to deliver in situ ocean and sea ice observations collected during two INTAROS field seasons (and partially also during the initial test field season) and to provide recommendations for future implementation of the moored observing system north of Svalbard that can be applied to define a roadmap for observing future changes in the Arctic. The aim is to make comprehensive observations of the ongoing climate and environmental change that can also be applied as a validation tool for conceptual and three-dimensional modelling.

The first implementation of the observing system North of Svalbard was deployed successfully in August 2018 using the Norwegian Coast Guard icebreaker KV Svalbard and retrieved with the same vessel in August/September and with the research icebreaker RV Kronprins Håkonin September and November 2019. All recovered instrument and sensor provided full data return therefore a full annual cycle of multidisciplinary data was obtained for 2018-2019.

The second field deployment took place in 2019-2020 (one mooring remained until 2021) and included mostly moorings instrumented for measurements of ocean physical variables (and dissolved oxygen) at the main INTAROS line north of Svalbard and additional instruments and sensors for biogeochemical measurements at the deep INTAROS mooring in the Nansen Basin (deployed under Task 3.4). INTAROS moorings north of Svalbard were deployed from the research icebreaker RV Kronprins Håkon in November 2019and recovered during the CAATEX cruises with the Norwegian Coast Guard icebreaker KV Svalbard in August and November 2020 and in June 2021 as part of the UAK 2021. Field operations in 2020 and 2021 were extremely difficult in terms of logistics and ship access under the limitations due to COVID-19.

Deliverable 3.11 aims to address the following goals:

–Document the performance of instruments and systems selected/integrated for measurements of key ocean physical variables on INTAROS moorings (subsurface temperature, salinity,and ocean currents) and describe the collected data and their analysis,

–Document the performance of instruments and sensors selected/integrated for measurements of key biogeochemical variables (dissolved oxygen, nutrients and carbonate system parameters)on the multidisciplinary BGC11 mooring and other INTAROS moorings, and describe the collected data and their analysis,

–Document the performance of novel instruments for sea ice measurements on the INTAROS moorings and describe the collected data,

–Document the performance of novel combination of ADCP with echo sounder selected for ocean currents and zooplankton/small fish abundance measurements and describe the collected data,

–Document the performance and the state of technical development for a moored multisensor Octopus system for biological measurements (with an Underwater Vision Profiler, nutrient sensor,and chlorophyll-a and CDOM fluorometer), and describe the collected data,–Document the performance and technical development for microplastic samplers, and describe the collected data sets,

–Document the performance of technologies and deployment methodology for the sensors mounted at the seafloor, including Ocean Bottom Pressure sensors and Ocean Bottom Seismometers, and describe the collected data and their analysis,

–Describe the performance and fitness-to-purpose of the platforms, sensors and systems implemented during INTAROS under Task 3.2 for a future sustained Arctic observing system