Glider-based observations of CO 2 in the Labrador Sea

• Published in: Ocean Science
• Main Authors: N. von Oppeln-Bronikowski, B. de Young, D. Atamanchuk, D. Wallace
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2021
• Subjects: Geography. Anthropology. Recreation; G; Environmental sciences; GE1-350; Newfoundland; Labrador Sea
• Online Access: https://doi.org/10.5194/os-17-1-2021; https://doaj.org/article/137c10bc6cd7406288f0282e23f4ddf2

Ocean gliders can provide high-spatial- and temporal-resolution data and target specific ocean regions at a low cost compared to ship-based measurements. An important gap, however, given the need for carbon measurements, is the lack of capable sensors for glider-based CO 2 measurements. We need to develop robust methods to evaluate novel CO 2 sensors for gliders. Here we present results from testing the performance of a novel CO 2 optode sensor ( Atamanchuk et al. , 2014 ) , deployed on a Slocum glider, in the Labrador Sea and on the Newfoundland Shelf. This paper (1) investigates the performance of the CO 2 optode on two glider deployments, (2) demonstrates the utility of using the autonomous SeaCycler profiler mooring ( Send et al. , 2013 Atamanchuk et al. , 2020 ) to improve in situ sensor data, and (3) presents data from moored and mobile platforms to resolve fine scales of temporal and spatial variability of O 2 and p CO 2 in the Labrador Sea. The Aanderaa CO 2 optode is an early prototype sensor that has not undergone rigorous testing on a glider but is compact and uses little power. Our analysis shows that the sensor suffers from instability and slow response times ( τ 95 >100 s), affected by different behavior when profiling through small ( <3 ∘ C) vs. large ( >10 ∘ C) changes in temperature over similar time intervals. We compare the glider and SeaCycler O 2 and CO 2 observations and estimate the glider data uncertainty as ± 6.14 and ± 44.01 µ atm, respectively. From the Labrador Sea mission, we point to short timescales ( <7 d) and distance ( <15 km) scales as important drivers of change in this region.