What is it about?
Deep ocean salinity drift is attributed to accretion of sediment or biofouling on Seabird instruments, which serve to clog the conductivity cell gradually before clearing upon ascent. Deep temperature is potentially linked to the Kuroshio Extension index, a measure of the meandering, intensity, and location of the Kuroshio Extension current.
Featured Image
Why is it important?
Deep ocean stations typically report consistent temperature and salinity, with only small variations and minimal year-to-year discontinuities. No known stations have reported salinity drift of this magnitude so consistently and across independent instruments and deployments. Features unique to the Kuroshio Extension (e.g. sediment, benthic storms, or a nepheloid layer) likely explain why drift occurs at the KEO mooring location, but not at nearby stations. Deep temperatures follow basin-wide warming rates from 2013-2017, but temperature is also thought to be linked to the state of the Kuroshio Extension current.
Perspectives
This paper explores a new sensor issues that recurs each year at the KEO mooring site, but is not observed (at least not to this degree) at other deep OceanSITES stations. A nearby station called S1 is even deeper than KEO, so pressure is not thought to be responsible for the sensor issue (salinity drift). Additionally, the issue immediately corrects upon ascent, suggesting that the accumulated debris "washes off" when the instrument is recovered. Deep ocean temperatures are also worth more exploration, as there are likely contributions from the Kuroshio Extension current, whose influence could be better quantified in the context of basin-wide warming rates.
Nathan Anderson
University of Washington System
Read the Original
This page is a summary of: Challenges of Measuring Abyssal Temperature and Salinity at the Kuroshio Extension Observatory, Journal of Atmospheric and Oceanic Technology, November 2020, American Meteorological Society,
DOI: 10.1175/jtech-d-19-0153.1.
You can read the full text:
Contributors
The following have contributed to this page
