A recent decline in North Atlantic subtropical mode water formation
As a manifestation of mixing dynamics in the upper ocean, interannual and decadal variability of subtropical mode water (STMW) properties in the North Atlantic Ocean provides a valuable insight into ocean–atmosphere interaction in a changing climate. Here, we use hydrographic data from the Bermuda A...
| Published in: | Nature Climate Change |
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| Main Authors: | , , , |
| Format: | Text |
| Language: | English |
| Published: |
Springer Science and Business Media LLC
2020
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| Subjects: | |
| Online Access: | https://doi.org/10.1038/s41558-020-0722-3 https://archimer.ifremer.fr/doc/00618/72973/72146.pdf https://archimer.ifremer.fr/doc/00618/72973/77554.pdf https://archimer.ifremer.fr/doc/00618/72973/ |
| Summary: | As a manifestation of mixing dynamics in the upper ocean, interannual and decadal variability of subtropical mode water (STMW) properties in the North Atlantic Ocean provides a valuable insight into ocean–atmosphere interaction in a changing climate. Here, we use hydrographic data from the Bermuda Atlantic Time-Series Study and Hydrostation S sites near Bermuda, as well as various ocean reanalysis products, to evaluate the modern variability of STMW properties. Our study finds an 86–93% loss of STMW thickness at these sites between 2010 and 2018 and a comparable loss throughout the western subtropical gyre, culminating in the weakest STMW pentad on record. We correlate this decline with a reduction in the annual outcropping volume and northward excursions of the formation region, suggesting a gyre-wide signal of weakening STMW generation. The outcropping volume of STMW is anti-correlated with surface ocean heat content, foreshadowing future STMW loss in the face of continued warming. |
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