Assessment of the carbonate chemistry seasonal cycles in the Southern Ocean from persistent observational platforms

Observations from Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) biogeochemical profiling Argo floats are used to characterize the climatological seasonal cycles and drivers of dissolved inorganic carbon, total alkalinity, pH, the partial pressure of carbon dioxide (CO2), and the saturation state of aragonite (ΩAr) at the surface and at 200 m across five Southern Ocean frontal regimes, including under sea ice. The Southern Ocean ranges from a temperature‐dominated system in the northernmost Subtropical Zone to a biologically dominated system in the most poleward Seasonal Sea Ice Zone. In all zones, the ingassing or outgassing of CO2 must be balanced by geostrophic and Ekman transport, mixing from below, and particle transport of carbon into or out of the euphotic zone. The climatological seasonal cycles spanning the period from 2014 to 2017 compare favorably with existing climatologies in spring and summer and less so during winter months, at higher latitudes, and in ice‐covered regions due, in part, to limited wintertime observations before SOCCOM. We observe increases in the carbon and nutrient content of surface waters south of the Subantarctic Front between climatological data products and the SOCCOM float climatologies, even after adjusting for anthropogenic change, suggesting a large‐scale increase in the amount of upwelled carbon‐ and nutrient‐rich deep waters. This increased upwelling corresponds to a positive Southern Annular Mode Index over 2014‐2017 and likely acts to decrease the magnitude of the Southern Ocean sink of total carbon by increasing outgassing of natural CO2, especially during winter months.

Williams N. L., Juranek L. W., Feely R. A., Russell J. L., Johnson K. S. & Hales B., in press. Assessment of the carbonate chemistry seasonal cycles in the Southern Ocean from persistent observational platforms. Journal of Geophysical Research. Article (subscription required).

0 Responses to “Assessment of the carbonate chemistry seasonal cycles in the Southern Ocean from persistent observational platforms”

  1. Leave a Comment

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Subscribe to the RSS feed

Powered by FeedBurner

Follow AnneMarin on Twitter

Blog Stats

  • 1,272,387 hits


Ocean acidification in the IPCC AR5 WG II

OUP book