Southern Ocean biogeochemical float deployment strategy, with example from the Greenwich meridian line (GO-SHIP A12)

TitleSouthern Ocean biogeochemical float deployment strategy, with example from the Greenwich meridian line (GO-SHIP A12)
Publication TypeJournal Article
Year of Publication2019
AuthorsTalley LD, Rosso I., Kamenkovich I., Mazloff MR, Wang J., Boss E., Gray A.R, Johnson K.S, Key R.M, Riser S.C, Williams N.L, Sarmiento J.L
JournalJournal of Geophysical Research-Oceans
Volume124
Pagination403-431
Date Published2019/01
Type of ArticleArticle
ISBN Number2169-9275
Accession NumberWOS:000458718600024
Keywordsantarctic intermediate water; carbon; general-circulation; global; heat; maud-rise; ocean; oceanography; overturning circulation; profiling floats; sea-ice; total geostrophic circulation
Abstract

Biogeochemical Argo floats, profiling to 2,000-m depth, are being deployed throughout the Southern Ocean by the Southern Ocean Carbon and Climate Observations and Modeling program (SOCCOM). The goal is 200 floats by 2020, to provide the first full set of annual cycles of carbon, oxygen, nitrate, and optical properties across multiple oceanographic regimes. Building from no prior coverage to a sparse array, deployments are based on prior knowledge of water mass properties, mean frontal locations, mean circulation and eddy variability, winds, air-sea heat/freshwater/carbon exchange, prior Argo trajectories, and float simulations in the Southern Ocean State Estimate and Hybrid Coordinate Ocean Model (HYCOM). Twelve floats deployed from the 2014-2015 Polarstern cruise from South Africa to Antarctica are used as a test case to evaluate the deployment strategy adopted for SOCCOM's 20 deployment cruises and 126 floats to date. After several years, these floats continue to represent the deployment zones targeted in advance: (1) Weddell Gyre sea ice zone, observing the Antarctic Slope Front, and a decadally-rare polynya over Maud Rise; (2) Antarctic Circumpolar Current (ACC) including the topographically steered Southern Zone chimney where upwelling carbon/nutrient-rich deep waters produce surprisingly large carbon dioxide outgassing; (3) Subantarctic and Subtropical zones between the ACC and Africa; and (4) Cape Basin. Argo floats and eddy-resolving HYCOM simulations were the best predictors of individual SOCCOM float pathways, with uncertainty after 2years of order 1,000km in the sea ice zone and more than double that in and north of the ACC.

DOI10.1029/2018jc014059
Short TitleJ Geophys Res-Oceans
Student Publication: 
No
sharknado