The age of iron and iron source attribution in the ocean
MetadataShow full item record
We use tracers to partition dissolved iron (dFe) into the contributions from each source within a numerical model of the iron cycle without perturbing the system. These contributions are further partitioned according to the time since injection into the ocean, which deﬁnes their iron-age spectrum and mean iron age. The utility of these diagnostics is illustrated for a family of inverse model estimates of the iron cycle, constrained by a data-assimilated circulation and available dFe measurements. The source contributions are compared with source anomalies deﬁned as the diﬀerences between solutions with and without the source in question. We ﬁnd that in the Southern Ocean euphotic zone, the hydrothermal and sediment contributions range from 15% to 30% of the total each, which the anomalies underestimate by a factorof∼2becauseofthenonlinearityofscavenging.Theironageisonlyresetbyscavengingandattains a mean of several hundred years in the Southern Ocean euphotic zone, revealing that aeolian iron there is supplied primarily from depth as regenerated dFe. Tagging iron according to source region and pathways shows that 70–80% of the aeolian dFe in the euphotic zone near Antarctica is supplied from north of 46∘S via paths that reach below 1 km depth. Hydrothermal iron has the oldest surface mean ages on the order of middepth ventilation times. A measure of uncertainty is provided by the systematic variations of our diagnostics across the family of iron cycle estimates, each member of which has a diﬀerent aeolian sourcestrength.
Showing items related by title, author, creator and subject.
Keating, Charles B.; Bradley, Joseph M.; Katina, Polinpapilinho F.; Arndt, Craig (Monterey, California. Naval Postgraduate School, 2018-04-30); SYM-AM-18-100The defense acquisition system has been the source of intense scrutiny and calls for reform for over four decades. This research is to examine the contributions of Systems Theory to enhance prospects related to acquisition ...
Jacoby, Grant A. (Monterey, California. Naval Postgraduate School, 2003-12);This research provides the first theoretical model--the Intranet Efficiency and Effectiveness Model (IEEM)--for the Family of Measures approach to measure Web activity as well as a holistic framework and multi-disciplinary ...
Zyda, Michael; Pratt, David; Falby, John; Barham, Paul; Kelleher, Kristen (1993-09);The Naval Postgraduate School Networked Vehicle Simulator IV (NPSNET-IV) is a lowcost, student written, real-time networked vehicle simulator that runs on commercial, off-theshelf workstations (the Silicon Graphics ...