American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article (file size: 1442014 bytes)    Cited by

GLOBAL BIOGEOCHEMICAL CYCLES, VOL. 18, GB2022, doi:10.1029/2003GB002211, 2004

Debate over the ocean bomb radiocarbon sink: Closing the gap

Synte Peacock

Department of the Geophysical Sciences, University of Chicago, Chicago, Illinois, USA


Abstract

There has over recent years emerged a controversy as to how much of the radiocarbon released into the atmosphere by nuclear weapons testing has been taken up by the ocean. Hesshaimer et al. [1994] made a case based on stratospheric and tropospheric measurements coupled with estimates of total bomb radiocarbon yield that it was not possible to explain both atmospheric observations and existing ocean-based bomb radiocarbon uptake estimates [ Broecker et al., 1985 , 1995]. They therefore proposed that estimates of the oceanic sink should be revised downward by about 25%. One reason for concern over this discrepancy is that the widely used wind speed dependent air-sea gas exchange parameterization of Wanninkhof [1992] is scaled to give an average exchange rate matching that given by the ocean bomb-radiocarbon budget. An example of an application of the Wanninkhof [1992] parameterization is in estimating ocean CO2 uptake based on direct measurements of the air-sea pCO2 difference [ Takahashi et al., 1997 ]. Such estimates scale linearly with the air-sea gas exchange coefficient. Further, as has been highlighted by the Hesshaimer et al. [1994] study, an understanding of the global budget of radiocarbon is an important issue in and of itself. In this paper, a number of new approaches to assessing the size of the ocean bomb radiocarbon sink are explored, and estimates are given for the total ocean bomb radiocarbon inventory during both the mid-1970s and the mid-1990s. The revised estimates of bomb-radiocarbon ocean uptake yield a mid-1970s inventory in closer agreement with that proposed by Hesshaimer et al. [1994] than the inventory obtained by the Broecker et al. [1995] study.

Received 18 December 2003; accepted 28 April 2004; published 23 June 2004.

Keywords: ocean bomb-radiocarbon budget.

Index Terms: 0312 Atmospheric Composition and Structure: Air/sea constituent fluxes (3339, 4504); 4299 Oceanography: General: General or miscellaneous; 4599 Oceanography: Physical: General or miscellaneous; 4504 Oceanography: Physical: Air/sea interactions (0312).

Read Full Article (file size: 1442014 bytes)    Cited by

Citation: Peacock, S. (2004), Debate over the ocean bomb radiocarbon sink: Closing the gap, Global Biogeochem. Cycles, 18, GB2022, doi:10.1029/2003GB002211.