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Preliminary investigation of the WOCE Pacific C-14 data set shows a tremendous amount of detail/information which was completely missed during GEOSECS due to the low sample density of that program. Strong indication is given by the P6 and P16, P17 data sets of the return flow pathways at mid depth of Pacific deep water (both along the eastern margin and at approximately 170°W above the northward flowing bottom waters). When coupled with He-3 data these two tracers will place strong constraints on rates as well as pathways for this deep circulation. The main pathway of northward fl owing bottom water is very clearly indicated in the P6 section. Details of this deep circulation implicated in the C-14 section are supported by other tracer data. In the North Pacific the C-14 minimum is shifted well south of the Alaskan slope. The distribution in this area lends strong support to the deep circulation along this coast described by Warren and others. Preliminary calculations yield a transport of deep/bottom water (below 2500 m) into the North Pacific of 9.1Sv which translates to a mean upwelling rate below that surface of 4.2m/yr.
Changes in the distribution of C-14 in the Pacific thermocline are significant since GEOSECS. In the Northeast Pacific, the changes are primarily limited to the upper few hundred meters of the water column. In the South Pacific the C-14 contours have deepened by as much as 300 m since GEOSECS. Early qualitative investigations imply that SAMW is the primary ventilation source.
Early analysis indicates that prior calculation of integrated bomb C-14 may have significantly more error than previouly assumed. Having two realizations of the C-14 distribution allows these integral quantities to be estimated more reliably. These quantities are extremely important to estimates of CO2 flux balance. Additionally, recent model calculations imply that that during the 1990's C-14 may be a much more reliable proxy for anthropogenic CO2 than in prior years. The difference is due to the fact that the C-14 distribution in earlier years was primarily controlled by air-sea gas exchange processes while over time this has shifted to the point that the distribution now is more dependent upon large scale circulation processes.
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