Atmosphere-ocean flux

Table 6.4 Summary of Gases in Seawater and the Importance of Their Global Atmosphere/Ocean Flux. ...

Table 2 Summary of gases in seawater and the importance of their global atmosphere/ocean flux. 

Fluxes are linear functions of reservoir contents. Reservoir size and the residence time of the carbon in the reservoir are the parameters used in the functions. Between the ocean and the atmosphere and within the ocean, fluxes rates are calculated theoretically using size of the reservoir, surface area of contact between reservoirs, concentration of CO2, partial pressures of CO2, temperature, and solubility as factors. The flux of carbon into the vegetation reservoir is a function of the size of the carbon pool and a fertilization effect of increased CO2 concentration in the atmosphere. Flux from vegetation into the atmosphere is a function of respiration rates estimated by Whittaker and Likens (79) and the decomposition of short-lived organic matter which was assumed to be half of the gross assimilation or equal to the amount transferred to dead organic matter. Carbon in organic matter that decomposes slowly is transferred... 

Once the model was complete, it was adjusted to a steady state condition and tested using historic carbon isotope data from the atmosphere, oceans and polar ice. Several important parameters were calculated and chosen at this stage. Sensitivity analysis indicated that results dispersal of the missing carbon - were significantly influenced by the size of the vegetation carbon pool, its assimilation rate, the concentration of preindustrial atmospheric carbon used, and the CO2 fertilization factor. The model was also sensitive to several factors related to fluxes between ocean reservoirs. 

While the natural exchange of mercury between the land and atmosphere and the atmosphere and oceans is balanced, human activity has tipped this balance. There is now about three times more mercury in the atmosphere and fluxes of more than four times to and from the atmosphere. 

In this tectonic situation, intense bimodal volcanism and associated seawater circulation occur, resulting to the formation of Kuroko deposits on the seafloor and formation of vein-type mineralization under subaerial condition and intense hydrothermal and volcanic CO2 fluxes to ocean and atmosphere. Such fluxes affect the long-term environmental changes (see Chapter 4). 

An early attempt to resolve the discrepancy between the high values of Sugimura and Suzuki (1988) and more traditional analyses failed to reach a definitive conclusion (Williams, 1992). The start of the Joint Global Ocean Flux Study (JGOFS) field program with the North Atlantic Bloom Experiment in 1989 put additional pressure on the various groups to resolve this issue quickly. The National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA) funded a workshop held in Seattle in July 1991 to resolve the issue. 

Figure 20. Calculated Fe isotope composition of seawater from different ocean basins based on a simple two-component mixing between Fe from aerosol particles and Fe from mid-oceanic-ridge (MOR) hydrothermal solutions. Atmospheric Fe fluxes (Jatm) for different ocean basins from Duce and Tindale (1991) MOR hydrothermal Fe flux ( mor) to different ocean basins were proportioned relative to ridge-axis length. Modified from Beard et al. (2003a).

By contrast, the gas transfer estimates utilizing Rn measurements assumes steady state between Rn production from radioactive decay of nonvolatile Rd and gas transfer with the atmosphere. This assumption is possible because Rn has a half-life of only 3.8 days, so accumulation and lateral ocean fluxes of Rn is assumed to be minimal. Again, a potential problem is the active, versus inactive layer of the ocean in this case, the mixed layer depth that may change during an experiment. 

Studies by Kondratyev et al. (2004a, b) showed that consideration of the spatial heterogeneity of sinks and sources of atmospheric carbon and specification of the parameters of its fluxes at the atmosphere-land and atmosphere-ocean boundaries raised the accuracy of estimates, but did little to remove either imbalances or differences between carbon fluxes and the dynamics of the change in C02 partial pressure in the terrestrial atmosphere. 

Regional transfer of carbon in 2000 due to production of and trade in crops, wood, and paper constituted 0.72 GtC yr 1. The pure global carbon flux at the atmosphere-ocean boundary in 1995 was estimated at 2.2 GtC (—19% +22%) with an interannual variability of about 0.5 GtC. The greatest extent of C02 flux oscillations in the system can be observed in the equatorial Pacific. 

An important stage in understanding the processes of C02 exchange between biospheric reservoirs is study of the laws of the development of various ecosystems in pre-industrial epochs, when there was little human involvement. Natural carbon fluxes between the atmosphere, oceans, land ecosystems, and inland water bodies... 

Table 3.10 exemplifies the calculation of C02 sinks into the vegetation cover of Russia. Such calculations using the GMNSS demonstrate the dynamics of the C02 flux mosaic in the atmosphere-plant-soil system. Knowledge of this mosaic makes it possible to assess the role of specific types of soil-plant formations in the regional balance of carbon, and on this basis to calculate the global fluxes of carbon dioxide across the atmosphere-land border. Similar calculations are also possible for the atmosphere-ocean system. 

Figure 3.11. The annual distribution of carbon flux across the atmosphere-ocean border in different latitudinal zones.

Figure 4.16. Reserves and fluxes of methane in the atmosphere-ocean-land system. From Fung et al. (1991). Notation Tg= 1012 g.

Since the World Ocean is the most inertial component of the global climate system, analyzing its variability is a top priority, especially as Levitus et al. (2001) detected annual increases in the heat content of the upper layer of all oceans over the last 45 years. With this in mind, Barnett et al. (2001) compared numerical modeling results of the heat content of the upper 3 km layer of various oceans with observational data. Calculations were made using the parallel climate model (PCM) for the atmosphere-ocean system without any flux adjustment. Calculations were made of five versions of the forecast growth in GHG concentration and sulfate aerosol content in the atmosphere. 

Jiang C. Cronin M.F. Kelly K.A. and Thompson L. (2005). Evaluation of a hybrid satellite-and NWP-based turbulent heat flux product using Tropical Atmosphere-Ocean (TAO) buoys. J. Geophys. Res., U0(C9), C09007, doi 10.1029/2004JC002824. 

---