Joint International Conference on Long-term Experiments ...

∂ C
Φ = - ε
(3)
∂z
where Φ is in mmol⋅m -2 ⋅ s - 1 . Gas flux inside the atmospheric film is represented by the
expression:
)
0
0 k
Φ = − k ( p − p ) = − a ( C − C
(4)
a a a a S a a
and inside the ocean film we have the relation:
Φ = − k ( C
0
− C )
(5)
o o o o
Table 1: The atmospheric composition influenced by chemical and biological
processes
________________________________________________________________
(a)The atmospheric composition (b) Influenced by chemical
(molar fraction in dry air) and biological processes
___________________________ppm___________________Yes___________ No___
N2 0,78084 ± 0,00004 CO2 358 Ar N2
O2 0, 20946 ± 0,00002 Ne 18,18 ± 0,04 Ne O2
Ar 0,00934 ± 0,00001 He 5,24 ± 0,004 He CO2
CH4 1,72 Kr CH4
Kr 1,14 ± 0,01 Xe H2
H2 0,55 N2O
N2O 0,312 CO
Xe 0,087 ± 0,001 O3
CO 0,05 - 0,20
O3 0,01 - 0,50
See West and East, 1982, for all gases, with exception of CO2, CH4 and N2O, that are
given after Houghton, 1996.
The index 0 indicates the concentration and the partial pressure at the air-water
interface, where z = 0.
This partial atmospheric pressure of a gas was converted in the concentration
equivalent in water, C, by using the solubility S. In these equations ka and ko are the gas
exchange coefficients, having the units of velocity and respectively of solubility. ko is
also named transfer velocity. ka ⁄ S and ko have values of ε ⁄ Δz in the model of stagnant
film, where Δz is the depth of this film.
The measurements of pressures and of partial concentrations are made above the
air-water interface, never on this ocean surface. We will consider from the continuity at
this interface that Φa = Φo = Φ and Ca 0 = Co 0 , with the aim to eliminate the surface
concentrations from eq.(4) and eq.(5) . It will be obtained that:
Φ = − K( C − C )
(6)
a o
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