Chapter 7: APPLICATIONS
Soloviev et al. (2002) evaluated the effect of mixed layer dynamics on
the air-sea O 2 exchange during GasEx-98 leg 2. This study employed a 1-D
model with mixing parameterization (3.105)-(3.106). The equation for gas
diffusion without biology effects was added to estimate the influence of the
mixed layer dynamics on the bulk-flux for the air-sea gas exchange. The
averaged error due to diurnal warming for leg 2 was relatively small (~4%).
Extrapolation of the results obtained with O 2 to CO 2 cannot be done
directly. One reason is that the effect of the gas depletion/accumulation is
less important for CO 2 than for O 2 since the former is a part of the carbonate
system with large buffering capacity. Temperature dependence of solubility
therefore primarily determines the effect of the fine thermal structure on the
CO 2 exchange in the near-surface layer of the ocean.
The temperature dependence of CO 2 solubility in seawater can be
described with the Takahashi et al (1993) coefficient:
2
(ln
) /
T
pCO
T
J w
w ,
(7.29)
where
2
a
pCO S p
P
, and the partial derivative denotes isochemical
conditions. At 15
o C and 35 psu, T 0.033
J |
o C
-1 .
McNeil and Merlivat (1996) combined (7.29) and (1.45) to obtain
formula for the relative deviation of the CO 2 flux
2
2
/
CO
CO
G
G
G
as follows:
2
2
2
2
2
/
/ (
)
CO
CO
T
w
w
a
G
G
T pCO
pCO
pCO
G
J
,
(7.30)
where T
G is the perturbation of the sea surface temperature; pCO 2 is the
CO 2 partial pressure (indices a and w refer to the atmosphere and water
respectively). During GasEx-98 leg, the ratio
2
2
2
/(
)
w
w
a
pCO
pCO
pCO
varied between 2.7 and 4.1 (McGillis et al., 2004) and the diurnal warming
in a few cases exceeded 1
o
C.
Calculation of the temperature difference within the upper 4 m due to
diurnal warming is possible with a one-dimensional model of diurnal mixed
layer and diurnal thermocline. Under the assumption of horizontal
homogeneity, equations (1.6), (1.7), (1.10), and (1.11) are as follows:
M
u
u
K
f v
t
z
z
w
w
w
§
·
¨
¸
w
w
w
©
¹
,
(7.31)
M
v
v
K
f u
t
z
z
w
w
w
§
·
¨
¸
w
w
w
©
¹
,
(7.32)
491
G
Soloviev et al. (2002) evaluated the effect of mixed layer dynamics on
the air-sea O 2 exchange during GasEx-98 leg 2. This study employed a 1-D
model with mixing parameterization (3.105)-(3.106). The equation for gas
diffusion without biology effects was added to estimate the influence of the
mixed layer dynamics on the bulk-flux for the air-sea gas exchange. The
averaged error due to diurnal warming for leg 2 was relatively small (~4%).
Extrapolation of the results obtained with O 2 to CO 2 cannot be done
directly. One reason is that the effect of the gas depletion/accumulation is
less important for CO 2 than for O 2 since the former is a part of the carbonate
system with large buffering capacity. Temperature dependence of solubility
therefore primarily determines the effect of the fine thermal structure on the
CO 2 exchange in the near-surface layer of the ocean.
The temperature dependence of CO 2 solubility in seawater can be
described with the Takahashi et al (1993) coefficient:
2
(ln
) /
T
pCO
T
J w
w ,
(7.29)
where
2
a
pCO S p
P
, and the partial derivative denotes isochemical
conditions. At 15
o C and 35 psu, T 0.033
J |
o C
-1 .
McNeil and Merlivat (1996) combined (7.29) and (1.45) to obtain
formula for the relative deviation of the CO 2 flux
2
2
/
CO
CO
G
G
G
as follows:
2
2
2
2
2
/
/ (
)
CO
CO
T
w
w
a
G
G
T pCO
pCO
pCO
G
J
,
(7.30)
where T
G is the perturbation of the sea surface temperature; pCO 2 is the
CO 2 partial pressure (indices a and w refer to the atmosphere and water
respectively). During GasEx-98 leg, the ratio
2
2
2
/(
)
w
w
a
pCO
pCO
pCO
varied between 2.7 and 4.1 (McGillis et al., 2004) and the diurnal warming
in a few cases exceeded 1
o
C.
Calculation of the temperature difference within the upper 4 m due to
diurnal warming is possible with a one-dimensional model of diurnal mixed
layer and diurnal thermocline. Under the assumption of horizontal
homogeneity, equations (1.6), (1.7), (1.10), and (1.11) are as follows:
M
u
u
K
f v
t
z
z
w
w
w
§
·
¨
¸
w
w
w
©
¹
,
(7.31)
M
v
v
K
f u
t
z
z
w
w
w
§
·
¨
¸
w
w
w
©
¹
,
(7.32)
491
G