THE NEAR-SURFACE LAYER OF THE OCEAN
d) Solar absorption and turbidity
The volume absorption of penetrating solar radiation in the ocean plays
an important role in determining the temperature and density structure of the
upper ocean. Changes of turbidity alter the profile of shortwave radiation,
and episodic or seasonal changes of productivity may significantly affect
turbidity (Lewis et al., 1990; Siegel et al., 1995; Ohlmann et al., 1996). The
impact of altered penetration of shortwave radiation can be significant for
climate models (Schneider and Zhu, 1998; Murtugudde et al., 2002; Miller et
al., 2003). Biological influences on turbidity are not amenable to
parameterization at this time. Biogeochemical submodels are required
(Christian et al., 2002). Though for the upper ten centimeters of the open
ocean the effect of turbidity on the absorption of solar radiation is
e) CO 2 uptake by the ocean
Greenhouse gas exchanges are important for global climate change. The
CO 2 uptake by the oceans is largely controlled by the physical processes in
the near-surface layer of the ocean. The estimates of the global ocean CO 2
uptake depends on the parameterization for the gas transfer velocity (Tans et
al, 1990; Takahashi, 2000). The realistic parameterizations of the air-sea gas
exchange should be based on the physics of the turbulent boundary layer and
the properties of the sea surface rather than on empirics (Soloviev and
, 2001). The parameterization of the former type described in
Section 7.5 appears to be consistent with the reanalysis of the bomb
14 C
global data by Sweeny et al. (2005) using the inverse method.
A strong dependence of CO 2 solubility on temperature suggests that the
diurnal warming and the cool skin may cause deviations from bulk-flux
formulation (7.20). For example, for the typical western equatorial Pacific
pCO 2a ~350 Patm and pCO 2w ~360 Patm, the McNeil and Merlivat (1996)
formula (7.30) gives an error of about 150% per
o
C, while in the eastern
equatorial Pacific the difference, 'pCO 2w , can achieve ~100 Patm, which
results in an error of about -10% per degree C. (Remarkably, the McNeil and
Merlivat (1996) formula is invariant with respect to the type of gas transfer
parameterization.)
According to Robertson and Watson (1992), a 0.3
o
C difference in SST
due to the cool skin results in an increased oceanic global uptake of about
0.7 Pg of carbon per year, which constitutes a substantial correction, from
17% to 36%, of the global carbon uptake by the oceans. (A high-resolution
approach by Van Scoy et al. (1995) showed a somewhat lower effect of the
cool skin on the global estimate.) Global estimates of the CO 2 uptake by the
ocean may also have to be corrected for the large diurnal warming events as
500
nevertheless relatively small (see Section 1.4.6.)
Schl ssel
ü
d) Solar absorption and turbidity
The volume absorption of penetrating solar radiation in the ocean plays
an important role in determining the temperature and density structure of the
upper ocean. Changes of turbidity alter the profile of shortwave radiation,
and episodic or seasonal changes of productivity may significantly affect
turbidity (Lewis et al., 1990; Siegel et al., 1995; Ohlmann et al., 1996). The
impact of altered penetration of shortwave radiation can be significant for
climate models (Schneider and Zhu, 1998; Murtugudde et al., 2002; Miller et
al., 2003). Biological influences on turbidity are not amenable to
parameterization at this time. Biogeochemical submodels are required
(Christian et al., 2002). Though for the upper ten centimeters of the open
ocean the effect of turbidity on the absorption of solar radiation is
e) CO 2 uptake by the ocean
Greenhouse gas exchanges are important for global climate change. The
CO 2 uptake by the oceans is largely controlled by the physical processes in
the near-surface layer of the ocean. The estimates of the global ocean CO 2
uptake depends on the parameterization for the gas transfer velocity (Tans et
al, 1990; Takahashi, 2000). The realistic parameterizations of the air-sea gas
exchange should be based on the physics of the turbulent boundary layer and
the properties of the sea surface rather than on empirics (Soloviev and
, 2001). The parameterization of the former type described in
Section 7.5 appears to be consistent with the reanalysis of the bomb
14 C
global data by Sweeny et al. (2005) using the inverse method.
A strong dependence of CO 2 solubility on temperature suggests that the
diurnal warming and the cool skin may cause deviations from bulk-flux
formulation (7.20). For example, for the typical western equatorial Pacific
pCO 2a ~350 Patm and pCO 2w ~360 Patm, the McNeil and Merlivat (1996)
formula (7.30) gives an error of about 150% per
o
C, while in the eastern
equatorial Pacific the difference, 'pCO 2w , can achieve ~100 Patm, which
results in an error of about -10% per degree C. (Remarkably, the McNeil and
Merlivat (1996) formula is invariant with respect to the type of gas transfer
parameterization.)
According to Robertson and Watson (1992), a 0.3
o
C difference in SST
due to the cool skin results in an increased oceanic global uptake of about
0.7 Pg of carbon per year, which constitutes a substantial correction, from
17% to 36%, of the global carbon uptake by the oceans. (A high-resolution
approach by Van Scoy et al. (1995) showed a somewhat lower effect of the
cool skin on the global estimate.) Global estimates of the CO 2 uptake by the
ocean may also have to be corrected for the large diurnal warming events as
500
nevertheless relatively small (see Section 1.4.6.)
Schl ssel
ü