14
Chemical Oceanography, 4th Edition
plant material and the dissolution of CaCO 3 (Millero, 2000a). In equatorial and tropical
regions, there is a shallow upper layer of nearly uniform density, then a layer where the
density increases rapidly. This depth region is called the pycnocline. Below this region,
the density increases slowly with depth. Most deep waters have a σ T near 27.9. At higher
latitudes, the surface values of σ T = 27, so that the increase of density with increasing
depth is much smaller. For deep ocean waters the values of σ T at the adiabatic temperature should be used to examine the stability of deep waters (i.e., σ T , Θ).
Table 1.2
The 1980 International Equation of State for Seawater (m 3 kg –1 )
v P = v 0 (1 – P/ K)
ρ P = ρ 0 [1/(1 – P/ K)]
Where
ρ0 = 999.842594 + 6.793952 × 10-2 t – 9.095290 × 10 –3 t 2 + 1.001685 × 10 –4 t 3 – 1.120083 × 10 –6 t 4
+ 6.536336 × 10 –9 t 5 + (8.24493 × 10 –1 – 4.0899 × 10 –3 t + 7.6438 × 10 –5 t 2 –8.2467 × 10 –7 t 3
+ 5.3875 × 10– 9 t 4 ) S + (– 5.72466 × 10 –3 + 1.0227 × 10 –4 t – 1.6546 × 10 –6 t 2 ) S 1.5 + 4.8314 × 10 –4 S 2
K = 19652.21 + 148.4206 t – 2.327105 t 2 + 1.360477 × 10 –2 t 3 – 5.155288 × 10 –5 t 4 + S(54.6746 – 0.603459 t
+ 1.09987 × 10 –2 t 2 – 6.1670 × 10 –5 t 3 ) – S 1.5 (7.944 × 10 –2 +1.6483 × 10 –2 t – 5.3009 × 10 –4 t 2 )
+ P [3.239908 + 1.43713 × 10 –3 t + 1.16082 × 10 –4 t 2 – 5.77905 × 10 –7 t 3
+ S (2.2838 × 10 –3 – 1.0981 × 10 –5 t – 1.6078 × 10 –6 t 2 ) + S 1.5 (1.91075 × 10 –4 )]
+ P 2 [8.50935 × 10 –5 – 6.12293 × 10 –6 t + 5.2787 × 10 –8 t 2 + S (–9.9348 × 10 –7
+ 2.0816 × 10 –8 t + 9.1697 × 10 –10 t 2 )]
Check values:
S
t
P
v(m 3 kg– 1 )
K(b)
35
5°C
0 b
1,027.67547
22,185.93358
1,000
1,069.48914
25,577.49819
Source: Millero, F.J., Deep- Sea Res., 27, 255, 1980; Millero, F.J., and Poisson, A., Deep- Sea Res., 28, 625, 1981.
Note: ρ is the density and K the secant bulk modulus, S is practical salinity, and v = 1/ρ is the specific
volume. The superscript 0 is for water and P is for pressure in bar.
4000
3000
Depth (m)
2000
1000
Density σ t
Equator
0
23
24
25
26
27
28
Tropics
High Latitude
Figure 1.18
Typical sigma- T profiles in the ocean.
Chemical Oceanography, 4th Edition
plant material and the dissolution of CaCO 3 (Millero, 2000a). In equatorial and tropical
regions, there is a shallow upper layer of nearly uniform density, then a layer where the
density increases rapidly. This depth region is called the pycnocline. Below this region,
the density increases slowly with depth. Most deep waters have a σ T near 27.9. At higher
latitudes, the surface values of σ T = 27, so that the increase of density with increasing
depth is much smaller. For deep ocean waters the values of σ T at the adiabatic temperature should be used to examine the stability of deep waters (i.e., σ T , Θ).
Table 1.2
The 1980 International Equation of State for Seawater (m 3 kg –1 )
v P = v 0 (1 – P/ K)
ρ P = ρ 0 [1/(1 – P/ K)]
Where
ρ0 = 999.842594 + 6.793952 × 10-2 t – 9.095290 × 10 –3 t 2 + 1.001685 × 10 –4 t 3 – 1.120083 × 10 –6 t 4
+ 6.536336 × 10 –9 t 5 + (8.24493 × 10 –1 – 4.0899 × 10 –3 t + 7.6438 × 10 –5 t 2 –8.2467 × 10 –7 t 3
+ 5.3875 × 10– 9 t 4 ) S + (– 5.72466 × 10 –3 + 1.0227 × 10 –4 t – 1.6546 × 10 –6 t 2 ) S 1.5 + 4.8314 × 10 –4 S 2
K = 19652.21 + 148.4206 t – 2.327105 t 2 + 1.360477 × 10 –2 t 3 – 5.155288 × 10 –5 t 4 + S(54.6746 – 0.603459 t
+ 1.09987 × 10 –2 t 2 – 6.1670 × 10 –5 t 3 ) – S 1.5 (7.944 × 10 –2 +1.6483 × 10 –2 t – 5.3009 × 10 –4 t 2 )
+ P [3.239908 + 1.43713 × 10 –3 t + 1.16082 × 10 –4 t 2 – 5.77905 × 10 –7 t 3
+ S (2.2838 × 10 –3 – 1.0981 × 10 –5 t – 1.6078 × 10 –6 t 2 ) + S 1.5 (1.91075 × 10 –4 )]
+ P 2 [8.50935 × 10 –5 – 6.12293 × 10 –6 t + 5.2787 × 10 –8 t 2 + S (–9.9348 × 10 –7
+ 2.0816 × 10 –8 t + 9.1697 × 10 –10 t 2 )]
Check values:
S
t
P
v(m 3 kg– 1 )
K(b)
35
5°C
0 b
1,027.67547
22,185.93358
1,000
1,069.48914
25,577.49819
Source: Millero, F.J., Deep- Sea Res., 27, 255, 1980; Millero, F.J., and Poisson, A., Deep- Sea Res., 28, 625, 1981.
Note: ρ is the density and K the secant bulk modulus, S is practical salinity, and v = 1/ρ is the specific
volume. The superscript 0 is for water and P is for pressure in bar.
4000
3000
Depth (m)
2000
1000
Density σ t
Equator
0
23
24
25
26
27
28
Tropics
High Latitude
Figure 1.18
Typical sigma- T profiles in the ocean.