Hanna Instruments HI5321, Инструкция по эксплуатации

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50
S = - 0.08996 + 28.2929729 R
15
+ 12.80832 R
15
2
- 10.67869 R
15
3
+ 5.98624 R
15
4
- 1.32311 R
15
5
Note:
The formula can be applied for temperatures between 10 °C and 31 °C.
PRACTICAL SALINITY SCALE (UNESCO 1978)
The PSU scale extends from 0-42. The Practical salinity (
S
) of seawater relates the ratio of electrical
conductivity of a normal seawater sample at 15 °C and 1 atmosphere to a potassium chloride solution
(
KCl
) with a mass of 32.4356 g/kg water at the same temperature and pressure. Under these conditions
the ratio is equal to 1 and
S
=35. The Practical salinity scale may be applied to values 2 through 42 PSU
at temperature between -2 °C to 35 °C.
S
is defined in terms of the ratio
K
15
.
S = 0.0080-0.1692 K
15
1/2
+25.3851 K
15
+14.0941 K
15
3/2
-7.0261 K
15
2
+2.7081 K
15
5/2
Where
C
is Conductivity;
C (35,15,0)
=0.042933 S/cm
The simplified equation above is derived from
With the following coefficients and
k =
0.0162 and
Seawater temperature coefficient
r
T
= c
0
+ c
1
·T + c
2
·T
2
+ c
3
·T
3
+ c
4
·T
4
S = a
0
+ a
1
·R
T
1/2 + a
2
·R
T
+ a
3
·R
T
3/2 + a
4
·R
T
2 + a
5
·R
T
5/2 +
( T - 15)
·
[ b
0
+ b
1
·R
T
1/2
+ b
2
·R
T
+ b
3
·R
T
3/2
+ b
4
·R
T
2
+ b
5
·R
T
5/2
]
1 + k ( T -15)
R =
C
(S,T,P)
= ( R
P
·R
T
·r
T
)
C
(35,15,10)
K
15
=
C ( S ,15,0)
C ( KCl ,15,0)
C
(35,15)·
r
T
R
15
=
C
T
(sample)
R
T
=
R
R
P
·r
T
R
P
= 1+
P · (A
1
+ A
2
·P + A
3
·P
2
)
1+ B
1
·T + B
2
·T 2 + B
3
·R + B
4
·R·T
;
where
R
15
is the conductivity ratio, and Salinity is defined by the following equation.
NATURAL SEA WATER SCALE (UNESCO 1966)
The Natural Sea Water Scale extends from 0 - 80.0 ppt. It determines salinity based upon a conductivity
ratio of sample to “standard seawater” at 15 °C.
Three methods for calculating seawater salinity are supported ( Natural Sea Water Scale, Practical Salinity
Scale and Percent Scale).
PERCENT SCALE (1902)
This salinity scale extends from 0 to 400%. The formula followed is:
S
%
= 1.805 Cl + 0.03
where salinity is defined as the total amount of solid materials in grams dissolved in one kilogram of
seawater. 100% Salinity has ~10% solids and is considered normal seawater.
SALINITY MEASUREMENT
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