Light and Temperature
25
surface irradiance (0 m = 100%) versus depth using (a) a linear scale and (b) a logarithmic
scale.
13. With your data, calculate using the formulas given on p. 18 the extinction coefficients oflight
at each meter interval and determine the mean extinction coefficient (all depth intervals
below 1 m) for total light and observed light absorption with blue, green, and red filters.
OPTION 2. LABORATORY ANALYSES
1. Using the water samples provided by your laboratory instructor, perform the spectrophotometric analyses on unfiltered and filtered water as outlined in Option 1, section 8.
Compare graphically the data of absorption versus wavelength.
2. Using the data provided (Table 2.2), calculate using the formulas given on p. 18 the extinction
coefficients and determine the mean extinction coefficient (all depth intervals below 1 m) for
total light and that for light absorption with blue, green, and red filters.
3. Graph the vertical profiles (Table 2.2) of spectral attenuation as a percentage of surface
irradiance (Om = 100%) versus depth using (a) a linear scale and (b) a logarithmic scale.
4. Graph the vertical profiles of temperature versus depth (Table 2.3).
5. Using the data provided (Table 2.3) and procedures discussed below, plot isopleths of uniform
parameter values in depth-time diagrams of:
(a) Temperature (isotherms) seasonally.
(b) Underwater incident light (isophots).
(c) Underwater reflected scattered light.
Table 2.2. Percentage transmission of light underwater, Gull Lake, Kalamazoo-Barry
counties, MI, June 28, 1976.
Depth
Neutral
Blue filter
Green filter
Yellow filter
Red filter
(m)
filter
(460-500mnm)
(5OO-580nm)
(580-590nm)
(640-720nm)
0
100%
100%
100%
100%
100%
0.1
94.05
87.32
94.74
88.42
87.50
73.81
63.38
70.53
50.00
60.00
2
50.00
53.52
55.79
35.26
35.50
3
33.04
32.25
44.21
19.74
22.50
4
25.00
27.46
35.79
16.58
15.00
5
17.86
22.68
28.42
12.37
8.75
6
13.10
18.73
19.37
7.89
6.15
7
9.82
13.24
14.21
6.58
4.50
8
5.33
7.75
10.16
5.39
3.55
9
4.02
5.92
6.84
3.95
2.50
10
2.83
3.66
4.84
2.32
1.60
11
1.96
1.72
3.47
1.56
0.70
12
1.19
1.11
1.84
1.00
0.44
13
0.52
0.63
1.16
0.66
0.26
14
0.33
0.44
0.74
0.42
0.17
15
0.22
0.24
0.47
0.21
0.12
16
0.15
0.17
0.33
0.14
0.08
17
0.10
0.13
0.21
0.10
0.06
18
om
0.08
0.15
om
0.04
19
0.05
0.02
0.12
0.05
0.03
20
0.04
0.09
0.04
0.01
21
0.03
0.02
0.02
22
0.02
0.01
0.01
23
0.01
25
surface irradiance (0 m = 100%) versus depth using (a) a linear scale and (b) a logarithmic
scale.
13. With your data, calculate using the formulas given on p. 18 the extinction coefficients oflight
at each meter interval and determine the mean extinction coefficient (all depth intervals
below 1 m) for total light and observed light absorption with blue, green, and red filters.
OPTION 2. LABORATORY ANALYSES
1. Using the water samples provided by your laboratory instructor, perform the spectrophotometric analyses on unfiltered and filtered water as outlined in Option 1, section 8.
Compare graphically the data of absorption versus wavelength.
2. Using the data provided (Table 2.2), calculate using the formulas given on p. 18 the extinction
coefficients and determine the mean extinction coefficient (all depth intervals below 1 m) for
total light and that for light absorption with blue, green, and red filters.
3. Graph the vertical profiles (Table 2.2) of spectral attenuation as a percentage of surface
irradiance (Om = 100%) versus depth using (a) a linear scale and (b) a logarithmic scale.
4. Graph the vertical profiles of temperature versus depth (Table 2.3).
5. Using the data provided (Table 2.3) and procedures discussed below, plot isopleths of uniform
parameter values in depth-time diagrams of:
(a) Temperature (isotherms) seasonally.
(b) Underwater incident light (isophots).
(c) Underwater reflected scattered light.
Table 2.2. Percentage transmission of light underwater, Gull Lake, Kalamazoo-Barry
counties, MI, June 28, 1976.
Depth
Neutral
Blue filter
Green filter
Yellow filter
Red filter
(m)
filter
(460-500mnm)
(5OO-580nm)
(580-590nm)
(640-720nm)
0
100%
100%
100%
100%
100%
0.1
94.05
87.32
94.74
88.42
87.50
73.81
63.38
70.53
50.00
60.00
2
50.00
53.52
55.79
35.26
35.50
3
33.04
32.25
44.21
19.74
22.50
4
25.00
27.46
35.79
16.58
15.00
5
17.86
22.68
28.42
12.37
8.75
6
13.10
18.73
19.37
7.89
6.15
7
9.82
13.24
14.21
6.58
4.50
8
5.33
7.75
10.16
5.39
3.55
9
4.02
5.92
6.84
3.95
2.50
10
2.83
3.66
4.84
2.32
1.60
11
1.96
1.72
3.47
1.56
0.70
12
1.19
1.11
1.84
1.00
0.44
13
0.52
0.63
1.16
0.66
0.26
14
0.33
0.44
0.74
0.42
0.17
15
0.22
0.24
0.47
0.21
0.12
16
0.15
0.17
0.33
0.14
0.08
17
0.10
0.13
0.21
0.10
0.06
18
om
0.08
0.15
om
0.04
19
0.05
0.02
0.12
0.05
0.03
20
0.04
0.09
0.04
0.01
21
0.03
0.02
0.02
22
0.02
0.01
0.01
23
0.01