Chapter 1: INTRODUCTION
wavelengths, eventually becoming negligible at wavelengths greater than
0.7-0.8 Pm.
Investigation of the progressive attenuation of daylight with depth must
simultaneously take into account the inherent properties of the water
(absorbing and scattering) and the angular and the spectral distributions of
light incident on the sea surface. Numerous experimental and theoretical
studies have been carried out with these aims especially in relation to the
remote sensing of the ocean color (see Section 7.1.6). Here, we will limit the
following discussion to an analysis of the solar energy absorption as a
function of depth, for this is the term entering the equation for heat
conservation.
Absorbed part of total solar radiation, %
Depth, m
Bethoux (1968)
Pruvost (1972)
0.01
17
13
0.1
35
31
0.2
41
41
0.5
~50
-
1
-
56.5-65
The attenuation of solar radiation with depth appears to follow a more or
less exponential form depending on the wavelength or spectral band.
Absorption of solar radiation in the top meter of the ocean (integrated over
wavelength), according to measurements of Bethoux (1968) and calculations
of Pruvost (1972), is given in Table 1-1. This data indicates that solar
radiation is absorbed very unevenly in the upper ocean.
The absorption and scattering of light for wavelengths exceeding 0.7-0.8
Pm mainly determine the transmission of solar radiation within the upper
meter of the ocean. Chlorophyll, organic substances, or suspended matter do
not affect the inherent optical properties of the oceanic water for these
wavelengths. According to the radiative transfer model of Ohlmann et al
(2000a) a tenfold increase in chlorophyll concentration results in less than
1% change in solar transmission for the upper ten centimeters of the ocean
(Figure 1-9).
For depths greater than 1 m, with a greater portion of the irradiance in
the visible spectral region (i.e., for less than 0.7-0.8 Pm wavelength), the
dependence of solar irradiance on the inherent optical properties of the water
classification of oceanic surface waters by distinguishing three major water
types: I, II, and III and later adding two intermediate types: IA and IB and
Table 1-1. Absorption of solar radiation in the top 1 m below the water surface.
31
is more evident. Respectively, Jerlov (1976) proposed an optical
wavelengths, eventually becoming negligible at wavelengths greater than
0.7-0.8 Pm.
Investigation of the progressive attenuation of daylight with depth must
simultaneously take into account the inherent properties of the water
(absorbing and scattering) and the angular and the spectral distributions of
light incident on the sea surface. Numerous experimental and theoretical
studies have been carried out with these aims especially in relation to the
remote sensing of the ocean color (see Section 7.1.6). Here, we will limit the
following discussion to an analysis of the solar energy absorption as a
function of depth, for this is the term entering the equation for heat
conservation.
Absorbed part of total solar radiation, %
Depth, m
Bethoux (1968)
Pruvost (1972)
0.01
17
13
0.1
35
31
0.2
41
41
0.5
~50
-
1
-
56.5-65
The attenuation of solar radiation with depth appears to follow a more or
less exponential form depending on the wavelength or spectral band.
Absorption of solar radiation in the top meter of the ocean (integrated over
wavelength), according to measurements of Bethoux (1968) and calculations
of Pruvost (1972), is given in Table 1-1. This data indicates that solar
radiation is absorbed very unevenly in the upper ocean.
The absorption and scattering of light for wavelengths exceeding 0.7-0.8
Pm mainly determine the transmission of solar radiation within the upper
meter of the ocean. Chlorophyll, organic substances, or suspended matter do
not affect the inherent optical properties of the oceanic water for these
wavelengths. According to the radiative transfer model of Ohlmann et al
(2000a) a tenfold increase in chlorophyll concentration results in less than
1% change in solar transmission for the upper ten centimeters of the ocean
(Figure 1-9).
For depths greater than 1 m, with a greater portion of the irradiance in
the visible spectral region (i.e., for less than 0.7-0.8 Pm wavelength), the
dependence of solar irradiance on the inherent optical properties of the water
classification of oceanic surface waters by distinguishing three major water
types: I, II, and III and later adding two intermediate types: IA and IB and
Table 1-1. Absorption of solar radiation in the top 1 m below the water surface.
31
is more evident. Respectively, Jerlov (1976) proposed an optical