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  • 1
    Electronic Resource
    Electronic Resource
    Estimation of water quality parameters from irradiance reflectance using optical models (1985)
    Springer
    Journal of oceanography 41 (1985), S. 399-406 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract In order to evaluate near-surface water quality parameters from spectral irradiance reflectance observed just below the surface, models of both radiative transfer and optical properties of sea water are used. The computed water quality parameters are compared with those determined directly from concurrent surface water samples. In this comparison, efforts have been made to minimize the number of spectral irradiance reflectance used in the computation while ensuring that the computed water quality parameters fit well to the observed ones. The observed water quality parameters were found to be closely represented by those computed from the irradiance reflectance at wavelengths of 400 nm, 440 nm, 510 nm and 600 nm, and the fit is as good as the fit of observed water quality parameters to those computed from the irradiance reflectances at 151 wavelengths located between 400 nm and 700 nm at intervals of 2 nm. This implies that the water quality parameters can be evaluated from at least four radiances observed at high altitude, if the effects of the atmosphere and the sea surface can be correctly removed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02109034
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  • 2
    Electronic Resource
    Electronic Resource
    Bio-Optical Relationship of Case I Waters: The Difference Between the Low- and Mid-Latitude Waters and the Southern Ocean (2000)
    Springer
    Journal of oceanography 56 (2000), S. 605-605 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011165414413
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  • 3
    Electronic Resource
    Electronic Resource
    Contribution of Raman scattering to upward irradiance in the sea (1984)
    Springer
    Journal of oceanography 40 (1984), S. 397-404 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Measurements of underwater irradiance revealed that the vertical attenuance in upward irradiance for wavelengths above 520 nm decreased with increasing depth, while the attenuance in the remaining wavelength region and also the attenuance in the downward irradiance in the whole wavelength range kept almost constant values. In this paper, it is suggested that the decrease in the attenuance for the upward irradiance above 520 nm can be ascribed to the Raman scattering of water molecules excited by the intense blue-green light in the downward irradiance. The pure water Raman scattering function at a scattering angle of 90° is measured and the results are used for the theoretical computation of upward irradiance generated by Raman scattering. Then, the difference between observed upward irradiance and the upward irradiance obtained by extrapolation from that in the shallow layers is computed under the assumption of constant irradiance attenuance. Since this difference is expected to represent the upward irradiance generated by Raman scattering, its value is compared with the upward irradiance due to Raman scattering obtained by theoretical computation. The similarity between the two upward irradiances so evaluated supports the view that Raman scattering makes a significant contribution to upward irradiance in the longer wavelength region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02303065
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  • 4
    Electronic Resource
    Electronic Resource
    A preliminary study of micro-spatial heterogeneity in the light spectral environment of seeds and seedlings in a grassland (1989)
    Springer
    Ecological research 4 (1989), S. 399-404 
    Details
    ISSN: 1440-1703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02348458
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  • 5
    Electronic Resource
    Electronic Resource
    Estimation of chlorophyll concentration from the specific fluorescence at 685nm in the upward irradiance just below the sea surface (1986)
    Springer
    Journal of oceanography 42 (1986), S. 99-105 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract An algorithm for estimating the chlorophyll concentration from the fluorescence intensity at 685nm in upward irradiance observed just below the sea surface is presented and discussed. The observed chlorophyll concentration is closely related to the ratio of the fluoresced quanta to the total incident quanta (downward plus upward quanta) in the spectral range between 350nm and 600nm. The correlation between them, however, is not good and the rate of increase of the ratio decreases as the chlorophyll concentration increases. This is due to the fact that the number of fluoresced quanta varies with attenuation of the incident light by various materials in the sea. A better correlation is obtained between the ratio of the fluoresced quanta to the upward quanta at wavelengths around 480nm. This is explained by the fact that dividing by the upward quanta at the appropriate wavelength compensates for apparent variation of fluorescence intensity with attenuation by the sea water. In this method, upward quanta at the four wavelengths of 480nm, 640nm, 685nm and 740nm are necessary for estimation of chlorophyll concentration. The quanta at 640nm and 740nm are used for interpolating the quanta at 685nm in the absence of fluorescence. It is also shown that the correlation of the observed chlorophyll concentration with the ratio of upward quanta at the wavelengths of 685nm and 480nm is also good. Use of this ratio is recommended for remote sensing of chlorophyll concentration since the number of spectral channels required by the remote multispectral imager can be minimized.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02109096
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  • 6
    Electronic Resource
    Electronic Resource
    Analysis of ocean color spectra (I) (1982)
    Springer
    Journal of oceanography 38 (1982), S. 208-214 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract By using the two-flow optical model, the variation in the irradiance reflectance of the ocean just below the surface has been calculated for varying water optical properties, for the interpretation of remotely-sensed ocean color data. The input variables used in our model are the concentration of phytoplankton (chlorophyll-a), the absorption coeffiicient of yellow substance, the particle scattering coefficient, the ratio of the back-scattering coefficient to the total scattering coefficient of particles, and the ratio of the absorption to scattering coefficients for particles. The irradiance reflectance increases monotonically with the ratio of the back-scattering coefficient to the total scattering coefficient. Spectral changes occur in the irradiance reflectance for increases in chlorophyll-a concentration and yellow substance as well as the ratio of the absorption to scattering coefficients. Because slightly different mathematical expressions have been derived by other investigators using the two-flow model, an evaluation of the resulting calculation differences is presented and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02111103
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  • 7
    Electronic Resource
    Electronic Resource
    Analysis of ocean color spectra (II) (1982)
    Springer
    Journal of oceanography 38 (1982), S. 300-306 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract A method for evaluating the radiance due to sky light reflected by the sea surface and radiance emerging from the sea is described. The calculation is made as a function of the sun altitude, sky condition and sea state for varying optical properties of sea water. As a result of the contribution of reflected sky light, the shape of the spectral distribution for radiance just below the surface is considerably distorted above the surface, especially when chlorophyll concentrations are high. Special attention is paid to the ratio of radiance emerging from the sea to total upwelling radiance at the wavelength of 670 nrn. The variation in the ratio with wind-speed is small and the ratio decreases with increase in the atomospheric turbidity factor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02114534
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  • 8
    Electronic Resource
    Electronic Resource
    Analysis of ocean color spectra (III) (1983)
    Springer
    Journal of oceanography 38 (1983), S. 362-372 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The spectral measurements of the attenuation coefficient of sea water and the absorption coefficient of suspended particles and of yellow substance were made with a spectrophotometer for the sea waters sampled in Tokyo Bay. These parameters can be used to compute the expected spectral irradiance reflectance. Some relationships between the optical properties of sea water and the concentration of dissolved organic carbon, the dry weight of suspended matter and chlorophyll-a concentration are presented. On the basis of these results, the possibility of modelling the relationship between optical and material properties is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02111033
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  • 9
    Electronic Resource
    Electronic Resource
    Temporal and Spatial Variability of Phytoplankton Pigment Concentrations in the Japan Sea Derived from CZCS Images (2000)
    Springer
    Journal of oceanography 56 (2000), S. 527-538 
    Details
    ISSN: 1573-868X
    Keywords: Japan Sea ; pigment concentration ; critical depth ; mixed layer depth ; seasonal variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Temporal and spatial variability of phytoplankton pigment concentrations in the Japan Sea are described, using monthly mean composite images of the Coastal Zone Color Scanner (CZCS). In order to describe the seasonal changes of pigment concentration from the results of the empirical orthogonal function (EOF) analysis, we selected four areas in the south Japan Sea. The pigment concentrations in these areas show remarkable seasonal variations. Two annual blooms appear in spring and fall. The spring bloom starts in the Japan Sea in February and March, when critical depth (CRD) becomes equal to mixed layer depth (MLD). The spring bloom in the southern areas (April) occurs one month in advance of that in the northern areas (May). This indicates that the pigment concentrations in the southern areas may increase rapidly in comparison with the northern areas since the water temperature increases faster in spring in the southern than in the northern areas. The fall bloom appears first in the southwest region, then in the southeast and northeast regions, finally appearing in the northwest region. Fall bloom appears in November and December when MLD becomes equal to CRD. The fall bloom can be explained by deepening of MLD in the Japan Sea. The pigment concentrations in winter are higher than those in summer. The low pigment concentrations dominate in summer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011148910779
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  • 10
    Electronic Resource
    Electronic Resource
    Correlation of chlorophyll concentrations and suspended solids with near-surface upward irradiance within LANDSAT bands 4, 5 and 6 (1985)
    Springer
    Journal of oceanography 41 (1985), S. 81-88 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Near-surface upward irradiances within each band of the MSS (multi spectral scanner) of LANDSAT, were computed from observed spectral upward irradiances measured just beneath the sea surface. Computation of these irradiances is a useful first step in the analysis of remotely-sensed radiance because the data are not affected by the effects of the atmosphere and sea surface. The computed irradianceE in LANDSAT bands 4, 5 and 6 was normalized by forming ratios,i.e., R 45=E4/E5, R46=E4/E6, andR 56=E5/E6, and then the relationship between these ratios and chlorophylla plus phaeopigment concentration (C) observed simultaneously at 59 stations was examined by linear regression analysis. The observedC ranged over nearly three orders of magnitude, and there is a close to linear relationship between log10-R 45 and log10 C. This suggests that it may be possible to evaluateC from LANDSAT data, if an appropriate atmospheric correction is made. The relationship between suspended solids determined at 35 stations and the same ratios of upward irradiance is also presented and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02109177
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