Open AccessA model for the diffuse attenuation coefficient of downwelling irradiance
Author(s) -
Lee ZhongPing,
Du KePing,
Ar Robert
Publication year - 2005
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2004jc002275
Subject(s) - downwelling , radiative transfer , irradiance , attenuation , remote sensing , attenuation coefficient , environmental science , function (biology) , computational physics , meteorology , physics , geology , optics , oceanography , evolutionary biology , upwelling , biology
The diffuse attenuation coefficient for downwelling irradiance ( K d ) is an important parameter for ocean studies. For the vast ocean the only feasible means to get fine‐scale measurements of K d is by ocean color remote sensing. At present, values of K d from remote sensing are estimated using empirical algorithms. Such an approach is insufficient to provide an understanding regarding the variation of K d and contains large uncertainties in the derived values. In this study a semianalytical model for K d is developed based on the radiative transfer equation, with values of the model parameters derived from Hydrolight simulations using the averaged particle phase function. The model is further tested with data simulated using significantly different particle phase functions, and the modeled K d are found matching Hydrolight K d very well (∼2% average error and ∼12% maximum error). Such a model provides an improved interpretation about the variation of K d and a basis to more accurately determine K d (especially using data from remote sensing).