Establishing the remote sensing algorithm of retrieving the absorption coefficient of seawater petroleum substances is an efficient way to improve the accuracy of retrieving a seawater petroleum concentration using a remote sensing technology. A remote sensing reflectance is a basic physical parameter in water color remote sensing. Apply it to directly retrieve the absorption coefficient of seawater petroleum substances is of potential advantage. The absorption coefficient of waters containing petroleum [ACWCP,ao (λ)], consists of the absorption coefficient of pure water [ACPW,aw(λ)], plankton [ACP,aph(λ)], colored scraps [ACCS,ad, g(λ)], and petroleum substance [ACPS,aoil(λ)]. Among those, ACCS consists of the absorption coefficient of nonalgal particle [ACNP,ad (λ)] and colored dissolved organic matter [ACCDOM,ag(λ)]. For waters containing petroleum, the retrieved ACCS using the existing method is a combination absorption coefficient of ACNP, ACCDOM and ACPA [CAC,ad,g,oil (λ)]. Therefore, the principle question is how to extract ACPS from CAC. Through the analysis of the three proportion tests conducted between the year of 2013 and 2015 and the corresponding remote sensing data, an algorithm of retrieving the absorption coefficient of petroleum substances is proposed based on remote sensing reflectance. First of all, ACPS and CAC are retrieved from the reflectance using the quasi-analytical algorithm (QAA), with some parameter modified. Secondly, given the fact that the backscatter coefficient [BC,bbp(555)] of total particles at 555 nm can be obtained completely from the reflectance, the relation between BC and ACNP in petroleum contaminated water can be established. As a result, ACNP can be calculated. Then, combining the remote sensing retrieving algorithm ofag(440), the method of achieving the spectral slope of the absorption coefficient can be established, from which ACCDOM, can be calculated. Finally, ACPS can be computed as the residual. The accuracy of ACPS based on this algorithm is 86% compared with thein situ measurements.
Miaofen HUANG, Xufeng XING, Qingjun SONG, Yang LIU, Wentong DONG. A new algorithm of retrieving a petroleum substances absorption coefficient in sea water based on a remote sensing image[J]. ACTA OCEANOLOGICA SINICA, 2016, 35(11): 97-104. doi: 10.1007/s13131-016-0952-4.