Publications

Shang, S; Lee, Z; Lin, G; Li, YH; Li, X (2019). Progressive scheme for blending empirical ocean color retrievals of absorption coefficient and chlorophyll concentration from open oceans to highly turbid waters. APPLIED OPTICS, 58(13), 3359-3369.

Abstract
To achieve a smooth transition between algorithms for "clear" water and "turbid" water, we propose a single formula to calculate the input parameter (ip) used for empirical retrieval of absorption coefficients (a) or chlorophyll concentration ([Chl]) from remote-sensing reflectance (R-rs). This formula for ip takes the ratio of the maximum R-rs in the blue-green bands to the sum of R-rs(green) and the scaled R-rs in the red and infrared bands (termed as ip(Max-Sum)). We found that, compared to the widely used OC4-type formula for ip, ip(Max-Sum) can improve the coefficient of determination from similar to 0.88 to 0.99 for absorption coefficient at 440 nm [a(440)] in similar to 0.01-20.0 m(-1) ([Chl] similar to 0.01-500 mg m(-3)). Especially, the sensitivity of ip(Max-Sum) to the change in a(440) is about five times greater than that of OC4-type for a(440) > similar to 1.0 m(-1) ([Chl] > similar to 10 mg m(-3)). These results indicate an advantage of ip(Max-Sum) for generating robust and seamless a(440) or [Chl] from clear to highly turbid waters. The inclusion of such a scheme in a quasi-analytical algorithm is also presented. (C) 2019 Optical Society of America

DOI:
10.1364/AO.58.003359

ISSN:
1559-128X