Abstract: A recent methodology is used for the reconstruction of vertical profiles of the absorption and scattering coefficients in natural waters. It is possible to estimate these coefficients from in situ radiance measurementes in several depths. In order to use only the water leaving upwelling radiance at the surface, extra information must be provided by means of the bio-optical models that correlate the chlorofill concentration to the absorption and scattering coefficients, and from multi-spectral radiances. A candidate vertical profile for this concentration is used to calculate the absorption and scattering vertical profiles, and thus the single scattering albedo profile for each wavelength. The radiative transfer equation is solved using the Laplace transform discrete ordinate (LTSn) method, and the calculated upwelling radiances for each wavelength are compared to the experimental data through a convenient norm. As hundreds of iterations may be demanded, a parallel implementation of the LTSn technique is proposed in a distributed memory machine, for reducing the processing time [1, 2].

[1] R.P. Souto, H.F. de Campos Velho, S. Stephany, A.J. Preto, C. F. Segatto, M.T. Vilhena (2003): "A Parallel Implementation of the LTSN Method for a Radiative Transfer Problem", The 15th Symposium on Computer Architecture and High Performance Computing (SBAC-PAD 2003), 10-12 November, São Paulo (SP), Brazil, pages 116-122, (proc. Edited by Liria M. Sato, Phillipe O. A. Navaux, Edson T. Midorikawa), published by IEEE Computer Society, 2003 - ISBN 0-7695-2046-4.

[2] R.P. Souto, H.F. de Campos Velho, S. Stephany, E.S. Chaulhoub (2003): "Performance Analysis of Radiative Transfer Algorithms in a Parallel Environment", International Conference on Transport Theory (18-ICTT), 20-25 July, Rio de Janeiro, Brazil, pp. 69-75.