Relationship between backscattering and beam scattering coefficients

1. Relationship between backscattering and beam scattering coefficients derived from new measurements of light scattering phase functions Vladimir I. Haltrin, Michael E. Lee, Eugeny B. Shybanov, Robert A. Arnone, Alan D. Weidemann, Victor I. Mankovsky,W. Scott Pegau, andSherwin D. Ladner • Naval Research Laboratory, Ocean Optics Section, Code 7333, Stennis Space Center, MS 39529-5004, USA, • e-mail:haltrin@nrlssc.navy.mil, webpage: http://calcium.nrlssc.navy.mil • Marine Hydrophysical Institute of the Ukrainian Academy of Sciences, • 2 Kapitanskaya Street, Sevastopol, Crimea, 99011, Ukraine, e-mail: lee@alpha.mhi.iuf.net • Oregon State University, 104 Ocean Admin Bldg, Corvallis, OR 97331, USA, e-mail: spegau@coas.oregonstate.edu • Planning Systems Inc., MSAAP Bldg. 9121, Stennis Space Center, MS 39529, USA, e-mail:ladner@nrlssc.navy.mil Ocean Optics XVI November 18-22, 2002, Santa Fe, New Mexico, USA Who measured phase functions in the last 40 years? Introduction 1. T. J. Petzold, Scripps Institute of Oceanography, California, USA: 15 phase functions published. 2. O. V. Kopelevich, Shirshov Insitute of Oceanology, Moscow, USSR: no tables published. “Universal” relationship between bB and b: Processing of optical remote sensing information requires a knowledge of dependence between backscattering and beam scattering coefficients. Until recently this dependency was primarily derived from 15 angular scattering coefficients measured more than 30 years ago by Petzold. A few years ago a new probe to measure an angular scattering coefficient of natural waters was developed and built in Marine Hydrophysical Institute in Sevastopol, Crimea. Since 2000 his device was employed in several LEO-15 expeditions near the coast of New Jersey, and in May 2002 expedition in northern Gulf of Mexico. The results of these measurements show that coastal waters could be divided into two distinct types: one - similar to the waters of Petzold experiment near the California coast, and another one - biologically more pure type that was experimentally detected during LEO-15 experiment in 2001. This presentation analyzes more than 800 high-resolution angular scattering coefficients measured during the 2001 experiment. The main difference between Petzold-type coastal waters and biologically pure waters is characterized by the dependence between backscattering and beam scattering coefficients. The backscattering probability, or ratio of these coefficients, for the biologically pure coastal waters is several times smaller than the backscattering probability for the Petzold-type waters. This result is very important for algorithms to process optical information measured from satellites and aircrafts. This presentation proposes and several regressions between major inherent optical properties that may be useful for the enhancement of remote sensing algorithms and for modeling of optical properties of coastal seawater. 3. V. I. Mankovsky, Marine Hydrophysical Institute, USSR, now Ukraine: (2 tables with 41 phase functions measured all over the World Ocean were published in 2000). 4. Michael Lee, Marine Hydrophysical Institute, Sevastopol, Ukraine: during 200-2002 about 1000 high-resolution phase functions were measured in waters near the New Jersey coast and in Gulf of Mexico. These measurements were funded by ONR and NRL. This is a view of Marine Hydrophysical Institute, Sevastopol, Crimea. It was founded in 1930-ies in Moscow by academician Shuleikin and moved in 1962 to Sevastopol, Crimea. The bulk of known phase functions were mesured with devices built in the optics department of this Institute (V. I. Mankovsky, M. E. Lee). The legacy of this optics department goes back to the optics laboratory of the State Optical Institute, St. Petersburg (Leningrad) Russia, that was founded in early 30-ies of 19th century by A. A. Gershun. Based on ~ 1000 measurements of light scattering phase functions r2 ~ 0.7 These results are not included on CD-ROM What are attenuation and scattering coefficients, and phase function of scattering? - They are ‘inputs’ to the following radiation of transfer equation: c - attenuation coefficient b - scattering coefficient p- phase function of scattering Acknowledgments What areprobability of backscattering and backscattering coefficient? The authors from the Naval Research Laboratory (NRL) thank continuing support at the NRL, Stennis Space Center, through the Volume Scattering Functions Program 736641-02-5. This work represents a NRL contribution PP/7330—02-0058 Where backscattering probability and backscatteringcoefficients appear? Regressions between bB and b: • In approximate solutions of radiative transfer equation for • irradiances, pulse propagation, visibility. For example: Based on Petzold and Mankovsky (56 Phase functions): bB - backscattering coefficient B =bB / b - backscattering probability Diffuse Reflection Coefficient: Based on Petzold , Mankovsky, and LEO15 (2000) (116 Phase functions): Based on LEO15 (2001) (>800 phase functions) BS waters: Remote Sensing Reflectance: