An Instrument for In Situ Measuring the Volume Scattering Function of Water: Design, Calibration and Primary Experiments

The optical volume scattering function (VSF) of seawater is a fundamental property used in the calculation of radiative transfer for applications in the study of the upper-ocean heat balance, the photosynthetic productivity of the ocean, and the chemical transformation of photoreactive compounds. A new instrument to simultaneously measure the VSF in seven directions between 20° to 160°, the attenuation coefficient, and the depth of water is presented. The instrument is self-contained and can be automatically controlled by the depth under water. The self-contained data can be easily downloaded by an ultra-short-wave communication system. A calibration test was performed in the laboratory based on precise estimation of the scattering volume and optical radiometric calibration of the detectors. The measurement error of the VSF measurement instrument has been estimated in the laboratory based on the Mie theory, and the average error is less than 12%. The instrument was used to measure and analyze the variation characteristics of the VSF with angle, depth and water quality in Daya Bay for the first time. From these in situ data, we have found that the phase functions proposed by Fournier-Forand, measured by Petzold in San Diego Harbor and Sokolov in Black Sea do not fit with our measurements in Daya. These discrepancies could manly due to high proportion of suspended calcium carbonate mineral-like particles with high refractive index in Daya Bay.

[1]  Gene C. Feldman,et al.  Influence of penetrating solar radiation on the heat budget of the equatorial Pacific Ocean , 1990, Nature.

[2]  R. Arnone,et al.  Deriving inherent optical properties from water color: a multiband quasi-analytical algorithm for optically deep waters. , 2002, Applied optics.

[3]  R A Maffione,et al.  Measurement of the spectral absorption coefficient in the ocean with an isotropic source. , 1993, Applied optics.

[4]  V. Vantrepotte,et al.  Effect of inherent optical properties variability on the chlorophyll retrieval from ocean color remote sensing: an in situ approach. , 2010, Optics express.

[5]  John E. Tyler,et al.  SCATTERING PROPERTIES OF DISTILLED AND NATURAL WATERS1 , 1961 .

[6]  Hideki Kobayashi,et al.  RAMI4PILPS: An intercomparison of formulations for the partitioning of solar radiation in land surface models , 2011 .

[7]  R. Maffione,et al.  Instruments and methods for measuring the backward-scattering coefficient of ocean waters. , 1997, Applied optics.

[8]  R. Gould,et al.  Comparisons of optical properties of the coastal ocean derived from satellite ocean color and in situ measurements. , 2006, Optics express.

[9]  Norman J. McCormick,et al.  Inherent optical property estimation in deep waters. , 2011, Optics express.

[10]  N. K. Højerslev,et al.  A spectral light absorption meter for measurements in the sea , 1975 .

[11]  David Doubilet.  Light in the Sea , 2022, World Literature Today.

[12]  R. W. Austin,et al.  The Index of Refraction of Seawater , 1976 .

[13]  Michael S. Twardowski,et al.  Resolving size distributions of bubbles with radii less than 30 μm with optical and acoustical methods , 2011 .

[14]  Alberto Tonizzo,et al.  Measurements and simulations of polarization states of underwater light in clear oceanic waters. , 2011, Applied optics.

[15]  Collin S. Roesler,et al.  ARE THE INHERENT OPTICAL PROPERTIES OF PHYTOPLANKTON RESPONSIBLE FOR THE DISTINCT OCEAN COLORS OBSERVED DURING HARMFUL ALGAL BLOOMS ? , 2022 .

[16]  C. Mobley,et al.  Phase function effects on oceanic light fields. , 2002, Applied optics.

[17]  A. Morel.  Optical properties of pure water and pure sea water , 1974 .

[18]  M. Lewis,et al.  A New Method for the Measurement of the Optical Volume Scattering Function in the Upper Ocean , 2003 .

[19]  Malik Chami,et al.  Variability of the relationship between the particulate backscattering coefficient and the volume scattering function measured at fixed angles , 2006 .

[20]  Michael J. Behrenfeld,et al.  Significant contribution of large particles to optical backscattering in the open ocean , 2009 .

[21]  P. Barber.  Absorption and scattering of light by small particles , 1984 .

[22]  Mati Kahru,et al.  Ocean Optics Protocols for Satellite Ocean Color Sensor Validation, Revision 4, Volume IV: Inherent Optical Properties: Instruments, Characterizations, Field Measurements and Data Analysis Protocols , 2013 .

[23]  E. Boss,et al.  Calibrated near-forward volume scattering function obtained from the LISST particle sizer. , 2006, Optics express.

[24]  K. Baker,et al.  Oceanic chlorophyll concentrations as determined by satellite (Nimbus-7 Coastal Zone Color Scanner) , 1982 .

[25]  G. Kullenberg,et al.  Observations of light scattering functions in two oceanic areas , 1984 .

[26]  M Chami,et al.  Parameterization of volume scattering function of coastal waters based on the statistical approach. , 2010, Optics express.

[27]  J. Luc Forand,et al.  Analytic phase function for ocean water , 1994, Other Conferences.

[28]  M Jonasz.  Volume scattering function measurement error: effect of angular resolution of the nephelometer. , 1990, Applied optics.

[29]  Giuseppe Zibordi,et al.  Measurements and modeling of the volume scattering function in the coastal northern Adriatic Sea. , 2007, Applied optics.

[30]  S. Sathyendranath,et al.  Effect of pigment composition on absorption properties of phytoplankton , 1991 .

[31]  Xiaodong Zhang,et al.  The volume scattering function of natural bubble populations , 2002 .

[32]  Michael S Twardowski,et al.  Angular shape of the oceanic particulate volume scattering function in the backward direction. , 2009, Applied optics.

[33]  Gunnar Kullenberg,et al.  Scattering of light by Sargasso Sea water , 1968 .

[34]  Fred Moshary,et al.  Polarized light in coastal waters: hyperspectral and multiangular analysis. , 2009, Optics express.