Method for Measuring the Volume-Scattering Function of Water
Goddard Space Flight Center, Greenbelt, Maryland
The volume scattering function (VSF)
of seawater affects visibility, remote sensing
properties, in-water light propagation,
lidar performance, and the like.
Currently, it’s possible to measure only
small forward angles of VSF, or to use
cumbersome, large, and non-auton -
omous systems. This innovation is a
method of measuring the full range of
VSF using a portable instrument. A single rapid-sensing photosensor is
used to scan a green laser beam, which
delivers the desired measurement. By
using a single sensor, inter-calibration is
avoided. A compact design is achieved
by using drift-free detector electronics,
fiber optics, and a new type of photomultiplier.
This provides a high angular
resolution of 1° or better, as well as the
ability to focus in on a VSF region of particular
Currently, the total scattering of light
is measured as a difference from the
other two parts of the light budget equation.
This innovation will allow the
direct calculation of the total scattering
of light by taking an integral of the VSF
over all angles. This directly provides
one of the three components of the light
budget equation, allowing greater versatility
in its calculation.
This work was done by Yogesh C. Agrawal
of Sequoia Scientific, Inc. for Goddard Space
Flight Center. For further information, contact
the Goddard Innovative Partnerships
Office at (301) 286-5810. GSC-15395-1
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