The papers presented in the marine session may be broadly grouped into several classes: microwave region instruments compared to infrared and visible region sensors, satellite techniques compared to aircraft techniques, open ocean applications compared to coastal region applications, and basic research and understanding of ocean phenomena compared to research techniques that offer immediate applications

Sherman, J. W., III

English

NASA Technical Reports Server

N 7 6 - 1 7 6 2 0
VII. Marine Resources
John W. Sherman, IIf
The papers presented in the marine session may be
broadly grouped into several classes: microwave region
instruments compared to infrared and visible region
sensors; satellite techniques compared to aircraft
techniques; open ocean applications compared to coastal
region appl ica t ions ; and basic research and
understanding of ocean phenomena compared to
research techniques that offer immediate applications.
The fact that no papers were based on operational
applications to the marine environment was not
surprising since the instrumentation was designed for
ter res t r ia l applications and/or marine research.
Nevertheless, the ensemble of papers has clear and direct
impact on the Nimbus-G and Seasat-A research
platforms planned by NASA for observational capability
in 1978.
In this summary, overall implications of the marine
session papers will be presented. First, the,,jLandsat series
of satellites has a greater role in coastal'.applications
beyond that of serving as a surveillance tool and for
general circulation observations (M-5, vol. I-C). The need
for establishing a standard technique for measuring the
linear distance of coastlines was illustrated (M-13, vol.
I-C). Variations of two to one were found in the
measured value depending on the agency making the
measurement; automatic techniques using Landsat offer
a systematic means of making this measurement on a
time scale sufficient to show changes in the linear
definition of the coastline.
Continuing with Landsat applications, a comparison
of the information derived from the Skylab SI90 and
S192 experiments suggests that water penetration in
tropical waters to depths of approximately 20 meters
can be achieved (M-10, vol. I-C). This finding suggests
that an operational Landsat system could have improved
application to shallow water areas by including more of
the blue-green portion of the visible spectrum. Further,
it was illustrated (M-9, vol. I-C) that a rapid turnaround
time of Landsat data, using onsite analysis of
high-data-rate Landsat images at the NASA Goddard
Space Flight Center coupled with low-data-rate facsimile
transmissions by way of Applications Technology
Satellite 3, can support oceanic applications in field
survey data collection using in situ techniques. The
implications of this possibility are important from needs
expressed (M-8, vol. I-C) in relation to game fish and the
work of the National Marine Fisheries Service in
establishing relationships between water clarity and the
locations of specific schools of fish. Near-real-time
information potentially could support fishing vessel
operations keyed to the 18-day Landsat repeat cycle or
could extend the applications of the Nimbus-G coastal
zone color scanner (CZCS) to immediate field utility and
to circulation activities (M-5, vol. I-C).
The CZCS system was described (M-6, vol. I-C) in
conjunction with performance of measurements using a
breadboard scanner flown on an NASA U-2. Numerous
implications are found concerning the measurement of
ocean color. Also, such sensitive parameters as
atmospheric and Sun-angle effects, which have been
previously described as theoretical, are now being
measured empirically and will soon be measured
quantitatively. The use of the blue region has been
demonstrated together with requirements for reducing
atmospheric effects. This CZCS system will provide data
on a more routine basis and will extend some suggested
applications (M-7 and M-l 1, vol. I-C).
The oceanic use of active and passive microwave
sensors from space was demonstrated in the Skylab SI93
experiment. The altimeter portion and results from
Experiment S193 were described (M-l, vol. I-C). This
altimeter has been fundamental in the development of
the third Geodynamics Experimental Ocean Satellite,
launched in April 1975, and will be used for both
instrument and experiment design for Seasat-A. This
SI93 experiment was one of the most successful Skylab
oceanic experiments with the measurement of many
large geoidal features to a resolution of ±1 meter.
National Oceanic and Atmospheric Administration/National
Environmental Satellite Service, Washington, D.C.
39
https://ntrs.nasa.gov/search.jsp?R=19760010532 2020-03-22T16:13:47+00:00Z
Two prinje oce$nog«aphic variables for which reliable
data are needed 'to improve safety at sea (surface
roughness and wind) were discussed in papers M-2 and
M-3 (vol. I-C). Both papers have direct bearing on the
research and demonstration experiments planned for
Seasat-A. Of particular note in paper M-2 is the possible
parameterization of the wind field in terms of the wave
spectrum by means of a nondimensional determination
of the total energy. This approach may significantly
reduce the computer time required by forecasting
models. The usefulness of 1.4-gigahertz radiometers for
measuring surface salinity in brackish water having
salinity greater than 5 to 10%o was demonstrated
(M-12, vol. I-C). Spatial resolution limitations prevent
development of this technique for satellite applications
in the near future, but it could be implemented on an
operational basis from aircraft.
The importance of monitoring the interface between
the land and the sea was exemplified (M-14, vol. I-C).
The marshland, vital to many forms of marine life, is
being subjected increasingly to pressure from population
expansion. The ability to monitor and observe changes
in vegetation and vegetation health becomes increasingly
important. Multispectral techniques for monitoring
salinity-level effects on vegetation using aircraft scanners
were described in this paper. Although the areas involved
in some regions are large, relatively narrow bands of
salinity-dependent vegetation may exist. Therefore,
existing satellite resolutions may not be sufficient to
classify all marshlands. It appears this technique could
also be implemented on an operational basis from
airborne p la t forms. It is noted that the
1.4-gigahertz-radiometer salinity measurement forms an
excellent complementary tool for tracking brackish
water characteristics near and within wetland areas free
of immediate vegetation.
In summary, the papers included in the marine
session were both timely and appropriate. Ten papers
dealt primarily with coastal activity, an area that will
receive increasing attention during the next decade as a
result of both national and international needs. National
needs are most strongly identified through the Outer
Continental Shelf program involving the development of
offshore facilities and international needs through the
attention being given to extending jurisdictions from 12
to 200 nautical miles offshore. Studies of the global
aspects of the ocean, reported in four papers, will lead to
improved environmental forecasts both in the coastal
states and in the open ocean. Safety at sea will become
increasingly important as larger cargo and tanker vessels
operate on the high seas and in the coastal region.
Remote-sensing technology appears to be keeping pace
with national and international needs; the problem is to
translate and integrate the demonstrated technology into
operational capability.
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Marine Resources

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