Mission to Planet Earth Space Science in the Twenty-First Century -- Imperatives for the Decades 1995 to 2015 (1988) / Chapter Skim
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5. Elements of the Mission to Planet Earth
5. Elements of the Mission to Planet Earth
Pages 87-105
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From page 87... ...
, automated ground stations, and simple ground stations such as corner reflectors, rain gages, and tide gages. Microchip, computer, and low-power technology can make these sea and land observations extremely powerful in their capabilities, and satellite relay links will make it possible to collect data from a large area of the Earth's surface.
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From page 88... ...
Others such as ocean drifting instruments, pop-up buoys, and smart ground stations are relatively new concepts. Some of these would be called landers, penetrators, unmanned stations, or rovers if they were being developed for other planets.
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From page 89... ...
C Soil moisture M M Soil erosion M M Surface strain A A, D A Seismic wave velocities D S S Tectonic deformation D, L S S NOTE: Instrument categories are as follows: M Multispectral imaging R Radar imaging A Altimetry ranging P Vertical profile remote sensing D Data links T Meteorological instruments O Oceanography instruments S Seismographs- acoustic detectors G Gravimeter-magnetometer C Chemical composition instruments L Locations, precise geodetic data processing capabilities, and then suggest the broad outlines of a Mission to Planet Earth after the turn of the century. The two reports on which this chapter is partially based are Earth Observing System (NASA Goddard Space Flight Center, Tech.
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From page 90... ...
These data should be placed and maintained in forrr~s that optimize their use in combination with the data generated by the missions already specified for project starts in the period 1986 to 1995, and with the EOS information system described below, to be implemented in the m~-1990s. Earth observables can be characterized in two broad categories: quasi-static—properties varying slowly enough that mappings at intervals of several years suffice (e.g., rock types, vegetation regimes, magnetic field)
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From page 91... ...
The report does not address the needs for observations from geosynchronous orbits, specialized orbiters, or nonorbiting devices, all of which are important aspects of a total earth observing system. As this report and many others have emphasized, the global nature of atmospheric, oceanic, and land processes makes it necessary to view Earth as a single interactive system in order to describe, understand, and predict significant trends in its state.
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From page 92... ...
In order to accomplish the Mission to Planet Earth we will need development of new technology to measure some of the more elusive parameters, combine data from the ground network of stations, buoys, and pop-ups with those Corning from satellites, and develop further the data processing, merging, selection, and distribution capabilities. For instance, satellite data collection from autonomous drifting platforms at sea has become routine in the past decade through the French System ARGOS, carried by the TIROS/NOAA A-]
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From page 93... ...
These are examined below. Seismic Measurements An SGS could measure the structure of the Earth's interior, earthquake source mechanisms, strong ground motion in seismic areas, volcanic activities, and tidal forces.
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From page 94... ...
However, mobile GPS receivers will be needed to obtain spatial resolution complementary to the temporal resolution of the fixed instruments. Meteorological and Hydrological Measurements The purpose of obtaining long-term calibrated data in these areas is to understand the coupling of radiative, dynamical, and chemical processes in the atmosphere; to improve the accuracy and extend the range of weather forecasting; to assess the influences of changes in sea surface temperature, ocean surface currents, and sea and land ice cover on climate; and to determine what factors control the hydrological cycle.
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From page 95... ...
Measurement of Soil Properties Smart ground stations wiD help determine the relationship between climate, vegetation, soil moisture, and topography. They will also assist in our understanding of the effects of changes in land surface evaporation, albedo, and roughness on local and global climate.
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From page 96... ...
Generally, the capacity of the processor should be similar to that of an SGS, except that if power consumption considerations should so indicate, part of the necessary computations could be performed at the data collection center. A primary purpose of this type of observatory would be to monitor seismic activity on the ocean floor, including the structure of earthquake source mechanisms, strong ground motions in seismic areas, volcanic activities, and tidal motions.
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From page 97... ...
Seisrn~c measurements, sirn~lar to those of the ocean bottom package, could be performed as well. Floating Buoys These devices, in addition to the oceanographic capabilities described in connection with moored buoys, allow for mapping of ocean currents.
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From page 98... ...
There is a need for permanent stations, including moored buoys, that monitor geodetic positions continuously and also for mobile stations that can monitor position on closely spaced networks in areas of concern, such as the San Andreas fault in California. In addition, the GPS system will provide accurate locations for satellites, aircraft, and ships, and thereby greatly improve their measurement capabilities.
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From page 99... ...
It may well be that a series of GPS and WVR observations stretching over several years in a variety of climatic zones will be required to separate systematic errors from plate motion and to fully understand atmospheric effects on GPS location techniques. Continuous observations would be necessary in order to characterize the dynamic effects of weather with periods of several days, in addition to longer period seasonal atmospheric effects.
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From page 100... ...
in an untended, fully automated mule. The benefits that would accrue from such a development include unproved atmospheric models and accuracy, reduced cost of field operations, a better description of the temporal spectrum of plate motion, and the ability to carry out precise location of surface buoys in support of a sea floor geodetic program.
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From page 101... ...
An overview of the measurement requirements specified in the discipline areas indicates a number of common data issues. It is apparent that over the next 20 to 30 years the increase in data volume will be due largely to meeting measurement requirements for high spatial and spectral resolutions, repetitive measurements, measurement of long-duration phenomena, and measurement of many short-duration phenomena with large-scale effects.
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From page 102... ...
In oceanography, a similar research program in data interpretation techniques should be supported for new data acquisition systems. The development of such techniques must be accelerated to ensure that space measurements for earth science will produce the maximum scientific return within reasonable time periods following data acquisition.
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From page 103... ...
The scope and complexity of current and proposed remote sensing instruments, such as unaging spectrometers and synthetic aperture radar systems, promise to dramatically change the situation with respect to the science data analysis needs. Today's scientist must not only cope with a greater variety and complexity of data, but must also attempt to understand and utilize computer hardware and software technologies, which are themselves undergoing a phenomenal growth in capabilities.
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From page 104... ...
Studies of the solid Earth will be advanced most significantly by the geodetic and seismological systems proposed in this chapter. Detailed complexes of geodetic measurements and seismometers will give a mapping of crustal motions in zones of deformation, such as the San Andreas, necessary to a greatly improved insight into the occurrence of earthquakes and other processes that determine the structure of the lithosphere.
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From page 105... ...
In particular, this separation exists between solid earth processes on the one hand, and oceanic and atmospheric processes on the other. The coupling of these different subsystems occurs on a much longer time scale: millions of years.
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