Mission to Planet Earth Space Science in the Twenty-First Century -- Imperatives for the Decades 1995 to 2015 (1988) / Chapter Skim
Currently Skimming:
1. Design and Implications of a Research Mission to Planet Earth
1. Design and Implications of a Research Mission to Planet Earth
Pages 1-15
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 1... ...
It might better be called the blue and white planet in recognition of the white clouds that obscure large areas. Our blue and white Earth contrasts sharply with the red of dusty Mars, the dazzling whiteness of Venus, and the complex swirls of paste!
|
From page 2... ...
If organic matter continued to accumulate in the deposes sediments, all the nutrients released by weathering would eventually return to insoluble forms and Earth's plants would starve. Similarly, if limestone sediments continued to accumulate in the ocean without a compensating inflow of carbon dioxide from the deep-sea ridges and other volcanic eruptions, the concentration of atmospheric carbon dioxide could become so Tow that photosynthesis would be impossible.
|
From page 3... ...
But it is Earth's own inner life the convective processes deep within its interior, perhaps largely controlled by the flux of heat from radioactive decay and to an unknown extent by the primordial heat of agglomeration that has determined its history and our own. Why does the phenomenon of plate tectonics exist on Earth but not on Venus, a near twin of Earth?
|
From page 4... ...
The Earth Is the only planet on which we can simultaneously make global satellite observations and deploy adequate instrumentation to image the interior, including the mantle and core, in order to address such fundamental questions as the origin of the magnetic field and the nature of the convective overturning of the Earth's mantle and crust. In this report the task group proposes a Mission to Planet Earth as an essential part of our country's program of space exploration.
|
From page 5... ...
The Earth's crustal surface is the home of man and the interface between the rapid variation in the fluid envelopes and the usually slow, sometimes catastrophic motions of the interior. The crust contains the record of past events on Earth, which is the main object of the study of geology.
|
From page 6... ...
The land surface needs to be more systematically monitored to map and establish trends in surface composition, tectonics, soil erosion and salinization, geomorphology, vegetation (state, as well as distribution of types) , hydrologic phenomena (snow cover, ground water)
|
From page 7... ...
This great welter of causative effects with di~erent time scales requires measurements by a variety of means, all requiring completeness, simultaneity, and continuity. MEASUREMENT STRATEGY The issues of overall measurement strategy for an earth oh serving system have been considered in detail in a number of previous reports, including the two volumes of A Strategy for Earth Science from Space in the 1980's and 1990's by the Committee on Earth Sciences (CES)
|
From page 8... ...
However, even if we restrict ourselves to decadal time changes the human time scale statistics dictate that measurements over many years will be required before we can make accurate statements about the energetics of the system. As we look into the future, we see the need for geodynamic, climate, and biosphere measurements for decades, and we can see that the addition of gravity and magnetic fields, continental drift, and solar-terrestrial interactions to these processes extends the necessary observational time periods to centuries.
|
From page 9... ...
As is noted in the CES reports, the changes to be expected from the worldwide deforestation and consumption of fossil fuels, from increased erosion of continents, from the sensitivity of the stratospheric ozone to trace gases such as chIorofluorocarbons, and from the causes of past and present extinctions of whole classes of living species are all questions of fundamental importance. They can only be addressed from a global, interdisciplinary perspective, drawing on a wide spectrum of observations and skills beyond the range of any one individual, institution, or agency.
|
From page 10... ...
1. A Satellite-based Observing System The task group recommends that the centerpiece of the global observing system be a network of satellites and platforms in the following arrangement: ~ A set of five geostationary satellites, designed to carry a wide variety of instruments to cover the entire Earth for long-term measurements.
|
From page 11... ...
In situ measurements from PLATO would include, for example, detailed studies of terrestrial and oceanic biomes, ocean bottom stations designed to monitor pressure, seismic and acoustic signals, a variety of probes ranging from balloons to boreholes, and GPS receivers and laser corner reflectors for monitoring tectonic deformation. The number of sites for these instruments would range from 100s to 10,000s; their distribution typically would be nonuniform in accordance with the problem under study.
|
From page 12... ...
As world population and economic aspirations press harder on finite resources, the need for improved understanding grows year by year, and environmental problems are transformed into ever more prominent social and political problems, while becoming less amenable to successful solutions.
|
From page 13... ...
, now in the planning stages, will study global change with a focus on the interactive ocean-atmosphere-landbiota system on a time scale of decades to centuries. The success of these ongoing and planned programs is keyed to our ability to obtain accurate global and repetitive data on certain geophysical parameters from satellites, and to complement the space data with reliable surface-based observations, as well as to develop realistic, interactive models that can be tested by diagnostic measurements.
|
From page 14... ...
guarantee the uniformity of the data acquisition and archiving system so as to facilitate their use by the research community, and ensure that future improvements in data processing technology can be applied with a minimum impact on the continuity of the data streams. From this description it should be evident that the solution of the major problems in earth science requires an integrated approach.
|
From page 15... ...
These science policy issues are addressed in more detail in Chapter 6. Finally, the strategies of the Space Science Board's Committee on Earth Sciences (CES)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.