Availability of data is critical to the success of NASA's ESE. The EOS Data and Information System (EOSDIS) (eosdis link) must be responsive to this requirement. EOSDIS manages data from NASA's past and current Earth science research satellites and field measurement programs. During the coming EOS era, EOSDIS will allow command and control of satellites and instruments, and will generate data products based on orbital observations. In addition, EOSDIS will generate data sets made by assimilation of satellite and in situ observations into global climate models.

EOSDIS's services will include:

• User Support
• Data Archive Management and Distribution
• Information Management
• Product Generation
• Spacecraft Command and Control
• Data Capture and Telemetry Processing

NASA planners base the present plans for EOSDIS on an open system, with distributed architecture. This permits data controllers to allocate EOSDIS elements to various locations to take best advantage of different institutional capabilities and science expertise..

EOSDIS consists of several components including:

1. A core system (ECS), which provides the Science Data Processing Segment (SDPS), the Flight Operation Segment (FOS), and the Communications and System Management Segment (CSMS).
2. Eight Distributed Active Archive Centers (DAACs);
3. Scientific Computing Facilities (SCFs);
4. the EOS Data and Operations System (EDOS); and EOS Networks

Together, these components will address all command and control; data acquisition, transport, reduction, storage, and visualization; and user access needs.

16-20: As was noted in the answer to question 16-15, the daily load on EOSDIS will be the largest yet faced by any NASA or other space agency mission - on the order of 3 terabytes, Can you think of some way to ease or lighten that load? ANSWER

As we noted earlier, the basic impetus for the kinds of studies we described is to provide input to planners and policy makers. Having access to raw (or even processed) data is of little use to such groups. What they need is information for making decisions about allocating and, perhaps, regulating resources. This information answers questions, such as, "If we do not curb automobile pollution, what may be its effect on atmospheric composition and temperatures over the next 5-10 years?" Or, "If we continue to deforest the Pacific northwest, what may be the effect on biodiversity, land cover, land use, and water run-off patterns?"

No one can actually predict the future accurately, but we can create mathematical models that generate useful predictive functions. Such models can be as simple as that shown in the first figure, which describes the distribution of incoming solar energy through major portions of the Earth's systems. It's similar to balancing the books: The sum of all components that use solar energy must equal the amount of incoming solar radiation. If they don't add up, our model is wrong, or we're missing something.

Christopherson, R.W., GEOSYSTEMS: An Introduction to Physical Geography, 2nd Ed. © 1994. Reproduced by permission of Prentice Hall, Upper Saddle River, New Jersey)

16-21: This diagram, while not constructed to explain or support the EOS program, does suggest that the various sensors in the EOS missions are all measuring aspects of the same phenomenon. What might that be? ANSWER

But the models we need for an Earth-system, predictive capability are much more complex than what we show here. Such models must account for energy budgets, sources and sinks of carbon and other biogeochemically related materials, effects of temperature on wind speed and direction, precipitation patterns, land use patterns, speed and direction of oceanic currents, increases in so-called greenhouse gases, and more. A full understanding of how these components interact with each other supports our willingness to trust the output from such models. We show an example of the complexity of these models, along with a color-coded indication of how EOS and other MTPE platforms contribute to a better understanding, in the figure below, which we based on the Bretherton diagram:

Because of the complexity of such models, we must accumulate multitudes of timely data from many different sources, over a relatively long period, by a highly advanced data and information system that ingests, processes, and distributes those data to interested parties around the world.

Based on the predictive models described above, we must make decisions based on our understanding of the potential magnitude of global change, in order for planners and policy-makers to define strategies for mitigation or adaptation. These strategies may have widely different economic and societal impact, involving health, standard of living, and quality of life. EOS studies address how climate changes affect water resources, agriculture and ecosystems, and provide fundamental data sets on land-cover change, and measures of sea level change. These EOS measurements and the resulting predictive models address such topics as marine productivity, ozone depletion, air quality, and resources monitoring. These activities give us the tools we need to understand our Earth system and its many subsystems, and to understand the role we play in modifying such systems, and the roles they play in our daily lives.

As you may guess, NASA has a current, extensive homepage dedicated to EOS Project Science (http://eospso.gsfc.nasa.gov/). They have in-depth coverage and reviews of topics, such as, Earth System Science, EOS Investigations, Mission Profiles, Airborne Simulator imagery, Data Products, Educational Material, Publications and Sources, and connectable EOS-related servers. We drew some of the images and textual information in this section from these sources. We invite you to browse the EOS homepage to expand your awareness of the status and future plans of the GCRP, MTPE, and EOS, which together constitute one of the most ambitious and involved research programs in the history of mankind.

We remind you that ESE is actually only a part of the multi-national (international) efforts to fly a series of satellites and other missions dedicated to a broad variety of Earth observations. This next diagram is a near-current summary of this vast program.

Collaborators: Code 935 NASA GSFC, GST, USAF Academy
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