. "Summary." Ensuring the Climate Record from the NPOESS and GOES-R Spacecraft: Elements of a Strategy to Recover Measurement Capabilities Lost in Program Restructuring. Washington, DC: The National Academies Press, 2008.
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Ensuring the Climate Record from the NPOESS and GOES-R Spacecraft: Elements of a Strategy to Recover Measurement Capabilities Lost in Program Restructuring
2006, following significant cost growth and estimates that the total program cost would nearly double,4 NOAA reduced the scope of the program, removed a key instrument on the spacecraft, the Hyperspectral Environmental Suite (HES),5 and revised the procurement process so that only two satellites are guaranteed.6
These events prompted a request from NASA and NOAA for two National Research Council (NRC) efforts. The first, a workshop titled “Options to Ensure the Climate Record from the NPOESS and GOES-R Spacecraft” and held in Washington, D.C., on June 19-21, 2007, gave participants an opportunity to discuss options to recover measurement capabilities, especially those related to climate research, that were lost as a result of the Nunn-McCurdy actions and the cancellation of the HES on GOES-R. Some 100 scientists and engineers from academia, government, and industry attended the workshop, commenting on a draft mitigation plan developed by NASA and NOAA7 as well as exploring options not included in the NASA-NOAA report. A prepublication version of the workshop report (NRC, 2008) was released in October 2007.
The second NRC effort, a study documented in the present report, builds on the information gathered at the June 2007 workshop. In their request for this study (Appendix A), NASA and NOAA asked that a committee of the NRC “prioritize capabilities, especially those related to climate research, that were lost or placed at risk following recent changes to NPOESS and the GOES-R series of polar and geostationary environmental monitoring satellites” [emphasis added].
The Committee on a Strategy to Mitigate the Impact of Sensor Descopes and Demanifests on the NPOESS and GOES-R Spacecraft understands “climate” to be “the statistical description in terms of the mean and variability of relevant measures of the atmosphere-ocean system over periods of time ranging from weeks to thousands or millions of years” (Climate Change Science Program and the Subcommittee on Global Change Research, 2003, p. 12). In the present study, the committee primarily considered climate-related physical, chemical, and biological processes that vary on interannual to centennial timescales. It is also important to note that the committee did not a priori assume a longer-duration measurement record would be assigned a higher priority than a shorter-duration measurement record. Instead, the committee considered each measurement’s value to climate science in a more comprehensive sense as described in the section below on prioritization. The committee interprets the information needed for climate research broadly to be that which enables:
Detection of variations in climate (through long-term records),
The cost growth resulted in part from the risk reduction achieved by a deliberate shift from a 50 percent cost probability to the more conservative 80 percent probability, based on lessons learned from NPOESS.
The Hyperspectral Environmental Suite consisted of two components: an advanced hyperspectral sounder and a coastal waters imager. The hyperspectral sounder was intended to greatly advance current operational geostationary sounding capability; its cancellation will instead end the long-term geostationary sounding record started by GOES-I. The coastal waters imager component was planned primarily to benefit coastal monitoring, management, and remediation applications.
Prediction (climate) is a probabilistic description or forecast of a future climate outcome based on observations of past and current climatological conditions and quantitative models of climate processes (e.g., a prediction of an El Niño event) and projection (climate) is a description of the response of the climate system to an assumed level of future radiative forcing. Changes in radiative forcing may be due to either natural sources (e.g., volcanic emissions) or human-induced causes (e.g., emissions of greenhouse gases and aerosols, or changes in land use and land cover). Climate “projections” are distinguished from climate “predictions” in order to emphasize that climate projections depend on scenarios of future socioeconomic, technological, and policy developments that may or may not be realized (Climate Change Science Program and the Subcommittee on Global Change Research, 2003, p. 12).