Space Studies Board Annual Report 2007 (2008)

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104 Space Studies Board Annual Report—2007 5.11 Options to Ensure the Climate Record from the NPOESS and GOES-R Spacecraft: A Workshop Report A Report of the Ad Hoc Panel on Options to Ensure the Climate Record from the NPOESS and GOES-R Spacecraft Summary The nation’s next-generation National Polar-orbiting Operational Environmental Satellite System (NPOESS) was created by Presidential Decision Directive/National Science and Technology Council (NSTC)-2 of May 5, 1994, whereby the military and civil meteorological programs were merged into a single program. Within NPOESS, NOAA is responsible for satellite operations, the Department of Defense (DOD) is responsible for major acquisitions, and NASA is responsible for the development and infusion of new technologies. In 2000, the NPOESS program anticipated purchasing six satellites for $6.5 billion, with a first launch in 2008. Costs have since escalated dramatically, and the expected date of first launch has slipped to 2013. By November 2005, it became apparent that NPOESS would overrun its cost estimates by at least 25 percent, triggering the so-called Nunn-McCurdy review by the Department of Defense. As a result of the June 2006 Nunn-McCurdy certification of NPOESS, the planned acquisition of six spacecraft was reduced to four, the launch of the first spacecraft was delayed until 2013, and several sensors were canceled or descoped in capability as the program was re-focused on “core” requirements related to the acquisition of data to support numerical weather prediction. “Secondary” sensors that would provide crucial continuity to some long-term climate records, as well as other sensors that would have provided new measurement capabilities, are not funded in the new NPOESS program. Costs for NOAA’s next generation of geostationary weather satellites, GOES-R, have also risen dramatically, and late last year NOAA canceled plans to incorporate a key instrument on the spacecraft—HES (Hyperspectral Environmental Suite). As described in the Preface to this report, the National Research Council held a workshop, “Options to Ensure the Climate Record from the NPOESS and GOES-R Spacecraft,” in Washington, D.C., on June 19-21, 2007, to review 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 sensor on GOES-R. Some 100 scientists and engineers from academia, government, and industry attended the workshop, which gave participants a chance to review and comment on a mitigation plan developed by NASA-NOAA as well as to explore options that were not included in the NASA-NOAA study. This report is meant to summarize these discussions; by design, it does not present the organizing panel’s findings or recommendations. A follow-on study that will develop consensus find- ings and recommendations is underway; a report from this study is scheduled for release on January 31, 2008. Subjects that were raised repeatedly by workshop participants, and that will be explored in more detail in the follow-on NRC study, include: • Preservation of long-term climate records. Many participants noted that the demanifesting of climate sensors from NPOESS has placed many long-term climate records at risk, including multi-decadal records of total solar irradiance, Earth radiation budget, sea surface temperature, and sea ice extent. Some of these most fundamental data records require observational overlap to retain their value and require immediate attention to ensure their continuation. To ensure continuity of critical long-term climate measurements, many participants NOTE: “Summary” reprinted from prepublication version of Options to Ensure the Climate Record from the NPOESS and GOES-R Space- craft: A Workshop Report, The National Academies Press, Washington, D.C., approved for release in 2007. 1In congressional testimony, the NOAA administrator stated, “Although the primary mission for NPOESS is to provide data for weather forecasting, many of the core sensors mentioned above and some of the secondary sensors would provide some additional climate and space weather observations. Unfortunately, difficult choices and trade-offs had to be made and the cost to procure these sensors is not included in the certified program; however, the program will plan for and fund the integration of these sensors on the spacecraft. Some of these sensors provide continuity to certain long-term climate records while other sensors would provide new data. . . . We specifically decided that the NPOESS spacecraft will be built with the capability to house all of the sensors and the program budget will include the dollars to integrate them on the spacecraft. This decision was made because the EXCOM agreed any additional funding gained through contract renegotiation or in unutilized management reserve would be used to procure these secondary sensors.” Written testimony of Vice Admiral Conrad C. Lauten- bacher, Jr. (U.S. Navy, ret.), Under Secretary of Commerce for Oceans and Atmosphere and NOAA Administrator, “Oversight Hearing on the Future of NPOESS: Results of the Nunn-McCurdy Review of NOAA’s Weather Satellite Program,” before the Committee on Science, U.S. House of Representatives, June 8, 2006. 

Summaries of Major Reports 105 also stressed the need to pursue international partnerships and, when feasible, the leveraging of foreign Earth observation missions. • The potential benefits of relatively minor and low-cost changes to the NPOESS program. In several cases, a participant suggested small non-hardware changes to NPOESS that could address areas of climate ­interest. These included improved pre-launch characterization and documentation of all NPOESS instruments, adding minor software improvements to VIIRS to make the data more climate-relevant, and downlinking full-resolution spectral data from CrIS to enable creation of additional climate products. • The potential role of spacecraft formation flying in mitigation strategies. Formation flight can allow for the synergistic combination of measurements from multiple satellites, sometimes launched years apart. In order to allow for subsequent formation flight with NPOESS platforms, some participants suggested consideration of the requisite orbit maintenance and operations requirements as part of the mitigation strategy for restoring deleted NPOESS and GOES-R climate observing capabilities. • Mitigation options beyond changes to NPOESS. While particular long-term records can be secured via the remanifesting of certain sensors onto NPOESS, many participants noted that several could not be addressed even with the original suite of NPOESS instruments. Long-term records of sea level and ocean vector winds, for example, require different orbits and/or instruments to address critical climate needs. As a result, some participants heavily favored dedicated altimetry and scatterometry missions to fill this need. Further, some participants noted the critical importance of hyperspectral sounder measurements to climate science, suggesting restoration of CrIS/ ATMS to the early-morning NPOESS orbit as well as the earliest-possible flight of a geostationary hyperspectral sounder to further improve temporal resolution. • The challenge of creating climate data records. Although NPP- and NPOESS-derived environmental data records (EDRs) may have considerable scientific value, climate data records (CDRs) are far more than a time series of EDRs. Many participants at the workshop emphasized the fundamental differences between products that are generated to meet short-term needs (EDRs) and those for which consistency of processing and reprocessing over years to decades is an essential requirement. Creation and maintenance of climate data records require differ- ent algorithms, data handling systems, calibration/validation, archival standards, access protocols, and pre-launch characterization compared to operational data products. • The specifications of the MIS instrument. The specifications of the MIS instrument on NPOESS, which is to replace the now canceled CMIS instrument, were not known at the time of the workshop. Absent this informa- tion, participants were unable to fully analyze mitigation options. In addition, several participants warned about the consequences of not having an all-weather sea surface temperature retrieval capability, emphasizing the importance of retaining a low-frequency 6.9 GHz channel as the instrument is reconsidered. • Sustaining climate observations. In the view of many participants, the loss of climate observations from NPOESS is of international concern and also imperils U.S. climate science leadership. Further, many participants noted that while discussions at the workshop were focused on solving near-term climate measurement continuity issues, there would remain a longer-term problem of sustaining support for climate science. Issues noted included finding an appropriate balance between new and sustained climate observations and managing technology infusion into long-term observational programs (including the challenges of doing so with a multiple-spacecraft—block- buy—procurement). Workshop discussions also included what many participants cited as a key challenge: accom- modating research needs within an operational program. Some participants argued that the relative priority of climate measurement needs would have to be heightened across the implementing agencies if climate and opera- tional weather functions remain combined. Their concern was that in exploiting the commonalities of weather and climate observations, the unique needs of climate scientists would be overlooked. The perceived lack of attention to climate science needs within the IPO, particularly calibration and validation requirements, led many participants to favor free-flyer options over integration with the NPOESS platforms. 2The Visible/Infrared Imager/Radiometer Suite, VIIRS, collects visible/infrared imagery and radiometric data. A key sensor on the NPOESS spacecraft, VIIRS contributes to 23 environmental data records (EDRs) and is the primary instrument for 18 EDRs. See description at http:// www.ipo.noaa.gov/Technology/viirs_summary.html. 3In conjunction with the Advanced Technology Microwave Sounder (ATMS), the Cross-track Infrared Sounder collects atmospheric data to permit the calculation of temperature and moisture profiles at high temporal (~daily) resolution. See discussion at http://www.ipo.noaa. gov/Technology/cris_summary.html. 4See NRC, Ensuring the Climate Record from the NPP and NPOESS Meteorological Satellites, National Academy Press, Washington, D.C., 2000, and NRC, Climate Data Records from Environmental Satellites: Interim Report, The National Academies Press, Washington, D.C., 2004.