• How will coastal and ocean ecosystems respond to changes in physical forcing, particularly those subject to intense human harvesting? How will the boreal forest shift as temperature and precipitation change at high latitudes? What will be the impacts on animal migration patterns and on the prevalence of invasive species?

  • Will previously rare diseases become common? How will mosquito-borne viruses spread with changes in rainfall and drought? Can we better predict the outbreak of avian flu? What are the health impacts of an expanded ozone hole that could result from a cooling of the stratosphere, which would be associated with climate change?

  • Will tropical cyclones and heat waves become more frequent and more intense? Are major fault systems nearing the release of stress via strong earthquakes?

The required observing system is one that builds on the current fleet of space-based instruments and brings to a new level of integration our understanding of the Earth system.

SETTING THE FOUNDATION: OBSERVATIONS IN THE CURRENT DECADE

As documented in this report, the extraordinary U.S. foundation of global observations is at great risk. Between 2006 and the end of the decade, the number of operating missions will decrease dramatically, and the number of operating sensors and instruments on NASA spacecraft, most of which are well past their nominal lifetimes, will decrease by some 40 percent (see Figures ES.1 and ES.2). Furthermore, the replacement sensors to be flown on the National Polar-orbiting Operational Environmental Satellite System (NPOESS)3 are generally less capable than their Earth Observing System (EOS) counterparts.4 Among the many measurements expected to cease over the next few years, the committee has identified several that are providing critical information now and that need to be sustained into the next decade—both to continue important time series and to provide the foundation necessary for the recommended future observations. These include measurements of total solar irradiance and Earth radiation and vector sea-surface winds; limb sounding of ozone profiles; and temperature and water vapor soundings from geostationary and polar orbits.5

As highlighted in the committee’s interim report, there is substantial concern that substitution of passive microwave sensor data for active scatterometry data will worsen El Niño and hurricane forecasts as well as weather forecasts in coastal areas.6 Given the status of existing surface wind measurements and the substantial uncertainty introduced by the cancellation of the CMIS instrument on NPOESS, the committee believes it imperative that a measurement capability be available to prevent a data gap when the NASA QuikSCAT mission, already well past its nominal mission lifetime, terminates.

Questions about the future of wind measurement capabilities are part of a larger set of issues related to the development of a mitigation strategy to recover capabilities lost in the recently announced descoping and cancellations of instruments and spacecraft planned for the NPOESS constellation. A request for

3

See a description at http://www.ipo.noaa.gov/.

4

NASA’s Earth Observing System (EOS) includes a series of satellites, a science component, and a data system supporting a coordinated series of polar-orbiting and low-inclination satellites for long-term global observations of the land surface, biosphere, solid Earth, atmosphere, and oceans. See http://eospso.gsfc.nasa.gov/eos_homepage/description.php.

5

As discussed in the Preface and in more detail in Chapter 2, the continuity of a number of other critical measurements, such as sea-surface temperature, is dependent on the acquisition of a suitable instrument on NPOESS to replace the now-canceled CMIS sensor.

6

Also, see pp. 4–5 of the Oceans Community Letter to the Decadal Survey, available at http://cioss.coas.oregonstate.edu/CIOSS/Documents/Oceans_Community_Letter.pdf, and the report of the NOAA Operational Ocean Surface Vector Winds Requirements Workshop, June 5–7, 2006, National Hurricane Center, Miami, Fla., P.Chang and Z.Jelenak, eds.



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