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Climate Absolute Radiance and Refractivity Observatory

Phase: Under Study

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Program(s):Earth Systematic Missions

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The Climate Absolute Radiance and Refractivity Observatory (CLARREO) Mission has been recommended in the NRC Decadal Survey as a key component of the future climate observing system. NASA and NOAA share responsibility for CLARREO. The NOAA component involves the continuity of measurements of incident solar irradiance and Earth energy budget by flying the TSIS and CERES sensors that were removed from NPOESS. The NASA portion involves the measurement of spectrally resolved thermal IR and reflected solar radiation at high absolute accuracy. Coupled with measurements from on-board GPS radio occultation receivers, these measurements will provide a long-term benchmarking data record for the detection, projection, and attribution of changes in the climate system. In addition, the SI traceable radiances will provide a source of absolute calibration for a wide range of visible and IR Earth observing sensors, greatly increasing their value for climate monitoring.

CLARREO is a Highly Leveraged Interdisciplinary Climate Change Mission

  • Accurate decadal-length records are essential for climate change detection, attribution, and for testing climate prediction accuracy. They represent the most critical test of uncertainty in future climate change prediction.
  • While process study missions (e.g. CALIPSO/CloudSat) are critical to improve underlying climate model physics (e.g. clouds), decadal change observations are critical to determine the impact of those climate model improvements on the accuracy of predicting future climate change. Both elements are critical, and CLARREO is the major Decadal Study mission addressing serious accuracy issues in decadal climate change observation.
  • The CLARREO mission is unique in its broad interdisciplinary impact on climate change science: the other NRC Decadal Survey missions are primarily focused on one climate process or discipline.
  • CLARREO provides new solar reflected and infrared emitted high spectral resolution benchmark radiance climate data records that can be used to test climate model predictions, improve climate change fingerprinting, and attribution.
  • CLARREO provides an orbiting calibration observatory that can be used to calibrate other solar and infrared space-borne sensors (e.g. VIIRS, CrIS, Landsat, Geostationary, CERES) and thereby improve to climate accuracy a wide range of sensors across the GEO observing system. It also improves the scientific value of all of these instruments.
  • Key climate variable decadal records impacted by CLARREO include: atmospheric temperature and water vapor profiles, land and sea surface temperatures, cloud properties, radiation budget including Earths albedo, vegetation, surface snow and ice properties, ocean color, and aerosols. The data is also relevant to greenhouse gas monitoring.
  • The absolute accuracy of CLARREO, when used to calibrate other sensors in orbit can dramatically reduce the impact of data gaps on decadal change data records across many climate variables.
  • CLARREO provides the first spectrally resolved climate observation of the Far-Infrared spectrum from 15 to 50 micron wavelengths, where half of the thermal infrared emission of the earth to space occurs, and the source of almost all of the Earth's water vapor greenhouse effect.
  • CLARREO’s ability to calibrate other instruments across the full solar and infrared spectrum can change the future prioritization of different elements of instrument pre-launch characterization (e.g. spectral response), stability, and calibration, thereby resulting in increased programmatic flexibility and savings.