CLARREO: Cornerstone of the Future Climate Observing System

The Climate Absolute Radiance And Refractivity Observatory (CLARREO) is a climate-focused mission designed to rigorously observe climate change on decade time scales and to use decadal change observations as the most critical method to determine the accuracy of climate change projections such as those used in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4). The CLARREO mission accomplishes this critical objective through highly accurate decadal change observations tied to SI standards and sensitive to many of the key uncertainties in climate radiative forcings, responses, and feedbacks that in turn drive uncertainty in current climate model projections.

NASA and NOAA share responsibility for CLARREO. The NOAA component involves the continuity of measurements of incident solar irradiance and the Earth energy budget by flying the Total Solar Irradiance Sensor (TSIS) and the Clouds and the Earth's Radiant Energy System (CERES) sensors that were removed from the National Polar-orbiting Operational Environmental Satellite System (NPOESS). The NASA portion includes the measurement of spectrally resolved reflected solar and infrared radiances and Global Navigation Satellite System Radio Occultation refractivities. These high accuracy observations of long-term climate change trends and their use in the testing and improvement of climate will enable knowledgeable policy decisions based on internationally acknowledged climate measurements and models. In addition, CLARREO will serve as a key component of the climate observing system by providing a set of reference spectrometers in orbit capable of improving the calibration of other weather and climate sensors.