NASA Teams With NIST to Achieve Calibration Breakthroughs on CLARREO


Langley VA, USA -- The National Institute of Standards and Technology (NIST) and the National Aeronautics and Space Administration (NASA) have launched a joint effort to gather enhanced climate data from spaceborne climate observation instruments planned for a group of satellites now under development.

NASA’s Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission, led by Langley’s Science Directorate, is designed to lay the foundation for a future climate-observing system marked by greatly improved accuracy. Many current satellite missions observe the Earth using sensors designed for weather observation and prediction.

Policymakers require a climate record built on greater accuracy to make the best decisions about climate change mitigation.

The goal of CLARREO is to establish a climate data record against which all future changes will be measured for factors such as the Earth’s infrared radiation lost to space, reflected sunlight and changes in ice, snow and vegetation.

The CLARREO mission will provide an accurate climate record of the complete spectrum of energy that Earth reflects and radiates back into space, measurements that should provide a clearer understanding of the climate system.

NIST’s role will focus on the calibration of the instruments aboard CLARREO satellites, as well as on the accuracy that the sensors must meet.

CLARREO’s sensors will meet the mission’s accuracy goals by employing improved on-board calibration technology that will be developed through the partnership between NIST and NASA.

NASA scientists will bring their expertise in climate and satellite observations, and NIST will bring its technical expertise in standards and calibration.

NASA and NIST have a history of collaborating on satellite-based climate missions that stretches back to the early 1990s and the development of EOS, the Earth Observing System.

CLARREO will be the first satellite mission to have its measurements tied so rigorously to the International System of Units (SI), the internationally recognized system of measuring seven basic quantities such as temperature and luminous intensity.

“CLARREO is such a calibration-oriented mission, and one of our most basic premises is to tie our measurements back to international standards,” said NASA Langley’s David F. Young, project scientist for CLARREO.

“NIST is the custodian of those standards in the U.S. We want to get them involved early on in the mission so we can be sure to have this unbroken chain of measurements tied back to international standards.”

“A key difference for CLARREO is the large amount of attention devoted to keeping this chain short so that uncertainties do not compound as much as the various steps along the chain,” said Eric Shirley, leader of NIST’s Optical Thermometry and Spectral Methods group.

“NIST is teaming with NASA to ensure the SI traceability at a level far exceeding what was done for any previous satellite.”

“According to plan, CLARREO satellites could be used to compare the Earth’s radiance, reflectance and state of its atmosphere decades apart in order to detect change with good accuracy and confidence,” Shirley said.

The mission plans for CLARREO call for two orbiting satellites, each with three instruments that will measure infrared radiation, reflected solar radiation and GPS radio signals.

The infrared and reflected solar properties are key drivers of the Earth’s energy balance, which largely determines the planet’s climate. The memorandum of understanding between Langley and NIST calls for developing a suite of instruments and calibration technology that will greatly improve the accuracy of infrared and solar reflectance measurements.

“There have been improvements in the equipment and there have been improvements in the methods that permit CLARREO to achieve its required accuracy,” said Kurtis Thome, CLARREO’s deputy project scientist, based at Goddard Space Flight Center, who is overseeing the development of the reflected solar instruments.

“We need to be able to have this level of accuracy to know that the changes we’re seeing are different from what would happen naturally.”

To learn more about the CLARREO Mission visit: clarreo.larc.nasa.gov