CLARREO

CLARREO (Climate Absolute Radiance and Refractivity Observatory) is a high-priority NASA decadal survey mission, originally selected as such by the National Research Council in 2007.

It would serve as a reference calibration standard in orbit,[2] making climate trends apparent in their data sets by 2055, within a 30-year time frame after its planned launch in the 2020s.

Due to funding cuts in announced for the 2012 budget, the CLARREO mission was significantly scaled back, while remaining spaceborne projects were eyed to fill the gap.

[5] That funding will potentially support the flight of the Reflected Solar (RS) spectrometer, which is one piece of the full Decadal Survey-recommended mission, hosted on the International Space Station (ISS) from December 2023.

A CLARREO mission on the International Space Station, to include one each of the RS and IR spectrometers, was found to provide the best science value for the lowest feasible cost.

The CLARREO mission will meet these goals through careful consideration of the instrument design, calibration traceability at all stages of development and operation, with spectral, spatial and temporal sampling focused specifically on the creation of climate records.

For example, at solar wavelengths this is intended to be confirmed after launch using comparison of actual data to theoretical simulations of lunar/solar radiance generated within a high-fidelity sensor model,[17] although it is unclear how such a non-experimental approach will ensure SI traceability.

3 which is the NASA estimate of when CERES will detect such trends without the aid of CLARRE0 (grey dashed line), Pathfinder will likely be of much reduced benefit to climate science compared to the original 0.3% (k=2) concept[19] in response to the 2007 decadal survey (with a 2013 launch date[20]).

Fig. 1. The CLARREO RS spectrometer has the capability to match measurements from other spaceborne sensors spatially, temporally, spectrally, and angularly. [ 13 ] This approximate on-orbit data matching is enabled by CLARREO's ability to point its RS instrument in two dimensions.
Fig. 3. Reproduced estimates of time needed after climate mission launch to detect predicted CRF climate trends with 95% confidence, at different calibration accuracies.