The role of CLARREO as an IR intercalibration reference for JPSS and GOES-R

In addition to the primary goals of CLARREO of producing climate products and providing rigorous tests of climate forecasts, a secondary goal is to provide an in-orbit standard for the inter-calibration of other infrared space-borne sensors. The goal is to use CLARREO to improve the absolute calibration and consistency of other infrared observations from space. This study considers the case where CLARREO satellites in 90-degree polar orbits are used to transfer the absolute calibration from the CLARREO instruments to an operational advanced IR sounder in a sun-synchronous orbit, e.g. IASI on MetOp or CrIS on NPOESS, as well as to GOES-R sensors. This particular inter-calibration goal addresses the needs of the operational weather community for improved absolute accuracy while opening the possibility of using the weather observations to contribute to the long-term climate record. Since it has already been demonstrated that the calibration of the advanced infrared sounder can be transferred to infrared imagers, the ability to transfer absolute calibration on orbit from CLARREO to the advanced IR sounders means that the absolute calibration can then also be transferred to the IR imagers. This provides the additional benefit of a potential NIST trace- able path to absolute standards for products, e.g. Sea Surface Temperature, which are derived from the operational infrared imagers.

This presentation will include an overview of the intercalibration approaches envisioned to improve the calibration accuracy of JPSS and GOES-R sensors, and the results of simulation studies conducted to determine the uncertainty of the intercalibrations.