Recommendation 1 Solar Calibration Testing: – Construct a time-series over AVHRR LAC data over relevant CEOS sites for testing existing AVHRR solar calibrations(i.e. PATMOS-x, ISCCP). Construction of CEOS subsets is on-going via the TIMELINE project and should be done by Fall 2015.

Recommendation 2 Global Verification of Solar Calibration: – Analysis of AATSR global counts has shown a very consistent diurnal cycle that should be able to help verify long-term calibrations. A similar behavior is expected for AVHRR. Should offer an independent assumption-free source of verification.

Recommendation 3 Geolocation: – Need a round-robin comparison of available geolocation correction methods. These include the TIMELINE(DLR), ANA (SMHI) and University of Bern. University of Bern seems most applicable at this time.

Recommendation 4 Thermal Calibration: – It appears that the FIDUCEO approach is most relevant and should available in the time-frame of this project. – The FIDUCEO approach should be implementable into the Level-1a processing directly. This includes all AVHRR sensors and fixed most of the thermal calibration issues.

Recommendation 5 Improved Quality Control: – Data filtering needs to be standardized and improved. This includes solar contamination and corrupted space, black-body views. This is important to remove bad data from further processing.

Recommendation 6 International Collaboration: – Activities should be reported on in the existing WMO SCOPE-CM AVHRR FCDR project (K-G Karlsson). – We recommend a workshop to discuss the testing of the solar calibration data. – We recommend linking with CEOS and other relevant bodies.