SABER Measurement Quality: Limb Scan Performance, Calibration and Validation

The SABER instrument is a limb viewing radiometer designed to study the energetics of the mesosphere and thermosphere. It was launched aboard the NASA TIMED satellite in December 2001. Radiance from the target tangent altitudes of 70+ kilometers can be 3 to 6 orders of magnitude smaller than radiance emanating from just below the tropopause. This requires effective (either actual or mathematically corrected) field-of-view performance that provides 10-6 rejection over less than 2 arc-degrees, which is extremely difficult to quantify in the lab. The in-orbit validation/calibration methods used to precisely determine and verify this performance are described. Also presented are other performance factors and related retrieval results.