Reference and Spectral Response Rdiger Kessel NIST Ruediger

Reference and Spectral Response Rüdiger Kessel NIST Ruediger. kessel@nist. gov 2010 -11 -18 Rüdiger Kessel (NIST)

Calibration of a Sensor under calibration Data selection Regression a, b Collocations Reference Spectral convolution 2010 -11 -18 Rüdiger Kessel (NIST) 2

Existing calibration / validation concept Calibration Sensor MSG 1 Validation Regression MSG 1/IASI Collocations a 1, b 1 Sensor MSG 1 Sensor IASI (reference) MSG 1/MSG 2 Collocations Sensor MSG 2 Correction function 2 f (a 2, b 2) Regression MSG 2/IASI Collocations f (a 1, b 1) Sensor MSG 2 Spectral response of MSG 1 Correction function 1 L 1, corr Non comparable results L 2, corr a 2, b 2 An error term DL 1, 2 is needed to account for the difference in spectral response functions. Sensor IASI (reference) Consistency criterion to validate the correction: 2010 -11 -18 Spectral response of MSG 2 Rüdiger Kessel (NIST) 3

Modifiziertes calibration / validation concept Calibration Sensor MSG 1 Validation Regression MSG 1/IASI Collocations a 1, b 1, d Lrs 1 Sensor MSG 1 Sensor IASI (reference) Reference Sensor MSG 2 MSG 1/MSG 2 Collocations Measurement function 2 f (a 2, b 2, d Lrs 2) Regression MSG 2/IASI Collocations f (a 1, b 1, d Lrs 1) Sensor MSG 2 Limited bandwidth Measurement function 1 L 1, cal Comparable results L 2, cal a 2, b 2, d Lrs 2 Sensor IASI (reference) Reference 2010 -11 -18 Consistency criterion for comparable results: Limited bandwidth Rüdiger Kessel (NIST) 4

Multiple calibration functions Sensor MSG Regression a, b, d Lrs MSG/IASI Collocations Sensor IASI (reference) Ref. 1 Limited bandwidth Sensor IASI (reference) Ref. 2 2010 -11 -18 Nominal response • The same sensor can be calibrated using multiple references • References are different when the sensor is different • References are different when the spectral specification is different Important: The user need to be educated that results can only be compared if the same reference was used Rüdiger Kessel (NIST) 5