Radiometer-to-imager in-flight cross calibration and verification

Area of Science:

• Remote Sensing
• Atmospheric Science
• Optical Instrumentation

Background:

• Accurate calibration of remote sensing instruments is crucial for reliable atmospheric and Earth surface monitoring.
• Existing calibration methods can be time-consuming and dependent on surface conditions.
• Cross-calibration between different sensor types, like radiometers and imagers, presents unique challenges.

Purpose of the Study:

• To develop and validate a method for in-flight cross-calibration between a radiometer (POSP) and an imager (SIPC) on the same aircraft.
• To improve the measurement accuracy of the imaging polarization camera (SIPC) by transferring calibration coefficients from the particulate observing scanning polarimeter (POSP).
• To enable high-precision, large-spatial-coverage remote sensing of atmospheric fine particles.

Main Methods:

• Developed a data transmission method using time, space, and spectral matching between the POSP and SIPC.
• Formulated polarization models for both instruments using Mueller matrixes.
• Deduced an in-flight cross-calibration model specific to the POSP-SIPC system.
• Conducted in-flight experiments to validate the cross-calibration model.

Main Results:

• Successfully established an in-flight cross-calibration method applicable regardless of surface type, reducing calibration cycles.
• Transferred high-precision calibration coefficients from the POSP to the SIPC.
• Demonstrated the ability to minimize SIPC polarization degree errors, achieving a bias of approximately 0.01 relative to POSP over land.

Conclusions:

• The developed radiometer-to-imager in-flight cross-calibration method is effective for improving imager accuracy.
• This technique facilitates high-precision remote sensing of atmospheric fine particles over large areas.
• The method offers a robust and efficient approach to instrument calibration in airborne remote sensing applications.