Detector Based Calibration of a Portable Imaging Spectrometer for CLARREO Pathnder Mission

摘要

The Climate Absolute Refractivity and Reectance Observatory (CLARREO) Pathfinder (CPF) mission is beingdeveloped to demonstrate SI-traceable retrievals of reectance at unprecedented accuracies for global satelliteobservations. An Independent Calibration of the CPF sensor using the Goddard Laser for Absolute Measurementof Radiance (GLAMR) is planned to allow validation of CPF accuracies. GLAMR is a detector-based calibrationsystem relies on a set of NIST-calibrated transfer radiometers to assess the spectral radiance from the GLAMRsphere source to better than 0.3 % (k=2). The current work describes the calibration of the Solar, Lunar AbsoluteReectance Imaging Spectroradiometer (SOLARIS) that was originally developed as a calibration demonstrationsystem for the CLARREO mission and is now being used to assess the independent calibration being developedfor CPF. The methodology for the radiometric calibration of SOLARIS is presented as well as results fromthe GLAMR-based calibration of SOLARIS. The portability of SOLARIS makes it capable of collecting fieldmeasurements of earth scenes and direct solar and lunar irradiance similar to those expected during the on-orbitoperation of the CPF sensor. Results of SOLARIS field measurements are presented. The use of SOLARIS inthis effort also allows the testing protocols for GLAMR to be improved and the eld measurements by SOLARISbuild condence in the error budget for GLAMR calibrations. Results are compared to accepted solar irradiancemodels to demonstrate accuracy values giving condence in the error budget for the CLARREO reectanceretrieval.