Best practice guidelines for pre-launch characterization and calibration of instruments for passive optical remote sensing

Abstract

The pre-launch characterization and calibration of remote sensing instruments should be planned and carried out in conjunction with their design and development to meet the mission requirements. The onboard calibrators such as blackbodies and the sensors such as spectral radiometers should be characterized and calibrated using SI traceable standards. In the case of earth remote sensing, this allows inter-comparison and intercalibration of different sensors in space to create global time series of climate records of high accuracy where some inevitable data gaps can be easily bridged. The recommended best practice guidelines for this pre-launch effort is presented based on experience gained at National Institute of Standards and Technology (NIST), National Aeronautics and Space Administration (NASA) and National Oceanic and Atmospheric Administration (NOAA) programs over the past two decades. The currently available radiometric standards and calibration facilities at NIST serving the remote sensing community are described. Examples of best practice calibrations and intercomparisons to build SI (international System of Units) traceable uncertainty budget in the instrumentation used for preflight satellite sensor calibration and validation are presented.

Comparison of the Calibration Algorithms and SI Traceability of MODIS, VIIRS, GOES, and GOES-R ABI Sensors

“…Equation (24) is in integral form to account for wavelength dependence within the band. Also, in Reference [4] the relative spectral response, RSR is defined as in Equation (6) in Section 1.…”

“…The recommended practice for enabling harmonization and establishing SI traceability gathered more impetus for meeting the need for high accuracy observations across the globe for monitoring climate change. A series of workshops sponsored by NOAA and supported by National Aeronautics and Space Administration (NASA) and National Institute of Standards and Technology (NIST) over the last decade culminated in the establishment of NOAA NCC in 2011 as a virtual center to provide a knowledge base for calibration algorithm harmonization following best practices for achieving SI traceability of operational sensors [2][3][4][5][6][7]. The center's knowledge base helps the Calibration Working Groups (CWG) and teams on each operational sensor at NOAA/NESDIS/STAR to work with NASA and the instrument vendors towards SI traceability from pre-launch testing to on-orbit operations.…”

Radiance Uncertainty Characterisation to Facilitate Climate Data Record Creation

“…Retrieval parameters are likely to be strongly related for nearby pixels, and generally so too will be their errors. Noise may be the largest uncertainty in radiances, and although noise may often be independent between pixels, the noise frequency spectrum can be such that there is inter-pixel error correlation [24]. On-board calibration cycles for imagers are once-per-scan-line or less frequent, and calibration errors are correlated across scans and across the duration of the calibration cycle.…”

The Global Space-Based Inter-Calibration System

“…For example, NIST has prepared a report for GSICS on best practices for optical sensors (Datla et al 2009). …”