Validation of CrIS Radiometric Performance through Its Comparison to ABI

Zhipeng Wang,Peter Beierle,Flavio Iturbide-Sanchez,Kun Zhang,Denis Tremblay

doi:10.3390/rs14040876

Abstract

Radiometric intercomparison between satellite remote sensing instruments has become an increasingly common practice to monitor the stability and even the accuracy of their radiance products. The assessment also enables the evaluation of calibration improvements made to these products, as well as the identification and resolution of remaining calibration inadequacies. In this paper, the radiance products of the Cross-track Infrared Sounder (CrIS), an interferometer-based hyperspectral IR sounder in low Earth orbit (LEO), is compared with the level-1b (L1b) radiance products of the infrared (IR) bands of the Advanced Baseline Imager (ABI), an imaging radiometer in geostationary (GEO) orbit. Two CrIS instruments are currently in operation on S-NPP and NOAA-20 satellites, respectively, and two ABI instruments are in operation on GOES-16 and GOES-17 satellites, respectively. Radiometric intercomparisons are performed between each CrIS-ABI pair. An established procedure by GSICS for such GEO-LEO instrument comparison is principally followed to emulate the radiance of ABI IR bands from CrIS spectra of the collocated pixels to be compared with the actual ABI radiance. Results show that the long-term time series of CrIS-ABI radiance bias have been stable within 0.2 K for nearly all ABI IR bands within a spectral range from 3.7 μm to 13.3 μm, except those with known calibration issues. Miscellaneous calibration events that had occurred to either instrument and altered the biases are identified and explained. While the main goal of the work is to support the on-orbit Cal/Val of CrIS, including the future JPSS-2/3/4 CrIS, such observations can also be referenced to further improve the calibration of ABI.

Highlights

The increasing availability of the space-borne remote sensing instruments for climate monitoring, weather forecasting, and various environmental applications populates the calibration strategy of radiometric intercomparison, a process to directly compare the measured radiances from collocated scenes from a pair of instruments and assess the radiance bias
GOES-16 moved to its current position, to 20 May 2021, right before the recent permanent failure of the Suomi National Polar-orbitingPartnership (S-NPP) Cross-Track Infrared Sounder (CrIS) Electronics Side 2
calibration and validation (Cal/Val) of S-NPP and National Oceanic and Atmospheric Administration (NOAA)-20 CrIS instruments. Both CrIS instruments are radiometrically compared with GOES-16 and GOES-17 Advanced Baseline Imager (ABI) with the their brightness temperature (BT) bias results presented in terms of both their temporal trending and radiometric dependency

Summary

Introduction

The increasing availability of the space-borne remote sensing instruments for climate monitoring, weather forecasting, and various environmental applications populates the calibration strategy of radiometric intercomparison, a process to directly compare the measured radiances from collocated scenes from a pair of instruments and assess the radiance bias. Most of these instruments nowadays have their own capabilities of on-board calibration, making their intercomparison a powerful tool to cross-check the performance of, and improve the on-orbit calibration [1]. Both satellites fly on nearly sun-synchronous polar orbits at an ascending node equator crossing time of 13:30 p.m. locally, where the two spacecraft positions have a phase separation of 180 degrees within a common orbital plane

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