Mitigation of calibration ringing in the context of the MTG-S IRS Instrument

TL;DR

This paper investigates calibration ringing errors in the MTG-S IRS Fourier transform spectrometers and proposes a principal component-based correction method to mitigate these errors, improving radiometric accuracy.

Contribution

The authors introduce a novel RTF uniformisation correction method using principal component decomposition for the MTG-S IRS instrument.

Findings

RTF uniformisation reduces calibration ringing errors

Simulation shows improved radiometric accuracy

Method effective in LWIR band

Abstract

EUMETSAT is currently developing the on-ground processing chain of the infrared Fourier transform spectrometers (IRS) on-board of the Meteosat Third Generation sounding satellites (MTG-S). In this context, the authors have investigated the impact of a particular type of radiometric error, called hereafter the calibration ringing. It arises in Fourier transform spectrometers when the instrument Radiometric Transfer Function (RTF) varies within the domain of the instrument Spectral Response Function (SRF). The expected radiometric errors are simulated in the context of the MTG-S IRS instrument in the long wave infrared (LWIR) band. Making use of a principal components (PC) decomposition, a software correction, called RTF uniformisation, is designed and its performance is assessed in the context of MTG-S IRS.