Slit homogenizer introduced performance gain analysis based on the Sentinel-5/UVNS spectrometer

Abstract. Spatially heterogeneous Earth radiance scenes affect the atmospheric composition measurements of high-resolution observation spectrometer missions. The scene heterogeneity creates a pseudo-random deformation instrument spectral response function (ISRF). ISRF is direct link between forward radiative transfer model, used to retrieve state, and spectra measured by instrument. Hence, distortions owing radiometric inhomogeneity imaged will degrade precision Level-2 retrievals. Therefore, requirements an are often parameterized in knowledge over non-uniform terms shape, centroid position channel full width at half maximum (FWHM). Sentinel-5/UVNS first push-broom that makes use concept referred as slit homogenizer (SH) for mitigation spatially scenes. This done employing formed two parallel mirrors scrambling along track direction (ALT) hence averaging contrast only direction. flat do not imaging across (ACT) thus preserve spatial information multiple reflections inside SH act coherent virtual light sources resulting interference pattern exit plane can be described simulations using scalar diffraction theory. By homogenizing illumination, strongly modifies spectrograph pupil illumination input scene. In this work we investigate impact strength variations different cases quantify on stability types aberration present optics.