Advanced Visible-infrared Imaging Spectroradiometer (AVIS) for global, high spatial resolution atmospheric sounding and hyperspectral imaging

This paper reports on recent design studies to evaluate building a next generation UV-VLWIR dispersive hyperspectral module with active cooling into an optimized rotating telescope design architecture similar to that used in the Suomi National Polar Partnership (NPP) and Joint Polar Satellite System (JPSS) Visible Infrared Imaging Radiometer Suite (VIIRS). Performance of a multi-grating imaging spectroradiometer was studied across a broad trade space defined primarily by spatial sampling, spectral range and spectral sampling interval. This Advanced Visible-infrared Imaging Spectroradiometer (AVIS) provides nearly contiguous coverage across 0.35 – 14.8 ìm with a spectral sampling interval of 10 nm, thereby extending spectral range of the current operational polar imager VIIRS to the ultraviolet and to the shortwave side of the 15.5 ìm CO2 band while encompassing the 6.7 ìm H2O band currently missing in VIIRS coverage. Spatial sampling occurs at VIIRS I-band (~0.4 km at nadir) spatial resolution with aggregation to M-band (~0.8 km) and larger pixel sizes to improve sensitivity. Radiometric sensitivity (NEdT) at a “S-band” spatial resolution of ~1.5 km is ~0.1 K or better for a 250 K scene across a wavelength range of 6.1 ìm to 14.8 ìm, which compares favorably with JPSS Cross Track Infrared Sounder (CrIS) requirements but at much better spatial resolution. The large number of high resolution sounding FOVs provided by AVIS improves chances for retrievals of temperature and water vapor profiles all the way to the surface in cloudy regions relative to current sounders. Spectral aggregation to VIIRS multispectral bands would continue legacy I-band and M-band measurements with better sensitivity – MODIS bands could be synthesized, too. Additional work is needed to optimize spectral range and spectral sampling approaches for the hyperspectral module and to further refine this powerful high spatial resolution imaging sounder concept.