ADVANCES IN IMAGING SPECTROMETER ATMOSPHERIC CORRECTION WITH THE OPEN-SOURCE ISOFIT CODEBASE

Accurate atmospheric correction is critical for remote imaging spectroscopy of Earth’s surface. We present an overview of recent advances in the open-source atmospheric correction codebase ISOFIT that is designed for the application to NASA’s Earth Surface Mineral Dust Source Investigation (EMIT). The approach uses Bayesian Maximum A Posteriori (MAP) inference to simultaneously solve for the most likely surface and atmospheric state given a particular measurement. The main advantage is a rigorous uncertainty accounting and propagation, and the flexibility to incorporate diverse radiative transfer modeling assumptions. Released in 2018, the codebase has been used for a multitude of validation studies at several terrestrial and aquatic field sites, and is the current operational retrieval algorithm for the EMIT, AVIRIS-NG, and AVIRIS-C instruments.