Retrieval of the Ocean Skin Temperature Profiles From Measurements of Infrared Hyperspectral Radiometers—Part I: Derivation of an Algorithm

Abstract

The retrieval of vertical profiles of the sea surface temperature through the electromagnetic and thermal skin layers is demonstrated. The inversion equation applied to the high-resolution radiance spectra measurements obtained from hyperspectral infrared spectrometers is introduced and is known to be nonlinear and ill-conditioned. To constrain the solution and reduce the errors in this ill-conditioned retrieval problem, the truncated singular value decomposition regularization technique is adopted. This technique's feasibility is demonstrated on synthetic data with and without the addition of noise. Results sometimes include an unphysical temperature inversion in the solution which was avoided by iteratively adjusting the lower boundary condition. The presence of noise required an additional step of averaging the radiance spectrum into 11 wavenumber intervals to solve the issue of an overconstrained problem and reduce the errors involved.