Interferometric multispectral imaging as a candidate sensor for monitoring global greenhouse gases

The authors consider an interferometric multispectral imagery as a spaceborne sensor for monitoring global greenhouse gases. A striking feature of this radiometer is that, unlike the usual imaging spectroradiometer boarded on a satellite platform, the system requires, in principle, neither imaging device such as a lens and a scanner, nor a spectral filter. Instead, it uses a three-dimensional Fourier transform to recover spectral radiance. Specifically, this radiometer retrieves multispectral images from the three-dimensional spatial coherence function measured by a simple volume interferometer. This interferometer is a combination of a Michelson interferometer and a wave-front shearing interferometer, and is essentially equivalent to a parallel two dimensional array of the usual Fourier transform spectrometers. This paper presents the general principle of the authors' imaging spectroradiometry, some limitations in a practical implementation, and a example of conceptual design of spaceborne interferometer for conducting global observation.