Abstract
Abstract. This paper presents a new algorithm for the joint retrieval of surface reflectance and aerosol properties with continuous variations of the state variables in the solution space. This algorithm, named CISAR (Combined Inversion of Surface and AeRosol), relies on a simple atmospheric vertical structure composed of two layers and an underlying surface. Surface anisotropic reflectance effects are taken into account and radiatively coupled with atmospheric scattering. For this purpose, a fast radiative transfer model has been explicitly developed, which includes acceleration techniques to solve the radiative transfer equation and to calculate the Jacobians. The inversion is performed within an optimal estimation framework including prior information on the state variable magnitude and regularisation constraints on their spectral and temporal variability. In each processed wavelength, the algorithm retrieves the parameters of the surface reflectance model, the aerosol total column optical thickness and single-scattering properties. The CISAR algorithm functioning is illustrated with a series of simple experiments.
Highlights
Radiative coupling between atmospheric scattering and surface reflectance processes prevents the use of linear relationships for the retrieval of aerosol properties over land surfaces
Though multispectral information is critical for the retrieval of aerosol properties, the spectral dimension alone does not allow full characterisation of the underlying surface reflectance, which often offers a significant contribution to the total signal observed at the satellite level
This paper describes the Combined Inversion of Surface and AeRosol (CISAR) algorithm designed for the joint retrieval of surface reflectance and aerosol properties
Summary
Radiative coupling between atmospheric scattering and surface reflectance processes prevents the use of linear relationships for the retrieval of aerosol properties over land surfaces. The discrimination between the contribution of the signal reflected by the surface and that scattered by aerosols represents one of the major issues when retrieving aerosol properties using space-borne passive optical observations over land surfaces. This problem can be modelled to solve a radiative system composed of at least two sets of layers, where the upper layers include aerosols and the bottom ones represent the soil–vegetation strata. Though multispectral information is critical for the retrieval of aerosol properties, the spectral dimension alone does not allow full characterisation of the underlying surface reflectance, which often offers a significant contribution to the total signal observed at the satellite level. The additional information contained in multispectral and multi-angular observations has proven essential to characterising aerosol properties over land surfaces
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
