Linearizing the MISR Inverse Problem using the Matrix Operator Method for Radiative Transfer Calculations: Synthetic Studies and Retrievals using Real Data

Recent studies have proved the feasibility of retrieving aerosol properties from simulated MISR data using an optimized Levenberg Marquardt approach. The simplicity and speed of using precomputed look-up tables is relinquished for an expected gain in accuracy and fidelity to the observed scenario. This involves the computation of Jacobian matrices, which can be extremely time consuming using the finite difference method. To alleviate this computational burden, linearization of the forward model used for optimization is advisable. We choose the Matrix Operator Method as our forward model and describe its linearization with respect to aerosol microphysical parameters. We compare this approach with the finite difference method, with a focus on speed and accuracy. We provide a synthetic sensitivity analysis of our optimized retrieval before proceeding to demonstrate our method using MISR observations over ocean.