Sensors 2008, 8(12), 7850-7865; doi:10.3390/s8127850
Article

Coupling a Neural Network-Based forward Model and a Bayesian Inversion Approach to Retrieve Wind Field from Spaceborne Polarimetric Radiometers

Department of Electronic Engineering, Sapienza University of Rome, via Eudossiana 18, 00184 Rome, Italy
* Author to whom correspondence should be addressed.
Received: 2 June 2008; in revised form: 29 October 2008 / Accepted: 21 November 2008 / Published: 3 December 2008
(This article belongs to the Special Issue Ocean Remote Sensing)
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Abstract: A simulation study to assess the potentiality of sea surface wind vector estimation based on the approximation of the forward model through Neural Networks and on the Bayesian theory of parameter estimation is presented. A polarimetric microwave radiometer has been considered and its observations have been simulated by means of the two scale model. To perform the simulations, the atmospheric and surface parameters have been derived from ECMWF analysis fields. To retrieve wind speed, Minimum Variance (MV) and Maximum Posterior Probability (MAP) criteria have been used while, for wind direction, a Maximum Likelihood (ML) criterion has been exploited. To minimize the cost function of MAP and ML, conventional Gradient Descent method, as well as Simulated Annealing optimization technique, have been employed. Results have shown that the standard deviation of the wind speed retrieval error is approximately 1.1 m/s for the best estimator. As for the wind direction, the standard deviation of the estimation error is less than 13° for wind speeds larger than 6 m/s. For lower wind velocities, the wind direction signal is too weak to ensure reliable retrievals. A method to deal with the non-uniqueness of the wind direction solution has been also developed. A test on a case study has yielded encouraging results.
Keywords: Microwave radiometry; polarimetry; sea surface winds

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MDPI and ACS Style

Pulvirenti, L.; Pierdicca, N.; Marzano, F.S. Coupling a Neural Network-Based forward Model and a Bayesian Inversion Approach to Retrieve Wind Field from Spaceborne Polarimetric Radiometers. Sensors 2008, 8, 7850-7865.

AMA Style

Pulvirenti L, Pierdicca N, Marzano FS. Coupling a Neural Network-Based forward Model and a Bayesian Inversion Approach to Retrieve Wind Field from Spaceborne Polarimetric Radiometers. Sensors. 2008; 8(12):7850-7865.

Chicago/Turabian Style

Pulvirenti, Luca; Pierdicca, Nazzareno; Marzano, Frank S. 2008. "Coupling a Neural Network-Based forward Model and a Bayesian Inversion Approach to Retrieve Wind Field from Spaceborne Polarimetric Radiometers." Sensors 8, no. 12: 7850-7865.

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