Effects of Ocean Wind, Foam/Spray and Atmosphere on Four Stokes Parameters in Passive Polarimetric Remote Sensing of the Ocean Based on Numerical Simulations and Analytic Theory

The research last year consisted of three parts: A. Microwave emission and scattering of foam based on Monte Carlo simulations of dense media using the fcc structures and realistic Lord Kelvin’s Tetrakaidecahedron Model of minimal contact area; B. Polarimetric passive microwave remote sensing of wind vectors with foam-covered, rough ocean surfaces; C. Brightness temperature of ocean with wind based on paralleled code of MoM with RWG basis function in conjunction with SMCG fast method. A: MICROWAVE EMISSION AND SCATTERING OF FOAM BASED ON MONTE CARLO SIMULATIONS OF DENSE MEDIA Emissivities of ocean surfaces are affected by the presence of foam. Recently, field experiments have been conducted at the Chesapeake Bay Detachment to study the foam emissivity as a function of polarization, observation angle and frequencies at 10.8 GHz and 36.5 GHz. The measurements exhibit important frequency dependence [1]. The results are not explained by simple mixing formulae nor past empirical models. In particular, the emissivities at 10.8 GHz are observed to be comparable to that of 36.5 GHz. Foam is a mixture of air bubbles and sea water. The bubbles range from sizes of hundreds of microns to millimeters. We conduct theoretical modeling based on modeling the microstructure of foam taking into account bubble size, fractional volume of water to rigorously study the emission, absorption and scattering properties and to account for the observed frequency dependence and polarimetric dependence of emissivities. In a previous paper, wave scattering and emission in a medium consisting of densely packed coated particles are solved by using the quasicrystalline approximation in combination with the dense-media radiative-transfer theory [2] (DMRT). Recently, we applied Monte Carlo simulations of solutions of Maxwell equations of densely packed coated particles to analyze the microwave emission and scattering of foam. The absorption, scattering and extinction coefficients are calculated. These quantities are then used in dense-media radiative-transfer theory to calculate the microwave emissivity. In order to have high density packing, we use a facecentered-cubic (fcc) structure to place the air bubbles. Salient features of the numerical results are (1) Report Documentation Page Form Approved OMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. 1. REPORT DATE SEP 2003 2. REPORT TYPE 3. DATES COVERED 00-00-2003 to 00-00-2003 4. TITLE AND SUBTITLE Effects of Ocean Wind, Foam/Spray and Atmosphere on Four Stokes Parameters in Passive Polarimetric Remote Sensing of the Ocean Based on Numerical Simulations and Analytic Theory 5a. CONTRACT NUMBER