Advances in Polar Science 2013/24:4 PP.248-257
Remote sensing has been used in Antarctic studies as an earth observation technique to study the polar region.A remote sensing forward model is an important tool in polar research to study and understand scattering mechanisms and sensitivity of physical parameters of snow and sea ice.In this paper,a reliable theoretical model to study sea ice is developed.The theoretical model in a prior work was improved by including multiple-surface scattering,based on an existing integral equation model and additional second-order surface-volume scattering.This model is applied to a desalinated ice layer above thick saline ice and analyzed using different frequencies,bottom surface roughness and sea-ice layer thickness.Improvement in calculation of the backscattering coefficient of the sea-ice layer is investigated for both co-polarized and cross-polarized returns.The effect on each scattering mechanism is also investigated,to understand in more detail the effect of surface multiple scattering and second-order surface-volume scattering.Comparisons are also made with field measurement results,to validate the theoretical model.Results show improvement in the total backscattering coefficient for cross-polarized return in the studied range,suggesting that multiple-surface scattering and surface-volume scattering up to second order are important scattering mechanisms in the sea-ice layer and should not be ignored in polar research.
1 Lee Y J, Lim W K, Ewe H T. A study of an inversion model for sea ice thickness retrieval in Ross Island, Antarctica. Prog Electromagn Res, 2011, 111: 381-406.
2 Ewe H T, Chuah H T, Fung A K. A backscatter model for a dense discrete medium: analysis and numerical results. Remote Sensing of Environment, 1998, 65(2): 195-203.
3 Chandrasekhar S. Radiative transfer. New York: Dover Publications, 1960.
4 Syahali S. A study of surface and surface-volume scattering. Saarbrucken, Germany: LAP Lambert Academic Publishing, 2012.
5 Syahali S, Ewe H T, Ibrahim S A. Theoretical modeling and analysis of multiple surface scattering and surface-volume scattering in snow layer // AKEPTs 1st annual young researchers conference and exhibition (AYRC X3 2011). Kuala Lumpur: AYRC, 2011.
6 Syahali S, Ewe H T. Model development and analysis of multiple surface scattering and surface-volume scattering in sea ice layer//IEEE Asia-Pacific Conference on Applied Electromagnetics (APACE 2012). Melaka, Malaysia: IEEE, 2012: 22-27.
7 Fung A K. Microwave scattering and emission models and their applications. Norwood, MA: Artech House, 1994: 164-275.
8 Ewe H T, Chuah H T. A study of dense medium effect using a simple backscattering model // Proceedings of IEEE International Geoscience and Remote Sensing Symposium. Singapore: IEEE, 1997, 3: 1427-1429.
9 Chuah H T, Tjuatja S, Fung A K, et al. A phase matrix for a dense discrete random medium: evaluation of volume scattering coefficient. IEEE Transactions on Geoscience Remote Sensing, 1996, 34(5): 1137-1143.
10 Chuah H T, Tjuatja S, Fung A K, et al. Radar backscatter from a dense discrete random medium. IEEE Transactions on Geoscience and Remote Sensing, 1997, 35(4): 892-899.
11 Wen B, Tsang L, Winebrenner D P, et al. Dense medium radiative transfer theory: Comparison with experiment and application to microwave remote sensing and polarimetry. IEEE Transactions on Geoscience and Remote Sensing, 1990, 28(1): 46-59.
12 Ishimaru A, Kuga Y. Attenuation constant of a coherent field in a dense distribution of particles. J Opt Soc America, 1982, 72(10): 1317-1320.
13 Fung A K, Eom H J. A study of backscattering and emission from closely packed inhomogeneous media. IEEE Transactions on Geosciences and Remote Sensing, 1985, GE-23(5): 761-767.
14 Fung A K, Liu W Y, Chen K S, et al. An improved IEM model for bistatic scattering from rough surfaces. J Electromagnet Wave, 2002, 16(5): 689-702.
15 Álvarez-Perez J. An extension of the IEM/IEMM surface scattering model. Wave Random Med, 2001, 11(3): 307-329.
16 Wu T D, Chen K S. A reappraisal of the validity of the IEM model for backscattering from rough surfaces. IEEE Transactions on Geoscience and Remote Sensing, 2004, 42(4): 743-753.
17 Wu T D, Chen K S, Shi J C, et al. A study of an AIEM model for bistatic scattering from randomly rough surfaces. IEEE Transactions on Geoscience and Remote Sensing, 2008, 46(9): 2584-2598.
18 Grenfell T C. Surface-based passive microwave studies of multiyear sea ice. J Geophys Res, 1992, 97(C3): 3485-3501.
19 Fung A K, Eom H J. Coherent scattering of a spherical wave from an irregular surface. IEEE Transactions on Antennas and Propagation, 1983, 31(1): 68-72.
20 Albert M D, Lee Y J, Ewe H T, et al. Multilayer model formulation and analysis of radar backscattering from sea ice. Prog Electromagn Res, 2012, 128: 267-290.