The Study of the COF Feature in the Antarctic Ice Sheet Based on 3‐D Anisotropy FDTD Method

• Published in: Chinese Journal of Geophysics
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2009
• Subjects: Antarctic; The Antarctic; Antarc*; Ice Sheet
• Online Access: http://dx.doi.org/10.1002/cjg2.1361; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fcjg2.1361; https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/cjg2.1361

Abstract The application of RES technology is the most important method for the study of inner structure on the Antarctic ice sheet. The multi‐polarization radar method developed in recent years can deduce the feature and changing rule of COF in the ice sheet according to the variation of the reflecting power in different orientations, and determine the history of stain and stress in the ice sheet further. It is important to understand the flow mechanism and dynamic process and explain the changing law of the ice sheet in the past, present and future. In this paper we deduced the 3‐D FDTD equations which were derived from Maxwell equation and adapted to permittivity anisotropy medium. Then we simulate the response and spatial‐temporal distributing features. The simulating results show that the wave front is ellipsoid and its long axis lies on the axis of minimum permittivity while the radar wave propagating in the anisotropy medium. The amplitude of the reflecting wave propagating in the traverse anisotropy medium has an 180° period in the horizon plane. We find the delay and periodical amplitude variations from the bottom of anisotropy layer between different antenna types, and the delay and periodical amplitude variation is related to the permittivity difference between the different directions of anisotropy layers and between the adjacent layers. Then we discuss the reason for the delay and periodical amplitude variation because of permittivity anisotropy. The results and conclusions can help to instruct the data processing and interpretation from the Antarctic RES exploration.