Efficient spatial and temporal representations of global ionosphere maps over Japan using B-spline wavelets
文献类型：期刊论文
| 作者 | Mautz, R; Ping, J; Heki, K; Schaffrin, B; Shum, C; Potts, L |
| 刊名 | JOURNAL OF GEODESY
 |
| 出版日期 | 2005-05-01 |
| 卷号 | 78期号:11-12页码:660-667 |
| 关键词 | B-spline wavelets ionosphere total electron content (TEC) multi-resolution representation |
| 英文摘要 | Wavelet expansion has been demonstrated to be suitable for the representation of spatial functions. Here we propose the so-called B-spline wavelets to represent spatial time-series of GPS-derived global ionosphere maps (GIMs) of the vertical total electron content (TEC) from the Earth's surface to the mean altitudes of GPS satellites, over Japan. The scalar-valued B-spline wavelets can be defined in a two-dimensional, but not necessarily planar, domain. Generated by a sequence of knots, different degrees of B-splines can be implemented: degree 1 represents the Haar wavelet; degree 2, the linear B-spline wavelet, or degree 4, the cubic B-spline wavelet. A non-uniform version of these wavelets allows us to handle data on a bounded domain without any edge effects. B-splines are easily extended with great computational efficiency to domains of arbitrary dimensions, while preserving their properties. This generalization employs tensor products of B-splines, defined as linear superposition of products of univariate B-splines in different directions. The data and model may be identical at the locations of the data points if the number of wavelet coefficients is equal to the number of grid points. In addition, data compression is made efficient by eliminating the wavelet coefficients with negligible magnitudes, thereby reducing the observational noise. We applied the developed methodology to the representation of the spatial and temporal variations of GIM from an extremely dense GPS network, the GPS Earth Observation Network (GEONET) in Japan. Since the sampling of the TEC is registered regularly in time, we use a two-dimensional B-spline wavelet representation in space and a one-dimensional spline interpolation in time. Over the Japan region, the B-spline wavelet method can overcome the problem of bias for the spherical harmonic model at the boundary, caused by the non-compact support. The hierarchical decomposition not only allows an inexpensive calculation, but also separates visualisation at different levels of detail. Each level corresponds to a certain spatial frequency band, leading to a detection of structures and enhancement in the ionosphere at different resolutions. |
| WOS标题词 | Science & Technology ; Physical Sciences ; Technology |
| 类目[WOS] | Geochemistry & Geophysics ; Remote Sensing |
| 研究领域[WOS] | Geochemistry & Geophysics ; Remote Sensing |
| 关键词[WOS] | GPS NETWORK |
| 收录类别 | SCI |
| 语种 | 英语 |
| WOS记录号 | WOS:000229856700003 |
| 源URL | [http://119.78.226.72/handle/331011/19474]  |
| 专题 | 上海天文台_天文地球动力学研究中心 |
| 作者单位 | 1.Ohio State Univ, Lab Space Geodesy & Remote Sensing, Columbus, OH 43210 USA 2.Univ London Imperial Coll Sci Technol & Med, Dept Civil & Environm Engn, Ctr Transport Studies, London SW7 2AZ, England 3.Shanghai Astron Observ, Shanghai 200030, Peoples R China 4.Hokkaido Univ, Grad Sch Sci, Div Earth & Planetary Sci, Kita Ku, Sapporo, Hokkaido 0600810, Japan |
| 推荐引用方式 GB/T 7714 | Mautz, R,Ping, J,Heki, K,et al. Efficient spatial and temporal representations of global ionosphere maps over Japan using B-spline wavelets[J]. JOURNAL OF GEODESY,2005,78(11-12):660-667. |
| APA | Mautz, R,Ping, J,Heki, K,Schaffrin, B,Shum, C,&Potts, L.(2005).Efficient spatial and temporal representations of global ionosphere maps over Japan using B-spline wavelets.JOURNAL OF GEODESY,78(11-12),660-667. |
| MLA | Mautz, R,et al."Efficient spatial and temporal representations of global ionosphere maps over Japan using B-spline wavelets".JOURNAL OF GEODESY 78.11-12(2005):660-667. |
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来源：上海天文台
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