A Study On Monitoring Antarctic Ice Sheet Using Space-borne Microwave Remote Sensing Data

Mass balance of Antarctic ice sheet and mean sea level are the factors in global change study. The atrocious geographical and natural conditions in Antarctica make it quite difficult for the scientists to carry out more and frequent field expeditions. Microwave satellite remote sensing is a practical way of monitoring long-term changes in the properties of the entire Antarctic ice sheet. Data acquired from microwave instruments can be acquired day and night in all weather conditions and provides detailed information on the surface and subsurface of polar glaciers and ice sheets.Synthetic Aperture Radar(SAR) is proved to be an effective tool to generate high-accuracy digital elevation model (DEM) generation and to measure ice flow on Antarctic glaciers. Presently, most research is concentrated on the coastal ice shelves of WAIS (West Antarctic Ice Sheet), very few work has been done for in-land glaciers in East Antarctica.Scatterometer and radiometer image data have a greater spatial and more frequent coverage, albeit at a lower spatial resolution, making these instruments ideal for monitoring the Antarctic ice sheet. The long-term continuous scatterometer and radiometer image data are best for time series analysis to study the trend and abnormity of Antarctic ice sheet.The dissertation investigates application of SAR interferometry in Antarctic inland glacier for DEM and complex ice flow measurement, also large-scale scatterometer and radiometer data for ice sheet monitoring.Main research topics and initiatives in this dissertation include:(1) DEM generation in Grove MountainsDigital elevation model (DEM) of Grove Mountain in East Antarctica is generated by means of SAR Interferometry (InSAR), as is validated partly using the pre-existed GPS DEM mapped in 2000. It is proved to be accurate. The error source and feasibility of INSAR DEM construction on inland ice sheet is well analyzed.(2) Research and application of interferometric decorrelation on Antarctic ice sheet.The impact of several decorrelation factors on interferometric correlation is studied through interferometric experiments with multiple SAR image pairs (different baseline, L-band and C-band). The critical baseline here is much shorter than the normal length. The long spatial perpendicular baseline is a main deccorelation factor. Also are found that high correlation can always be seen in blue ice region and L-band interferometry is preponderant in keeping fine correlation within long interval.(3) Modeling and Applications of DINSAR ice flow measurementsDifferent topographic phase removal methods in differential SAR interferometry, the relations between radar look-of-sight displacement and actual ice motion are studied. The models of derive actual ice displacement from single-direction and bi-directional (ascending and descending flight) INSAR measurements are described in detail. Multi-source L-band (JERS-1) and C-band (ERS-1/2, ENVISAT) SAR data are used for ice motion measurements in Grove Mountain. The 4-pass differential interferometric combination of JERS/ERS gets good result. The possible error sources are given and discussed in detail.(4) Study of deriving ice flow parameters from wrapped interferometric phase The calculation models of deriving ice flow parameters from wrappedinterferometric phase are given. Thus we could get the ice flow information regardless of the interferometic phase is unwrapped or not, which widens the usability of high-gradient and failing-to-unwrap interferogram.(5) Research of SAR interferometry based on ENVISAT-ASAR dataThe latest ENVISAT-ASAR SLC data are put to interferometric experiment, which produced high-quality interferogram. The pattern of ice flow fringes presented is coincident with the former ones in ERS and JERS interferograms.(6) Ice sheet monitoring with space-borne microwave scatterometer and radiometer data.Starting from the theory of interaction between microwave and snow, the behavior characteristics of microwave scattering and radiation of fim layers...