ACRES Update, Issue 20, 20th Anniversary Edition, December 1999 ACRES releases SPOT 4 products Celebrating 20 years Satellie imagery used in projects to reduce global warming Alice Springs Landsat 7 poster

This document describes a tape format used by ACRES Data Acquisition Facility (DAF) in Alice Springs and the Tasmanian Earth Resources Satellite Station (TERSS) in Hobart for raw data storage of satellite data. Although the format is generic enough to be used with a variety of tape drive technologies, the ADF implementation is currently using Digital Linear Tapes (DLTs). This format description is therefore explicitly discussing (and may therefore appear limited to) the DLT. More specifically, the tape drives used at the DAF and TERSS ground stations are DLT7000s. PURPOSE OF THE DOCUMENT This is an Interface Control Document (ICD). The intent is to produce a description detailed enough for any developer of a system or software module to make use of and interface in an optimum way to the device/module/format subject of this description.

The product SAR.GTC is a digital image generated from raw SAR data takes using up-tp-date auxiliary parameters, with the best available instrumental corrections applied, precisely located, corrected for terrain varieations and rectified onto a map projection. The ESA SAR.GTC format is based on the general definition of the SAR CEOS format (ref. ER-IS-EPO-GS-5902).

The product SAR.SLC is a single look complex digital image generated from raw SAR data using up-to-date auxiliary parameters. The image, projected on sland range, referred to as 'quarter scene' or quadrant corresponds to approximately one half (range) by one half (azimuth) of a full scence image. The ESA SAR.SLC format is based on the general definition of the SAR CEOS format (ref. ER-IS-EPS-GS-5902).

The product SAR.GEC is a digital image generated from raw SAR data takes using up-to-date auxiliary parameters, with the best available instrumental corrections applied, precisely located and rectified onto a map projection. The JERS SAR.GEC format is based on the general definition of the SAR CEOS format (ref. ER-IS-EPO-GS-5902).

The product SAR.GEC is a digital image generated from raw SAR data takes using up-to-date auxiliary parameters, with the best available instrumental corrections applied, precisely located and rectified onto a map projection. The JERS SAR.GEC format is based on the general definition of the SAR CEOS format (ref. ER-IS-EPS-GS-5902).

Legacy product - no abstract available

The purpose of this paper is to investigate and quantify the near-field and far-field contamination effects from GRACE data to assess whether or not they influence the accuracy with which hydrological signals in the Murray-Darling Basin, southeast Australia can be estimated. Far-field contamination was assessed by modelling some of the world's largest geophysical processes which generate major gravitational signals (e.g. melting of the Greenland icesheet, hydrology in the Amazon Basin) while near-field contamination was modelled by simulating gravitational variability of the Australian continent. Contamination was measured by simulating each of the processes and measuring the proportion of the simulated signal detected in the Murray - Darling Basin. The sum of the cumulative near-field and far-field effects revealed a maximum of ~10 mm (equivalent water height) of spurious signal within the Murray - Darling Basin. This equates to only one quarter of the formal uncertainty of the basin-scale estimates of changes in total water storage. Thus, GRACE products can be used to monitor broad scale hydrologic trends and variability in the Murray-Darling Basin without the need to account for contamination of the estimates from external geophysical sources.

Archived imagery

We investigate two intraplate earthquakes in a stable continental region of southwest Western Australia. Both small-magnitude events occur in the top »1 km of crust and their epicenters are located with an accuracy of »100 m (1¾) using satellite Interferometric Synthetic Aperture Radar (InSAR). For the Mw 4.7 Katanning earthquake (10 October 2007) the average slip magnitude is 42 cm, over a rupture area of »1 km2. This implies a high stress drop of 14-27 MPa and, even for this very shallow earthquake, has important implications for regional seismic hazard assessment. The earthquake rupture extends from a depth of around 640 m to the surface, making it a rarely observed intraplate, surface-rupturing event. Using InSAR observations we estimate the coseismic slip distribution of the shallow earthquake, such estimates being rarely available for small magnitude events. For the Mw 4.4 composite Kalannie earthquake sequence (21-22 September 2005) we use a long-term time series analysis technique to improve the measurement of the co-seismic signal, which is a maximum of 27 mm in the line-of-sight direction. Double difference seismic analysis shows some relocated cluster seismicity which corresponds in timing, location and source parameters to the InSAR-observed deformation. This earthquake is the smallest magnitude seismic event investigated using InSAR and demonstrates the capability of the technique to provide important constraints on small-magnitude coseismic events. The shallow depth of both these events adds weight to the suggestion that earthquakes associated with tectonic processes in this area of Western Australia often initiate in the upper 1 km of crust.