31 March 2006
Landsat 5 imagery acquired 9 October 2005 shows the Tully, Innisfail, Babinda and Atherton tablelands region. The cropped areas are seen as a geometric pattern in various shades of pink, the bright green areas are predominantly natural vegetation. The dull blue or mauve areas are built-up/urban areas.
Geoscience Australia, ACRES has scheduled acquisition of imagery to capture post Cyclone Larry damage. See Cyclone Larry emergency response - Satellite imagery acquisition for a current list of scheduled acquisitions.
Landsat 5 (BGR) Bands 147. © Commonwealth of Australia, Geoscience Australia - ACRES (2006)
For more information contact ACRES on 02 6249 9779 or e-mail earth.observation@ga.gov.au
28 March 2006
A comparison of Radarsat Synthetic Aperture Radar (SAR) images acquired on 27 January 2000 (pre-cyclone) and 25 March 2006 (post-cyclone) shows the effects of Cyclone Larry around Innisfail.
In the SAR image acquired on 25 March 2006, 5 days after Cyclone Larry hit Innisfail, the patterns associated with agricultural areas are less distinct in the post-cyclone image. Flooding from heavy rain following the cyclone can be seen in the image as dark patches to the north-west and the south-east of Innisfail. Reduced brightness within the built-up areas and the surrounding agricultural areas is typical in SAR images following damage to buildings and crops. However, moisture in the ground and orientation of ground features with respect to the SAR sensor have a profound effect on how features appear in the image.
Optical satellite images are of limited use under cloudy conditions but SAR can penetrate through cloud & rain to image the ground below. Although the two SAR images shown here were acquired under similar viewing geometries and spatial resolutions, features seen in the images are influenced by a number of variables, which need to be considered while using these images. Interpretation associated with these SAR images needs to be validated by verification on the ground.
While using these SAR images please provide acknowledgement as follows: RADARSAT-CSA2006, SAR images acquired and processed by Geoscience Australia.
See ACRES Digital Catalogue for further imagery.
For more information contact ACRES on 02 6249 9779 or e-mail earth.observation@ga.gov.au
Pre-cyclone Larry image of Innisfail district, Queensland - 27 January 2000
Post-cyclone Larry image of Innisfail district, Queensland - 25 March 2006
23 March 2006
ACRES is acquiring Satellite imagery over the cyclone affected area of Queensland. Pre-cyclone imagery includes MODIS, Landsat 5 and Radarsat-1. Imagery is viewable in the Digital Catalogue.
For more information contact ACRES on 02 6249 9779 or e-mail earth.observation@ga.gov.au
15 March 2006
On 15 March 2006 an unexpected problem occurred in Landsat 5's ability to transmit data, causing an interruption in data acquisition. Engineers are studying the problem and testing is underway. For more information visit the USGS website.
13 March 2006
ACRES is in the process of changing the Level 1 MODIS processing software from IMAPP (International MODIS and AIRS Processing Package) to SeaDAS MODISL1DB (SeaWiFS Data Analysis System). The change is primarily due to the lack of support for current radiometric Look Up Tables (LUTs) in the IMAPP system and improvements in both product quality and interoperability of SeaDAS products with image processing packages and tools.
Sample products are provided on our website and give potential users the opportunity to examine differences in the proposed L1B SEADAS and current IMAPP products.
A guide to data in sample folders:
More information about the SeaDAS MODISL1DB processor.
ACRES is considering a move to MRTSwath (MODIS Reprojection Tool Swath) from MS2GT (MODIS Swath To Grid Toolbox) for the production of our map oriented products as well as producing a GEOTIFF format product (still with ER Mapper and ENVI headers). The Map Oriented products in the SeaDAS sample ftp folder were produced using the MRTSwath tool. Current users of these products should not be disadvantaged as the move to GEOTIFF will enable GIS users to more readily ingest ACRES Level 1B Map products. The move to MRTSwath is made in an attempt to maintain consistency between our L1B Map Oriented products and our soon to be released MOD09 Surface Reflectance Map Oriented and higher level products. Users of ACRES Level 1B Map Oriented products will notice some changes including a subtle difference in appearance due to a change in resampling method (Elliptical Weighted average to Nearest Neighbour resampling) and background or null area value.
Your feedback is important so please let us know if you have any improvement suggestions relating to the proposed changes - earth.observation@ga.gov.au
01 March 2006
We are pleased to announce the public release of our upgraded online digital catalogue. The upgrade makes it even easier to search and find your desired scene from a comprehensive archive of over 200Tb of Satellite data dating back to 1979.
The upgraded catalogue retains the same look and feel as the old catalogue, but includes the following additional features:
The ability to more accurately define the geographical extents of products within the catalogue will help ACRES Distributors to more efficiently transfer customers' product parameters to ACRES for ordering. If customers prefer to perform their own scene searches, the new functionality will help them more accurately define their needs to distributors.
Another useful feature of the new catalogue is that ACRES now has the in-house capability to customise the look and feel of the pages. This allows us to be more flexible in making future suggested changes.
Please go to the Digital Catalogue to search the catalogue and see the changes.
25 January 2006
Samples of the new MODIS products have been prepared to enable potential users to get an idea of the "look and feel" of the products prior to their official release later in the year. The MOD09 products are the result of significant steps being made by ACRES operations in the implementation of the MODIS Surface Reflectance algorithm (MOD09). As a result, The MOD09 products represent an estimate of the land surface spectral reflectance as would be measured at ground level in the absence of atmospheric absorption and scattering.
MODIS sample products corrected for the Bidirectional Reflectance Distribution Function (BRDF) and atmospheric coupling effects are also planned to be available later this year. The advance has special implications in multi-temporal analysis and allows users to more accurately relate spectral responses in an image to actual field measurements.
As with ACRES L1B MODIS products, users will be able to choose between MOD09 HDF format and MOD09 map projected (Lambert Conformal Conic Projection) generic binary format with ER Mapper and ENVI headers. Sample products are available on our website. We would greatly appreciate feedback from users on these sample products. Please send comments to earth.observation@ga.gov.au. For more information on MOD09 including details on product contents see the MODIS Land Surface Reflectance Science Computing Facility website.
24 January 2006
The Japanese ALOS satellite was successfully launched on 24 January 2006.
23 January 2006
We are pleased to announce that Landsat 5 is in the process of being returned to full operational status.
You will recall that on 26 November 2005 the back-up solar array drive on Landsat 5 began exhibiting unusual behaviour. The solar array drive maintains the proper pointing angle between the solar array and the sun. After the immediate implementation of power saving measures, a series of tests were performed to establish the exact cause of the problem and investigate the possibility of returning the satellite to service.
Through the first phase of testing, it was determined that the standard 1-omega rotation speed (orbital rate) of the array was no longer reliable. This confirmed the condition that was identified last November. The good news was that the 2- and 3-omega rotation speeds (which are faster than omega-1) did appear to operate normally. Analysis of the drive system and the leading 1-omega failure scenario were consistent with the solar array drive functioning at these higher rotational rates.
Next, testing was done to assess the health of the TM after its 45-day operational hiatus and determine the impacts to its Bumper Mode function. This was critical as the new mission concept of operation now included the periodic rotation of the array at 2-omega to maintain an optimal angle to the sun. Again, there was good news in that the instrument operated well with a quiescent satellite (to be expected) and even appeared to produce acceptable imagery when the array was stopped and started during an imaging event. (This last claim is still undergoing test and evaluation.)
As of 23 January we are able to announce that ACRES was the first international ground station (outside the US) to downlink Landsat 5 data as it returned to service.
Other worldwide ground stations are being incrementally added to the schedule as the satellite operator monitors the power budget on the spacecraft and the sensor's state of health. These further tests may lead to some interruptions in the short term, but these will be kept to a minimum.
10 January 2006
Testing of the Landsat 5 solar array began on January 3, 2006. Preliminary results are being reviewed and testing is expected to continue through the end of January. Landsat 5 back-up solar array drive difficulties started in November 2005.
Any new information will be available from the USGS website.
The design of the Landsat 5 satellite, which was launched on March 1, 1984, has lasted longer than anticipated and has established a tremendous record for reliability.
The currently operating Landsats 5 and 7 orbit at an altitude of 705 km. Each of the satellites has a 16-day orbit cycle, but the two orbits are offset by eight days, thus allowing 8-day repeat coverage. Landsats 5 and 7 are also designed to collect data over a 185km swath, and continue to provide important observations of the Earth.
10 January 2006
On January 10, 2006, the encapsulated "Advanced Earth Observing Satellite (ALOS)" left the Spacecraft and Fairing Assembly Building 2 (SFA2), for the launch of the Multi-functional Transport Satellite 2 by the H-IIA Launch Vehicle No. 8 (H-IIA F8). The Scheduled date of the "Advanced Earth Observing Satellite (ALOS)" launch is January 24, 2006 (Japan Standard Time, JST) at the Tanegashima Space Center (TNSC) in Kagoshima.
After launch, there will be an extensive testing phase lasting for between 6 to 9 months before any products will become operationally available. ACRES will be one of four worldwide data Nodes for the reception and distribution of ALOS data.
The ALOS satellite has been developed to contribute to the fields of mapping, precise regional land coverage observation, disaster monitoring, and resource surveying. ALOS has three sensors: