Advanced Spaceborne Thermal Emission and Reflection Radiometer

ASTER ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) is a Japanese sensor which is one of five remote sensory devices on board the Terra satellite launched into Earth orbit by NASA in 1999. The instrument has been collecting superficial data since February 2000. ASTER image draped over terrain model of Mount Etna

ASTER ASTER provides high-resolution images of the planet Earth in 14 different bands of the electromagnetic spectrum, ranging from visible to thermal infrared light. The resolution of images ranges between 15 to 90 meters. ASTER data are used to create detailed maps of surface temperature of land, emissivity, reflectance, and elevation. The ASTER GDEM is available at no charge to users worldwide via electronic download. ASTER image of Rub' al Khali(Arabia's Empty Quarter)

ASTER Bands ASTER false-colour satellite image of 2010 eruption of Mount Merapi, showing evidence of a large pyroclastic flow along the Gendol River south of Mount Merapi

Long-wave infrared or thermal IR Band Label Wavelength (µm) Resolution (m) Nadir or Backward Description B1 VNIR_Band1 0.520–0.600 15 Nadir Visible green/yellow B2 VNIR_Band2 0.630–0.690 Visible red B3 VNIR_Band3N 0.760–0.860 Near infrared B4 VNIR_Band3B Backward B5 SWIR_Band4 1.600–1.700 30 Short-wave infrared B6 SWIR_Band5 2.145–2.185 B7 SWIR_Band6 2.185–2.225 B8 SWIR_Band7 2.235–2.285 B9 SWIR_Band8 2.295–2.365 B10 SWIR_Band9 2.360–2.430 B11 TIR_Band10 8.125–8.475 90 Long-wave infrared or thermal IR B12 TIR_Band11 8.475–8.825 B13 TIR_Band12 8.925–9.275 B14 TIR_Band13 10.250–10.950 B15 TIR_Band14 10.950–11.650

Version 1 ASTER Global Digital Elevation Model On 29 June 2009, the Global Digital Elevation Model (GDEM) was released to the public.  A joint operation between NASA and Japan's Ministry of Economy, Trade and Industry (METI), the Global Digital Elevation Model is the most complete mapping of the earth ever made, covering 99% of its surface.  The previous most comprehensive map, NASA's Shuttle Radar Topography Mission, covered approximately 80% of the Earth's surface, with a global resolution of 90 meters, and a resolution of 30 meters over the USA.

The GDEM covers the planet from 83 degrees North to 83 degrees South (surpassing SRTM's coverage of 56 °S to 60 °N), becoming the first earth mapping system that provides comprehensive coverage of the polar regions.  It was created by compiling 1.3 million VNIR images taken by ASTER using single-pass stereoscopic correlation techniques, with terrain elevation measurements taken globally at 30 meter (98 ft) intervals.

Despite the high nominal resolution, however, some reviewers have commented that the true resolution is considerably lower, and not as good as that of SRTM data, and serious artifacts are present. Some of these limitations have been confirmed by METI and NASA, who point out that the current version of the GDEM product is "research grade".

Version 2 During October 2011 version 2 of Global Digital Elevation Model was publicly released.  This is considered an improvement upon version 1. These improvements include increased horizontal and vertical accuracy, better horizontal resolution, reduced presence of artifacts, and more realistic values over water bodies. 

However, one reviewer still regards the Aster version 2 dataset, although showing 'a considerable improvement in the effective level of detail', to still be regarded as 'experimental or research grade' due to presence of artefacts.  A recent study has shown that over rugged mountainous terrain the ASTER version 2 data set can be a more accurate representation of the ground than the SRTM elevation model.

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