ASTER First Light Images

January 01, 2000

Visible/near Infrared (VNIR) Image (monochrome)

This ASTER image of the San Francisco River region in Brazil was recorded in the near-infrared wavelength region (band 3N). Bright clouds and their shadows obscure some of the area, but the the river and numerous lakes are well defined by their low reflectance in this wavelength region. Bright areas along the river suggest dense vegetation, perhaps related to tropical rain forests and agricultural development.
(Image area: approximately 20km. x 20 km.; ground resolution - 15m x 15m)

Thermal-Infrared (TIR) Image (color)

This ASTER thermal-infrared composite image, the first high spatial resolution multispectral thermal infrared data from satellite, is of an area in the Afar Triangle, about 60 km to the south of image 2. It shows color variations which are mainly due to rock and soil composition differences; temperature differences are expressed as brightness variations. Areas shown in the red hues on the left and right sides are probably underlain by rocks with high silicon-dioxide content, whereas those areas appearing white and lavender in the central part are a more mafic composition, dominantly basaltic lava flows and cinder cone deposits. The dark areas within the complex of basaltic rocks are mainly domes, which are highly fractured. The multispectral thermal-infrared capability of ASTER will permit compositional determinations that are not possible in the shorter wavelength regions. The ten very bright pixels in the lower center of the image show high temperatures of molten lava in the summit crater of the active Erta Ale volcano.
(The size of image: 60km x 60km approx., ground resolution 90m x 90m approx. A decorrelation stretch was applied to bands 10, 12 and 14 in blue, green and red respectively.)
Images courtesy of MITI, ERSDAC, JAROS, and the U.S./Japan ASTER Science Team
See the NASA Visible Earth image directory at for additional scenes from instruments on the satellite.