Satellite Eye for Galathea 3

Australia seen from Envisat, 17 to 22 October 2006.

ESA’s environmental satellite Envisat watches Earth from a polar orbit. The instrument MERIS observes Earth through recordings in 15 bands of the electromagnetic spectrum. Here is shown a combination of bands including the near-infrared light which is invisible to the human eye. As green vegetation does not use the near-infrared light for photosynthesis, the reflection of this type of light is large from green vegetation.

When we place the near-infrared light band in the red image channel, the red light band in the green image channel and the green light band in the blue image channel, we obtain a so-called false-color image of the surface of the earth. In this case vegetation is shown in reddish colors.

The areas in red color show green vegetation and this is located in a region near Perth in Southwestern Australia as well as in Eastern Australia between Sydney and Melbourne. In Perth a dry summer will follow the wet Australian winter that is nearly over now. The climate in Perth much resembles the climate known in the Mediterranean area in Europe. In contrast, Eastern Australia has precipitation year round which gives lush natural vegetation as well as good conditions for agriculture. The inner part of Australian is very dry with sparse vegetation.

Technical information

The mosaic is produced in Google Earth using MERIS images from Envisat. The spatial resolution is reduced to 2 km x 2 km per pixel.

You can produce the mosaic yourself using Google Earth. Each of the parts of the stripes of images that origin from each individual orbit of Envisat can be taken from: http://galathea.oersted.dtu.dk/google/kmz/images/Vejr/

The same images in jpg- and in geotif-format for analysis in the image processing program LEOWorks can be downloaded from: http://galathea.oersted.dtu.dk/base/areas/Australia/

The weekly image is produced by Ørsted-DTU, one of the partners in the project Satellite Eye for Galathea 3.