The Global AVHRR 1KM dataset was commissioned by the International Geosphere Biosphere Programme (IGBP), and has generated a series of global composite images at 1Km resolution.
Each image comprises ten days data, and is generated by merging all available scenes from a ten-day period. Pixels are selected using a maximum-NDVI rule, ensuring that cloud-free scenes are preferred over cloudy ones. Nevertheless, the quality is variable, and most of the composite images are less than complete.
The archive spans the period April 1992 - May 1996, but is subject to gaps in its coverage, and production is currently suspended pending funding decisions. The browse archive on this CD includes all the data products currently available. The available scenes are numbered as follows in the archive:
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1992 | 01-3 | 04-6 | 07-9 | 10-2 | 13-5 | 16-8 | 19-21 | 22-4 | 25-7 | |||
| 1993 | 28-30 | 31-3 | 34-6 | 37-9 | 40-2 | 43-5 | 46-8 | 49-51 | 52-4 | |||
| 1994 | ||||||||||||
| 1995 | 103-5 | 106-8 | 109-11 | 112-4 | 115-7 | 118-20 | 121-3 | 124-6 | 127-9 | 130-2 | 133-5 | |
| 1996 | 136-8 | 148-50 |
Each AVHRR scene comprises ten data bands: AVHRR Bands 1-5, NDVI, Satellite Zenith, Solar Zenith, Relative Azimuth, and Date Index. In the HyperDAAC browse archive, each band except the Date Index is shown as an 8-bit greyshade image. A slightly different colourmap has been assigned to each band: this gives each a slight colouring and helps to distinguish them visually when viewing several bands in one display.
The Date Index identifies the HRPT scenes from which each pixel in the composite dataset is taken. It is presented in a similar manner to the Land Classification Bands, with a ColourMap Editor that enables you to highlight scenes in your choice of colours.
Please note that WebÞing is not responsible for, and cannot support, the data except insofar as we may update this product as and when new data become available.