Earth Orbiting Satellites Page 3 of 6 Low spatial resolution applications The National Oceanic and Atmospheric Administration (NOAA) polar orbiting satellites were primarily designed to meet the requirements for weather forecasting. The main imaging sensor, the Advanced Very High Resolution Radiometer (AVHRR) produces low-resolution satellite data, with a spatial resolution of over 1 kilometre. The system obtains data in five wavebands (one red, one near infrared and three thermal infrared) from a 2,400-kilometre strip directly below the remote sensing vehicle. Apart from meteorological data NOAA satellites also provide other important information, particularly terrain analysis and environmental applications, which include vegetation assessments and natural hazard monitoring. Vegetation assessments The vegetation index, a measure of vegetation greenness or health, has been developed as a method of improving the visibility of healthy vegetation on satellite images, and is now a valuable tool for environmental monitoring. Vegetation indices are calculated using infrared and red images and used for applications such as, vegetation mapping and broad scale vegetation assessments. Datasets from NOAA have been used for global monitoring, where a general view of large areas are required and enable 'trouble spots' to be identified and targeted for further analysis, particularly through detailed ground surveys. This method of image analysis thus ensures scarce resources are used effectively. These dataset can also be studied in conjunction with meteorological images that have been analysed for rainfall, to provide indications of looming disasters, such as drought and crop failures. For example, have a look at the following images of Europe, which areas would be more likely to experience crop failures? Click on the thumbnails to enlarge the image   Europe Vegetation Health 2002 Total precipitation for Europe between 1 June - 31 August 2002 | 1 | 2 | 3 | 4 | 5 | 6 | Page 3 of 6