Direct assessment of burned areas with the use of Modis satellite images.
One of the main activities of Map International is the application of observation and study technology of the characteristics of the Earth’s surface, based on the interaction of the materials on the surface with the electromagnetic radiation. Map International, with the precious help of its scientific partners, monitored and recorded, being one of the first to do, the devastating results of the recent fires.
MODIS satellite images, provided free of charge from NASA, are a very strong tool for the monitoring of the natural terrestrial surface, the oceans and the atmosphere of our planet. MODIS program has receivers in two different satellites (Terra and Aqua) that view the entire Earth’s surface two times daily at most. The resolution provided ranges from 250m to 1km and the program improves and complements the data acquisition with satellites NOAA-AVHRR. MODIS receivers have designed to provide measurements of high spectral resolution in 36 different areas of the electromagnetic spectrum. Apart from the visible channels (blue, green and red), there are channels scattered in areas of the spectrum that record very useful information for the applications of remote sensing. In brief, there are channels in the infrared spectrum that allow the detection and recording of vegetation and water volumes and combined with visible channels, information for the coverage and land use is extracted. There are channels in the thermal infrared that record the temperature of the surface as well as of the atmosphere and the oceans. In addition, there are some specialized channels that record the phytoplankton of the sea, the sea currents, the ozone, the height of the clouds in the atmosphere and many more. Regarding fires, the spectral and temporal resolution of MODIS receivers are the great advantages on the opposite of mediocre geometric resolution. However, due to the great area they record, MODIS satellite images can be used directly for an initial assessment of the burned areas but also for a valuation of green areas’ reduction on the planet’s surface.
The methodology for the assessment of the burned area is based on modern methods of Digital Remote Sensing. These are: enhancement of the images, creation of color composites, use of filters, application of mathematical operators and execution of mathematical operations between different channels of the electromagnetic spectrum. Most technologically advanced methodologies concern the detection of changes from temporal data acquisition, the use of thermal channels for the detection of thermal irregularities on the natural terrestrial surface and the classification of the images for the automated recording of land use categories. On a research level, artificial intelligence and identification of patterns for the automated identification, marking and area measurement of the burned areas are used.
Based on the above, Map International measured 1752.10 thousand stremmata of burned areas in Peloponnese, 227.5 in Evia, and 32.1 in Attica and the rest Sterea, for the period between the 18th and the 30th of August 2007.