DETER system- Deforestation Detection in Real Time, from National Institute for Space Research (INPE) as informed in the project’s main page (www.obt.inpe.br/deter/) is a support tool for the surveillance and not a faithful evaluation for the Amazon monthly deforestation, due to the satellites resolution and from the inconstant clouds coverage that varies from one month to another. DETER must be used only as a trend indicator of annual deforestation.
DETER system has pointed out for August 756km2 of deforestation in the Legal Amazon. From this total, 435 km2 in Para and 229km in Mato Grosso state. Are twice more than those happened in July that was 323km 2. However, according to DETER this number is less that the one registered in June, May and April, being the present one the worst from 2008, when the Amazonia lost in 30 days, 1,1124km2.
These numbers consider the areas that suffered shallow cut (total deforestation), or progressive degradation, must be analyzed together with the data, regarding the occurrence of clouds, that prevents the satellite monitoring.
Em agosto, 74% da Amazônia Legal pôde ser vista, porém ficaram encobertos 99% do Amapá e 77% de Roraima. O Mato Grosso ficou livre das nuvens em agosto, enquanto o Pará teve 24% de sua área encoberta. Esta cobertura é para o conjunto de imagens MODIS que foram utilizadas.
In August, 74% of the Legal Amazon could be seen, although were covered 99% of Amapá and 77% of Roraima. Mato Grosso got free of clouds in August, while Para had 24% of its area totally covered. This cover is for images obtained from MODIS.
The table below shows the 756 km2 deforestation, distributed by state
Evaluation
With the Landsat and CBERS satellite images, which present better spatial resolution (20 and 30 meters), INPE process DETER’s data qualification, that uses low resolution sensor (250 meters) that is compensated by the daily observation capacity. The Evaluation Report that you can find at www.obt.inpe.br/deter, shows 89% of the pointed areas by DETER were confirmed as deforested ones. Were estimated 420 alert, which represent 446 km2 or 59% of the total polygons area (756km2) indicated by DETER in August.
The alert indicated mainly shallow cut deforestation (67,5%) for high intensity forestall degradation (17%), categories that the soil answering prevails over the rare
The polygons not confirmed as deforestation (11%) were in the whole sense less than 2km2. For INPE’s technicians, these results prove that DETER’s alert are able enough to orientate the surveillance and point out the priority areas for monitoring the field.
DETER
Being in operation since 2004, DETER was created by INPE as an alert system to support surveillance and deforestation control. Both shallow cut and areas in process of deforestation are mapped. It is possible to detect only deforestation polygons with an area larger than 25 hectares due to spatial resolution (DETER uses MODIS sensor data from Terra satellite, and WFI sensor data from China Brazil Earth Resources Satellite -CBERS, with spatial resolution of 250 meters). Due to cloud coverage, not all deforestation larger than 25 hectares is able to be identified by the system.
