About satellites monitoring of Amazon deforestation, National Institute for Space Researche (INPE) states:
1. Nowadays INPE has two operational systems – PRODES and DETER for the Amazon monitoring deforestation . They are complementary systems and were conceived to attend different objectives.
2. PRODES measures the shallow cut annual taxes for increments superior to 6.25 hectares. Those measurements are made in months when there are good conditions of observation in the Amazon territory; in general it occurs from July to September (when 90% of the region is seen without clouds coverage). Because it is more detailed and depends on dry season climate conditions to capture images free of clouds, it has been done only once a year, and every year has its disclosure foreseen for December.
3. Working since 2004, DETER was created by INPE as an alert system to support surveillance and deforestation control of Amazon. With this device, INPE monthly make public alert maps with areas bigger than 25 hectares. These maps show deforested areas (shallow cut) and those in deforestation process computed together in the deforested measured area. As an alert system, DETER needs to point the deforestation as a process and not only in the final phase (shallow cut). DETER only counts huge areas and there are some months on which those monitoring are affected by clouds presence.
4. INPE does not recommend DETER’s data use for tax estimative deforestation. The inter annual variability of meteorological conditions affects detection capacity of DETER’s mapping objects, (shallow cut and forestall degradation) making possible quantitative comparisons between DETER results from different years and tax projections of annual deforestations. The four years old temporal series of PRODES and DETER’s joint conjunction is not sufficient for the strong statistical relationships establishment from DETER’s results in the estimative production of the annual tax deforestation in shallow cut category, a PRODES attribution that uses appropriate sensors for this purpose since 1988.
5. However DETER’s number indicates, that the annual deforestation tax to be measured by PRODES for August/07 – July/08 will be probably the biggest from the one measured in August/06 – July/07. To make it short, INPE does not recommend prognostics about the magnitude of this deforestation raising. It is good to remind that DETER’s indication areas aims the planning from the surveillance activities by IBAMA and the Department of the Environment The system is totally transparent and INPE publishes in DETER’website all information available, including images and other coverage cloud maps and deforesting polygons.
