EMBRAPA - CNPMMap-synthesis of 228 Landsat satellite images: definition of up to 30 metersEMBRAPA - CNPM
The Brazilian Company for Farming Research (Embrapa) has put the more than 5 million square kilometers of the Amazon onto nine CDs. By joining the images provided by the Landsat satellite, the Embrapa Satellite Monitoring of Campinas, has set up the complete photography, more updated and with the greatest definition yet done, of the national Amazon territory. The definition is of 30 to 90 meters per pixel (point), between 11 and 16 times more detailed than its predecessors. Each pixel of the mosaic, of invisible joints, corresponds to between 30 and 60 meters, except in the territories of the states Amazonas and Pará, where it is equivalent to 90 meters. Until this moment, the satellite picture of the Amazon basin with the clearest definition had pixels equivalent to 1 kilometer.
By providing improved data on natural resources and the environmental impacts of rural and urban activities, the mosaic facilitates the ecological and economic zoning of the region, an instrument that is decisive for planning and for rational occupation, in a manner that minimizes environmental damage. With the images, one can also identify, for example, new areas with a potential towards ecotourism. This is the case of the region of Barcelos, just north of the river Rio Negro in the Amazon basin. The images help to identify areas with potential or restrictions for agricultural use, especially in the States of Mato Grosso, Tocantins and Maranhão.
The mosaic even provides an unprecedented vision of the magnitude of the giant bamboo forests of in the States of Acre and Amazonas, present in soils influenced in the past by the volcanic activity of the Andes. The comparison of the new images with the previous ones shows even the dimension and the rapidity of the grassing of the forest by the excessive use of burning in areas of Cerrado (wooded savanna). This is particularly noticeable in the north of Pará, where the Cerrado, along all of its border of hundreds of kilometers, is advancing dozens of meters per year.
Embrapa is also at the final stage of satellite images for the Northeast of Brazil, which should throw considerable light on the discussion about the impact of the eventual transposition of the SãoFrancisco river, about the convenience of an expansion of irrigation, of the impacts of drought and the intensity of the deforesting of (Caatinga) (The semi-arid vegetation) . By the end of the year, the company intends to have concluded satellite images of all of the States.
Less forest fires
The environmentalist Evaristo Eduardo de Miranda, research manager of Embrapa Satellite Monitoring who is responsible for the project, says that the idea of producing the mosaic of satellite images is old, but that it only became viable two years ago through the financing of the FAPESP Infrastructure Program for the modernization of the computer networks of the company. “We didn’t have the capacity to analyze, select and process so many images, with so much detail”, he recalls. The final push was given by the increase in burnings. “The Ministry of Agriculture understood that fines and laws weren’t enough. It was necessary to offer alternative technologies to the farmers to substitute the burnings in diverse situations”, reveals the researcher.
With the information of ten years of satellite monitoring of burnings, Embrapa called the attention of the Ministry to the fact that 75% of the problem was concentrated in four States: Mato Grosso, Tocantins, Pará and Maranhão. “We proposed identifying the municipalities where the problems were most serious and to concentrate on them a campaign for the better use of resources.” This required mosaics of satellite images with a level of detail much greater that that available at that time.
At the beginning of 2000, the Ministry financed the purchase of the images which were then processed. Within a month and a half, the work was ready. It showed not only where the problems were concentrated, but the type of soil use in each area, which helped to bring alternative technologies to each case. Impressed, the Ministry decided to finance the purchase of images of the remainder of the Amazon basin and afterwards of the whole of the country. The result was that, after years of uninterrupted growth in burned-over lands, for the first time last year the number of forest fires in the country fell. The average reduction was 24.5% in the states where the government promoted the campaign directed by satellite and of only 8.6% in the others.
Internet and CDs
Besides guiding the official campaign to combat forest fires, the Amazon basin mosaic is a powerful instrument for non-governmental organizations to monitor environmental impacts. Many pictures are already being used by high school students, since part of the material was put on the Internet in June (www.cdbrasil.cnpm.embrapa.br). More than 90% of the 228 pictures that make up the mosaic are from 1999 and 2000. Older material was only used when the current images were of inferior quality or there was a high cloud cover.
“We carried out a true picture of the Amazon basin at the turn of the century and we placed it within the reach of the general public. Never before had anyone seen the whole of the region with all of this richness of detail”, says Miranda.The material is also available on nine CD-ROMs, one for each Amazon state at a cost of R$ 40.00 each. The CDs can be acquired through the Embrapa site given above or by telephone at (0xx19)3252-5977. On request, Embrapa will freely make them available to Brazilian research institutions. Also there are copies of a large photograph of high definition of the Amazon basin that is almost 3 meters in length.
The CDs offer four successive zooms on the general map of each State, arriving at a closeness that corresponds more or less to that which one would see from a helicopter under conditions of little cloud. It is possible to distinguish rivers, fluvial deltas, roads, towns, mountains, pastures, burned and reforested areas, various agricultural lands, as well as natural pastures of the region – high and lowland forests, plains, swamplands, Cerrados, cultivated lands and even bamboo forests. The CDs also offer basic guidance for the user to interpret the images.
The project confirmed certain studies and brought surprises, such as the intensity of urbanization and the large extent of the use of forest burning in indigenous populated areas. Special attention was brought to the Tiriós Indian reserve on the frontier with Suriname, where the burned strip of land is greater than 100 kilometers wide. Many tribes have used fires for thousands of years for hunting or for preparing land for cultivation.
Deforested towns
On crossing the information from its mosaic with the satellite program DMSP (Defense Meteorological Satellite Program), which provides night images of the planet, Embrapa mapped out more than 1,300 Amazonian towns, villages and settlements which have electricity available. The official estimate was that there would be less than 1,000. The work confirmed that today it is the towns which command deforesting. The majority of the areas deforested are concentrated in a circle of 30 kilometers around urban zones. “Today it is mainly urban investment in the land that is deforesting and not so much the large ranchers or the traditional small farmer”, says Miranda.
“For example, we discovered that a town practically unknown such as Itaituba, the end of the line for the TransAmazon Highway in Pará , has a hinterland much more deforested than the city of Manaus. What is missing is to investigate why.”The mosaic even shows the intensity of the contamination caused by the pig iron foundries in the region of the town of Açailândia, in Maranhão. The soot impregnated into the roads and on the rooftops transformed the town into a dark purple mark.
Even small areas of mining can be located. This is because the satellite registers in very distinct tones mud-colored waters (black) and those that are translucent (clear blue). Since mining takes place on the margins of the river, it creates a visible stain. “At the origins of these stains, we almost always see a deforested area”, reports the researcher. The work points out illegal occupation, especially in the State of Rondônia. Here the clue is not color but form. According to Miranda, in an area of small properties, – identified by geometric stains on the side of the highways, – a straight entrance which finishes in a large area of deforesting is a definite indicator of illegal and devastating occupation. Also one can observe how much in indigenous areas in Pará, Mato Grosso and Tocantins are invaded or surrounded
Alternatives to burning
On the positive side, an increase in productivity in the growing of grain and cotton in the south of Maranhão and in Mato Grosso has been confirmed. Although the total planted area has not increased, the agricultural production has not stopped growing over the past few years, as the images reveal. It is believed that the images might even be helpful in combating locust swarms, a plague that hits Mato Grosso, as they would permit locating and qualifying thetype of habitat where the locust reproduces, and monitoring the direction of the swarm in function of the climatic conditions, and thus of act on the first signs of super populations.
As to the alternatives to burning, one needs to identify firstly what is the reason behind it. In pasture regions, such as Mato Grosso, the south of Pará and Bananal island, in Tocantins, the burning usually serves to combat the tick or for the elimination of soil straw, so that the grass will germinate quicker. To combat the tick, it is enough to leave the pasture range without cattle for two to three months. Also, to guarantee food for the cattle, the storage of straw at the end of summer, for use during winter, is recommended. And furthermore, the researchers remind that without burning the productivity of the pasture increases.
In agriculture, burning eliminated the leftovers of the last harvest as well as assisting the new planting. In reality, the alternative depends on the size of the property, which can be evaluated on the orbital images. In whatever case, there is equipment, manual or motorized, which allows for planting in the presence of straw or the incorporation of it into the ground.
Research impulse
The picture of the Amazon basin on the CDs is likely to lower costs and accelerate projects on the monitoring of environmental impact. Alejandro Dorado, a doctor in environmental administration from the Public Health School of the University of São Paulo (USP), gave an example. “To carry out my thesis, I had to purchase 28 satellite images at a cost of R$ 1,000 each and to spend months selecting and mounting the strips with the least cloud cover. Now all of this is available on CDs.” As the images correspond exactly to the maps of the Brazilian Institute of Geography and Statistics (IBGE), and can be easily printed on paper or transparencies, the CDs allow that geographers at all levels can make use of these maps.
Even in research that took place years ago, the images allow for qualitative leaps. This is the case of the study of the environmental impact of settling in Machadinho do Oeste, in the north of Rondônia, in an area of 5,000 km2 with 10,000 settlers. The study has followed up 500 rural property owners for 16 years, looking at 250 environment variables, economic activities and social indicators. The properties were classified in according to their situation in these three areas, and 36 were selected with good performance in all of them and a survey was conducted on the standards of exploration adopted.
The spatial diversification in the use of the land of each property was observed, and also the ratio between perennial and annual crops and the relationship between cattle rearing and agriculture. “With the more detailed satellite images we can now observe each property and obtain much more information. Today we have one of the most complete data bases on environmental impact and the sustainability of agriculture in the Amazon basin.”
State zoning
With the images, Embrapa helps the State of Maranhão to carry out economic and ecological zoning. In this manner, once the problems and necessities in each area have been identified, a policy of sustainable development can be sketched out. Already, the dimension of the deforesting of the strip to the west of the railway line from Carajás has been revealed, the invasion of the lumber dealers into indigenous reserves and conserved units such as the Gurupi Reserve, and the modernization of the growing of soybeans and cotton in the south of the State. “The information provided by the images, now available on the Internet (www.ma.gov.br), is being analyzed together with the communities of each area in the state to find the best means of reconciling development and preservation,” says Miranda.
Colors and East Timor
The increase in the capacity for image processing by Embrapa is generating sub-products. By processing them through the computer, more detailed information (of up to 15 meters) and comprehensive areas (the registration of light in seven visible colors and others invisible to the human eye) can be obtained. This is because the computer distinguishes 256 tones of gray while the human eye can only differentiate around 13. “By identifying which of these tones corresponds to water contaminated by sediment, for example, we can ask the computer to artificially color these points, in a manner that then allows us to look at pollution which is invisible to the naked eye.
This is already being done with the sewers of domestic sewage going into rivers and lakes”, adds Miranda.Another sub-product was a present. During the dramatic process of the struggle for the independence of East Timor, Embrapa decided to give the country its complete map taken from space.
Touched when seeing the image on photographic paper of nearly three meters in length, one of the East Timor leaders stated: “I’ve been fighting for my country for 20 years, but this is the first time that I see it in its entirety.” The photos for the poster were taken exactly on one of the days of the large massacres promoted by the militia pro-Indonesia. Fires, smoke and destruction are perfectly visible. “We ended up producing a historical document of the independence of East Timor”, comments the researcher.
The Project
Expansion of Local Network by Embrapa Satellite Monitoring (nº 96/10284-9); Modality Infrastructure Program; Coordinator Evaristo Eduardo de Miranda -Embrapa Satellite Monitoring; Investment R$ 115,320.00
