ANÁLISE MULTITEMPORAL DAS LAGOAS DA REGIÃO DOS LENÇÓIS MARANHENSES ENTRE 1985 E 2020

Abstract

The long-term history of water has been used to produce thematic products that document different facets of surface water dynamics, thus guiding the pursuit of responsible water management and placing it on the agenda for discussion in many countries around the world. This required more information about changes in the Earth's surface, making constant monitoring essential. With remote sensing we have the possibility of a multitemporal analysis of the landscape, that is, through the evaluation of the spectral response patterns of satellite images at different periods. Thus, the research used data from the TRMM-3B34 Satellite together with data from rainfall stations for analysis and validation. The main objective of this dissertation is to analyze the spatial-temporal dynamics of the interdune ponds of the Lençóis Maranhenses National Park (LMNP) from 1985 to 2020, based on product classifications and analysis made available on the Google Earth Engine platform, as well as evaluating through from language R, the identification and monitoring of changes in the Conservation Areas using descriptive statistics and graphic production. The study area is located in the northeast region of Brazil, east coast of the state of Maranhão, and became an environmental protection area through Federal Decree Nº. 86.060, of June 2, 1981. Field observations were carried out for collection of control points in the visited lakes, to assess the advance and retraction, as well as help in the classification of water bodies. Occurrence and transition maps of the lakes were drawn up over a period of more than 3 (three) decades, and a trend of advance towards NE-SW and regions with positional stability of the ponds was identified. The variation of precipitation in relation to the wind system of the monitoring points was used to identify the period of occurrence of the change in years of historical maximum and minimum precipitation, such as in 2009 and 2012. The results showed the areas of change and no change and the positional variations of the ponds in relation to the area of the PNLM. It was also identified the expansion of the lakes, from the coast towards the interior of the continent, occurs in the northeast-southwest direction (NE-SW) following the circulation of the trade winds and that the vegetation region helps in the fixation of the dunes and consequently in the permanence of the ponds in certain regions. Data from the TRMM satellite and rainfall stations were of great importance in translating the changes in the analyzed area quite accurately in relation to the reference data stations. The multitemporal analysis proved to be effective to understand and monitor the displacement of ponds in the PNLM, in addition to being of great relevance for the planning of environmental and social policies in the region.