Evolução multitemporal da linha de costa (1972-2040) do município de Soure, Ilha do Marajó (Amazônia - Brasil)

Abstract

Exogenous agents that act in the Coastal Zone (ZC) act as morphological modelers of the CoastLine (LC) and this action modifies the erosive and accretive scenario of the LC over time. To assess these temporal changes in the ZC, remote sensing (SR), from orbital remote sensors, is an opening that makes it possible to identify these variations, where the main objective around the world is the management and protection of these coastal areas. Thus, the present composition aims to present the evolution of the LC line during the period 1972-2020 (48 years) and estimate the evolution of the LC for the years 2030 and 2040 in the ZC of the Soure municipality, located in the northeastern part (NE) of the Marajó island (Pará-Eastern Amazon), inserted in the Pará Estuarine Coastal Zone (ZCEP), conditioned by the hydrodynamics of the South channel of the Amazon River and by the estuary of the Pará River. A set of 6 images from a time series of the satellite were acquired: Landsat 1 (MSS) from 1972 and 1994 (bands 7.6.5 and 5.4.3, respectively), Landsat 5 (TM) from 1985, 2004, 2009 ( bands 5.4.3), with a spatial resolution of 30m, and Landsat 8 (OLI) 2020 (bands 6.5.4.8), with a spatial resolution of 15 m after the fusion of band 8 (panchromatic), being obtained from the USGS (United States Geological Survey) site, all already georeferenced and geoprocessing techniques for: a) LC delimitation: where it was created from semi-automatic methods combined with manual methods, using the normalized water difference index (NDWI) technique; b) DSAS version 5.0 (v5.0), being used to compose the LC analysis hrough this tool: NSM, EPR and LRR, version v5 brings the Kalman Filter, which was used to calculate the future estimate in the LC for the years 2030 and 2040. As a result, it was identified that in sectors I and II (southern channel of the Amazon River), accretion predominates, in sector III (Maguari Cape) it is where it obtained the highest accretion rates, and in sector IV the accretion process predominates with a tendency erosive, sector V erosion predominates. These data are linked to the total number of 654 transects comprising an average distance of 214.4 m, where the mean retreat is indicated with a negative rate of - 179.5 m and a positive rate of 451.9 m. For the years 2030 and 2040, the trend is that this process will continue, where the greatest coastal retraction, around 271.46 m, will be in the Northeast (NE) (sector II), and a CL advance of 625.26 m in sector III.