@Article{LoboCostNovoTelm:2016:DiArSm,
               author = "Lobo, Felipe and Costa, Maycira and Novo, Evlyn M{\'a}rcia 
                         Le{\~a}o de Moraes and Telmer, Kevin",
          affiliation = "{University of Victoria} and {University of Victoria} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)} and {University 
                         of Victoria}",
                title = "Distribution of artisanal and small-scale gold mining in the 
                         Tapaj{\'o}s River Basin (Brazilian Amazon) over the past 40 years 
                         and relationship with water siltation",
              journal = "Remote Sensing",
                 year = "2016",
               volume = "8",
               number = "7",
                 note = "{Setores de Atividade: Pesquisa e desenvolvimento 
                         cient{\'{\i}}fico.}",
             keywords = "gold mining, remote sensing, Tapaj{\'o}s Basin.",
             abstract = "An innovative remote sensing approach that combines land-use 
                         change and water quality information is proposed in order to 
                         investigate if Artisanal and Small-scale Gold Mining (ASGM) area 
                         extension is associated with water siltation in the Tapaj{\'o}s 
                         River Basin (Brazil), containing the largest small-scale gold 
                         mining district in the world. Taking advantage of a 40-year period 
                         of the multi-satellite imagery archive, the objective of this 
                         paper is to build a normalized time-series in order to evaluate 
                         the influence of temporal mining expansion on the water siltation 
                         data (TSS, Total Suspended Solids concentration) derived from 
                         previous research. The methodological approach was set to deliver 
                         a full characterization of the ASGM expansion from its initial 
                         stages in the early 1970s to the present. First, based on 
                         IRS/LISSIII images acquired in 2012, the historical Landsat image 
                         database (19732001) was corrected for radiometric and atmospheric 
                         effects using dark vegetation as reference to create a normalized 
                         time-series. Next, a complete update of the mining areas 
                         distribution in 2012 derived from the TerraClass Project (an 
                         official land-use classification for the Brazilian Amazon) was 
                         conducted having IRS/LISSIII as the base map with the support of 
                         auxiliary data and vector editing. Once the ASGM in 2012 was 
                         quantified (261.7 km2 ) and validated with photos, a reverse 
                         classification of ASGM in 2001 (171.7 km2 ), 1993 (166.3 km2 ), 
                         1984 (47.5 km2 ), and 1973 (15.4 km2 ) with the use of Landsat 
                         archives was applied. This procedure relies on the assumption that 
                         ASGM changes in the land cover are severe and remain detectable 
                         from satellite sensors for decades. The mining expansion area over 
                         time was then combined with the (TSS) data retrieved from the same 
                         atmospherically corrected satellite imagery based on the 
                         literature. In terms of gold mining expansion and water siltation 
                         effects, four main periods of ASGM activities were identified in 
                         the study area: (i) 19581977, first occurrence of mining 
                         activities and low water impacts; (ii) 19781993, introduction of 
                         low-budget mechanization associated with very high gold prices 
                         resulting in large mining area expansion and high water siltation 
                         levels; (iii) 19942003, general recession of ASGM activities and 
                         exhaustion of easy-access gold deposits, resulting in decreased 
                         TSS; (iv) 2004 to present, intensification of ASGM encouraged by 
                         high gold prices, resulting in an increase of TSS.",
                  doi = "10.3390/rs8070579",
                  url = "http://dx.doi.org/10.3390/rs8070579",
                 issn = "2072-4292",
                label = "lattes: 9857505876280820 3 LoboCostNovoTelm:2016:DiArSm",
             language = "en",
        urlaccessdate = "25 abr. 2024"
}