A historical and future impact assessment of mining activities on surface biophysical characteristics change : A remote sensing-based approach

Mining activities and associated actions cause land-use/land-cover (LULC) changes across the world. The objective of this study were to evaluate the historical impacts of mining activities on surface biophysical characteristics, and for the first time, to predict the future changes in pattern of vegetation cover and land surface temperature (LST). In terms of the utilized data, satellite images of Landsat, and meteorological data of Sungun mine in Iran, Athabasca oil sands in Canada, Singrauli coalfield in India and Hambach mine in Germany, were used over the period of 1989-2019. In the first step, the spectral bands of Landsat images were employed to extract historical LULC changes in the study areas based on the homogeneity distance classification algorithm (HDCA). Thereafter, a CA-Markov model was used to predict the future of LULC changes based on the historical changes. In addition, LST and vegetation cover maps were calculated using the single channel algorithm, and the normalized difference vegetation index (NDVI), respectively. In the second step, the trends of LST and NDVI variations in different LULC change types and over different time periods were investigated. Finally, a CA-Markov model was used to predict the LST and NDVI maps and the trend of their variations in future. The results indicated that the forest and green space cover was reduced from 9.95 in 1989 to 5.9 Km(2) in 2019 for Sungun mine, from 42.14 in 1999 to 33.09 Km(2) in 2019 for Athabasca oil sands, from 231.46 in 1996 to 263.95 Km(2) in 2016 for Singrauli coalfield, and from 180.38 in 1989 to 133.99 Km(2) in 2017 for Hambach mine, as a result of expansion and development of of mineral activities. Our findings about Sungun revealed that the areal coverage of forest and green space will decrease to 15% of the total study area by 2039, resulting in reduction of the mean NDVI by almost 0.06 and increase of mean standardized LST from 0.52 in 2019 to 0.61 in 2039. our results further indicate that for Athabasca oil sands (Singrauli coalfield, Hambach mine), the mean values of standardized LST and NDVI will change from 0.5 (0.44 and 0.4) and 0.38 (0.38, 0.35) in 2019 (2016, 2017) to 0.57 (0.5, 0.47) and 0.33 (0.32, 0.28), in 2039 (2036, 2035), respectively. This can be mainly attributed to the increasing mining activities in the past as well as future years. The discussion and conclusions presented in this study can be of interest to local planners, policy makers, and environmentalists in order to observe the damages brought to the environment and the society in a larger picture.Peer reviewe

Analyzing the Impacts of Urbanization and Seasonal Variation on Land Surface Temperature Based on Subpixel Fractional Covers Using Landsat Images

Impervious surface areas (ISAs) and vegetation are two major urban land cover types. Estimating the spatial distribution of ISA and vegetation is critical for analyzing urban landscape patterns and their impact on the thermal environment. In this paper, linear spectral mixture analysis (LSMA) is used to extract their respective subpixel land cover composition from bitemporal Landsat images and the accuracy of the fractional covers is assessed with a subpixel confusion matrix at the category level and the map level by comparing with the reference data from high-resolution images. The percent ISA was divided into discrete categories representing different urban development density areas. Mean land surface temperature (LST) is calculated for each ISA category to analyze the thermal characteristics of different levels of development in the urban area of Fuzhou, China. ISA and vegetation variations are also quantified between different ISA categories and different dates. The contribution index is also calculated based on each ISA category to analyze the impact of different landscape patterns on the urban thermal environment. The results show that ISA category is an important determinant of the urban thermal environment. Furthermore, seasonal variations significantly impact the strength of this relationship. In the study area, the contribution indices were highest in the 90%–100% ISA category in summer 2013 and early spring 2001. The analytical methodologies used in this study can help to quantify urban thermal environmental functions under conditions of urban expansion and explore the climate adaptation potential of cities

Influence of Permeable Interlocking Concrete Paver Performance on Infiltration and Temperature in and Urban Watershed

Urbanization is a form of land use change that typically results in an expansion of impervious surfaces and increased soil compaction. These urban-induced changes in watershed hydrology can result in stream channel erosion, degraded water quality and stream aquatic habitat, increased ambient air temperatures, and increased peak flows, all of which pose challenges to stormwater management. Recent efforts to improve stormwater treatment have included the implementation of green stormwater infrastructure (GSI), which include a range of measures that use plant or soil systems, permeable surfaces or other features to store, infiltrate, or evapotranspire stormwater and reduce flows to storm sewer systems and surface waters. Permeable Interlocking Concrete Pavers (PICP) are one type of GSI implemented in urban settings to reduce runoff through infiltration of stormwater at its source. Over the past decade, East Carolina University has been implementing GSI on their Greenville, NC East Campus, and has installed approximately 0.3 hectares (3,000 square meters) of PICPs, to reduce flooding and ponding and urban stormwater impacts to local streams. Surface infiltration rates were measured at 18 PICP, 10 forested, 21 campus lawn, and 12 fractured asphalt locations to evaluate the effectiveness of PICPs on campus. Infiltration rates between the groups were significantly different (p < 0.05). The median infiltration rate of PICP sites was 587.41 cm/h and it was estimated that peak discharge to local streams may be reduced by approximately 11.47 cubic feet per second (cfs) with current PICP installations. Regular asphalt (RA) sites were tested for infiltration where fractures in the pavement intersected, with a median infiltration rate of 3.8 cm/h; however, there were not enough data to draw conclusions on the secondary permeability of fractured asphalt in this study. Forested and campus lawn soils had median infiltration rates of 5.46 cm/h and 0.95 cm/h, respectively. A total of 93 soil cone index values (kPa) were taken at campus lawn (n = 63) and forested (n = 30) sites to determine the effect of existing surface conditions on infiltration rates. There was a significant difference between infiltration rates (p = 0.007) and maximum compaction values (p = 0.000) for forested and campus lawn sites. Surface temperatures were taken at each PICP site and RA parking lots for comparison. Recorded surface temperatures for both asphalt and PICP were lowest between 9 pm and 6 am, with the median temperature of asphalt being 1.64 °C warmer. Data collected and analyzed from this study showed that fractured asphalt and campus lawns had significantly lower infiltration rates compared to forested soils and PICP installations. Moreover, relative to PICPs, asphalt displayed elevated surface temperatures for longer periods of time that contribute to local environmental warming. The results in this study indicate that PICPs are effective in sandy soils for the management of stormwater runoff in urban settings as an alternative or addition to traditional gray infrastructure (pipes, ditches, concrete curbs, and culverts), and PICPs have the potential to minimize effects of the UHI by maintaining lower nighttime temperatures and shorter periods of peak temperatures

Dinâmicas da temperatura de superfície no município de Porto Alegre : diagnósticos e prognósticos a partir de sensoriamento remoto

No Brasil em 2015 a população urbana era de 85,7%, com a projeção de aumento para 91% em 2050. Entre os impactos causados pelo rápido processo de urbanização estão as mudanças drásticas no uso e cobertura da terra (LULC), alterações meteorológicas e principalmente o aumento da Temperatura de Superfície Terrestre (LST). Sendo assim, a presente pesquisa tem como objetivo o estudo da dinâmica de crescimento urbano no município de Porto Alegre-RS, a partir da recuperação da LST e técnicas de redução de dados de sensoriamento remoto proximal a orbital. A primeira etapa constituiu a análise da evolução da LST entre áreas vegetadas e urbanizadas a partir da correlação de 30 anos de dados calculados de LST e o Índice de Vegetação por Diferença Normalizada (NDVI), em três bairros do município de Porto Alegre-RS. A sengunda etapa foi a expansão da área de estudo da primeira etapa, para o limite territorial do município. Nesta etapa, imagens da primavera de 1995, 2006 e 2017 foram utilizadas na caracterização histórica, previsão e relação do crescimento urbano e LST. A terceira etapa compõs uma análise da LST a partir de agrupamentos (k-médias) de NDVI obtidos em 1989 e 2018 especificamente sobre a área urbana dos bairros citados na primeira etapa. Na análise espaço-temporal do LULC e LST da primeira etapa foi possível observar que a retirada de 98% e 79% das áreas de floresta e campo, respectivamente, e o crescimento da mancha urbana de 31% em 1989 para 75% em 2018 contribuiram para o aumento de 4,18°C na LST média entre a primeira e ultima década. Entre os mesmos períodos, a influência sazonal pode ser observada no aumento de 6,36°C no outono, 4,40°C na primavera, 4,09°C no verão e 2,41°C no inverno. Além disso, a relação entre NDVI e LST em áreas urbanizadas mostrou um aumento associado ao coeficiente de correlação de - 0,55 em 1989 para -0,76 em 2018. Na segunda discussão, observou-se o aumento da área urbana de Porto Alegre em 10,16% e aumento 2,03 das áreas com LST entre 35 e 40°C, no período de 1995 a 2017. A previsão para 2028 caracterizou o aumento de 1,41% e 2,33% até 2039 na área urbana e previsão de aumento de 2,39% e 2,64% nas áreas com LST entre 35 e 40°C, respectivamente. Na terceira discussão, a retirada de ~89% da vegetação da área de estudo para ocupação urbana aliada ao aumento de aproximadamente 21% para ~43% das áreas urbanas classificadas como baixo índice de vegetação, ocasionou o aumento da amplitude térmica (diferença de LST média das áreas de baixo e alto NDVI em 1989 e 2018) de 1,12°C. As informações acerca da evolução e previsão da LST frente as mudanças no LULC contribuem para tomada de decisões e mitigação do fenômeno de Ilhas de Calor Urbanas (ICUs) por parte de adminstradores responsáveis pelo planejamento urbano e pela manutenção dos serviços públicos no município de Porto Alegre- RS.In Brazil, in 2015, the urban population was 85.7%, with a projected increase to 91% in 2050. Among the impacts caused by the rapid urbanization process are drastic changes in land use and land cover (LULC), meteorological changes and mainly the increase in the Land Surface Temperature (LST). Thus, this research aims to study the dynamics of urban growth in the city of Porto Alegre-RS, based on the recovery of LST and data reduction techniques from proximal to orbital remote sensing. The first stage consisted of analyzing the evolution of LST between vegetated and urbanized areas based on the correlation of 30 years of data calculated from LST and the Vegetation Index by Normalized Difference (NDVI), in three districts of the city of Porto Alegre-RS. The second stage was the expansion of the study area of the first stage, to the territorial limit of the municipality. In this step, images from the spring of 1995, 2006 and 2017 were used in the historical characterization, forecast and relationship of urban growth and LST. The third stage comprises an analysis of the LST based on groupings (k-means) of NDVI obtained in 1989 and 2018 specifically on the urban area of the neighborhoods mentioned in the first stage. In the spatiotemporal analysis of the LULC and LST of the first stage, it was possible to observe that the removal of 98% and 79% of the forest and field areas, respectively, and the growth of the urban area from 31% in 1989 to 75% in 2018 contributed for the 4.18°C increase in mean LST between the first and last decade. Between the same periods, the seasonal influence can be observed in the increase of 6.36°C in autumn, 4.40°C in spring, 4.09°C in summer and 2.41°C in winter. Furthermore, the relationship between NDVI and LST in urbanized areas showed an increase associated with the correlation coefficient from - 0.55 in 1989 to -0.76 in 2018. In the second discussion, the increase in the urban area of Porto Alegre was observed by 10.16% and a 2.03 increase in areas with LST between 35 and 40°C, in the period from 1995 to 2017. The forecast for 2028 characterized an increase of 1.41% and 2.33% by 2039 in the urban area and a forecast increase of 2.39% and 2.64% in areas with LST between 35 and 40°C, respectively. In the third discussion, the removal of ~89% of the vegetation in the study area for urban occupation, together with the increase from approximately 21% to ~43% of urban areas classified as low vegetation index, caused an increase in the thermal amplitude (difference of LST average of low and high NDVI areas in 1989 and 2018) of 1.12°C. Information about the evolution and prediction of LST in the face of LULC changes contribute to decision-making and mitigation of the phenomenon of ICUs by administrators responsible for urban planning and maintenance of public services in Porto Alegre city