| 1. |
- Rafee, Sameh A.Abou, et al.
(författare)
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Spatial trends of extreme precipitation events in the Paraná river basin
- 2020
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Ingår i: Journal of Applied Meteorology and Climatology. - 1558-8424. ; 59:3, s. 443-454
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Tidskriftsartikel (refereegranskat)abstract
- This work presents an analysis of the observed trends in extreme precipitation events in the Paraná River basin (PRB) from 1977 to 2016 (40 yr) based on daily records from 853 stations. The Mann–Kendall test and inverse-distance-weighted interpolation were applied to annual and seasonal precipitation and also for four extreme precipitation indices. The results show that the negative trends (significance at 95% confidence level) in annual and seasonal series are mainly located in the northern and northeastern parts of the basin. In contrast, except in the autumn season, positive trends were concentrated in the southern and southeastern regions of the basin, most notably for annual and summer precipitation. The spatial distributions of the indices of annual maximum 5-day precipitation and number of rainstorms indicate that significant positive trends are mostly located in the south-southeast part of the basin and that significant negative trends are mostly located in the north-northeast part. The index of the annual number of dry days shows that 88% of significant trends are positive and that most of these are located in the northern region of the PRB, which is a region with a high number of consecutive dry days (>90). The simple daily intensity index showed the highest number of stations (263) with mostly positive significant trends.
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| 2. |
- Rudke, A. P., et al.
(författare)
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Landscape changes over 30 years of intense economic activity in the upper Paraná River basin
- 2022
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Ingår i: Ecological Informatics. - : Elsevier BV. - 1574-9541. ; 72
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we show the complexity associated with the recent land cover changes by elucidating the paths of 30 years of changes in the Upper Paraná River Basin (UPRB), a region severely impacted by agricultural activity, one of the areas with the highest density in the production of hydroelectricity, biofuels and food in the world. In this sense, a post-classification comparison approach based on Landsat images was used to identify detailed ‘from-to’ paths behind those land cover changes. The most expressive changes were the expansion of Cropland and Forest areas and the reduction in savannas, with a net change of 17.9%, 4.1%, and −16.9% of the UPRB area, respectively. Cropland areas showed an expressive increase between 1985 and 2015, rising from 249,439 km2 (27.7%) to 412,909 km2 (45.9%). Forest areas increased from 149,389 km2 to 185,839 km2 in the period. Notably, for this class, an intense spatial dynamic of losses (7.5%) and gains (11.6%) took place between 1985 and 2015. This behavior is related to the disappearance of native vegetation fragments in some sub-basins, as well as to afforestation, reforestation, and/or forest restoration in others. The Cerrado (a typical tropical savanna in South America), the most impacted natural biome of the Basin, decreased from 21.9% of the UPRB in 1985 (196,746 km2) to only about 5% of the whole UPRB area in 2015. Grassland areas, mostly used for livestock, decreased from 271,827 km2 (30.2%) to 229,007 km2 (25.5%). This net decrease was associated with a reduction of 160,830 km2 (17.8%) and the appearance of 118,010 km2 (13.2%) in new areas, previously occupied by tropical savannas in 1985. In conclusion, economic factors were the main drivers for land cover changes, especially agriculture and livestock activities, besides forestry and hydroelectric energy production. In addition, Grassland areas that predominated on the left banks of the UPRB in 1985 retreated with the advance of Cropland areas, mainly due to the expansion of sugarcane for ethanol production, a biofuel widely used in Brazil. In turn, pasture areas migrated to the right bank and occupied a significant part of the Cerrado. Finally, our results demonstrate that the transition dynamics among land cover classes can involve complex political-economical mechanisms that are not always captured by remote sensing.
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| 3. |
- Rudke, A. P., et al.
(författare)
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Mapping past landscapes using landsat data : Upper Paraná River Basin in 1985
- 2021
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Ingår i: Remote Sensing Applications: Society and Environment. - : Elsevier BV. - 2352-9385. ; 21
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Tidskriftsartikel (refereegranskat)abstract
- During the last decades, the science of remote sensing of the Earth's surface has produced an enormous amount of data. In parallel, with the increase in computational capacity, several classification methods have been applied to the satellite retrievals. This timely combination allows recovering more accurate knowledge about the land cover maps of past times. Therefore, the main goal of this work was to develop a land cover product for the year 1985 in the Upper Paraná River Basin (UPRB-1985), one of the largest and most economically important river basins in the world. The land cover map was developed using a supervised classifier - SVM (Support Vector Machine) applied to data from Landsat TM (Thematic Mapper) sensor. The classification process was carried out based on 52 scenes collected during 1985 and a total of 17,040 training samples across the basin. Pixel and Object-based methods were used to classify Landsat scenes. The generated mapping accuracy was assessed using statistical criteria adopted in the literature - Global Accuracy and Kappa Index. The McNemar's test result showed no significant differences (at the 5% level) between the Pixel-based and Object-based classifications, even with the Object-based classification accuracy was slightly higher (Global Accuracy of 79.8%). However, some relationship between the relief and the classification approach was observed. In sub-basins with high slopes, the mean overall accuracy values of the Pixel-based classification approach were 13.1% higher than the Object-based approach. By mapping past land cover, this work is strategic information to understand ongoing processes, as well as to assess changes in land cover that have occurred over time and evaluate to what extent they explain the variability in the hydrology of the region.
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| 4. |
- Rudke, A. P., et al.
(författare)
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How mobility restrictions policy and atmospheric conditions impacted air quality in the State of São Paulo during the COVID-19 outbreak
- 2021
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Ingår i: Environmental Research. - : Elsevier BV. - 0013-9351. ; 198
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Tidskriftsartikel (refereegranskat)abstract
- Mobility restrictions are among actions to prevent the spread of the COVID-19 pandemic and have been pointed as reasons for improving air quality, especially in large cities. However, it is crucial to assess the impact of atmospheric conditions on air quality and air pollutant dispersion in the face of the potential variability of all sources. In this study, the impact of mobility restrictions on the air quality was analyzed for the most populous Brazilian State, São Paulo, severely impacted by COVID-19. Ground-based air quality data (PM10, PM2.5, CO, SO2, NOx, NO2, NO, and O3) were used from 50 automatic air quality monitoring stations to evaluate the changes in concentrations before (January 01 - March 25) and during the partial quarantine (March 16 - June 30). Rainfall, fires, and daily cell phone mobility data were also used as supplementary information to the analyses. The Mann-Whitney U test was used to assess the heterogeneity of the air quality data during and before mobility restrictions. In general, the results demonstrated no substantial improvements in air quality for most of the pollutants when comparing before and during restrictions periods. Besides, when the analyzed period of 2020 is compared with the year 2019, there is no significant air quality improvement in the São Paulo State. However, special attention should be given to the Metropolitan Area of São Paulo (MASP), due to the vast population residing in this area and exposed to air pollution. The region reached an average decrease of 29% in CO, 28% in NOx, 40% in NO, 19% in SO2, 15% in PM2.5, and 8% in PM10 concentrations during the mobility restrictions period compared to the same period in 2019. The only pollutant that showed an increase in concentration was ozone, with a 20% increase compared to 2019 during the mobility restrictions period. Before the mobility restrictions period, the region reached an average decrease of 30% in CO, 39% in NOx, 63% in NO, 12% in SO2, 23% in PM2.5, 18% in PM10, and 16% in O3 concentrations when compared to the same period in 2019. On the other hand, Cubatão, a highly industrialized area, showed statistically significant increases above 20% for most monitored pollutants in both periods of 2020 compared to 2019. This study reinforces that the main driving force of pollutant concentration variability is the dynamics of the atmosphere at its various time scales. An abnormal rainy season, with above average rainfall before the restrictions and below average after it, generated a scenario in which the probable significant reductions in emissions did not substantially affect the concentration of pollutants.
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| 5. |
- Rafee, Sameh A.Abou, et al.
(författare)
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Large-scale hydrological modelling of the Upper Paraná River Basin
- 2019
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Ingår i: Water. - : MDPI AG. - 2073-4441. ; 11:5
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Tidskriftsartikel (refereegranskat)abstract
- The Upper Paraná River Basin (UPRB) has undergone many rapid land use changes in recent decades, due to accelerating population growth. Thus, the prediction of water resources has crucial importance in improving planning and sustainable management. This paper presents a large-scale hydrological modelling of the UPRB, using the Soil andWater Assessment Tool (SWAT) model. The model was calibrated and validated for 78 outlets, over a 32-year simulation period between 1984 and 2015. The results and the comparison between observed and simulated values showed that after the calibration process, most of the outlets performed to a satisfactory level or better in all objective functions analyzed with 86%, 92%, 76%, 88%, and 74% for Percent bias, Coefficient of determination, Nash-Sutcliffe efficiency, Kling-Gupta efficiency, and the Ratio of Standard deviation of observations to root mean square error, respectively. The model output provided in this work could be used in further simulations, such as the evaluation of the impacts of land use change or climate change on river flows of the Upper Paraná Basin.
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| 6. |
- Moreira, Camila A.B., et al.
(författare)
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Natural variability in exposure to fine particles and their trace elements during typical workdays in an urban area
- 2018
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Ingår i: Transportation Research Part D: Transport and Environment. - : Elsevier BV. - 1361-9209. ; 63, s. 333-346
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Tidskriftsartikel (refereegranskat)abstract
- Studies on the natural human exposures to fine particulate matter (PM2.5) and their elements composition are practically non-existent in South America. In order to understand the natural exposure of the typical Brazilian population to PM2.5 and their trace element composition, we measured PM2.5 concentrations and collected mass on filters for nine continuous hours during a typical workday of volunteers. In addition, bus routes were performed at peak and non-peak periods, mimicking the routine activity of the population. Mean concentrations of PM2.5 in the bus and car groups were similar while the fraction of BCe was higher for the bus group. For all routes, mean PM2.5 concentrations were higher during peak than non-peak hours, with an average of 43.5 ± 33.1 μg m−3 and 14.3 ± 10.2 μg m−3, respectively. The trace elements S, K and Na originated mainly from vehicle emissions; Na was associated with the presence of biofuel in diesel. Toxic elements (Pb, Cr, Cu, Ni, Zn, Mn) were found at low levels as evident by the total hazard index that ranged from 2.15 × 10−03 to 1.38 for volunteers. For all routes, the hazard index ranged from 2.25 × 10−03 to 5.03. Average PM2.5 respiratory deposition dose was estimated to be 0.60 μg/kg-hour for peak hours. Potential health damages to people during their movements and at workplaces close to the traffic were identified. Improvements in the design of the building to reduce the entrance of air pollutants as well as the use of filters in the buses could help to limit population exposure.
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