Emissions from biomass burning challenge efforts to curb air pollution in cities downwind of fire-prone regions,as they contribute large amounts of brown carbon(Br C)and black carbon(BC)particles.We investigated the p...Emissions from biomass burning challenge efforts to curb air pollution in cities downwind of fire-prone regions,as they contribute large amounts of brown carbon(Br C)and black carbon(BC)particles.We investigated the patterns of Br C and BC concentrations using Aethalometer data(atλ=370 and 880 nm,respectively)spanning four years at a site impacted by the outflow of smoke.The data required to be post processed for the shadowing effect since,without correction,concentrations would be between 29%and 35%underestimated.The Br C concentrations were consistently higher than the BC concentrations,indicating the prevalence of aerosols from biomass burning.The results were supported by the Angstrom coefficient(A_(370/880)),with values predominantly larger than 1(mean±standard deviation:1.25±0.31).A_(370/880)values below 1 were more prevalent during the wet season,which suggests a contribution from fossil fuel combustion.We observed sharp Br C and BC seasonal signals,with mean minimum concentrations of 0.40μg/m^(3)and 0.36μg/m^(3),respectively,in the wet season,and mean maximum concentrations of 2.05μg/m^(3)and 1.53μg/m^(3)in the dry season.The largest concentrations were observed when northerly air masses moved over regions with a high density of fire spots.Local burning of residential solid waste and industrial combustion caused extreme Br C and BC concentrations under favourable wind directions.Although neither pollutant is included in any ambient air quality standards,our results suggest that transboundary smoke may hamper efforts to meet the World Health Organization guidelines for fine particles.展开更多
Socioeconomic and environmental losses caused by water erosion have highlighted the importance of quantifying and understanding the dynamics of soil redistribution in the landscape to develop effective soil management...Socioeconomic and environmental losses caused by water erosion have highlighted the importance of quantifying and understanding the dynamics of soil redistribution in the landscape to develop effective soil management practices.Several methods are applied to estimate erosion/deposition rates and identify sources of sediments,among them,the one that uses rare earth elements(REE)as a tracer stands out.However,an alternative not yet explored that can benefit the accuracy of the estimates provided by the method is using a tracer containing a chemical signature composed of more than one REE.The present study aimed to evaluate the performance of a new water erosion tracer based on montmoril-lonite labeled with rare earth elements(La40-MMT).The innovative aspects of this La40-MMT tracer include its highly stable multi-chemical signature(Nd^(3+),La^(3+),and Pr^(3+)),which enhances tracer detection in the environment,and its low production cost due to the use of an industrial residue in the synthesis process.The tracer was evaluated for a typical soil of the Cerrado biome,using a natural rainfall field-scale plot-NRFP(5 m × 20 m)and a physical predictive erosion model(WEPP).The results showed that the La40-MMT tracer could be used to estimate erosion/deposition rates,with agreement between the values observed with the tracer and the WEPP model.Thus,this study confirmed the great potential of La40-MMT as a tool to identify patterns of soil redistribution at the field scale and aid in the validation of erosion models.展开更多
This article shows experimentally the thermal performance of two test cells with different coverage systems, Ught Green Roof （LGR） and ceramic roof by analyzing internal surface temperatures （IST） in the ceiling a...This article shows experimentally the thermal performance of two test cells with different coverage systems, Ught Green Roof （LGR） and ceramic roof by analyzing internal surface temperatures （IST） in the ceiling and dry bulb temperatures （DBT）. The objective was to evaluate the spatial distnbution of temperatures in buildings according to spatial and temporal Dynamic CUmato[ogy approaches. An experimental, typical day for heat conditions was determined. The data of the main climatic vari- ables provided by an automatic weather station and temperatures inside the test cells were collected using thermocouples installed such that the entire space is included. The results led to the conclusion that the LGR has a balanced IST and DBT spatial distribution compared with ceramic roofs. Nevertheless, the analysis of the thermal performance is only one of the variables that must be considered when developing a construction proposal that is adapted to the context. The manner in which the thermocouples were placecl inside the test cells also showed the importance of specifying the location of the sensors in experimental studies on the behavior and thermal performance of buildings.展开更多
Present global maps of soil water retention(SWR)are mostly derived from pedotransfer functions(PTFs)applied to maps of other basic soil properties.As an alternative,'point-based'mapping of soil water content c...Present global maps of soil water retention(SWR)are mostly derived from pedotransfer functions(PTFs)applied to maps of other basic soil properties.As an alternative,'point-based'mapping of soil water content can improve global soil data availability and quality.We developed point-based global maps with estimated uncertainty of the volumetric SWR at 100,330 and 15000 cm suction using measured SWR data extracted from the WoSIS Soil Profile Database together with data estimated by a random forest PTF(PTF-RF).The point data was combined with around 200 environmental covariates describing vegetation,terrain morphology,climate,geology,and hydrology using DSM.In total,we used 7292,33192 and 42016 SWR point observations at 100,330 and 15000 cm,respectively,and complemented the dataset with 436108 estimated values at each suction.Tenfold cross-validation yielded a Root Mean Square Error(RMSE)of6380,7.112 and 6.48510^(-2)cm^(3)cm^(-3),and a Model Efficiency Coefficient(MEC)of0.430,0386,and 0.471,respectively,for 100,330 and 15000 cm.The results were also compared to three published global maps of SWR to evaluate differences between point-based and map-based mapping approaches.Point-based mapping performed better than the three map-based mapping approaches for 330 and 15000 cm,while for 100 cm results were similar,possibly due to the limited number of SWR observa-tions for 100 cm.Major sources or uncertainty identified included the geographical clustering of the data and the limitation of the covariates to represent the naturally high variation of SWR.展开更多
基金financial resources from the Coordination for the Improvement of Higher Education Personnel (CAPES/Brazil)。
文摘Emissions from biomass burning challenge efforts to curb air pollution in cities downwind of fire-prone regions,as they contribute large amounts of brown carbon(Br C)and black carbon(BC)particles.We investigated the patterns of Br C and BC concentrations using Aethalometer data(atλ=370 and 880 nm,respectively)spanning four years at a site impacted by the outflow of smoke.The data required to be post processed for the shadowing effect since,without correction,concentrations would be between 29%and 35%underestimated.The Br C concentrations were consistently higher than the BC concentrations,indicating the prevalence of aerosols from biomass burning.The results were supported by the Angstrom coefficient(A_(370/880)),with values predominantly larger than 1(mean±standard deviation:1.25±0.31).A_(370/880)values below 1 were more prevalent during the wet season,which suggests a contribution from fossil fuel combustion.We observed sharp Br C and BC seasonal signals,with mean minimum concentrations of 0.40μg/m^(3)and 0.36μg/m^(3),respectively,in the wet season,and mean maximum concentrations of 2.05μg/m^(3)and 1.53μg/m^(3)in the dry season.The largest concentrations were observed when northerly air masses moved over regions with a high density of fire spots.Local burning of residential solid waste and industrial combustion caused extreme Br C and BC concentrations under favourable wind directions.Although neither pollutant is included in any ambient air quality standards,our results suggest that transboundary smoke may hamper efforts to meet the World Health Organization guidelines for fine particles.
文摘Socioeconomic and environmental losses caused by water erosion have highlighted the importance of quantifying and understanding the dynamics of soil redistribution in the landscape to develop effective soil management practices.Several methods are applied to estimate erosion/deposition rates and identify sources of sediments,among them,the one that uses rare earth elements(REE)as a tracer stands out.However,an alternative not yet explored that can benefit the accuracy of the estimates provided by the method is using a tracer containing a chemical signature composed of more than one REE.The present study aimed to evaluate the performance of a new water erosion tracer based on montmoril-lonite labeled with rare earth elements(La40-MMT).The innovative aspects of this La40-MMT tracer include its highly stable multi-chemical signature(Nd^(3+),La^(3+),and Pr^(3+)),which enhances tracer detection in the environment,and its low production cost due to the use of an industrial residue in the synthesis process.The tracer was evaluated for a typical soil of the Cerrado biome,using a natural rainfall field-scale plot-NRFP(5 m × 20 m)and a physical predictive erosion model(WEPP).The results showed that the La40-MMT tracer could be used to estimate erosion/deposition rates,with agreement between the values observed with the tracer and the WEPP model.Thus,this study confirmed the great potential of La40-MMT as a tool to identify patterns of soil redistribution at the field scale and aid in the validation of erosion models.
文摘This article shows experimentally the thermal performance of two test cells with different coverage systems, Ught Green Roof （LGR） and ceramic roof by analyzing internal surface temperatures （IST） in the ceiling and dry bulb temperatures （DBT）. The objective was to evaluate the spatial distnbution of temperatures in buildings according to spatial and temporal Dynamic CUmato[ogy approaches. An experimental, typical day for heat conditions was determined. The data of the main climatic vari- ables provided by an automatic weather station and temperatures inside the test cells were collected using thermocouples installed such that the entire space is included. The results led to the conclusion that the LGR has a balanced IST and DBT spatial distribution compared with ceramic roofs. Nevertheless, the analysis of the thermal performance is only one of the variables that must be considered when developing a construction proposal that is adapted to the context. The manner in which the thermocouples were placecl inside the test cells also showed the importance of specifying the location of the sensors in experimental studies on the behavior and thermal performance of buildings.
文摘Present global maps of soil water retention(SWR)are mostly derived from pedotransfer functions(PTFs)applied to maps of other basic soil properties.As an alternative,'point-based'mapping of soil water content can improve global soil data availability and quality.We developed point-based global maps with estimated uncertainty of the volumetric SWR at 100,330 and 15000 cm suction using measured SWR data extracted from the WoSIS Soil Profile Database together with data estimated by a random forest PTF(PTF-RF).The point data was combined with around 200 environmental covariates describing vegetation,terrain morphology,climate,geology,and hydrology using DSM.In total,we used 7292,33192 and 42016 SWR point observations at 100,330 and 15000 cm,respectively,and complemented the dataset with 436108 estimated values at each suction.Tenfold cross-validation yielded a Root Mean Square Error(RMSE)of6380,7.112 and 6.48510^(-2)cm^(3)cm^(-3),and a Model Efficiency Coefficient(MEC)of0.430,0386,and 0.471,respectively,for 100,330 and 15000 cm.The results were also compared to three published global maps of SWR to evaluate differences between point-based and map-based mapping approaches.Point-based mapping performed better than the three map-based mapping approaches for 330 and 15000 cm,while for 100 cm results were similar,possibly due to the limited number of SWR observa-tions for 100 cm.Major sources or uncertainty identified included the geographical clustering of the data and the limitation of the covariates to represent the naturally high variation of SWR.
