Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.031
Filtrar
1.
Nat Commun ; 13(1): 2265, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35477962

RESUMO

The "marine ice-sheet instability" hypothesis continues to be used to interpret the observed mass loss from the Antarctic and Greenland ice sheets. This hypothesis has been developed for conditions that do not account for feedbacks between ice sheets and environmental conditions. However, snow accumulation and the ice-sheet surface melting depend on the surface temperature, which is a strong function of elevation. Consequently, there is a feedback between precipitation, atmospheric surface temperature and ice-sheet surface elevation. Here, we investigate stability conditions of a marine-based ice sheet in the presence of such a feedback. Our results show that no general stability condition similar to one associated with the "marine ice-sheet instability" hypothesis can be determined. Stability of individual configurations can be established only on a case-by-case basis. These results apply to a wide range of feedbacks between marine ice sheets and atmosphere, ocean and lithosphere.


Assuntos
Atmosfera , Camada de Gelo , Retroalimentação , Congelamento , Neve
2.
Nat Commun ; 13(1): 2116, 2022 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-35440103

RESUMO

Annual-to-decadal variability in northern midlatitude temperature is dominated by the cold season. However, climate field reconstructions are often based on tree rings that represent the growing season. Here we present cold-season (October-to-May average) temperature field reconstructions for the northern midlatitudes, 1701-1905, based on extensive phenological data (freezing and thawing dates of rivers, plant observations). Northern midlatitude land temperatures exceeded the variability range of the 18th and 19th centuries by the 1940s, to which recent warming has added another 1.5 °C. A sequences of cold winters 1808/9-1815/6 can be explained by two volcanic eruptions and unusual atmospheric flow. Weak southwesterlies over Western Europe in early winter caused low Eurasian temperatures, which persisted into spring even though the flow pattern did not. Twentieth century data and model simulations confirm this persistence and point to increased snow cover as a cause, consistent with sparse information on Eurasian snow in the early 19th century.


Assuntos
Clima , Neve , Mudança Climática , Estações do Ano , Temperatura
3.
Environ Monit Assess ; 194(5): 337, 2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35389121

RESUMO

In this study, an image segmentation algorithm ("OTSU") is applied for differentiation of snow/ice regions followed by interpretation of snowlines and estimation of mass budget of glaciers in Chandra basin, Western Himalaya, India between 2014 and 2020. The observations strongly suggest that the OTSU method can be used to differentiate the snow and ice regions on a glacier accurately from any satellite image, irrespective of the sensor characteristics. Also, this method suits well to delineate the snowlines for large sample of glaciers, other than the manual interpretation and semi-automated methods. The estimates of mass budget of the glaciers are observed varying from - 1.20 ± 0.51 m w.e to almost 0.64 ± 0.51 m w.e, with a total loss of - 61.91 ± 6.70 m w.e of ice mass at basin scale during the observation period. Based on this study, it is highly recommended the application of OTSU method for the differentiation of snow/ice zones of glaciers and snowline demarcation at a large spatial scale in the harsh weather rugged terrain of the Western Himalaya.


Assuntos
Camada de Gelo , Neve , Monitoramento Ambiental , Sistemas de Informação Geográfica , Tecnologia de Sensoriamento Remoto
4.
Oecologia ; 198(4): 889-904, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35325288

RESUMO

Global temperatures are increasing, affecting timing and availability of vegetation along with relationships between plants and their consumers. We examined the effect of population density, herd body condition in the previous year, elevation, plant productivity and phenology, snow, and winter onset on juvenile body mass in 63 semi-domesticated populations of Rangifer tarandus throughout Norway using spatiotemporal generalized additive models (GAMs) and varying coefficient models (VCMs). Optimal climate windows were calculated at both the regional and national level using a novel nonlinear climate window algorithm optimized for prediction. Spatial and temporal variation in effects of population and environmental predictors were considered using a model including covariates decomposed into spatial, temporal, and residual components. The performance of this decomposed model was compared to spatiotemporal GAMs and VCMs. The decomposed model provided the best fit and lowest prediction errors. A positive effect of herd body condition in the previous year explained most of the deviance in calf body mass, followed by a more complex effect of population density. A negative effect of timing of spring and positive effect of winter onset on juvenile body mass suggested that a snow free season was positive for juvenile body mass growth. Our findings suggest early spring onset and later winter permanent snow cover as reinforcers of early-life conditions which support more robust reindeer populations. Our methodological improvements for climate window analyses and effect size measures for decomposed variables provide important contributions to account for, measure, and interpret nonlinear relationships between climate and animal populations at large scales.


Assuntos
Mudança Climática , Rena , Animais , Regiões Árticas , Herbivoria , Plantas , Estações do Ano , Neve
5.
Bull Environ Contam Toxicol ; 108(4): 652-657, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35238990

RESUMO

Based on air samples within 24 h after snowfall, gaseous and particulate concentrations of 16 priority PAHs were obtained, which provided a good opportunity to study the temporal trend of atmospheric PAHs. An obvious temporal trend with atmospheric concentration was observed, which was mainly influenced by emission sources. It was found that the maximum concentration (Σ16PAHs) was 272.8 ng/m3, appeared in the rush hour of traffic. To the contrary, the minimum concentration was 82.39 ng/m3 at the period with the least anthropogenic activities. The values of particle-phase fraction[Formula: see text]) and G/P partitioning quotient (log K P) were increased along with molecular weight of PAHs. However, for individual PAHs, the differences with [Formula: see text] and log K P were not obvious within 24 h. Furthermore, similar statistically significant positive correlations were found between log K P and log K OA among different periods. According to the short sampling program, chemical properties should be the major influencing factor for the temporal trend of G/P partitioning. The results of the case study provided new insights into the research field of G/P partitioning of PAHs.


Assuntos
Poluentes Atmosféricos , Hidrocarbonetos Policíclicos Aromáticos , Poluentes Atmosféricos/análise , Atmosfera/química , Monitoramento Ambiental/métodos , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Estações do Ano , Neve
6.
Sci Justice ; 62(2): 152-155, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35277228

RESUMO

Successful DNA typing of forensically relevant evidence is reliant on both the quality and quantity of biological material recovered from a crime scene. In geographical areas of the world exposed to cold climates, it is not uncommon for biological evidence to encounter a diversity of challenging surfaces and environments, including snowy surfaces. Currently, there is no standard protocol for recovery of bloodstain evidence in snow and very few publications exploring adequate methods of recovering biological evidence from snowy surfaces. In this study, three common substrates (e.g., cotton swabs, FTA paper, and untreated filter paper) utilized by investigators for evidence recovery were evaluated for their ability to recover human blood (DNA) evidence from snow that would be viable for traditional forensic DNA typing. Each biological sample was extracted and quantified to evaluate the quality and quantity of DNA recovered. All samples yielded sufficient non-degraded DNA to proceed with DNA profiling, where complete DNA profiles were generated from each collection substrate. The experimental findings presented herein demonstrate that the ability to recover viable DNA from human blood collected on surface snow is possible using all three collection methods tested.


Assuntos
Repetições de Microssatélites , Neve , DNA/genética , Impressões Digitais de DNA/métodos , Humanos , Manejo de Espécimes/métodos
7.
Artigo em Inglês | MEDLINE | ID: mdl-35270700

RESUMO

Pedestrians' slipping injuries are a very typical problem in the Nordic countries, causing varying degrees of injuries and in the worst case, long sick leaves. There is a clear seasonal variation in the number of slips. Sidewalk slipperiness and the risk of slips is a complex combination of weather, winter maintenance activities, number of walkers, and the grip between shoes and surface, as well as human behavioral and physical factors. In this study, the effect of weather on pedestrians' slipping injuries is studied. Daily weather observations are compared to the slip statistics that have been collected from commuting accident statistics in cases where the way of commuting has been walking. A total of 16 cities from Finland for 14 winters are included in this study. The results reveal that snow on the ground increases the slip risk more than three times compared to no-snow situations. Near zero temperatures and precipitation are very typical on days when slip injuries occur more than usual. However, there are also days when high amounts of slips cannot be explained with the weather. The study also shows that there are significant differences as to the number and timing of slips between different parts of the country.


Assuntos
Pedestres , Humanos , Sapatos , Neve , Caminhada , Tempo (Meteorologia)
8.
Am J Bot ; 109(3): 406-418, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35191014

RESUMO

PREMISE: Future reductions in snow cover are expected in temperate climates, likely leading to more soil-freezing events and damage to plant tissues. However, whether and how plants can compensate for this damage may depend on the timing of damage and on plant allocations to seed size and number. We need more information about how seed production, germination, and seedling recruitment might respond to changes in snow cover. METHODS: We manipulated snow cover over three seasons in a common garden experiment with four treatments: (1) "control," where snowpack was left unmanipulated throughout the winter season; (2) "late addition," where snowpack was experimentally increased at the end of the winter season in order to delay the onset of spring; (3) "late removal," where snowpack was experimentally reduced at the end of the winter season in order to advance the onset of spring; and (4) "freeze," a consistent removal treatment, where snowpack was experimentally reduced following every substantial snowfall in order to induce freeze-thaw events in the soil. In all treatments, we measured survival, growth, reproduction, and recruitment of a native perennial herb, Thalictrum dioicum. RESULTS: Reduced snow cover minimally influenced adult survival. Instead, individuals that experienced reduced snow cover throughout the winter produced more massive seeds, whereas individuals that experienced a single snow removal at the end of the season produced less massive seeds. Seedling recruitment was lower in the removal treatments than in the control, as a result of failure to germinate in the freeze treatment and seedling mortality in the late removal treatment. CONCLUSIONS: Both reduced snow cover throughout the winter and a single late snow removal in the spring reduced seedling recruitment, but for different reasons, suggesting that a holistic approach to the life cycle is needed to understand responses to shifting climates.


Assuntos
Neve , Thalictrum , Mudança Climática , Plantas , Reprodução , Estações do Ano , Plântula , Solo
9.
Sci Total Environ ; 822: 153659, 2022 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-35122864

RESUMO

Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO), two successive satellite-based missions starting in 2002, have provided an unprecedented way of measuring global terrestrial water storage anomalies (TWSA). However, a temporal gap exists between GRACE and GRACE-FO products from July 2017 to May 2018, which introduces bias and uncertainties in TWSA calculations and modeling. Previous studies have incorporated hydroclimatic factors as predictors for filling the gap, but most of them utilized artificial intelligence or pure statistical models that generally de-trended TWSA and had no physical foundation. Thus, a physically-based reconstruction is required for increasing robustness. In this study, we bridge the temporal gap by developing an empirical hydrological model. The "abcd" model, a T-based snow component, and linear correction are utilized to represent runoff generation, snow dynamics, and long-term trends. The testing results indicate that our hydrological model can successfully reconstruct TWSA in tropical, temperature, and continental climates, although further improvement is needed for arid climates. Our reconstruction for the gap achieves high accuracy and robustness as shown by the evaluations against sea-level budget and GLDAS-derived TWSA. Compared to previous studies using artificial intelligence or statistical techniques, our hydrological model performs similarly in the gap filling but does not involve de-trended or de-seasonalized transformations, which will facilitate the combination of GRACE and GRACE-FO products and improve the physical understanding of global TWSA.


Assuntos
Água Subterrânea , Inteligência Artificial , Clima , Hidrologia , Neve
10.
Environ Monit Assess ; 194(3): 145, 2022 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-35122167

RESUMO

The runoff of Chandra river basin in the Himalayan India was assessed using a hydrological model combined with satellite remote sensing observations. During a test period between 2000 and 2015, in situ measurements of runoff and meteorological parameters were conducted in the glacial catchment areas of Sutridhaka and Chhotashigri. A good agreement was found between the observed and predicted runoff (correlation R2 > 0.8). The hydrological model was then used to simulate the runoff of Chandra River for a period of 2000 to 2015. Almost 68% of the predicted runoff occurred during the ablation period (May to September). A sensitivity study of the Chandra basin hydrology to a predicted warming climate of 1 to 4 K, toward the end of the century suggests that increased production of glacial melt water would have more impact on runoff than potential increase in precipitation. During the monsoon months (of June to August), increased runoff is predicted due to enhanced glacial melting but the runoff in other months to be lower than present mean runoff, except for the summer months (March to July).


Assuntos
Rios , Neve , Mudança Climática , Monitoramento Ambiental , Sistemas de Informação Geográfica , Hidrologia , Tecnologia de Sensoriamento Remoto
11.
Sci Rep ; 12(1): 2070, 2022 02 08.
Artigo em Inglês | MEDLINE | ID: mdl-35136116

RESUMO

Outdoor breathing trials with simulated avalanche snow are fundamental for the research of the gas exchange under avalanche snow, which supports the development of the international resuscitation guidelines. However, these studies have to face numerous problems, including unstable weather and variable snow properties. This pilot study examines a mineral material perlite as a potential snow model for studies of ventilation and gas exchange parameters. Thirteen male subjects underwent three breathing phases-into snow, wet perlite and dry perlite. The resulting trends of gas exchange parameters in all tested materials were similar and when there was a significant difference observed, the trends in the parameters for high density snow used in the study lay in between the trends in dry and wet perlite. These findings, together with its stability and accessibility year-round, make perlite a potential avalanche snow model material. Perlite seems suitable especially for simulation and preparation of breathing trials assessing gas exchange under avalanche snow, and potentially for testing of new avalanche safety equipment before their validation in real snow.The study was registered in ClinicalTrials.gov on January 22, 2018; the registration number is NCT03413878.


Assuntos
Óxido de Alumínio , Avalanches , Troca Gasosa Pulmonar/fisiologia , Respiração , Dióxido de Silício , Neve , Adulto , Reanimação Cardiopulmonar/métodos , Estudos Cross-Over , República Tcheca , Método Duplo-Cego , Humanos , Masculino , Modelos Teóricos , Projetos Piloto , Estudos Prospectivos , Treinamento por Simulação , Adulto Jovem
12.
Sci Rep ; 12(1): 1738, 2022 02 02.
Artigo em Inglês | MEDLINE | ID: mdl-35110599

RESUMO

Poaching is the main cause of mortality for many large carnivores, and mitigating it is imperative for the persistence of their populations. For Wisconsin gray wolves (Canis lupus), periods of increased risk in overall mortality and poaching seem to overlap temporally with legal hunting seasons for other large mammals (hunting wolves was prohibited). We analyzed monitoring data from adult, collared wolves in Wisconsin, USA (1979-2012, n = 495) using a competing-risk approach to test explicitly if seasons during which it was legal to train hunting hounds (hounding) or hunt other large mammals (hunting) affected wolves' hazard of cause-specific mortality and disappearance. We found increases in hazard for disappearances and documented ('reported') poaching during seasons with hunting, hounding or snow cover relative to a season without these factors. The 'reported poached' hazard increased > 650% during seasons with hunting and snow cover, which may be due to a seasonal surge in numbers of potential poachers or to some poachers augmenting their activities. Snow cover was a major environmental factor contributing to poaching, presumably through increased detection of wolves. Our study suggests poaching is by far the highest mortality hazard for wolves and reinforces the need for protections and policies targeting poaching of protected populations.


Assuntos
Conservação dos Recursos Naturais , Crime , Espécies em Perigo de Extinção , Lobos , Animais , Humanos , Mortalidade , Dinâmica Populacional , Estações do Ano , Neve , Wisconsin
13.
Sci Total Environ ; 822: 153451, 2022 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-35114223

RESUMO

Samples of fresh snow (n = 34) have been collected from 29 locations in various urban and remote regions of northern Iran following a period of sustained snowfall and the thawed contents examined for microplastics (MPs) according to established techniques. MP concentrations ranged from undetected to 86 MP L-1 (mean and median concentrations ~20 MP and 12 MP L-1, respectively) and there was no significant difference in MP concentration between sample location type or between different depths of snow (or time of deposition) sampled at selected sites. Fibres were the dominant shape of MP and µ-Raman spectroscopy of selected samples revealed a variety of polymer types, with nylon most abundant. Scanning electron microscopy coupled with energy-dispersive X-ray analysis showed that some MPs were smooth and unweathered while others were more irregular and exhibited significant photo-oxidative and mechanical weathering as well as contamination by extraneous geogenic particles. These characteristics reflect the importance of both local and distal sources to the heterogeneous pool of MPs in precipitated snow. The mean and median concentrations of MPs in the snow samples were not dissimilar to the published mean and median concentrations for MPs in rainfall collected from an elevated location in southwest Iran. However, compared with rainfall, MPs in snow appear to be larger and more diverse in their shape and composition (and include rubber particulates), possibly because of the greater size but lower terminal velocities of snowflakes relative to raindrops. Snowfall represents a significant means by which MPs are scavenged from the atmosphere and transferred to soil and surface waters that warrants further attention.


Assuntos
Microplásticos , Poluentes Químicos da Água , Monitoramento Ambiental , Irã (Geográfico) , Plásticos/análise , Neve , Poluentes Químicos da Água/análise
14.
Chemosphere ; 295: 133845, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35151704

RESUMO

Trace elements and water-soluble ions in snow can be used as indicators to reveal natural and anthropogenic emissions. To understand the chemical composition, characteristics of snow and their potential sources in the Ili River Valley (IRV), snow samples were collected from 17 sites in the IRV from December 2018 to March 2019. Inverse distance weighting, enrichment factor (EF) analysis, and backward trajectory modelling were applied to evaluate the spatial distributions and sources of water-soluble ions and dissolved arsenic (As) in snow. The results indicate that Ca2+ and SO42- were the dominant ions, and the concentrations of As ranged from 0.09 to 0.503 µg L-1. High concentrations of As were distributed in the northwest and middle of the IRV, and the concentrations of the major ions were high in the west of the IRV. The strong correlation of As with F-, SO42-, and NO2- demonstrates that As mainly originated from coal-burning and agricultural activities. Principal component analysis showed that the ions originated from a combination of anthropogenic and crustal sources. The EFs showed that K+, SO42-, and Mg2+ were mainly influenced by human activities. Backward trajectory cluster analysis suggested that the chemical composition of snow was affected by soil dust transport from the western air mass, the unique terrain, and local anthropogenic activities. These results provide important scientific insights for atmospheric environmental management and agricultural production within the IRV.


Assuntos
Poluentes Atmosféricos , Arsênio , Poluentes Atmosféricos/análise , Arsênio/análise , China , Monitoramento Ambiental/métodos , Humanos , Íons/análise , Rios , Neve/química , Água/análise
15.
Water Res ; 212: 118122, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35101694

RESUMO

The antiozonant N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6-PPD) is added to tires to increase their lifetime and is emitted with tire and road wear particles into the environment. Recently, one of its transformation products (TPs), 6-PPD quinone (6-PPDQ), has gained attention due to its toxicity towards coho salmon. In this study, the abiotic oxidative transformation of 6-PPD is investigated by a series of ozonation experiments in the lab followed by analysis of TPs using liquid chromatography-high resolution-mass spectrometry (LC-HRMS). A total of 38 TPs were detected and tentatively identified, which were formed either directly from 6-PPD or via 6-PPDQ as intermediate. A suspect screening by LC-HRMS showed 32 of these TPs to occur in snow collected from urban roads as surrogate of road-runoff, where 6-PPDQ, 4-aminodiphenylamine (4-ADPA), TP 213, and TP 249 were the most prominent besides 6-PPD. More than 90% of the total load of 6-PPD and its TPs was found in the particulate fraction of snow. Thus, retaining the particulate fraction of road runoff before its discharge into surface water would substantially reduce the emission of 6-PPD and many of its TPs. Some TPs prevailed in the water phase of the snow due to their higher polarity. A total of 13 TPs were detected by suspect screening in the dissolved phase of a wastewater treatment plant (WWTP) influent. Their total load was markedly enhanced during a day of snowmelt (approx. 1100 g/d) and rainfall (approx. 2000 g/d) compared to dry weather (approx. 190 g/d). 6-PPD and 6-PPDQ contributed to less than 1% to this total load in the water phase (estimated concentrations of max 0.1 µg/L). The elimination of the estimated total loads of 6-PPD related TPs from the water phase in WWTP ranged from 22 to 67% depending on weather conditions. Eventually TP 249, 4-ADPA and TP 259_2 dominated in WWTP effluent (estimated concentration from 0.5 up to 2 µg/L). Thus TP 249 and TP 259_2 are, likely, the most specific and stable TPs of 6-PPD to be determined in the environment.


Assuntos
Águas Residuárias , Poluentes Químicos da Água , Estresse Oxidativo , Fenilenodiaminas , Quinonas , Neve , Tuberculina , Águas Residuárias/análise , Poluentes Químicos da Água/análise
16.
Sci Total Environ ; 824: 153785, 2022 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-35182629

RESUMO

According to estimates put forward in multiple studies, tire and road wear particles are one of the largest sources to microplastic contamination in the environment. There are large uncertainties associated with local emissions and transport of tire and road wear particles into environmental compartments, highlighting an urgent need to provide more data on inventories and fluxes of these particles. To our knowledge, the present paper is the first published data on mass concentrations and snow mass load of tire and polymer-modified road wear particles in snow. Roadside snow and meltwater from three different types of roads (peri-urban, urban highway and urban) were analysed by Pyrolysis Gas Chromatography Mass Spectrometry. Tire particle mass concentrations in snow (76.0-14,500 mg/L meltwater), and snow mass loads (222-109,000 mg/m2) varied widely. The concentration ranges of polymer-modified particles were 14.8-9550 mg/L and 50.0-28,800 mg/m2 in snow and meltwater, respectively. Comparing the levels of tire and PMB particles to the total mass of particles, showed that tire and PMB-particles combined only contribute to 5.7% (meltwater) and 5.2% (mass load) of the total mass concentration of particles. The large variation between sites in the study was investigated using redundancy analysis of the possible explanatory variables. Contradictory to previous road studies, speed limit was found to be one of the most important variables explaining the variation in mass concentrations, and not Annual Average Daily Traffic. All identified variables explained 69% and 66%, for meltwater and mass load concentrations, respectively. The results show that roadside snow contain total suspended solids in concentrations far exceeding release limits of tunnel and road runoff, as well as tire particles in concentrations comparable to levels previously reported to cause toxicity effects in organisms. These findings strongly indicate that roadside snow should be treated before release into the environment.


Assuntos
Microplásticos , Plásticos , Monitoramento Ambiental/métodos , Cromatografia Gasosa-Espectrometria de Massas , Polímeros , Neve , Emissões de Veículos/análise
17.
Nat Commun ; 13(1): 984, 2022 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-35194040

RESUMO

Black carbon (BC) from fossil fuel and biomass combustion darkens the snow and makes it melt sooner. The BC footprint of research activities and tourism in Antarctica has likely increased as human presence in the continent has surged in recent decades. Here, we report on measurements of the BC concentration in snow samples from 28 sites across a transect of about 2,000 km from the northern tip of Antarctica (62°S) to the southern Ellsworth Mountains (79°S). Our surveys show that BC content in snow surrounding research facilities and popular shore tourist-landing sites is considerably above background levels measured elsewhere in the continent. The resulting radiative forcing is accelerating snow melting and shrinking the snowpack on BC-impacted areas on the Antarctic Peninsula and associated archipelagos by up to 23 mm water equivalent (w.e.) every summer.


Assuntos
Pegada de Carbono , Monitoramento Ambiental , Regiões Antárticas , Carbono/análise , Humanos , Neve , Fuligem/análise
18.
Environ Res ; 208: 112670, 2022 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-35021066

RESUMO

Previous studies have indicated that black carbon (BC) potentially induces snow albedo reductions across northern China. However, the effects of other light-absorbing particles (LAPs, e.g., mineral dust, MD), snow grain shape, or BC-snow mixing state on snow albedo have been largely ignored. Here we evaluate the BC- and MD-induced snow albedo reductions and radiative forcings (RFs) using an updated Snow, Ice, and Aerosol Radiation radiative transfer model, considering all of the potential factors that can be derived from the field observations across northern China. The results highlight that the LAP-induced albedo reductions for nonspherical snow grains are 2%-30% less than those for spherical grains. Furthermore, BC-snow internal mixing can significantly enhance albedo reduction by a factor of 1.42-1.48 relative to external mixing, with snow grain radius ranging from 100 to 1000 µm. The mean regional BC + MD-induced snow albedo reductions are amplified by the increase of snow grain radius, ranging from 0.012 to 0.123 for fresh snow to 0.016-0.227 for old snow. Finally, we discuss the relative contributions of BC and MD to the albedo reductions and RFs, highlighting the dominant role of BC in reducing snow albedo across northern China.


Assuntos
Monitoramento Ambiental , Neve , Carbono/análise , China , Poeira/análise , Minerais
19.
Sci Total Environ ; 820: 153254, 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35065131

RESUMO

Much of the research from Canada's oil sands region (OSR) shows contaminants of concern (CoCs) throughout the ambient environment surrounding the industrial facilities. While there are some well-established sources of the CoCs, there is also spatial and temporal variability suggesting activity intensity, changes in technology, types and amounts of fuels combusted at the facilities, and climate may affect the results of deposition studies. This study re-analysed published data on the deposition of elements and polycyclic aromatic compounds (PACs) in snow and the sediments of some lakes by incorporating production data from facilities and climate. Using the Elastic Net (EN) regularized regression, variables describing potential associations between facility-specific activity and climate on the deposition of CoCs were identified. Among the selected variables, the combustion of delayed petroleum coke at the Suncor Basemine was associated with the deposition of CoCs, including elements in snow and in some lakes. Similarly, combustion of petroleum coke at Syncrude Mildred Lake was also identified in some models. In both cases, the effects of petroluem coke combustion are likely associated with the emission and deposition of fly ash. The mass of stored petroleum coke was not selected in snow CoC models, but the speed of the wind was a common driver for PACs. However, the mass of stockpiled petcoke was more closely associated with both elements and PACs in lake sediments. While the potential influence of other variables on the occurrence of CoCs in the OSR was also identified, including the production of crude bitumen and synthetic crude, the use of process and natural gases, temperature, and precipitation, these analyses support much of the earlier work and provides additional nuance. While more work is required, these results suggest facility-specific production and climatic data can be coupled with existing approaches to improve the identification of sources of CoCs in Canada's OSR and practices associated with their release.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Poluentes Químicos da Água , Alberta , Canadá , Monitoramento Ambiental , Sedimentos Geológicos , Lagos/análise , Campos de Petróleo e Gás , Hidrocarbonetos Policíclicos Aromáticos/análise , Neve , Poluentes Químicos da Água/análise
20.
Environ Sci Pollut Res Int ; 29(19): 27875-27893, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34984614

RESUMO

Stormwater results from precipitation events and melting snow running off urban landscapes and typically being released into receiving water bodies with little to no treatment. Despite evidence of its deleterious impacts, snowmelt (SM) management and treatment are limited, partly due to a lack of quality and loading data. This study examines snowmelt quality during the spring for a cold climate, semi-arid Canadian city (Saskatoon, Saskatchewan). Four snow storage facilities receiving urban snow plowed from roads in mixed land use urban catchments (228 km2) were sampled including snow piles (five events) and SM (twelve events) runoff in 2019 and 2020. Samples were analyzed for pH, EC, TDS, TSS, COD, DOC, metals, chloride, PAHs, and Raphidocelis subcapitata and Vibrio fischeri toxicity. Notable event-specific TSS spikes occurred on April 13, 2019 (3,513 mg/L), and April 24, 2019 (3,838 mg/L), and TDS, chloride, and manganese on March 26, 2020 (15,000 mg/L, 5,800 mg/L, 574 mg/L), April 17, 2020 (5,200 mg/L, 2,600 mg/L, 882 mg/L), and April 23, 2020 (5,110 mg/L, 2,900 mg/L, 919 mg/L), though chloride remained elevated through May 1, 2020, samples (1,000 mg/L). Additionally, at two sites sampled April 13, 2019, pulses of aluminum (401 mg/L) and PAHs (pyrene, phenanthrene, anthracene; 71 µg/L, 317 µg/L, 182 µg/L) were detected. Concentrations of fluorene, benzo[a]pyrene, pyrene, phenanthrene, and anthracene in almost all SP samples exceeded national aquatic toxicity guideline thresholds, while 50% of SM samples exceeded guideline thresholds for benzo[a]pyrene and pyrene, and almost all exceeded the threshold for anthracene. Nevertheless, the EC50 for R. subcapitata and V. fischeri was observed, if at all, above expected toxicity thresholds.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Neve , Benzo(a)pireno , Cloretos , Monitoramento Ambiental , Hidrocarbonetos Policíclicos Aromáticos/análise , Saskatchewan
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...