Refractory black carbon (rBC) variability in a 47-year West Antarctic snow and firn core

Black carbon (BC) is an important climate-forcing agent that affects snow albedo. In this work, we present a record of refractory black carbon (rBC) variability, measured from a 20m deep snow and firn core drilled in West Antarctica (79°55’34.600” S, 94°21’13.3”W, 2122m above sea level) during the 2014–2015 austral summer. This is the highest elevation rBC record from West Antarctica. The core was analyzed using the Single Particle Soot Photometer (SP2) coupled to a CETAC Marin-5 nebulizer. Results show a well-defined seasonality with geometric mean concentrations of 0.015 μg L-1 for the wet season (austral summer–fall) and 0.057 μg L-1 for the dry season (austral winter–spring). The core was dated to 47 years (1968–2015) using rBC seasonality as the main parameter, along with sodium (Na), sulfur (S) and strontium (Sr) variations. The annual rBC concentration geometric mean was 0.03 μg L-1, the lowest of all rBC cores in Antarctica referenced in this work, while the annual rBC flux was 6.25 μgm-2 a-1, the lowest flux in West Antarctica rBC records. No long-term trend was observed. Snow albedo reductions at the site due to BC were simulated using SNICAR online and found to be insignificant (-0.48 %) compared to clean snow. Fire spot inventory and BC emission estimates from the Southern Hemisphere suggest Australia and Southern Hemisphere South America as the most probable emission sources of BC to the drilling site, whereas HYSPLIT model particle transport simulations from 1968 to 2015 support Australia and New Zealand as rBC sources, with limited contributions from South America. Spectral analysis (REDFIT method) of the BC record showed cycles related to the Antarctic Oscillation (AAO) and to El Niño–Southern Oscillation (ENSO), but cycles in common with the Amundsen Sea Low (ASL) were not detected. Correlation of rBC records in Antarctica with snow accumulation, elevation and distance to the sea suggests rBC transport to East Antarctica is different from transport to West Antarctica

Mass and Number Size Distributions of rBC in Snow and Firn Samples From Pine Island Glacier, West Antarctica

An extended‐range Single Particle Soot Photometer (SP2) coupled to a Marin‐5 nebulizer was used to measure the refractory black carbon (rBC) mass and number size distributions in 1,004 samples from a West Antarctica snow/firn core. The SP2 was calibrated using Aquadag and a Centrifugal Particle Mass Analyzer for BC particles ranging from 0.5 to 800 fg. Our results indicate a significant contribution of rare, large particles of mass‐equivalent diameter (DBC) \u3e 500 nm to the total rBC mass (36%), while small particles (DBC \u3c 100 nm) are abundant but contribute \u3c8% to total rBC mass. We observed a primary mass median diameter of 162 ± 40 nm, smaller than reported for snow in other regions of the globe but similar to East Antarctica rBC size distributions. In addition, we observed other modes at 673, 1,040, and \u3e1,810 nm (uncontained mode). We compared two sets of samples from different seasons (wet vs. dry) and observed that dry season concentrations are 3.4 and 2 times that of the wet season in the ranges of 80 nm \u3c DBC \u3c 500 nm (small particles) and 500 nm \u3c DBC \u3c 2,000 nm (large particles), respectively, while number of particles in the dry season is 3.5 and 2 times that of the wet season for the same size ranges. Millimeter thick melt layers have been observed in some samples, although they did not change the observed median diameter. This study provides the first detailed rBC mass and number size distribution from West Antarctica

The Amazon Glaciers

In this chapter, we will examine the relationship between the Andean tropical glaciers and the Amazon rainforest, presenting a comprehensive overview on those ice masses that are the headwaters of the Amazon River and examining changes in environmental processes that may affect their mass balance and how they may feedback into the Amazon lowlands environmental processes. The first part of this chapter describes the present glaciological knowledge on these Andean ice masses that flow towards the Amazon drainage basin, about 1666 km2 (of which 68% are in Peru, 24% in Bolivia and the remaining 8% in Ecuador). The mass balance of these glaciers is strongly dependent on the Amazon hydrological cycle, as water coming from the Atlantic Ocean and recycled though the rainforest is the main source of their precipitation. A second part of the chapter explores how two environmental systems are interconnected and interacted. The third part of chapter examines the present (last 50 years) human-made changes in the Amazon basin and how they may affect the Andean ice masses. These glaciers also hold the best proxy for the Amazon Holocene changes, the record left in the snow and ice chemistry. So, as a complement to this chapter, we review the information on the paleoenvironmental changes found in ice cores in Bolivia and Peru and what they may point about the future of the Andean tropical glaciers

Note on weather service in Rio Grande do Sul the XIX century

Análise de documentação histórica permitiu inventariar os recursos existentes para monitorar o clima durante o século XIX na Província de São Pedro do Rio Grande do Sul e no estado do Rio Grande do Sul. No inicio do século (1825) já existiam alguns trabalhos e em 1883 uma rede de 20 estações meteorológicas, montadas pela "Commisão da Barra de Rio Grande", estava operando, cobrindo parte do atual estado do Rio Grande do Sul. Este levantamento encontrou grande quantidade de informações, sobre a meteorologia no RS daquela época, que estavam perdidas, em arquivos, inclusive fora do país, por exemplo, as "Notas Meteorológicas da Commissão da Barra de Rio Grande" publicadas pelo geógrafo alemão Henry Lange.Historical documentation analysis allowed the inventory of existing resources to monitor the weather during the nineteenth century in the Provincia de St. Pedro do Rio Grande do Sul and in the state of Rio Grande do Sul In the beginning of the century (1825) there were some papers and. in 1883 a network of 20 weather stations, assembled by "Commisão da Barra do Rio Grande", was operating, covering part of the current state of Rio Grande do Sul. This survey found much information on the weather in RS that time, who were lost in files, including outside the country, for example, the "Weather Notes from the Commission da Barra do Rio Grande" published by the German Henry Lange geographer

Anomalias de precipitação na costa sul brasileira associadas aos modos de variabilidade climática SAM e ENOS

The precipitation pattern of the State of Rio Grande do Sul (RS) is changing, indicating an increase, although there are long periods of drought. Several studies indicate the influence of climate variability modes on RS precipitation. This work analyzes the influence of the Southern Annular Mode (SAM) and the El Niño - Southern Oscillation (ENSO) on precipitation anomalies (PP) of the Rio Grande do Sul Coastal Plain (RGSCP), dividing it into three regions: south, central and north. Contingency tables were used to correlate the indices, classifying them as neutral, below ou above the mean. To statistical significance we used percentage correctly classified with which the Student’s t was aplied for each region. The PP of the RGSCP and the south coast have correlation with the ENSO and SAM; the central only with SAM. The PP of the north is not correlated to either index. Periods with more than 5 months of PP, SAM and ENSO anomalies were identified. Below average events were majority. The results indicate greater influence of SAM + and La Niña. The trend towards SAM+ and intensification of ENSO, could increase the frequency of droughts in RGSCP. In addition, it was possible to interpret that the geographical differences of the RGSCP can influence the results of precipitation totals. This work contributes to the understanding of the effects of the new trends of climatic variability under regional and geographical aspects.O padrão de precipitação do estado do Rio Grande do Sul (RS) esta mudando, indicando aumento, ainda que se observe longos períodos de seca. Diversos estudos apontam influencia de modos de variabilidade climática na precipitação do RS. Este trabalho analisa a influência do Modo Anular do Hemisfério Sul (SAM) e do El Niño – Oscilação Sul (ENOS), nas anomalias de precipitação (PP) da Planície Costeira do Rio Grande do Sul (PCRGS), a dividindo em três regiões: sul, central e norte. Tabelas de contingência foram utilizadas para correlacionar os índices, os classificando como neutros, abaixo ou acima da média. Para significância estatística utilizamos o percentual corretamente classificado, com o qual se aplicou o teste t de Student para cada região. As PP da PCRGS e da costa sul possuem correlação com o ENOS e SAM; a central apenas com o SAM. As PP do norte não são correlacionadas há nenhum dos dois indices. Períodos com mais de 5 meses de PP, SAM e ENOS anômalos foram identificados. Eventos abaixo da média foram maioria. Os resultados indicam maior influência SAM+ e La Niña. A tendência ao SAM+ e intensificação do ENOS, poderá aumentar a frequência de secas na PCRGS. Além disso, foi possível interpretar que as diferenças geográficas da PCRGS podem influenciar nos resultados dos totais de precipitação. Este trabalho contribui para a compreensão dos efeitos das novas tendências da variabilidade climática sob aspecto regional e geográfico

Anthropogenic trace elements (Bi, Cd, Cr, Pb) concentrations in a West Antarctic ice core

Trace elements are emitted to the atmosphere from natural and anthropogenic sources. The increase in industrialization and mining occurring from the late 19th century released large quantities of toxic trace elements into the Earth’s atmosphere. Here we investigate the variability of concentrations of bismuth, cadmium, chromium, and lead in two Mount Johns – MJ (79°55’28”S, 94°23’18”W, 2100 m a.s.l) ice cores over 132 years (1883-2015). Trace element concentrations were determined using inductively coupled plasma mass spectrometry (CCI/UMaine). The data show evidence of pollution for these elements in Antarctica as early as the 1883. Several maxima concentrations were observed: first at the beginning of the 20th century and the last from 1970s to 1990s, with a clear decrease during recent years. Emissions occur from different anthropogenic sources and appear to be variable throughout the record. The main source of these elements is attributed to mining and smelting of non-ferrous metals in South America, Africa, and Australia. As well as a probable lead enrichment due to the use of fossil fuels. The MJ ice core record also reflects changes in atmospheric circulation and transport processes, probably associated with a strengthening of the westerlies

O uso de técnicas de sig para análise da dinâmica sedimentar da Enseada Martel, Ilha Rei George, Shetlands do sul

This paper presents results of the sediment dynamic analysis of the Martel Inlet, King George Island, South Shetlands. As a consequence of the rising trend in study area mean surface air temperature, a rapid glacier front retreat occurred in the last decades, which has caused noticeable environmental changes, including impacts on sediment dynamics on the Martel Inlet. GIS techniques were applied for spatial and temporal changes analysis of suspended sediment concentration (SSC), using: (1) visible bands of SPOT HRV imageries obtained in February, 1988 and 2000, and in March, 1995; (2) TERRA ASTER imagery obtained in November, 2005. Furthermore, SSC sample data from subglacial frontal zone of the glacier were correlated with meteorological data. SSC data presented significant correlation with glaciers retreat that drain into the fjord, and thus they can be used as indicators of the consequences of climatic variability for the sedimentary dynamic in the study area. This methodology allowed us to obtain satisfactory results for the pattern analysis of SSC spatial and temporal changes in the Martel Inlet, during the months analyzed. By using GIS techniques, we could evaluate the intensity of the glacier sediment production in the study area and its meltwater runoff.Este trabalho apresenta resultados da análise da dinâmica sedimentar da Enseada Martel, ilha Rei George, Shetlands do Sul. Como consequência da tendência de aumento da temperatura média do ar superficial nessa região, ocorreu um rápido recuo da frente de geleiras nas últimas décadas, as quais promoveram mudanças ambientais perceptíveis, incluindo impactos na dinâmica sedimentar da Enseada Martel. Técnicas SIG foram aplicadas na análise da variação espacial e temporal da concentração de sedimentos em suspensão (SSC) dessa enseada, com bandas do visível de imagens SPOT HRV obtidas em fevereiro de 1988 e 2000, e março de 1995, além de imagens TERRA ASTER obtidas em novembro de 2005. Além disso, foram correlacionados dados de coletas de Concentração de Sedimentos em Suspensão (SSC) em canais glaciofluviais com dados meteorológicos. Esses dados apresentaram correlação significativa com a retração das geleiras que drenam para o fiorde, podendo assim ser usados como indicadores das consequências da variabilidade climática para a dinâmica sedimentar da área de estudo. A metodologia proposta possibilitou a obtenção de resultados satisfatórios na análise das modificações no padrão espacial e temporal da SSC na Enseada Martel durante os meses analisados. Com o uso de técnicas SIG, pôde-se avaliar a intensidade dos processos de produção de sedimentos pelas geleiras da área de estudo e o seu fluxo de água de derretimento

Polycyclic aromatic hydrocarbons in Antarctic ice core : prior study by homogeneous liquid-liquid extraction and high-performance liquid chromatography

Organic contamination has been less investigated in Antarctic snow and ice than in other matrices due to analytical operational problems. In this study, the concentration of 14 Polycyclic Aromatic Hydrocarbons was determined in a shallow firn core by Homogeneous Liquid-Liquid Extraction and High–Performance Liquid Chromatography with a Fluorescence Detector. This investigation aimed to develop a simple analytical methodology for future application directly in fieldwork, taking advantage of the simplicity and small sample volumes. The analyte recoveries were 71–99% considering a 100 ng L⁻¹ initial concentration of each compound, with a relative standard deviation of 1.1–9.9%. Analytical sensitivity/ detection limit/ quantification limits varied from 7.8/ 20.3/ 67.6 ng L⁻¹ for fluoranthene to 0.6/ 1.5/ 5.1 ng L⁻¹ for anthracene. These analytical parameters allow us to apply the method to real samples. We found visible differences at various firn core depths when considering the sum of total analytes under study. The highest total concentration was 741 ng L-1 and the lowest one 134.9 ng L-1. The methodology can be applied without mixing samples with adequate analytical parameters, and it can preserve the firn core temporal resolution, which is an advantage for application in fieldwork