Jefferson C. Simoes

• Professor
• Professor (Full) at Federal University of Rio Grande do Sul

Stable water isotopes data extracted from polar ice/firn cores provides valuable climate information. This study presents isotopic time series from a shallow firn core (∼9 m deep) in the Möller Ice Stream basin, Weddell Sea sector, Antarctica. We investigated the relationships between water isotopic ratios (δs; i.e., δ¹⁸O and δD), d-excess data, he...

RESUMEN. Este estudio investiga el potencial de los biomarcadores (levoglucosano y galactosano) como indicadores indirectos de la actividad de los incendios forestales en la Amazonia y Bolivia, utilizando muestras obtenidas en la estación Chacaltaya Global Atmosphere Watch (GAW), situada en la región de los Andes Tropicales. Los análisis preliminar...

Este estudo investiga o potencial de biomarcadores (levoglucosan e galactosan) como proxies para a atividade de incêndios florestais na Amazônia e na Bolívia, utilizando amostras obtidas da estação Chacaltaya Global Atmosphere Watch (GAW) situada na região dos Andes Tropicais. Análises preliminares exploram as associações entre esses biomarcadores...

Artigo recebido em 02/10/2024 e aceito em 21/11/2024 R E S U M O O artigo investigou a ocorrência de migrações ambientais na comunidade de Phinaya, Cordilheira Vilcanota, Peru, nas duas últimas décadas (2000 e 2010). A metodologia foi estruturada em três etapas: primeiro, mapeou-se a rede hidrográfica. Posteriormente, realizou-se entrevistas semi-e...

Regional sea level rise varies from the global average and is influenced by climate variability. We studied sea level anomalies in southern Brazil from 1993 to 2022, finding increasing trend from 1993 to 2022. We used oceanic and atmospheric dynamics to understand the rapid sea level rise. Positive trends in the Southern Annular Mode and the South...

This study investigated the chemical content of a shallow snow core (4.95 m) named TT 6, collected during a Brazilian traverse of the West Antarctic Ice Sheet in the 2014/2015 Austral summer. Stable isotope ratios (δD and δ18O) and ionic content, determined at the Centro Polar e Climático of the Federal University of Rio Grande do Sul (CPC/UFRGS),...

Glaciers are sensitive to environmental climatic conditions and show their variability over time. This study investigates the environmental characteristics and variation in glacial cover of the Greenwich, Livingston, Robert and Snow islands, Antarctica, between 1956 and 2023. The glacier extension mapping was based on visual interpretation of the L...

The Antarctic Peninsula is undergoing rapid climate changes, impacting its surrounding marine ecosystem. At that site, sea ice plays a crucial role in this ecosystem by serving as a habitat for organisms and influencing primary productivity. Studying sea ice variability and primary productivity is essential for understanding environmental changes i...

Devido ao crescimento das pesquisas brasileiras na Antártica e no Andes, faz-se necessário ampliar o vocabulário glaciológico e de temas relacionados na língua portuguesa. Assim, esta segunda edição revisa o Glossário e duplica o número de definições, cobrindo 400 vocábulos relacionados ao ambiente glacial. Estes são definidos e seguidos por equiva...

Refractory black carbon (rBC) has great potential to increase melting when deposited on snow and ice surfaces. Previous studies attributed sources and impacts of rBC in the northern Antarctic Peninsula region by investigating long-range atmospheric transport from South Hemisphere biomass burning and industrial regions or by assessing impacts from l...

Sea ice is a critical component of the cryosphere and plays a role in the heat and moisture exchange processes between the ocean and atmosphere, thus regulating the global climate. With climate change, detailed monitoring of changes occurring in sea ice is necessary. Therefore, an analysis was conducted to evaluate the potential of using the Gray L...

Valente, P.T.; Aquino, F.E.; Marcher, A.; Simões, J.C. Modes of climate variability tends to influence and change precipitation patterns along the world. The current work observed both temporal and spatial influence of Pacific-South American (PSA), Southern Annular Mode (SAM) and El Niño-Southern Oscillation (ENSO) in precipitation anomalies occurr...

This work investigated the annual variations in dry snow (DSRZ) and wet snow radar zones (WSRZ) in the north of the Antarctic Peninsula between 2015-2023. A specific code for snow zone detection on Sentinel-1 images was created on Google Earth Engine by combining the CryoSat-2 digital elevation model and air temperature data from ERA5. Regions with...

The coastal plain of Rio Grande do Sul state, in Brazil, is highly vulnerable to expected changes in sea level, while having an increasing population and consequently increasing water demands. Adequate management is essential to restrain contamination, depletion and salinization of the region’s aquifers considering current and future challenges, bu...

The reconstruction of climatic conditions through continental records controlled by radiometric dating in a single columnar profile from Águas Claras peatland (30º06'24.39" S; 50º49'04.90") in the inner portion of the coastal plain of in Rio Grande do Sul State, Brazil (CPRS) within the Late Pleistocene/Holocene (38,900-38,155 cal yr B.P. to 1,590-...

The region of the Maritime Antarctic suffers significantly from climate change, resulting in regional warming and consequently affecting coverage. This study characterized three surface zones of Collins Glacier and three other zones in ice-free areas on the Fildes Peninsula, which has an area of 29.6 km². We used TerraSAR-X satellite images from 20...

The state of Rio Grande do Sul experienced intense cold at the end of the 15th century and heavy snowfalls in the 19th century, specifically in 1858, 1862, 1867, 1870, 1871, 1873, 1875, 1879 and 1885. Due to the social problems caused by these severe weather events, the need arose to create a meteorological service. There were several initiatives i...

A 22.48 m long ice core (BR-IC-4) was collected in the West Antarctic Ice Sheet (at 83°58'59.4" S, 80°07'01.4" W, 1,295 m above the sea level) during the Austral summer of 2004–2005, as a contribution to the International Trans-Antarctic Expedition program. The isotopic composition (δD and δ18O) of 599 samples, corresponding to the upper 12.98 m of...

Several studies have utilized passive microwave imagery for monitoring snowmelt in Antarctica. However, due to the low spatial resolution of these images (25 km), the quantification of snowmelt is not precise. To enhance the accuracy of these estimations, this study proposed a subpixel analysis approach based on a Spectral Linear Mixing Model. This...

We used Sentinel-2 imagery time series to generate a vegetation map for the Northern part of the Antarctica Peninsula and offshore islands, including the South Shetlands. The vegetation cover was identified in the NDVI maximum value composite image. The NDVI values were associated with the occurrence of algae (0.15 – 0.20), lichens (0.20 – 0.50), a...

This work aimed to characterize the variation in the thermal regime of the active layer in a permafrost area on Fildes Peninsula, Antarctica, and relate this variability with meteorological data between 2014 and 2016. The monitoring site was installed to continuously monitor the temperature and moisture of the active layer, radiation flow on the su...

This work consists of the sedimentological, mineralogical, and geochemical characterization of eight marine sediment cores collected in the Central Bransfield Basin, along a transect between the South Shetland Islands to the Antarctic Peninsula and its correlation to the sedimentary and oceanographic processes of the area. A chemical characterizati...

This study aims to investigate the glacier shrinkage and recent proglacial environment in King George Bay, Antarctica, since 1988 in response to climate change. Remote sensing data (SPOT, Sentinel, Landsat and Planet Scope images) were applied to glacial landforms and ice-marginal fluctuations mapping. Annual mean near-surface air temperature reana...

This article compares isotopic, ionic and climatic data from two firn cores from the West Antarctic Ice Sheet (WAIS). The IC-02 (88°01'21.3"S , 82°04'21.7"W) and the IC-05 (82°30'30.8"S , 79°28'02.7"W) closer to the coast. The IC-02 had 488 samples analyzed covering 14.58 meters depth while the IC-05 had 602 samples analyzed covering 19.73 meters d...

This study investigates the transient snowline (TSL) altitude for summer 2020, as well as glacial area loss in King George Island Icefields since 1988 using Sentinel-1 and 2 and Landsat Thematic Mapper (TM) imagery. Trends and anomalies in atmospheric temperature, U-wind, and V-wind were examined using ERA5 solutions. Results show the wet-snow zone...

This article compares isotopic, ionic and climatic data from two firn cores from the West Antarctic Ice Sheet (WAIS). The IC-02 (88°01'21.3"S , 82°04'21.7"W) and the IC-05 (82°30'30.8"S , 79°28'02.7"W) closer to the coast. The IC-02 had 488 samples analyzed covering 14.58 meters depth while the IC-05 had 602 samples analyzed covering 19.73 meters d...

This study evaluated feasibility statistically and analyzed, during the freezing period, the relationship between brightness temperature (Tb) data of the 37V polarisation and the GR3719 (Gradient Ratio 37V and 19V) obtained by Special Sensor Microwave/Imager from F11 and F13 satellites with sea ice thickness (SIT) data obtained in the Weddell Sea t...

The coastal plain of Rio Grande do Sul state is highly vulnerable to expected changes in sea level, while having an increasing population and consequently increasing water demands. Adequate management is essential to restrain contamination, depletion and salinization of the region’s aquifers considering current and future challenges, but geologic k...

The Lange glacier is an outlet glacier situated in the Admiralty Bay, King George Island, Peninsula Antarctica. It retreated about 1 km since the 1950s. Although recent observations do not show any significant change at the ice-ocean margin, it is not clear whether this glacier has reached a new steady state or whether it is still adjusting to new...

The paper aims to reconstruct the fluctuations of Dobrowolski Glacier, a tidewater glacier located in the inner position of the Admiralty Bay (King George Island, Antarctica), from the Little Ice Age (1400-1700) until the present. Measurements of the glacier’s area and length were based on multitemporal satellite imagery and submarine glacial landf...

Changes in sea ice conditions and atmospheric circulation over the Southern Ocean play an important role in modulating Antarctic climate. However, observations of both sea ice and wind conditions are limited in Antarctica and the Southern Ocean, both temporally and spatially, prior to the satellite era (1970 onwards). Ice core chemistry data can be...

Dados de radar de abertura sintética (SAR) e plataformas de processamento Big Earth Data (BED) têm sido utilizados para mapeamento de zonas de neve em mantos de gelo. Este trabalho investiga a variação de área das zonas de neve seca (ZNS) e da zona de neve úmida (ZNU), ao norte da Península Antártica (65°S de latitude) nos períodos de inverno/verão...

Since the early 1980s, the Antarctic environment has served as a natural field laboratory for researchers to investigate the effects of stratospheric ozone depletion, which has resulted in increased surface ultraviolet radiation levels. However, its effective threats still present gaps. We report new pieces of evidence of increased ultraviolet radi...

Brazilian Ten-Year Plan for the 2023–2032 cycle seeks to raise national polar research to a new level by articulating and integrating the National System of Science, Technology, and Innovation among federal, state, municipal, and private-sector actors. The updated guidelines for research programs proposed in this plan and the recommendations for th...

Insoluble particles in ice cores record signatures of past climate parameters like vegetation dynamics, volcanic activity, and aridity. For some of them, the analytical detection relies on intensive bench microscopy investigation and requires dedicated sample preparation steps. Both are laborious, require in-depth knowledge, and often restrict samp...

A formação inicial e continuada de professores é deficitária na temática polar, e não há muitos materiais didáticos de apoio para desenvolver conteúdos sobre estas regiões. Dessa forma, o objetivo desta pesquisa é apresentar um relato e metodologia inovadora voltada para a educação polar com alunos da educação básica. A metodologia se fundamenta na...

This study investigated the intensity and spatial distribution of precipitation anomalies in Rio Grande do Sul state (RS) during the 20th century by analyzing the influence of El Niño-Southern Oscillation (ENSO) in its three phases. Reanalyzes from the University of Delaware (V5) were used. Precipitation anomalies were divided into three zones (Cam...

Changes in sea ice conditions and atmospheric circulation over the Southern Ocean play an important role in modulating Antarctic climate. However, observations of both sea ice and wind conditions are limited in Antarctica and the Southern Ocean, both temporally and spatially. Ice core chemistry data can be used to reconstruct changes over annual, d...

This study analyzed the spatial and temporal influence of Pacific-South America (PSA), Southern Annular Mode (SAM) and El Niño-Southern Oscillation (ENSO) in precipitation anomalies in Southeast South America (SESA) from 1951 to 2020. Reanalysis from CRU (version 4.05) were used with 0.5ºx0.5º of resolution grid for precipitation database and NCEP/...

Stable water isotopes (δ 18 O, δD, and d-excess) and snow accumulation data are invaluable keys to reconstructing the paleoclimate information in polar regions. We evaluated the isotopic and accumulation records from the Criosfera 1 site (84°00'00''S; 79°29'39''W; 1276 m a.s.l.)-located in an upstream area of the Möller Ice Stream (MIS) basin, Wedd...

Recent advances in the scientific understanding of global environmental changes and their intensification motivates us to explore the weather and climate connections between Antarctica and the tropics and vice-versa. The Brazilian Cerrado is a global biodiversity hotspot with extremely high rates of natural vegetation suppression and wildfires over...

Shallow firn cores, in addition to a near-basal ice core, were recovered in 2018 from the Quelccaya ice cap (5470 m a.s.l) in the Cordillera Vilcanota, Peru, and in 2017 from the Nevado Illimani glacier (6350 m a.s.l) in the Cordillera Real, Bolivia. The two sites are ~450 km apart. Despite meltwater percolation resulting from warming, particle-bas...

Stable water isotopes and accumulation data extracted from polar ice/firn cores provide valuable climate information. Here, we present novel isotopic and accumulation time series from an upstream area of the Möller Ice Stream (MIS) basin, Weddell Sea Sector (WSS), Antarctica – a Brazilian research area (84°00’00’’S; 79°29’39’’W; 1276 m a.s.l.). Our...

Development of vegetation communities in areas of Antarctica without permanent ice cover emphasizes the need for effective remote sensing techniques for proper monitoring of local environmental changes. Detection and mapping of vegetation by image classification remains limited in the Antarctic environment due to the complexity of its surface cover...

A inda pouco discutida no Brasil, a ques-tão ártica vem ganhando a cada dia mais atenção pelo aumento do interesse in-ternacional decorrente, principalmente, das rápidas mudanças ambientais observadas desde o início deste século e que facilitam o acesso à região. Subtemas como aumento da exploração mineral, remilitarização, novas disputas territori...

O objetivo deste trabalho é investigar a evolução geomorfológica das áreas livres de gelo associadas às geleiras Ecology, Sphinx, Baranowski, Tower e Windy, da margem leste do campo de gelo Warszawa, ilha Rei George (IRG), Shetlands do Sul, Antártica Marítima (62°12’0” S - 58°30’0” W). Com base nas feições morâinicas encontradas através de análise...

This study proposes the use of a Spectral Linear Mixing Model (SLMM) on passive microwave data for mapping the concentration and area of young and/or first-year ice in the oceanic region located in the northwest of the Antarctic Peninsula. Sentinel-1A Synthetic Aperture Radar (SAR) data were used to estimate fraction images needed for subpixel anal...

We have estimated a 1-D permittivity model from a 100m long variable offset GPR in the West Antarctic ice sheet. That model inherits the inaccuracies in depth from the velocity model, which should be corrected before attempting to correlate it with the density log from a close-by borehole. We performed that correction by aligning a synthetic ice de...

This study investigated the water isotopic content (δ18O, δD, d-excess) of the surface snow along a 995 km traverse over the West Antarctic Ice Sheet from the Möller Ice Stream - Institute Ice Stream to the upper reaches of the Pine Island Glacier drainage basin. The purpose of this study was to evaluate the climatic record preserved in the snow. W...

This study investigated the terrestrial and submarine geomorphology and glacial landform records in the Martel inlet (King George Island) using a multi-resolution topobathymetric data based on seismic, multibeam surveys and terrestrial satellite datasets (REMA DEM). Geomorphometric analysis provided glacial landforms and sedimentary processes inter...

Abstract The remote sensing techniques must be used to obtain long-term information in remote areas, like the Antarctic continent, to monitor the environmental productivity and its changes. The aim of this work was to analyze the surface reflectance profile patterns for the Antarctic biological soil crusts (algae, lichens, and mosses) in an area of...

Monitoring and inventorying proglacial lakes in the Maritime Antarctica region is essential for understanding the effects of climate change on these environments. This study uses Landsat images to create a map of lakes in ice-free areas of the South Shetlands Islands (SSI) for 1986/89, 2000/03 and 2020, and verification of patterns of change in lak...

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...

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 Mou...

It is estimated that the explosive Hudson volcano eruption in Southern Chile injected approximately 2.7 km3 of basalt and trachyandesite tephra into the troposphere between August 8-15, 1991. The Hudson signal has been detected in Antarctica at the eastern sector and in South Pole snow. In this work, we track the Hudson volcanic plume using a dispe...

Dust particle studies in ice cores from the tropical Andes provide important information about climate dynamics. We investigated dust concentrations from a 22.7 m ice-core recovered from the Quelccaya Ice Cap (QIC) in 2018, representing 14 years of snow accumulation. The dust seasonality signal was still preserved with homogenization of the record...

We assessed fungal diversity present in glacial from the Antarctic Peninsula using DNA metabarcoding through high-throughput sequencing (HTS). We detected a total of 353,879 fungal DNA reads, representing 94 genera and 184 taxa, in glacial ice fragments obtained from seven sites in the north-west Antarctic Peninsula and South Shetland Islands. The...

Antarctic snow represents a microhabitat directly linked with atmospheric precipitation, and through it receives dust, sea spray, organic materials and microbial propagules. Among the microorganisms that inhabit Antarctic snow, fungi are not well known. In the current study, we assessed the uncultured fungal diversity in seasonal snow samples obtai...

The classification of Synthetic Aperture Radar (SAR) images by knowledge based algorithms with elevation and backscatter thresholds were used in several studies to detect the Wet Snow Radar Zone (WSZ) in the Antarctic Peninsula. To identify it more accurately based on its seasonal variations, this study proposed the additional use of a threshold in...

The Antarctic vegetation maps are usually made using very high-resolution images collected by orbital sensors or unmanned aerial vehicles, generating isolated maps with information valid only for the time of image acquisition. In the context of global environmental change, mapping the current Antarctic vegetation distribution on a regular basis is...

This article proposes the mapping of the concentration of sea ice in the oceanic region of the western Antarctic Peninsula using backscatter coefficients and textural features from synthetic aperture radar (SAR) C-band, horizontal single polarization (HH) images obtained by the Sentinel 1A satellite sensor. Pure samples of open water and sea ice we...

Dust particle studies in ice cores from the tropical Andes provide important information about climate dynamics. We investigated dust concentrations from a 22.7 m ice-core recovered from the Quelccaya Ice Cap (QIC) in 2018, representing 12 years of snow accumulation. The dust seasonality signal was still preserved with some homogenization of the re...

This work deals with reconstructing firn layer thicknesses at the deposition time from the firn's observed thickness in ice cores, thus reconstructing the annual accumulation, yielding a timescale and an ice-core chronology. We employed a dynamic time warping algorithm to find an optimal, non-linear alignment between an H2O2 concentration data seri...

Pressure gradients and winds play an important role in Southern Hemisphere (SH) sea levels, which are currently associated with the positive trend of the Southern Annular Mode (SAM). This study investigated regional sea level anomalies (SLAs) in the southern coast Brazil using altimeter data (1993–2019), post-processed by the X-TRACK (CTOH/LEGOS)....

This study aims to compare the glacial lake variation in 1988-2018 period by ice-free land sector in King George Island (KGI) and Nelson Island (NI). Lake sectors were grouped by multivariate statistics techniques. Areal lake and glacier evolution are estimated by Landsat and Sentinel images segmentation and NDWI (was obtained 68-77% of the accurac...

RESUMO O presente trabalho apresenta o primeiro inventário dos lagos glaciais nas áreas livres de gelo nas ilhas Rei George e Nelson, Antártica Marítima. Foram usadas imagens Landsat, Digital Globe, Planet Scope e Sentinel 2 para vetorização e mapeamento dos lagos através do Google Earth. Para a análise geomorfométrica foram utilizados os MDE Tande...

We assessed fungal diversity present in glacial of the Antarctic Peninsula using DNA metabarcoding through high throughput sequencing (HTS). We detected a total of 353,879 fungal DNA reads, representing 94 genera and 184 taxa, in glacial ice fragments obtained from seven sites in the north-west Antarctic Peninsula and South Shetland Islands. The ph...

O presente artigo analisa a acurácia vertical dos Modelos Digitais de Elevação (MDEs) TanDEM-X (TDX) e o Reference Elevation Model for Antarctica REMA2 e REMA8 e seu potencial no mapeamento de ambientes glaciais e periglaciais utilizando como estudo de caso a Península Keller (PK), localizada na Ilha Rei George (IRG), Antártica Marítima. A acurácia...

A deeper understanding of past atmospheric circulation variability in the Central Andes is a high-priority topic in paleoclimatology mainly because of the necessity to validate climate models used to predict future precipitation trends and to develop mitigation and/or adaptation strategies for future climate change scenarios in this region. Within...

This study aims to quantify the areal variation of glacial lakes in the coastal ice-free areas of King George Island (KGI) and Nelson Island (NI) from 1986 to 2020. Glacial lake and glacial area fluctuations are estimated using spaceborne remote sensing data and annual mean near-surface air temperature data from station observations and ERA-Interim...

Sea ice is one of the main components of the cryosphere that modifies the exchange of heat and moisture between the ocean and atmosphere, regulating the global climate. In this sense, it is important to identify the concentration of sea ice in different regions of Ant-arctica in order to measure the impact of environmental changes on the region's e...

This work deals with two distinct datasets, a well preserved hydrogen peroxide, H 2 O 2 , concentration data from firn cores at a high deposition location and a temperature time series, estimated from the daily records from four Antarctic stations around the Antarctic Peninsula. With them we have produced a time scale, an ice-core chronology, for t...

O artigo investiga alterações nos sistemas paraglaciais e interconexões com a retração glacial em setores da ilha Rei George, Antártica Marítima. Foi analisado o ambiente proglacial, resultado da deglaciação recente, e identificados os tipos de formas de relevo em suas diferentes escalas. Estes registros são úteis para a reconstrução de estágios su...

Este trabalho investiga o conteúdo iônico dos 28,73 m superiores do testemunho BR-IC-2 (88°01'21,3"S; 82°04'21,7"W), coletado durante a travessia antártica chileno-brasileira no verão austral de 2004/05. As concentrações dos íons majoritários Na+, K+, Mg2+, Ca2+, Cl-, NO3- e SO42- e do ácido orgânico H3CSO3- (metanosulfonato - MS-) foram determinad...

Expansion of Antarctic vegetation in ice-free areas underlines the need for effective remote sensing techniques to properly monitor the changes. Detection and mapping of vegetation remains limited in the Antarctic environment given the complexity of its surface coverage. Some cryptogamic species exhibit low reflectance in the near-infrared region a...

Abstract 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...