Rosemary Vieira

Sobre el calentamiento global en la isla Rey Jorge: procesos y evidencias en el Glaciar Wanda y su entorno

Geologic, geomorphologic and volcanic aspects, meteorological data and vegetation, both fossil and current, are considered in order to find answers to the dynamics of King George Island glaciers, into theSouth Shetlands Islands, with special emphasis on aspects of the glaciological dynamics submitted by Wanda glacier located in Martel inlet, Almirantazgo Sound, as well as by relevant aspects shown by theEcology glacier, located at the neighborhood. Glaciological and geomorphologic field analysis carried out, the morphological results of glacial sediments samples at laboratory, plant fossils kds, as well asthe interpretation of volcanic history of the Peninsula Antartica, joint with volcanic residual forms and piroclastic materials, also the direct experience of rain over ice, the hydrological responses generated, and the development of not pioneer plants, among other elements, reveal a complex island glaciological evolution. So, temperature rate increasing and the occurrence of rain in a significant number of days per year, scenery that seems not new in the past of the island, and the possible influence of latent heat derived fiom the volcanic context means in the case of Wanda glacier clear negative effects on his mass balance, registering from clear evidence of Cont retreat to moments of accelerated melting and generation of small torrents and lagoons, some of them with persistent character discontinuously damrned by Cont moraines at the coast, as weii as other of seasondy formed into the glacial environment.

Collins Glacier Retreat Process and Regional Climatic Variations, King George Island, Antarctica

Abstract This paper investigates the recent climatic variability and changes in snow line and ice front position in Collins Glacier, King George Island, South Shetland Islands, Antarctic Peninsula. This region has recorded one of the largest temperature increases in the past fifty years and has been demonstrated to be highly sensitive to climate changes. To monitor recent changes (1983–2006), we determined the fluctuations of the terminus and snow line of the glacier via remote sensing data and field observation in the summer of 2013. We conclude that the Collins Glacier has responded slowly to regional climate changes (decades or even centuries), as glacial responses to climatic events do not depend solely on one environmental variable. The glacier presented more retreat and elevation of the snow line in the north sector. The retreat data are correlated with the mean monthly temperature and annual number of days of melting‐degree variations.

Morfogénesis y dinámica de las vertientes submarinas en la costa de fiordos de norpatagonia, Chile.

The features of the Northern Patagonia submarine slopes and their relation with the basin bottoms in fjords and channels studied, by means of subbottom profiler records. Two morphogenetic phases show relationships between slope mass movements and bottom structure. The lower phase is represented by distinct acoustic structures, interpreted as posible debris flows of cohesionless material reaching as far as the slope base.The upper phase produced surface stratified sediments; it shows deformity processes produced by slope slides, which can reach far off the slope base. Resulting landforms of such processes are known as compressional depression and remoulded sediments, which has been developed at the lower slope angles. The plunge pools are observed at the slope base, but where the slope is steeper and deeper. As it has been verified in the shelf slopes, and in some basins fjords too, the majority of slope activities occur, effectively, on slopes less than 10°. The future employment of new technologies will be able to provide a important insight into landslide dynamics and process in different submarine sedimentary environment.

Use of COSMO-SkyMed imagery for recognition of geomorphological features in the Martel Inlet ice-free areas, King George Island, Antarctica

COSMO-SkyMed (Constellation of Small Satellites for Mediterranean Basin Observation) images in spotlight mode (1 m spatial resolution) were used for recognition of geomorphological features in Martel Inlet ice-free areas, King George Island, South Shetland Islands, Antarctica. This article shows the results from texture analysis and filtering of four X-band images with HH and VV polarization, acquired during fieldworks carried out in January and February 2011. Based on field checking and visual interpretation techniques, we identified several glacial landforms such as moraines, flutes, outwash, arêtes, glacial lineations, meltwater channels, lakes, lagoons, and shorelines. Some glacial linear features, such as lateral moraines, flutings, and arêtes are better identified with VV polarization, while supraglacial debris, debris flow, and shorelines are better discriminated with HH polarization. Meltwater channels, lakes, and lagoons were easily distinguished under both co-polarizations. Focal variance texture analysis and specific kernel size convolution filters yielded the best enhanced images for landform visual interpretation. For this propose, the Wallis adaptative, morphological Close, Prewitt with northwesterly and southeasterly directions, and some high-pass filters described in this study are the best filters. Images processed with these filters can be used for studies of geomorphic changes in Antarctica.

Formas glaciales y procesos glaciológicos del glaciar templado Wanda, Shetland del Sur

This paper presents the geomorphic mapping of the Wanda Glacier proglacial environment, King George Island, South Shetlands. All together investigates the glaciological dynamics related to the glacial landforms in the study area. The mapping was based on field analysis and image interpretation. The interpretation was also made by mean of identification and interpretation of the samples in laboratoty. Glaciofluvial, glaciomarine and subglacial processes predominate in the study area. As a result from the recent glacial retreat, several landforms and proglacial deposits, such as flutes, morainic ridges, striated rocks, have been exposed. Abraded and subglacially transported sediments predominate in the deglaciation environments, with meltwater flow in the bed. The generated map contributes in improving the knowledge about the processes that influence the glacial geomorphology and geodynamics. Furthermore this study serves as support to monitoring environmental change facing the glacier retreat processes as effect of climate variability verified in the study area.

Costa de fiordes da Patagônia central, Chile, morfologia submarina e fácies acústicas

This study interprets acoustic sub-bottom profiles and submarine 3D models of some of fjords adjacent to Campo de Hielo Patagonico Sur (Southern Patagonian Icefield), Chile. The overdeepened fjord basins show irregular morphology and distinctive landforms associated with a grounding-line, ice tongues and icebergs sedimentary system. Acoustic reflectors display two main facies: chaotic and laminated, according the internal reflection configuration and the external geometry. The sediments probably were deposited during the Holocene deglaciation, as shown by the visible reflectors of sub-bottom profiler. The geometry of the depocenters and the acoustic reflectors characteristic show evidence of pre-existing topography and bathymetry influence. Due to the great water depths of the fjord basins, terminal margins may have a mix of floating and grounded cliff behaviour, albeit the predominant temperate glacial regime.

Recent changes in the Wanda Glacier, King George Island, Antarctica

Recent glaciological changes in Wanda Glacier, King George Island (KGI), South Shetland Islands (61°54’ S and 62°16’S, 57°35’W and 59°02’W) off the Antarctic Peninsula, were quantified by ice flow velocity, direction and fluctuation of glacier termini measurements. Topographic changes and DGPS surveys as well as transverse and longitudinal profiles were carried out to generate a Digital Surface Model. Results show that Wanda Glacier has a small drainage basin, a high retreat rate through fusion processes and reduced ice thickness if compared to other glaciers in KGI. Surface-area changes are assessed using historical satellite imagery from 1979 to 2011. Wanda glacier lost about 31 % of its original (1.5 km2 of area in 1979). The current continuous and fast retreat phase is attributed to the recent regional warming. Maximum ice surface velocity, measured using a stake network, reached 2.2 cm d-1 during the period of 2007–2011. Transverse profiles show the influence of the topography on the ice flow. Due to its small size and thermal conditions, Wanda Glacier responds rapidly to climatic variations, revealing its relevance for environmental studies.Recent glaciological changes in Wanda Glacier, King George Island (KGI), South Shetland Islands (61°54’ S and 62°16’S, 57°35’W and 59°02’W) off the Antarctic Peninsula, were quantified by ice flow velocity, direction and fluctuation of glacier termini measurements. Topographic changes and DGPS surveys as well as transverse and longitudinal profiles were carried out to generate a Digital Surface Model. Results show that Wanda Glacier has a small drainage basin, a high retreat rate through fusion processes and reduced ice thickness if compared to other glaciers in KGI. Surface-area changes are assessed using historical satellite imagery from 1979 to 2011. Wanda glacier lost about 31 % of its original (1.5 km² of area in 1979). The current continuous and fast retreat phase is attributed to the recent regional warming. Maximum ice surface velocity, measured using a stake network, reached 2.2 cm d -1 during the period of 2007–2011. Transverse profiles show the influence of the topography on the ice flow. Due to its small size and thermal conditions, Wanda Glacier responds rapidly to climatic variations, revealing its relevance for environmental studies.

ANNEX: CROSSING THE DRAKE PASSAGE: FROM BRAZIL TO ANTARCTICA WITH THE ASSOCIATION OF POLAR EARLY CAREER SCIENTISTS (APECS-BRAZIL)

The Association of Polar Early Career Scientists (APECS) is an international and interdisciplinary organization for undergraduate and graduate students, postdoctoral researchers, early faculty members, educators, and others with interests in Polar Regions (Antarctic and Arctic environments) and the wider cryosphere. APECS aims to motivate young polar scientists to study several aspects related to the polar environments, to promote international networks, and to develop polar research, education and outreach activities (for further information visit www.apecs.is). APECS is an initiative of young and innovative polar researchers which started in the context of the 4th International Polar Year (IPY 2007-2008; www. ipy.org). During IPY, both scientific and public interests in Polar Regions increased mainly with the focus on global climate changes and their impacts in the near future. APECS members intend to promote the development of research networks, stimulate educational activities and public literacy campaigns. Letter to the Editor

MORPHOLOGICAL AND SEDIMENTARY CHARACTERIZATION THROUGH ANALYSIS OF MULTIBEAM DATA AT DECEPTION ISLAND, ANTARCTIC

ABSTRACT. Multibeam sonar systems have transformed the area of underwater geoacoustics and present an important tool for seabed characterization. This work aims to demonstrate the processing and interpretation of multibeam bathymetric data, supported by geological samples collected in the area of Deception Island, South Shetland Islands – Antarctic... Keywords: bathymetry, seabed, marine geology, underwater geoacoustic. RESUMO. Sonares multifeixe tem transformado a area de geoacustica submarina e se apresentado como uma ferramenta importante para a caracterizacao do fundo marinho... Palavras-chave: batimetria, fundo marinho, geologia marinha, geoacustica submarina.

O Megadesastre de Janeiro de 2011 na cidade de Nova Friburgo, Rio de Janeiro: aspectos históricos desde a colonização suíça e as condicionantes físicas

The mountainous region of Rio de Janeiro suffered intensely due to the the disaster of January 2011, where heavy rains triggered a series of landslides and floods. This study shows how the anthropic factor has historically influenced the event in the central area of the city of Nova Friburgo. The story of populating of the city was investigated, especially the Swiss colonization, a pioneer in the region. The city was originally built by the Swiss immigrants along the Bengalas river, and ultimately became home to other immigrants and people from other cities, who mainly settled on the slopes and at the bottom of the valley. These areas have become a time bomb for the consequences of high precipitation events. The disaster of January 2011 in the city of Nova Friburgo is an example of this, the occupation of areas which are considered to be at risk during intense rainfall and the regional and local physical conditions which cause deaths, as well as economic and environmental damages.