LARSEN B, RETRATO DEL CALENTAMIENTO: En la bahía Larsen B, noreste de la Península Antártica, desembocan numerosos glaciares de descarga, que son importantes reservas de agua dulce… ¿Cómo les está afectando el cambio climático?

Antártida contiene la mayor reserva de agua dulce del planeta y se encuentra en forma de hielo. El Panel Intergubernamental para el Cambio Climático reportó un aumento de 1,1 °C en la temperatura media global, lo cual preocupa a los países miembros del Tratado Antártico, entre ellos, Argentina. Para saber cómo afecta este aumento de la temperatura a las masas de hielo, el Instituto Antártico Argentino está realizando hace décadas un constante estudio de los glaciares de la Península Antártica. Se registró que, durante los últimos años, los glaciares situados en la bahía Larsen B, en el noreste de la Península Antártica, presentan un acelerado retroceso

Uncertainty Assessment of Ice Discharge Using GPR-Derived Ice Thickness from Gourdon Glacier, Antarctic Peninsula

Ice cliffs within a glacier represent a challenge for the continuity equations used in many glacier models by interrupting the validity of input parameters. In the case of Gourdon Glacier on James Ross Island, Antarctica, a ∼300–500 m high, almost vertical cliff, separates the outlet glacier from its main accumulation area on the plateau of the island. In 2017 and 2018 we conducted ice thickness measurements during two airborne ground penetrating radar campaigns in order to evaluate differences to older measurements from the 1990s. The observed differences are mostly smaller than the estimated error bars. In comparison to the in situ data, the published “consensus ice thickness estimate” strongly overestimates the ice thickness at the outlet. We analyse three different interpolation and ice thickness reconstruction methods. One approach additionally includes the mass input from the plateau. Differences between the interpolation methods have a minor impact on the ice discharge estimation if the used flux gates are in areas with a good coverage of in situ measurements. A much stronger influence was observed by uncertainties in the glacier velocities derived from remote sensing, especially in the direction of the velocity vector in proximity to the ice cliff. We conclude that the amount of in situ measurements should be increased for specific glacier types in order to detect biases in modeled ice thickness and ice discharge estimations

Meteorological data from 2017-2019 on the plateau of James Ross Island, Antarctic Peninsula

These data describe meteorological measurements on the plateau of James Ross Island [Position: 64.19889°S 57.59761°W]. Specifications of the applied sensors and their mounting heights are described in the attached metadata. All measurements (except of Relative Humidity with one sample measurement per hour) were done with a scanning interval of 10 seconds, and afterwards averaged over one hour. In the case of the sonic ranging sensor and the firn compaction, measurements were done for only 5 minutes per hour due to power consumptions. All data are only filtered by outliers which were easy to discover. Thus, erroneous measurements (e.g., in the case of the sonic raning sensor), can still be part of the data

Meteorological data from 2017-2020 on Gourdon Glacier, Antarctic Peninsula

These data describe meteorological measurements on Gourdon Glacier [Position February 2017: 64.23445°S 57.37473°W, February 2018: 64.23470°S 57.37329°W, February 2019 (approximated): 64.23496°S 57.37180°W, February 2020: 64.23492°S 57.37140°W]. Specifications of the applied sensors and their mounting heights are described in the attached metadata. All measurements (except of Relative Humidity with one sample measurement per hour) were done with a scanning interval of 10 seconds, and afterwards averaged over one hour. In the case of the sonic ranging sensor, measurements were done for only 5 minutes per hour due to power consumptions. All data are only filtered by outliers which were easy to discover. Thus, erroneous measurements (e.g., in the case of the sonic raning sensor), can still be part of the data

In-situ ice thickness measurements derived with ground penetrating radar from Gourdon Glacier, Antarctic Peninsula

These data report in-situ ground penetrating radar (GPR) ice thickness measurements at the outlet and the catchment area of Gourdon Glacier on James Ross Island, northern Antarctic Peninsula. Data were conducted in 2017-02-15 and 2018-02-10 with a 25 MHz GPR antenna flown as a sling load by a Bell 212 helicopter. The processing of the GPR data was done in the software REFLEXW v.8.5 (Sandmeier geophysical research) and includes interpolation to equidistant traces, bandpass filtering (10 MHz lower cutoff, 50 MHz upper cutoff), correction to real start time, application of a gain function, and a 2D-finite-difference migration. The travel-time in ice was converted to ice-thickness in meter ["IceThickness(m)"] by applying a constant velocity of 168 m/µs. In case of data from the plateau, a standard correction value for firn and snow of +10 m is applied. The associated error resulting from the GPR measurements ["IceThickness_GPR_error(m)"] and the error additional considering the horizontal positioning accuracy ["IceThickness_Data_error(m)"] are calculated after Lapazaran et al. (2016). Further details about the processing and the error calculation are described in Lippl et al. (in submission). In addition, the surface elevation in reference to the WGS84 ellipsoid [SurfaceElevation(m)] derived from the GNSS signal and the GPR backscatter is included. However, surface elevations can be prone to errors of several meters due to the large foodprint of the radar and the GNSS accuracy

Stock Market Co-Movement in Latin America

This paper investigates co-movement in eight Latin-American stock markets (Argentina, Brazil, Chile, Colombia, Ecuador, Mexico, Peru, and Venezuela) using common factor analysis. The common factors are obtained using principal component analysis (PCA) and therefore account for the maximum portion of the variance present in the stock exchanges investigated. We test for co-movement in different periods so as to ascertain any changes that have taken place from one period to the next. In particular, we examine rolling windows with 5-year, 3-year, 2-year, and 1-year periods. We also specify and estimate a vector autoregressive model and test for co-movement between the eight markets during the sample period by means of impulse response functions. The results of both methods suggest no convergence between (co-movement) the exchanges over the entire sample period. However, we find evidence of an increasing co-movement from 2002 to 2008, which implies a growing integration between these markets. However, the trend towards increasing integration between the stock markets seems to have suffered a setback in 2008 due to the world financial crisis. Since then, a possible resume to the trend of increasing integration is unclear. The impulse response analysis shows that Argentina, Brazil, Chile, Colombia, Mexico and Peru present moderate response to shocks in each other’s markets and very low responses to shocks in Ecuador and Venezuela’s markets. Also, responses of Ecuador and Venezuela’s market returns to shocks in the other markets are very low