Recent climate variability of the Antarctic Peninsula - isotopic characteristics and tele-connections of hydrological systems

Antarctica is among the regions with highest recent rapid regional warming (RRR) (Cullather et al. 1996, Vaughan et al. 2003, Schneider et al. 2006), most likely due to post-industrial anthropogenic influence. The Antarctic Peninsula (API) has even a stronger tendency (3.4°C (century)-1) and due to its marine climatic influence, a faster warming than the continental Antarctic is observed (Vaughan et al. 2003). The recent warming trend is estimated to be three times higher (or even more) than the global average of about 0.5°C between 1950-2000. This effect, also known as polar amplification, shows on one hand the vulnerability of this region to climate and environmental change, with retreating glaciers and reduced snow cover. On the other hand it may be considered as a natural laboratory to study and better understand these effects, teleconnections and feedback mechanisms. The objectives of this project are a contribution to the understanding of the hydrological system in the polar and sub-polar regions of the Antarctic Peninsula (including the nearby islands) and the South of Chile/Argentina: How are the study areas affected by the global climate change and anomalous climatic conditions like El Niño-La Niña phenomena, today and in the last century (or beyond)? Are these changes visible in the isotope record? Which climatic relations and differences exist between the regional climate systems? To achieve this goal we will compare the oxygen and hydrogen isotope signatures of recent precipitation (snow and rain) to existing climate data and the local hydrological system (lakes, small streams). Older archives such as ice cores and snow pits will be used to expand the measured data series to the past. Stable water isotopes are considered as excellent proxies for tracing air temperature changes (18O, D) and through the deuterium excess d (d = D - 8 * 18O), also for reconstruction of atmospheric moisture sources. Summarising all this climate proxies, it is possible to reconstruct an annual to seasonal resolution record for surface temperatures, wind tendencies and moisture sources of precipitation for the study area. Intercomparing the data sets will enable us to reconstruct the history of climate variability for this area

Hydro-Geochemical Water Inputs Identification in Glacierized Basin Hydrology

Mining activities are usually placed in the upper basin regions, especially in developing countries, with economies that strongly rely on natural commodities. Although glaciers do not occupy a large area of these mountain ranges, they deliver vital water for downstream populations. This is especially relevant during drought periods, when winter precipitation is strongly diminished and ice melt becomes relevant. They are also a key resource for highland wetland ecosystems and paradoxically at the same time for the development of mega-mining projects. Regularly, for environmental impact assessments and relevant public consultations, it will be stated that water from glaciers does not constitute an important source within the basin system, even though this has not been accurately quantified. Different water sources, given by spatial, geological, and hydrological features, can be identified using a combination of ionic and isotopic information from water, thus allowing to establish their proportions downstream, where water from different origins is mixed, and also to track their evolution over seasons. This approach should be useful especially for basins with strong pressures for the exploitation and consumption of water in mountainous basins and also with special relevance for basins with little or no knowledge of their water system and reservoirs

Primeras mediciones de isótopos estables de agua y su comportamiento en fiordos de los Campos de Hielo Patagónico Sur, Chile: First measurements of water stable isotopes and their behavior in fjords of the Southern Patagonian Icefield, Chile

Stable isotope measurements of seawater from fjords in the Southern Patagonian Icefields area are presented for the first time. Stable water isotope variability was associated with physiographic and oceanographic factors. Isotope depletion and lower salinity were observed at lower depths, which is consistent with shallow estuarine waters. At greater depths, the characteristics of the modified Subantarctic water mass are inferred, and the glacier proximity and temperature do not show a clear relationship with the isotopic contents. These results could be a robust basis for a possible new proxy associated with changes in water masses, freshwater mixing, and paleoclimatic studies

Where does the chilean aconcagua river come from? Use of natural tracers for water genesis characterization in glacial and periglacial environments

The Aconcagua river basin (Chile, 32◦S) has suffered the effects of the megadrought over the last decade. The severe snowfall deficiency drastically modified the water supply to the catchment headwaters. Despite the recognized snowmelt contribution to the basin, an unknown streamflow buffering effect is produced by glacial, periglacial and groundwater inputs, especially in dry periods. Hence, each type of water source was characterized and quantified for each season, through the combination of stable isotope and ionic analyses as natural water tracers. The δ18O and electric conductivity were identified as the key parameters for the differentiation of each water source. The use of these parameters in the stable isotope mixing “simmr” model revealed that snowmelt input accounted 52% in spring and only 22–36% during the rest of the year in the headwaters. While glacial supply contributed up to 34%, both groundwater and periglacial exhibited a remarkable contribution around 20% with some seasonal variations. Downstream, glacial contribution averaged 15–20%, groundwater seasonally increased up to 46%, and periglacial input was surprisingly high (i.e., 14–21%). The different water sources contribution quantification over time for the Aconcagua River reported in this work provides key information for water security in this territory.Fil: Crespo, Sebastián Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Pontificia Universidad Católica de Valparaíso; ChileFil: Lavergne, Céline. Universidad de Playa Ancha; ChileFil: Fernandoy, Francisco. Universidad Andrés Bello; ChileFil: Muñoz, Ariel A.. Pontificia Universidad Católica de Valparaíso; ChileFil: Cara Ramirez, Leandro Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Olfos Vargas, Simón. Pontificia Universidad Católica de Valparaíso; Chil

Persistent extreme ultraviolet irradiance in Antarctica despite the ozone recovery onset

Attributable to the Montreal Protocol, the most successful environmental treaty ever, human-made ozone-depleting substances are declining and the stratospheric Antarctic ozone layer is recovering. However, the Antarctic ozone hole continues to occur every year, with the severity of ozone loss strongly modulated by meteorological conditions. In late November and early December 2020, we measured at the northern tip of the Antarctic Peninsula the highest ultraviolet (UV) irradiances recorded in the Antarctic continent in more than two decades.The support of INACH (RT_69-20 & RT_70-18), ANID (ANILLO ACT210046, FONDECYT 1191932 & 1221122, DFG190004 and REDES180158), CORFO (19BP-117358 & 18BPE-93920) is gratefully acknowledged

Deciphering stable water isotope records of firn cores from a strongly maritime, high-accumulation site on the Antarctic Peninsula

Stable water isotope records of six firn cores retrieved from two adjacent plateaus on the northern Antarctic Peninsula between 2014 and 2016 are presented and investigated for their connections with firn-core glacio-chemical data, meteorological records and modelling results. Average annual accumulation rates of 2500 kg m−2 a−1 largely reduce the modification of isotopic signals in the snowpack by post-depositional processes, allowing excellent signal preservation in space and time. Comparison of firn-core and ECHAM6-wiso modelled δ18O and d-excess records reveals a large agreement on annual and sub-annual scales, suggesting firn-core stable water isotopes to be representative of specific synoptic situations. The six firn cores exhibit highly similar isotopic patterns in the overlapping period (2013), which seem to be related to temporal changes in moisture sources rather than local near-surface air temperatures. Backward trajectories calculated with the HYSPLIT model suggest that prominent δ18O minima in 2013 associated with elevated sea salt concentrations are related to long-range moisture transport dominated by westerly winds during positive SAM phases. In contrast, a broad δ18O maximum in the same year accompanied by increased concentrations of black carbon and mineral dust corresponds to the advection of more locally derived moisture with northerly flow components (South America) when the SAM is negative