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The volumetric variations of glaciers located between 41º S and 49º S are pre- sented, which have been compared with climatic trends. The analysis used data from meteorological stations, remote sensing, cartography and land survey. An overall retreat and thinning is detected, which are fairly related with the recent climate trends detected on this zone. The ratio between area lost and total area in each glacier fluctuates among 1.5 to 9%. For detailing more specifically, the relationship between the changes of these glaciers and the climate changes, geometric and morphologic features, was taken into account. This illustrates that the importance of the temperature and rainfall trends is different in each glacier.
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... Since the time of the first complete reconnaissance trip in 1937 (De Agostini, 1945), when splendid photographs of Monte San Lorenzo and its main glaciers were collected, few studies of these glaciers are available; exceptions include recent frontal variations of some glaciers (Fernández et al., 2006;Aravena, 2007), the glacial geology and geomorphology of the Holocene (Wenzens, 2002(Wenzens, , 2005 and the Little Ice Age (LIA) periods (Aravena, 2007;García-Zamora at al., unpublished data). Despite these studies, a complete and comprehensive glacier inventory and an assessment of changes in glacier extent for this area have not been carried out. ...
... For instance, there is no current proxy by which to distinguish whether or not a glacier had extensive debris coverage in the past. The lower section of the Fr ıas glacier is oriented to the north and resembles the neighboring Casa Pangue glacier, which currently is a regenerated glacier with a thick debris cover on its ablation zone [Fern andez et al., 2006]. This suggests that Fr ıas was also likely debris covered in the past, which may distort some climatic conclusions in . ...
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Here we review the literature preferentially concerned with modern glacier-climate modeling along the Andes. We find a diverse range of modeling approaches, from empirical/statistical models to relatively complex energy balance procedures. We analyzed these models at three different spatial scales. Firstly, we review global approaches that have included the Andes. Secondly, we depict and analyze modeling exercises aimed at studying Andean glaciers as a whole. Our revision shows only two studies dealing with glacier modeling at this continental scale. We contend that this regional approach is increasingly necessary because it allows for connecting the “average-out” tendency of global studies to local observations or models, in order to comprehend scales of variability and heterogeneity. Third, we revise small-scale modeling, finding that the overwhelming number of studies have targeted glaciers in Patagonia. We also find that most studies use temperature-index models and that energy balance models are still not widely utilized. However, there is no clear spatial pattern of model complexity. We conclude with a discussion of both the limitations of certain approaches, as for example the use of short calibration periods for long-term modeling, and also the opportunities for improved understanding afforded by new methods and techniques, such as climatic downscaling. We also propose ways to future developments, in which observations and models can be combined to improve current understanding of volumetric glacier changes and their climate causes. This article is protected by copyright. All rights reserved.
... Precipitation declines are expected to be most severe north of 40°S latitude, and to decrease from 40 to 60 percent in relation to current precipitation patterns (University of Chile-DGF 2006). Hydrologic regimes will be heavily altered through reductions in Andean snowpack and because of the accelerated glacial melting that already has been documented in the southern portion of the ecoregion (Rivera et al. 2006). ...
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At first glance, the Valdivian temperate rainforest of Chile and Argentina (see figure 5-1) is a mirror image of the Pacific Coast of North America in appearance and climate, but upon closer inspection this strikingly unique rainforest is dominated by broadleaf evergreen flowering trees that evolved in near complete isolation from the temperate forests of the Northern Hemisphere. This is truly a region worthy of global recognition. Figure 5-1. Valdivian temperate rainforests of Chile and Argentina (digitized from national vegetation surveys).
... Based on the satellite mapping of some terminal moraines, some changes of the glaciers were considered to occur during the Holocene (Glasser et al. 2005). More modern changes were detected for the last 60 years (Fernandez Rivera et al. 2006, Evolution of the Eastern flank of the North Patagonian Ice Field ...
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Patagonia had significant morphological changes when moraines at the foot of the Andes caused reversals in the drainage of rivers that crossed flat plateaus. Several examples of such basins are known from evidences of misfit valleys and the activation of short watersheds with rapids. The Deseado River drained the second largest lake of South America (Buenos Aires-General Carrera) and another glacial-valley system. The Deseado-Pinturas system conducted large amounts of water that satisfied herds of guanacos; paleoindians established to take advantage of such a quantity of proteins favored by the configuration of gorges at the upper valley (Cueva de las Manos site). However, during the shrinking of the North Patagonian Ice Field, the Baker River activated capturing the drainage of both basins towards the Pacific Ocean. The deactivation of the Pinturas and Deseado systems caused the lowering of progressive younger fluvial terraces, a record of hanging tidal flats at the inlet, and a progressive abandonment of the Las Manos site. The Baker River today supplies large amounts of water for planned hydroelectric dams. However, the watershed has not arrived into morphological equilibrium and recently suffered several Glacial-lake outbursts floods (GLOFs).
... Since the time of the first complete reconnaissance trip in 1937 (De Agostini, 1945), when splendid photographs of Monte San Lorenzo and its main glaciers were collected, few studies of these glaciers are available; exceptions include recent frontal variations of some glaciers (Fernández et al., 2006;Aravena, 2007), the glacial geology and geomorphology of the Holocene (Wenzens, 2002(Wenzens, , 2005 and the Little Ice Age (LIA) periods (Aravena, 2007;García-Zamora at al., unpublished data). Despite these studies, a complete and comprehensive glacier inventory and an assessment of changes in glacier extent for this area have not been carried out. ...
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We present the first glacier inventory of the Monte San Lorenzo region (47 degrees 35'S, 72 degrees 18'W) in the southern Patagonian Andes of Chile and Argentina. This region contains the largest and easternmost glaciers at these latitudes in South America. The inventory was developed using a combination of ASTER and Landsat ETM + scenes from 2005 and 2008, respectively, and a semi-automatic band ratio approach to map glacier ice. Manual corrections were applied to include debris-covered ice and ice in cast shadows. We inventoried 213 glaciers that cover a 2005/2008 total area of ca. 207 km(2) and lie between 520 m and 3700 m in elevation. Landsat TM images acquired in 1985 and 2000 were subsequently used to assess changes in glacierized area over the 1985-2008 interval. Based on all available information, we determined an 18.6% reduction in the total glacier area since 1985. Glaciers smaller than 1 km(2) have shown highly variable (0-100%) relative areal reduction, whereas the formation and growth of proglacial lakes promoted rapid recession of the larger valley glaciers, which concentrate the major ice losses, representing ca. 32% of the total glacier area reduction. Glacier fragmentation has occurred for 50% of the ice bodies larger than 1 km2. These results agree with the generalized pattern of glacier retreat observed throughout the Patagonian Andes, but the lack of detailed meteorological and glaciological data in the area preclude a more refined analysis of the climate-glacier relationships and processes explaining the recent glacier trends.
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