Glacier contribution to streamflow in two headwaters of the Huasco River, Dry Andes of Chile

Gascoin, Simon; Kinnard, Christophe; Ponce, Rodrigo; Lhermitte, Stef; MacDonell, Shelley; Rabatel, Antoine

doi:10.5194/tc-5-1099-2011

Cited by 90 publications

(103 citation statements)

References 36 publications

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“…The climate is characterized by predominantly clear skies, intense solar radiation, low air humidity and low precipitations. Higher peaks adjacent to Cerro Tapado, such as Cerro Olivares (30 • 17 S, 69 • 54 W, 6252 m), are currently free of glaciers, suggesting that the few glaciers existing in the area are atypical features and that local climatic conditions (e.g., excess precipitation due to wind redistribution of snow) play an important role (Gascoin et al, 2011(Gascoin et al, , 2013Ginot et al, 2006;Kull et al, 2002).…”

Section: Study Areamentioning

confidence: 99%

Albedo over rough snow and ice surfaces

2014

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Abstract. Both satellite and ground-based broadband albedo measurements over rough and complex terrain show several limitations concerning feasibility and representativeness. To assess these limitations and understand the effect of surface roughness on albedo, firstly, an intrasurface radiative transfer (ISRT) model is combined with albedo measurements over different penitente surfaces on Glaciar Tapado in the semiarid Andes of northern Chile. Results of the ISRT model show effective albedo reductions over the penitentes up to 0.4 when comparing the rough surface albedo relative to the albedo of the flat surface. The magnitude of these reductions primarily depends on the opening angles of the penitentes, but the shape of the penitentes and spatial variability of the material albedo also play a major role.Secondly, the ISRT model is used to reveal the effect of using albedo measurements at a specific location (i.e., apparent albedo) to infer the true albedo of a penitente field (i.e., effective albedo). This effect is especially strong for narrow penitentes, resulting in sampling biases of up to ±0.05. The sampling biases are more pronounced when the sensor is low above the surface, but remain relatively constant throughout the day. Consequently, it is important to use a large number of samples at various places and/or to locate the sensor sufficiently high in order to avoid this sampling bias of surface albedo over rough surfaces.Thirdly, the temporal evolution of broadband albedo over a penitente-covered surface is analyzed to place the experiments and their uncertainty into a longer temporal context. Time series of albedo measurements at an automated weather station over two ablation seasons reveal that albedo decreases early in the ablation season. These decreases stabilize from February onwards with variations being caused by fresh snowfall events. The 2009/2010 and 2011/2012 seasons differ notably, where the latter shows lower albedo values caused by larger penitentes. Finally, a comparison of the ground-based albedo observations with Landsat and MODIS (Moderate Resolution Imaging Spectroradiometer)-derived albedo showed that both satellite albedo products capture the albedo evolution with root mean square errors of 0.08 and 0.15, respectively, but also illustrate their shortcomings related to temporal resolution and spatial heterogeneity over small mountain glaciers.

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Section: Study Areamentioning

confidence: 99%

Albedo over rough snow and ice surfaces

2014

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“…(Nicholson et al, 2010), and cover up to 11 % of the land surface (Gascoin et al, 2011) of the upper Huasco catchments (29 • S, 70 • W, > 4000 m above sea level (a.s.l. ); Fig.…”

Section: Site Descriptionmentioning

confidence: 99%

“…Snowmelt is thought to be the dominant contributor to the watershed, however conclusive source comparisons are currently lacking, largely due to the difficulty of accurately measuring and modelling ablation processes in this area (Gascoin et al, 2012). Past studies in the region focusing on cryospheric contributions to streamflow have taken a watershed approach to the problem, and have used black-box approaches to give first estimations of the relative contributions from snowpacks and cold-based glaciers (Favier et al, 2009;Gascoin et al, 2011). These studies suggest that snow-and glacier melt contribute to the bulk of the runoff, but as the methods used in these studies do not capture the physical processes of ablation at a sufficiently high temporal or spatial resolution, it remains difficult to link ablation processes and melt water production with atmospheric conditions.…”

Section: Introductionmentioning

confidence: 99%

Meteorological drivers of ablation processes on a cold glacier in the semi-arid Andes of Chile

et al. 2013

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Abstract. Meteorological and surface change measurements collected during a 2.5 yr period are used to calculate surface mass and energy balances at 5324 m a.s.l. on Guanaco Glacier, a cold-based glacier in the semi-arid Andes of Chile. Meteorological conditions are marked by extremely low vapour pressures (annual mean of 1.1 hPa), strong winds (annual mean of 10 m s −1 ), shortwave radiation receipt persistently close to the theoretical site maximum during cloudfree days (mean annual 295 W m −2 ; summer hourly maximum 1354 W m −2 ) and low precipitation rates (mean annual 45 mm w.e.). Snowfall occurs sporadically throughout the year and is related to frontal events in the winter and convective storms during the summer months. Net shortwave radiation provides the greatest source of energy to the glacier surface, and net longwave radiation dominates energy losses. The turbulent latent heat flux is always negative, which means that the surface is always losing mass via sublimation, which is the main form of ablation at the site. Sublimation rates are most strongly correlated with net shortwave radiation, incoming shortwave radiation, albedo and vapour pressure. Low glacier surface temperatures restrict melting for much of the period, however episodic melting occurs during the austral summer, when warm, humid, calm and high pressure conditions restrict sublimation and make more energy available for melting. Low accumulation (131 mm w.e. over the period) and relatively high ablation (1435 mm w.e.) means that mass change over the period was negative (−1304 mm w.e.), which continued the negative trend recorded in the region over the last few decades.

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“…In most glacieriesed regions sublimation from the glacier is considered a negligible factor, with rates often far below the error of accumulation rates (Hock and Holmgren, 2005;Gascoin et al, 2011). This is mainly due to the fact that sublimation consumes ).…”

Section: Sublimationmentioning

confidence: 99%

Bridging glacier and river catchment scales: an efficient representation of glacier dynamics in a hydrological model

Wortmann

Bolch

Krysanova

et al. 2016

Preprint

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Abstract. Glacierised river catchments have been shown to be highly sensitive to climate change, while large populations depend on the water resources originating from them. Hydrological models are used to aid water resource management, yet their treatment of glacier processes is either rudimentary in large applications or linked to fully distributed glacier models that prevent larger model domains. Also, data scarcity in mountainous catchments has hampered the implementation of physically based approaches over entire river catchments. A fully integrated glacier dynamics module was developed for the eco-hydrological 5 model SWIM (SWIM-G) that takes full account of the spatial heterogeneity of mountainous catchments but keeps in line with the semi-distributed disaggregation of the hydrological model. The glacierised part of the catchment is disaggregated into glaciological response units that are based on subbasin, elevation zone and aspect classes. They seamlessly integrate into the hydrological response units of the hydrological model SWIM. Robust and simple approaches to ice flow, avalanching, snow accumulation and metamorphism as well as glacier ablation under consideration of aspect, debris cover and sublimation 10 are implemented in the model, balancing process complexity and data availability. The fully integrated is also capable of simulating a range of other hydrological processes that are common for larger mountainous catchments such as reservoirs, irrigation agriculture and runoff from a diverse soil and vegetation cover. SWIM-G is initialised and calibrated to initial glacier hypsometry, glacier mass balance and river discharge. While the model is intended to be used in medium to large river basins with data-scarce and glacierised headwaters, it is here validated in the data-abundant catchment of the Upper Rhone River, 15Switzerland and the data-scarce catchment of the Upper Aksu River, Kyrgyzstan/NW China.

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Glacier contribution to streamflow in two headwaters of the Huasco River, Dry Andes of Chile

Cited by 90 publications

References 36 publications

Albedo over rough snow and ice surfaces

Albedo over rough snow and ice surfaces

Meteorological drivers of ablation processes on a cold glacier in the semi-arid Andes of Chile

Bridging glacier and river catchment scales: an efficient representation of glacier dynamics in a hydrological model

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