Air Temperature Characteristics, Distribution, and Impact on Modeled Ablation for the South Patagonia Icefield

Bravo, Claudio; Quincey, Duncan J.; Ross, Andrew; Rivera, Andrés; Brock, Benjamin; Miles, Evan; Silva, A.

doi:10.1029/2018jd028857

Cited by 27 publications

(38 citation statements)

References 72 publications

(155 reference statements)

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“…3c), we used this NCEP-NCAR dataset to reconstruct the missing period, yielding an average value of 6.97 o C for the AWS JM air temperatures. The resulting 2012–2017 air temperature series, corrected by the cooling effect over the glacier boundary layer (Carturan and others, 2015; Bravo and others, 2019 b ) assuming a 1 o C reduction bias, is shown in Figure 3d. The distributed temperature model for the glacier shows a warmer area comprising the lower outlet tongue and a second area comprising the ice plateau where stronger winds and ice–atmosphere cooling feedbacks are evident (Fig.…”

Section: Resultsmentioning

confidence: 99%

Recent ice dynamics and mass balance of Jorge Montt Glacier, Southern Patagonia Icefield

et al. 2019

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The Southern Patagonia Icefield (SPI) withdrawal in recent decades shows contrasting behaviours between adjacent basins. One of the basins with highest volumetric losses is located at northernmost SPI. We refer to Jorge Montt tidewater glacier (48° 30′S/73° 30′W, 445 km2 in 2018), which retreated 2.7 km between 2011 and 2018 and thinned at rates of up to 21 m a−1 over this period. Based on the retreat record, remote-sensing imagery, field data, a mass-balance model and a calving parameterisation, we attempted to differentiate climatic-induced changes (i.e. surface mass balance) and dynamic responses (i.e. calving fluxes). The surface mass balance reached −4.15 km3 w.e. a−1 between 2012 and 2017. When frontal ablation is included, the net mass balance is −17.79 km3 w.e. a−1. This represents a change of trend compared with modelling estimations of positive surface mass balance prior to 2010. This shift is attributed to higher ablation rates given that accumulation is known to have increased between 1980 and 2015. The available evidence, therefore, indicates that frontal ablation is the main factor, supported by observed rates at Jorge Montt as high as 3.81 km3 w.e. a−1 in 2015, with ice velocities peaking at 11 km a−1.

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Section: Resultsmentioning

confidence: 99%

Recent ice dynamics and mass balance of Jorge Montt Glacier, Southern Patagonia Icefield

et al. 2019

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“…As the minimal glacier model requires the air temperature at the elevation of the front of the glacier, we used an environmental lapse rate of −0.0065 °C m −1 (Barry, 2008), which is a shallower lapse rate that has been typically observed over the glaciers (e.g. Petersen and Pellicciotti, 2011; Shaw and others, 2017; Bravo and others, 2019). Due to the uncertainty in the lapse rates, we use a range that comprises between −0.0045 and −0.0085 °C m −1 .…”

Section: Methodsmentioning

confidence: 99%

A near 90-year record of the evolution of El Morado Glacier and its proglacial lake, Central Chilean Andes

et al. 2020

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Using an ensemble of close- and long-range remote sensing, lake bathymetry and regional meteorological data, we present a detailed assessment of the geometric changes of El Morado Glacier in the Central Andes of Chile and its adjacent proglacial lake between 1932 and 2019. Overall, the results revealed a period of marked glacier down wasting, with a mean geodetic glacier mass balance of −0.39 ± 0.15 m w.e.a−1 observed for the entire glacier between 1955 and 2015 with an area loss of 40% between 1955 and 2019. We estimate an ice elevation change of −1.00 ± 0.17 m a−1 for the glacier tongue between 1932 and 2019. The increase in the ice thinning rates and area loss during the last decade is coincident with the severe drought in this region (2010–present), which our minimal surface mass-balance model is able to reproduce. As a result of the glacier changes observed, the proglacial lake increased in area substantially between 1955 and 2019, with bathymetry data suggesting a water volume of 3.6 million m3 in 2017. This study highlights the need for further monitoring of glacierised areas in the Central Andes. Such efforts would facilitate a better understanding of the downstream impacts of glacier downwasting.

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“…To partly overcome the lack of basic climatic information, many modeling studies have used data from the ERA or NCEP/NCAR climate reanalyses (Lenaerts et al, 2014;Weidemann et al, 2018b), and more recently the WRF simulations (e.g., Villarroel et al, 2013;Schaefer et al, 2015). Meteorological stations from lowlands away from glaciers have also been used, but the scarcity and lack of continuity remains a serious problem in this region (Masiokas et al, 2015;Bravo et al, 2019b).…”

Section: Recent Glacier Changes and Ice Dynamics In The Wet Andesmentioning

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A Review of the Current State and Recent Changes of the Andean Cryosphere

et al. 2020

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The Andes Cordillera contains the most diverse cryosphere on Earth, including extensive areas covered by seasonal snow, numerous tropical and extratropical glaciers, and many mountain permafrost landforms. Here, we review some recent advances in the study of the main components of the cryosphere in the Andes, and discuss the changes observed in the seasonal snow and permanent ice masses of this region over the past decades. The open access and increasing availability of remote sensing products has produced a substantial improvement in our understanding of the current state and recent changes of the Andean cryosphere, allowing an unprecedented detail in their identification and monitoring at local and regional scales. Analyses of snow cover maps has allowed the identification of seasonal patterns and long term trends in snow accumulation for most of the Andes, with some sectors in central Chile and central-western Argentina showing a clear decline in snowfall and snow persistence since 2010. This recent shortage of mountain snow has caused an extended, severe drought that is unprecedented in the hydrological and climatological records from this region. Together with data from global glacier inventories, detailed inventories at local/regional scales are now also freely available, providing important new information for glaciological, hydrological, and climatological assessments in different sectors of the Andes. Numerous studies largely based on field measurements and/or remote sensing techniques have documented the recent glacier shrinkage throughout the Andes. This observed ice mass loss has put Andean glaciers among the highest contributors to sea level rise per unit area. Other recent studies have focused on rock glaciers, showing that in extensive semi-arid sectors of the Andes these mountain permafrost features contain large reserves of freshwater and may play a crucial role as future climate becomes warmer and drier in this region. Many relevant issues remain to be investigated, however, including an improved estimation of ice volumes at local scales, and detailed assessments of the hydrological significance of the different components of the cryosphere in Andean river basins. The impacts of future climate changes on the Andean cryosphere also need to be studied in more detail, considering the contrasting

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Air Temperature Characteristics, Distribution, and Impact on Modeled Ablation for the South Patagonia Icefield

Cited by 27 publications

References 72 publications

Recent ice dynamics and mass balance of Jorge Montt Glacier, Southern Patagonia Icefield

Recent ice dynamics and mass balance of Jorge Montt Glacier, Southern Patagonia Icefield

A near 90-year record of the evolution of El Morado Glacier and its proglacial lake, Central Chilean Andes

A Review of the Current State and Recent Changes of the Andean Cryosphere

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