Abstract
AbstractGlaciers in the Southern Patagonia Icefield (SPI) have been shrinking in recent decades, but due to a lack of field observations, understanding of the drivers of ablation is limited. We present a distributed surface energy balance model, forced with meteorological observations from a west–east transect located in the north of the SPI. Between October 2015 and June 2016, humid and warm on-glacier conditions prevailed on the western side compared to dry and cold conditions on the eastern side. Controls of ablation differ along the transect, although at glacier-wide scale sensible heat (mean of 72 W m−2 to the west and 51 W m−2 to the east) and net shortwave radiation (mean of 54 W m−2 to the west and 52 W m−2 to the east) provided the main energy sources. Net longwave radiation was an energy sink, while latent heat was the most spatially variable flux, being an energy sink in the east (−4 W m−2) and a source in the west (20 W m−2). Ablation was high, but at comparable elevations, it was greater to the west. These results provide new insights into the spatial variability of energy-balance fluxes and their control over the ablation of Patagonian glaciers.
Highlights
Patagonia (40–55° S) comprises the most extensive icefields at mid-latitudes in the Southern Hemisphere: the Southern Patagonia Icefield (SPI) and the Northern Patagonia Icefield (NPI)
Surface massbalance modelling forced with climate data shows positive mean values for the entire SPI (Schaefer and others, 2015; Mernild and others, 2016), leading to questions around how the mass balance of glaciers in this region will evolve over coming decades
To assess how the meteorological differences forced by the orographic effect impact surface ablation, we present a distributed surface energy balance (SEB) model for glaciers located in the northern section of the SPI (48–49° S) and on both sides of the divide
Summary
Patagonia (40–55° S) comprises the most extensive icefields at mid-latitudes in the Southern Hemisphere: the Southern Patagonia Icefield (SPI) and the Northern Patagonia Icefield (NPI) Glacier wastage in this region (Rignot and others, 2003; Davies and Glasser, 2012; Willis and others, 2012; White and Copland, 2015; Foresta and others, 2018; Malz and others, 2018; Abdel Jaber and others, 2019; Braun and others, 2019; Dussaillant and others, 2019) is a matter of concern due to its observed and potential contribution to sea-level rise (Gardner and others, 2013; Zemp and others, 2019; Masiokas and others, 2020) and the role of receding glaciers in triggering hazardous natural events such as glacial-lake outburst floods (Wilson and others, 2018) and rock avalanche events associated with de-buttressing (Iribarren-Anacona and others, 2015). Surface massbalance modelling forced with climate data shows positive mean values for the entire SPI (Schaefer and others, 2015; Mernild and others, 2016), leading to questions around how the mass balance of glaciers in this region will evolve over coming decades
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