Gabbi, J., Carenzo, M., Pellicciotti, F., Bauder, A. In order to investigate the implications of these results for flat glaciers, we performed additional synthetic experiments in order to reproduce this lack of topographical feedback (Fig. A.R. However, the use of ANNs remains largely unexplored in glaciology for regression problems, with only a few studies using shallow ANNs for predicting the ice thickness14 or mass balance13 of a single glacier. Both the Lasso and the temperature-index MB model rely on linear relationships between PDDs, solid precipitation and MB. Change 120, 2437 (2014). Photographs taken by Simo Rsnen (Bossons glacier, European Alps, CC BY-SA 3.0) and Doug Hardy (Quelccaya ice cap, Andes, CC BY-SA 4.0). ice caps) that are found in other glacierized regions such as the Arctic, where the largest volumes of glacier ice (other than the ice sheets) are stored32, cannot retreat to higher elevations. From this behavior, inferences of past climate can be drawn. MathSciNet Glacier shrinkage in the Alps continues unabated as revealed by a new glacier inventory from Sentinel-2. Such ice caps cannot retreat to higher elevations in a warming climate, which inhibits this positive impact on MB40 (Fig. 58, 267288 (1996). creates a Nisqually Glacier response similar to those seen from its historical waves, suggesting that there are other factors contributing to kinematic wave formation, and 4) the Nisqually . In this study, we demonstrated the advantages of using deep learning to model glacier MB at regional scales, both in terms of variance and bias. Our projections highlight the almost complete disappearance of all glaciers outside the Mont-Blanc and Pelvoux (Ecrins region) massifs under RCP 4.5 (Fig. A small ablation increase may cause . (Photograph by Klaus J. Bayr, Keene State College, 1990) One method of measuring glaciers is to send researchers onto the ice with . Response of KarakoramHimalayan glaciers to climate variability and 3 (2015). In the United States, glaciers can be found in the Rocky Mountains, the Sierra Nevada, the Cascades, and throughout Alaska. Google Scholar. Strong Alpine glacier melt in the 1940s due to enhanced solar radiation. Nature Communications thanks Mohd Anul Haq, Lauren Vargo, and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. The glacier ice volume in the French Alps at the beginning of the 21st century is unevenly distributed, with the Mont-Blanc massif accounting for about 60% of the total ice volume in the year 2015 (7.06 out of 11.64km3, Fig. Regarding air temperature forcings, the linear Lasso MB model was found to be slightly under-sensitive to extreme positive cumulative PDD (CPDD) and over-sensitive to extreme negative CPDDs. A He uniform initialization45 was used for the network parameters. Glacier Research on Mt. Rainier - Portland State University Tour. Paul, F., Kb, A., Maisch, M., Kellenberger, T. & Haeberli, W. Rapid disintegration of Alpine glaciers observed with satellite data: disintegration of alpine glaciers. Several differences are present between ALPGM, the model used in this study, and GloGEMflow (TableS2), which hinder a direct meaningful comparison between both. The Karakoram and the Himalayan mountain range accommodate a large number of glaciers and are the major source of several perennial rivers downstream. How Will Melting Glaciers Affect Streamflow? - Eos Source: Mount Rainier National Park These results are in agreement with the main known drivers of glacier mass change in the French Alps28. Ice-surface altitude changes of as much as 25 meters occurred between 1944 and 1955. Soc. The model output data generated in this study have been deposited in netCDF and CSV format in a Zenodo repository under accession code Creative Commons Attribution 4.0 International. Mt. Annu. 282, 104115 (2003). 2008. Glaciers are experiencing important changes throughout the world as a consequence of anthropogenic climate change1. "Seeing the rapid and devastating collapse of this incredible and critical salmon in the Nisqually River is heartbreaking," said Troutt. Particularly in Asia, water demand exceeds supply due to rapid population growth, with glacier . All authors provided inputs to the paper and helped to write it. The images or other third party material in this article are included in the articles Creative Commons license, unless indicated otherwise in a credit line to the material. Temperature-index models are known to be over-sensitive to temperature changes, mainly due to important differences in the processes contributing to future warming. 47 (2020). This method has the advantage of including glacier-specific dynamics in the model, encompassing a wide range of different glacier behaviours. Z. et al. This is not the case for the nonlinear deep learning MB model, which captures the nonlinear response of melt and MB to increasing air temperatures, thus reducing the MB sensitivity to extreme positive and negative air temperature and summer snowfall anomalies (Fig. Through these surveys "bulges" have been tracked as they travel down the glacier (c). Despite the existence of slightly different trends during the first half of the century, both the Lasso and the temperature-index model react similarly under RCP 4.5 and 8.5 during the second half of the century, compared to the deep learning model. . Earth Planet. 1 and S1). volume13, Articlenumber:409 (2022) Lett. ADS 'When the Glaciers Disappear, Those Species Will Go Extinct' 41, 153160 (1995). The two recent iterations of the Glacier Model Intercomparison Project (GlacierMIP7,8) have proved a remarkable effort to aggregate, compare and understand global glacier evolution estimates and their associated uncertainties. By unravelling nonlinear relationships between climate and glacier MB, we have demonstrated the limitations of linear statistical MB models to represent extreme MB rates in long-term projections. Contrasting glacier responses to recent climate change in high-mountain Glacier topography is a crucial driver of future glacier projections and is expected to play an important role in determining the magnitude that nonlinearities will have on the mass balance signal: ice caps and large flatter glaciers are expected to be more influenced by these nonlinear sensitivities than steep mountain glaciers in a warming climate. The Lasso30, used for the linear mass balance model, is a linear regression analysis method which shrinks model parameters, thus performing both variable selection and regularization. Nat. Multiple copies of this dataset were created, and for each individual copy a single predictor (i.e. Glaciers in the European Alps have been monitored for several decades, resulting in the longest observational series in the world23,24. This synthetic experiment is an approximation of what might occur in other glacierized regions with ice caps. 3). Additionally, glacier surface area was found to be a minor predictor in our MB models31. Simulating these processes at a large geographical scale is challenging, with models requiring several parametrizations and simplifications to operate. energy balance), with differences increasing when the conditions considerably differ from the calibration period33. The Nisqually Glacier, Mount Rainier, Washington, 1857-1979: A summary This parametrization reproduces in an empirical manner the changes in glacier geometry due to the combined effects of ice dynamics and MB. MB rates only begin to approach equilibrium towards the end of the century under RCP 2.6, for which glaciers could potentially stabilize with the climate in the first decades of the 22nd century depending on their response time (Fig. Glacier Length Variations and Climate Change: Comparative Glacier Alternatively, the comparisons against an independent large-scale glacier evolution model were less straightforward to achieve. However, to further investigate these findings, experiments designed more towards ice caps, and including crucial mechanisms such as ice-ocean interactions and thermodynamics, should be used for this purpose. Uncertainties of existing projections of future glacier evolution are particularly large for the second half of the 21st century due to a large uncertainty on future climatic conditions. A physically-based method for mapping glacial debris-cover thickness from ASTER satellite imagery: development and testing at Miage Glacier, Italian Alps Discovery - the University of Dundee Research Portal Tom R. Andersson, J. Scott Hosking, Emily Shuckburgh, Shfaqat A. Khan, Anders A. Bjrk, Toni Schenk, Romain Hugonnet, Robert McNabb, Andreas Kb, Atanu Bhattacharya, Tobias Bolch, Tandong Yao, Christian Sommer, Philipp Malz, Matthias H. Braun, Romain Millan, Jrmie Mouginot, Mathieu Morlighem, Matthias H. Braun, Philipp Malz, Thorsten C. Seehaus, Nature Communications 12, 1959 (2020). In fact, in many cases the surface lowering into warmer air causes this impact on the MB to be negative, further enhancing extreme negative mass balance rates. The estimated ice thickness for Mer de Glace (28.87km2 in 2015) was increased by 25% in order to correct the bias with respect to field observations31. The performance of this parametrization was validated in a previous study, indicating a correct agreement with observations31. The largest snow depths measured this spring exceeded 10 meters on Nisqually Glacier and 7 meters on Emmons. Nature Geosciences, https://doi.org/10.1038/s41561-021-00885-z (2022). For such cases, we assumed that ice dynamics no longer play an important role, and the mass changes were applied equally throughout the glacier. The two models with linear MB responses to PDDs and accumulation simulate more positive MB rates under RCP 2.6, highlighting their over-sensitivity to negative air temperature anomalies and positive snowfall anomalies (Fig. Cauvy-Frauni, S. & Dangles, O. & Zumbhl, H. J. Zekollari, H., Huss, M. & Farinotti, D. On the Imbalance and Response Time of Glaciers in the European Alps. Hugonnet, R. et al. Lett. Res. Use the Previous and Next buttons to navigate the slides or the slide controller buttons at the end to navigate through each slide. Planet. J. Geophys. Since 2005, study finds that surface melt off glaciers in the North has risen by 900%. Nature Communications (Nat Commun) 10, 42574283 (2017). At the Edge: Monitoring Glaciers to Watch Global Warming - NASA The climatic forcing comes from high-resolution climate ensemble projections from 29 combinations of global climate models (GCMs) and regional climate models (RCMs) adjusted for mountain regions for three Representative Concentration Pathway (RCP) scenarios: 2.6, 4.5, and 8.525. Therefore, linear MB models present more limitations for projections of ice caps, showing a tendency to negative MB biases. Remote Sens. In our model, we specifically computed this parameterized function for each individual glacier larger than 0.5km2, representing 80% of the total glacierized area in 2015, using two DEMs covering the whole French Alps: a photogrammetric one in 1979 and a SPOT-5 one in 2011. Sign up for the Nature Briefing newsletter what matters in science, free to your inbox daily. I.G. A similar behaviour is observed when comparing temperature-index models to more complex models (e.g. This results in a higher complexity of the Lasso compared to a temperature-index model. McKinley, Alaska, change in response to the local climate. Rainier is considered by the USGS to be one of the most threatening volcanoes in the Cascade Mountains. This suggests that linear MB models are adequate tools for simulating MB of mountain glaciers with important topographical adjustment, with the only exception being the most optimistic climate scenarios and glaciers with long response times. Many studies have investigated the effects of climate change on glacier runoff using observations or modelling, with a recent focus on High Mountain Asia 14,16,17 and the Andes 18,19,20.The degree . An analysis of the climate signal at the glaciers mean altitude throughout the century reveals that air temperature, particularly in summer, is expected to be the main driver of glacier mass change in the region (Fig. Ice thickness accuracy varied significantly, with an overall correct representation of the ice distribution but with local biases reaching up to 100%. Since both MB models also include monthly temperature data as predictors, this CPDD anomaly was distributed evenly between the ablation season (April 1September 30), following the expected increase in mostly summer temperatures instead of winter temperatures in the future (Fig. 3c). Jordi Bolibar. IPCC. Reanalysis of 47 Years of Climate in the French Alps (19582005): Climatology and Trends for Snow Cover. Advances occurred from 1963-68 and from 1974-79. on various mass balance and radiation components) are opening the door for updated and better constrained projections. 1). We perform, to the best of our knowledge, the first-ever deep learning (i.e. On Mount Rainier, elevation surveys of Nisqually Glacier are regularly made to determine changes in the elevation of the surface. When working with spatiotemporal data, it is imperative to respect spatial and temporal data structures during cross-validation in order to correctly assess an accurate model performance48. The same was done with winter snowfall anomalies, ranging between 1500mm and +1500mm in steps of 100mm, and summer snowfall anomalies, ranging between 1000mm and +1000mm in steps of 100mm. performed simulations with another glacier model, provided results for comparison, and contributed to the glaciological analyses.
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