CR5.2 | Observing and measuring glacier changes from the Little Ice Age to the present based on in situ and remote sensing data
Observing and measuring glacier changes from the Little Ice Age to the present based on in situ and remote sensing data
Co-organized by GM10/HS13
Convener: Frank Paul | Co-conveners: Paul Weber, Md. Farooq Azam, Clare Boston, Jörg Franke, Samuel U. Nussbaumer, Laura Zalazar
Orals
| Fri, 19 Apr, 08:30–10:15 (CEST)
 
Room 1.34
Posters on site
| Attendance Fri, 19 Apr, 16:15–18:00 (CEST) | Display Fri, 19 Apr, 14:00–18:00
 
Hall X4
Posters virtual
| Attendance Fri, 19 Apr, 14:00–15:45 (CEST) | Display Fri, 19 Apr, 08:30–18:00
 
vHall X4
Orals |
Fri, 08:30
Fri, 16:15
Fri, 14:00
This session has come about through the merger of two Cryospheric Sciences sessions – one focusing on Little Ice Age (LIA) glacier advances and the other on glacier monitoring from in situ and remotely sensed observations. The aim of this joint session is to present the current state of science in both areas of research and to improve our understanding of the processes of glacier change, using detailed observations of the distribution of glaciers and the changes they have undergone since the LIA. This interval of worldwide, but asynchronous, glacier advances (ca. 1300–1900 CE) is of major significance because it offers a unique snapshot of the “natural”, pre-industrial state of the cryosphere, before the global glacier decline resulting from human-caused climate change. The studies presented in this session employ diverse methods and data sources, such as geochronology and remote sensing, and utilise field observations, satellite, instrumental, historical, pictorial, and other records. A specific focus of the presented research is on (i) strengths and limitations of different types of data for regional to global-scale assessments, (ii) uncertainty assessments, (iii) achieving better temporal resolution and spatial coverage, and (iv) improved process understanding by combining datasets across scales.

Orals: Fri, 19 Apr | Room 1.34

Chairpersons: Paul Weber, Frank Paul
The Little Ice Age
08:30–08:40
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EGU24-4392
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solicited
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On-site presentation
Kurt Nicolussi

The Little Ice Age (LIA) was originally understood as a period of increased glaciation in the late Holocene. Today, the term is used to describe the multi-centennial glacier advance and maximum level period in the last millennium, but it is also used to refer to the contemporaneous cooler climatic conditions beyond glaciated areas.

Glacier dynamics in the Alps during the last centuries of the LIA are especially known from historical documents, i.e., written and pictorial sources, which essentially date from around 1600 CE and cover some well-known glaciers. Today, these data are enhanced in particular by tree-ring analyses on remnants of trees buried during glacial advances, which can provide calendar dates for advances and glacier maxima, also for the early centuries of the LIA. Moreover, our knowledge of the LIA period is increasingly enhanced by regional climate reconstructions and analyses on climate forcings.

The LIA in the Alps can be defined as the period between the onset of climate cooling, which led to a first LIA-type maximum of glaciers, and the last LIA maximum level generally observed around the middle of the 1800s, i.e., between 1260 and 1860 CE. The first LIA-type maxima are demonstrable for the 1300s, around 1320 and 1380 CE, and then further, often seven maxima for the period ca. 1600-1860 CE. Accordingly, and taking into account the climatic variability, the LIA can be divided into an early (ca. 1260-1380), intermediate (ca. 1380-1575) and main phase (ca. 1575-1860 CE).

Compared to the preceding period of the Medieval Climate Anomaly, reconstructions demonstrate increased climatic variability for the LIA, marked by repeated and pronounced cooling phases that finally triggered the glacier advances. These climatic disturbances correlate remarkably directly with significant volcanic eruptions or phases of increased volcanic activity and, albeit less clearly, with periods of reduced solar insolation, which can be derived from reduced solar activity. Distinctive and historically documented glacier advance phases are often correlated with climatic disturbances following major volcanic eruptions, e.g., the advance period around 1820 CE is following the preceding volcanic events of 1809 and 1815 CE.

Today, the LIA is not only the coolest multi-centennial period of the last 10,000 years but also the reference period for assessing the changes from a system of climate and glacier variability largely determined by natural factors to an environmental system clearly shaped by human activities.

How to cite: Nicolussi, K.: Glacier variability in the Alps during the Little Ice Age - overview on course, evidences and causes, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4392, https://doi.org/10.5194/egusphere-egu24-4392, 2024.

08:40–08:45
08:45–08:55
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EGU24-4111
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ECS
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On-site presentation
Andreas Henz, Andreas Vieli, Samuel Nussbaumer, and Guillaume Jouvet

The maximum extent of the glaciers in the European Alps during the Little Ice Age (LIA) is relatively well known. However, the ice surface geometry and related ice volume are still poorly constrained. We provide an Alpine-wide reconstruction of glacier thickness using the novel Instructed Glacier Model (IGM). The IGM uses the innovative approach based on deep-learning and GPU to accelerate the solving of computationally expensive 3D physics of glacier flow, which is key to work in high-resolution at the Alpine scale. The mass-balance model is tuned to fit each glacier of the Alps to its known maximum LIA extent resulting in ice-surface geometries and volumes that are consistent with glacier physics and the principles of mass conservation. In addition, our approach provides the corresponding equilibrium-line altitudes (ELAs) for individual glaciers and thereby reveals regional ELA patterns. Comparing these patterns with pre-industrial climate model data permits to analyse the relationship between ELA and climate factors such as temperature, precipitation, aspect, and solar radiation. In conclusion, our approach not only contributes to the estimates of LIA glacier shapes and geometries, but also permits to infer first-order relationships between glacier dynamics and climate conditions.

How to cite: Henz, A., Vieli, A., Nussbaumer, S., and Jouvet, G.: Alpine-wide LIA glacier reconstruction and ELA patterns using glacier modelling, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4111, https://doi.org/10.5194/egusphere-egu24-4111, 2024.

08:55–09:05
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EGU24-15154
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On-site presentation
Haifeng Zhu, Peng Xu, and Xiaolong Zhu

This paper presents a dendroglaciological study of Hailuogou Glacier, a maritime glacier in Hengduan Mountains, southwest China. We used tree-ring data collected from the glacier forefield, including buried wood and oldest living trees on moraine ridges, to reconstruct the glacier fluctuations during the past six centuries. The tree-ring data were combined with radiocarbon dating and remote sensing interpretation to determine the ages of moraine ridges and glacial deposits. The results show that Hailuogou Glacier experienced five equilibrium stages since the Little Ice Age, with the most extensive advance around 1760s AD and the most rapid retreat since the 20th century. The glacier fluctuations were compared with temperature and precipitation reconstructions from nearby regions, and the response relationship between the glacier and climate change was discussed. The paper demonstrates the potential of dendroglaciology to provide high-resolution records of maritime glacier history and its link to climate change in the Tibetan Plateau. The paper also contributes to the better understanding of the long-term relationship between the fluctuation of maritime glaciers and climate change, and provides a scientific basis and basic data for the prediction of glacier change under the future climate change scenario.

How to cite: Zhu, H., Xu, P., and Zhu, X.:  Hailuogou Glacier activities during the past six centuries inferred from tree rings and 14C dating, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15154, https://doi.org/10.5194/egusphere-egu24-15154, 2024.

09:05–09:15
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EGU24-3498
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ECS
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Highlight
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On-site presentation
Anouk Vlug, Fabien Maussion, Paul Leclercq, Larissa van der Laan, Jonathan Carrivick, and Ben Marzeion

An accurate global reconstruction of glacier mass change since the Little Ice Age (LIA) is of importance for, e.g., glacier mass change attribution studies and constraining the past sea-level budget. However, there are significant inconsistencies between reconstructions of the global LIA volume derived from (i) glacier length change records and (ii) glacier models that include the build-up to the LIA. The inconsistencies are present in both the magnitude and timing of the LIA maximum. Model reconstructions have shown a smaller peak of glacier volume, occurring many decades later than glacier length records indicate. Furthermore, as the maximum LIA volume did not occur synchronously between glaciers, the sampling choice of glaciers from the global population will have an impact on the total reconstructed LIA volume. Here, we tested the effect of different sampling strategies on reconstructed LIA volume, using a model based reconstruction from the Open Global Glacier Model, forced with the Last Millennium Reanalysis, as a surrogate world. Our analysis shows that glaciers for which length change observations prior to 1945 are available (the “real-world sample”) are not representative of the global signal. This shortcoming has the potential to explain large inconsistencies between the model-based reconstructions of glacier mass and reconstructions from observations. While the real-world sample is skewed, it is still a better representation of the global signal than would be expected from a random sample of the same size.

How to cite: Vlug, A., Maussion, F., Leclercq, P., van der Laan, L., Carrivick, J., and Marzeion, B.: Reconstructed global glacier mass change since LIA strongly influenced by the sample of observed glaciers, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3498, https://doi.org/10.5194/egusphere-egu24-3498, 2024.

Glacier monitoring
09:15–09:25
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EGU24-4066
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Highlight
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On-site presentation
Michael Zemp, Livia Jakob, Inés Dussaillant, Samuel, U. Nussbaumer, Sophie Dubber, and Noel Gourmelen and the GlaMBIE Team

Glacier changes are a sign of climate change and have an impact on the local hazard situation, region runoff, and global sea level. In previous reports of the Intergovernmental Panel on Climate Change (IPCC), the assessment of glacier mass changes was hampered by spatial and temporal limitations as well as by the restricted comparability of different observing methods. The Glacier Mass Balance Intercomparison Exercise (GlaMBIE; https://glambie.org) aims to overcome these challenges in a community effort to reconcile in-situ and remotely sensed observations of glacier mass changes at regional to global scales.

In this contribution, we will present the approach and results of the new data-driven consensus estimation of regional and global mass changes from glaciological, DEM-differencing, altimetric, and gravimetric methods. Our reconciled estimate suggests a global glacier mass loss of about 5,500 Gt from 2000 to 2022, with an acceleration of about 25% when comparing the second with the first half period. Since 2000, glaciers regionally have lost between 1 and 30% of their total ice volume, and about 4.5% globally. We will discuss these results in view of differences between observation methods and in comparison to previous IPCC reports, the implications for regional glacier mass loss and global sea-level rise, and remaining opportunities for further research.

How to cite: Zemp, M., Jakob, L., Dussaillant, I., Nussbaumer, S. U., Dubber, S., and Gourmelen, N. and the GlaMBIE Team: Reconciled regional & global glacier mass changes 2000−2022, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4066, https://doi.org/10.5194/egusphere-egu24-4066, 2024.

09:25–09:35
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EGU24-15934
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Highlight
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On-site presentation
Evan Miles, Thomas Shaw, Shaoting Ren, Martina Barandun, Dilara Kim, Haruki Hagiwara, Sultan Belekov, Marlene Kronenberg, Eric Pohl, Joel Fiddes, Achille Jouberton, Stefan Fugger, Tomas Saks, Abdulhamid Kayumov, Martin Hoelzle, and Francesca Pellicciotti

In situ and satellite observations have unambiguously indicated the hastening rate of global glacier decay over the past two decades. In the region affected by the Karakoram Anomaly, however, the near-zero mass change and relatively high uncertainty from satellite observations combine with complex glacier dynamics to make glacier mass balances difficult to interpret, yet very few direct observations are available to confirm glacier mass changes. A pressing question for this region is therefore whether this glacier mass stability has already ended, or how long it will persist. Our observations over the past several years in the Pamir mountains, located on the periphery of this anomalous zone, have highlighted glaciers suffering from small accumulation areas at the end of the balance year, due to a combination of reduced winter snowfall and increased summer melt. In this study, we draw together a variety of field and remote sensing observations to assess the severity of Pamir glacier changes in recent years as compared to the historical baseline.

We first examine historic climatic records and reanalyses from the region to examine the degree to which recent years fit within the observed historic seasonal and annual ranges. We compare the recent period to historic in situ and remote sensing glacier mass balance measurements recorded at Abramov Glacier, the single long-term monitoring reference glacier for the region, and to the historic network of Soviet meteorological measurements. We then consider regional changes to glacier surface albedo and surface temperature over the past 23 years based on satellite measurements. Taken together, these data sources enable us to link direct meteorological and glaciological conditions to broad spatial and temporal patterns of change across the Pamir mountains.

Our results highlight progressively worsening conditions for glaciers since 2000, as indicated by warming air temperatures, decreasing precipitation, and decreasing albedo. 2021 and 2022 were likely the worst two years for glaciers at the regional scale, experiencing the hottest air temperatures and land surface temperatures in the 21st century, but poor conditions also occurred in 2006-2008. Our results highlight that Pamir surface albedos in these years were the lowest of the 21st century, excepting in the East Pamir, which also shows the least negative mass balances and the most moderated climatic changes. 

Satellite albedo and thinning measurements agree with both reanalysis data and in situ measurements at Abramov Glacier that mass losses have accelerated. However, historic glaciological measurements at Abramov and regional meteorological stations both highlight that similar periods in terms of hot air temperatures, low precipitation and rapid glacier mass loss occurred in the 1970s, and likely the 1940s, across much of the Pamirs.  Consequently, although observations and projections suggest trends towards hotter and drier conditions with increased mass loss, it may be too soon to draw the curtains on the 40-year mass stability of the Karakoram Anomaly.

How to cite: Miles, E., Shaw, T., Ren, S., Barandun, M., Kim, D., Hagiwara, H., Belekov, S., Kronenberg, M., Pohl, E., Fiddes, J., Jouberton, A., Fugger, S., Saks, T., Kayumov, A., Hoelzle, M., and Pellicciotti, F.: The pulse of the Pamirs: using remote sensing and in situ data to investigate accelerating glacier mass loss in the Pamirs, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15934, https://doi.org/10.5194/egusphere-egu24-15934, 2024.

09:35–09:45
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EGU24-18049
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ECS
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Virtual presentation
Challenges and uncertainties in geodetic mass balance estimates for HMA glaciers using space-borne data
(withdrawn)
Debmita Bandyopadhyay and Aparna Shukla
09:45–09:55
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EGU24-11248
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ECS
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On-site presentation
Lei Guo, Jia Li, Amaury Dehecq, Zhiwei Li, Xin Li, and Jianjun Zhu

Glacier surging is an unusual instability of ice flow, and inventories of surging glaciers are important for regional glacier mass balance studies and glacier dynamic studies. Glacier surges in High Mountain Asia (HMA) have been widely reported. However, the completeness of available inventories of HMA surging glaciers is hampered by the insufficient spatial and temporal coverage of glacier change observations or by the limitations of the identification methods. In this project, we established a new inventory of HMA surging glaciers based on glacier surface elevation changes and morphological changes over four decades. Three elevation change observations based on four elevation sources (the KH-9 DEM, NASA DEM, COP30 DEM, and HMA DEM), three publicly released datasets, and long-term Landsat satellite image series were utilized to assess the presence of typical surging features over two time periods (1970s–2000 and 2000–2020). Through a multi-criteria and cross-validation workflow, all surging glaciers within HMA were identified and indicated with different possibility of surging. Particular efforts were taken to exclude advancing glaciers and separate surging tributaries from glacier complexes. In total, 890 surging and 336 probably or possibly surging glaciers were identified in HMA. Compared to the most recent inventory of surging glaciers in HMA, our inventory incorporated 253 previously unidentified surging glaciers, and most of them are quite small glaciers due to the more complete coverage. The number and area of surging glaciers accounted for ∼ 2.49 % (excluding glaciers smaller than 0.4 km2) and ∼ 16.59 % of the total glacier number and glacier area in HMA, respectively. Glacier surges were found in 21 of the 22 subregions of HMA (except for the Dzhungarsky Alatau); however, the density of surging glaciers is highly uneven. Glacier surges occur frequently in the northwestern subregions (e.g., Pamir and Karakoram) but less often in the peripheral subregions. The inventory further shows that surge activity is more likely to occur for glaciers with a larger area, longer length, and wider elevation range. Among glaciers with similar areas, the surging ones usually have steeper slopes than non-surging ones. Finally, we leverage 50 years of multi-temporal glacier mass balance observations to investigate the relationship between glacier surges and mass balance.

How to cite: Guo, L., Li, J., Dehecq, A., Li, Z., Li, X., and Zhu, J.: A new inventory of High Mountain Asia surging glaciers derived from multiple elevation datasets since the 1970s, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11248, https://doi.org/10.5194/egusphere-egu24-11248, 2024.

09:55–10:05
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EGU24-7010
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On-site presentation
Zhongqin Li, Feiteng Wang, Puyu Wang, and Zexin Zhan

There are nearly half of the glaciers in China distributed in the Xinjiang Uygur Autonomous Region (XUAR) in northwestern China, where the largest glacierized centers outside polar region are nourished by the highest mountain ranges on earth such as Karakoram, western Kunlun mountains, eastern Pamir and Tianshan etc. Glaciers are water tower in this vast arid land in northwestern China. Up-to-date glacier inventory is highly demanded. Based on the latest glacier inventory compilation techniques including those for the first and second Chinese glacier inventories, we currently compiled the third glacier inventory of XUAR, named as Chinese Glacier Inventory of Xinjiang 2020 (CGI-X2020). Comparing to the second Chinese glacier inventory (CGI-2), three improvement has been made in the CGI-X2020. Firstly, CGI-X2020 is based on a total of 235 scenes Chinese satellite imageries were selected out of 30,000 :ZY1 (5); ZY3 (59);  GF1 (135); GF2 (1) ; GF7 (2) and GF6 (33) during the period 2018-2021, mainly during 2020 summer, having a resolution better the 2 m, whereas CGI-2 was based on Landsat TM/ETM+ imageries acquired during 2006–09 with a resolution of 30 m. Secondly, the glacier volume (an important parameter of the glacier inventory) was computed by scaling method which was validated by 22 in-suit glacier thickness measurements through GPR cross glacierized region in XUAR by our research team. Thirdly, the debris coverage of the glaciers were better identified on the basis of high-resolution imageries.

According to GIX2020, by 2020, there are 24,448 glaciers in XUAR, covering an area of 23,531.65 km2 with a total volume about 1548.80 km; There are 20,586 glaciers with an area smaller than 1km2, but the area and volume occupy only 19.16% and 7.95%. Glacier volume in Tarim basin accounts for 64.72% of that in total river systems; The glacier volume is distributed in Kunlun Mountains, followed by Tien Shan and Karakoram Mountains, respectively; 30.68% and 23.92% of the total glacier volume are distributed in Kashgar and Hotian region, respectively.

How to cite: Li, Z., Wang, F., Wang, P., and Zhan, Z.: Progress on third glacier inventory of Xinjiang Uygur Autonomous Region (XUAR), northwestern China, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7010, https://doi.org/10.5194/egusphere-egu24-7010, 2024.

10:05–10:15
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EGU24-10176
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ECS
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On-site presentation
Alireza Hamoudzadeh, Roberta Ravanelli, and Mattia Crespi

Climate change has notably altered the elevation of mountain glaciers, particularly in alpine regions. Alpine glaciers play a pivotal role not only as indicators of climate change but also as crucial elements for human and wildlife well-being, regulating freshwater supply and providing vital habitats in Europe. Consequently, continuous monitoring of these glaciers offers valuable insights into their changing structure and surface dynamics [1].

 

While Unmanned Aerial Vehicles (UAV) offer the most precise method for tracking glacier surface changes, their practicality is often hindered by cost limitations and challenging in-situ measurements in extreme weather or remote areas. Therefore, remote sensing and satellite altimetry emerge as a feasible alternative in such scenarios.

 

Numerous LiDAR and RADAR altimetry sensors, such as Jason-2 and 3, CryoSat, and ICESat-1 and 2, have been employed. However, the Global Ecosystem Dynamics Investigation (GEDI), a reliable source of altimetry data, has been overlooked due to its restricted latitude range of 51.6 and -51.6 [2]. GEDI has proven its efficacy in measuring forest and canopy top height, monitoring lakes and water resources and generating Digital Surface Models (DSM).

 

Google Earth Engine (GEE), a cloud-based platform renowned for its ability to integrate diverse datasets and potent analytical tools, has recently incorporated GEDI into its extensive repository [3].

Our initial analysis aims to assess the accuracy of GEDI data for glacier monitoring. Firstly, we focus on detecting and eliminating outliers. Secondly, we compare the glacier levels obtained from GEDI with reference ground truth. Thus, we've chosen the Rutor and Belvedere glaciers in Northern Italy, where we have access to reference-level measurements from UAV DEMs.

 

The proposed outlier detection consists of two steps for each GEDI passage over the glacier surface.
The first step relies on quality surface flags available within GEDI bands, In the subsequent phase, the outlier removal process was refined by employing the x-means algorithm, an unsupervised classifier available within GEE. This approach facilitated the identification and elimination of outliers within the GEDI data set, contributing to refining the dataset's accuracy for comparative analysis with the reference ground truth.

After the above-mentioned outlier removals, we obtained a median difference of -0.27m and NMAD of 4.9 m for Rutor Glacier in 2021 from more than 500 footprints, whereas for Belvedere a median difference of -0.43 and NMAD of 3.7m were obtained. These underestimated values might be due to the nearly 2-month difference between the DEM and the GEDI acquisitions.

 

[1] Belloni, V., et al. (2023). High-resolution high-accuracy orthophoto map and digital surface model of Forni Glacier tongue (Central Italian Alps) from UAV photogrammetry. Journal of Maps, 19(1), 2217508.

[2] Hamoudzadeh, A., et al.: Gedi Data Within Google Earth Engine: Potentials And Analysis For Inland Surface Water Monitoring, EGU General Assembly 2023, Vienna, Austria, EGU23-15083

 

[3] Hamoudzadeh, A., et al. (2023). GEDI data within google earth engine: preliminary analysis of a resource for inland surface water monitoring. In The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences.

How to cite: Hamoudzadeh, A., Ravanelli, R., and Crespi, M.: Glacier Monitoring Using GEDI Data in Google Earth Engine: Outlier Removal and Accuracy Assessment, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10176, https://doi.org/10.5194/egusphere-egu24-10176, 2024.

Posters on site: Fri, 19 Apr, 16:15–18:00 | Hall X4

Display time: Fri, 19 Apr, 14:00–Fri, 19 Apr, 18:00
Chairpersons: Frank Paul, Paul Weber
X4.13
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EGU24-5311
Samuel U. Nussbaumer and Heinz J. Zumbühl

Interdisciplinary approaches are needed to reconstruct the behaviour of glaciers beyond the beginning of systematic, direct measurements. Particularly for the period of the Little Ice Age (LIA), historical documents have been very valuable to successfully reconstruct former glacier extents at different sites. An analysis of historical documents on the well-documented Mont Blanc region, for example, provides unique insights into the LIA glacier development.

The Mont Blanc area became popular with artists, scientists, and travellers in the mid-18th century, including Jean-Antoine Linck from Geneva, who is probably the artist to whom we owe the greatest number of unique glacier views. Jean-Antoine Linck was particularly interested in the icy regions, which he discovered and drew with alpinistic daring and naturalistic accuracy, preferably in gouache, although many pencil sketches have also been preserved. From a glacier history perspective, Linck's work is indispensable, even if many of his artworks are not precisely dated by the author: It represents the whole development of the Mont Blanc glaciers, specifically the Mer de Glace and Glacier des Bossons, but also other glaciers during the period from the end of the 18th century until the 19th century glacier maximum around 1820. As an amazing novelty, Linck was probably the first observer to show a glacier advance with the help of two realistic and accurate views from the same position; one as the Glacier des Bossons retreats and the other as it advances. In addition, various views by Linck make it possible to quantify smaller glacier extents, e.g. around 1800 at the Glacier des Bois (Mer de Glace), which were depicted much more rarely.

To distribute his work, Linck subtly used the etching technique to create easily reproducible plates in large format, which are then hand-coloured with gouache and watercolour. This technique allowed him to create numerous reproductions of the same view, while still giving them a unique and original aspect, views that are remarkable for their serenity and silence, while offering luminous atmospheres. These illustrations introduced the realistic representation of the high mountains into the iconography of Genevese painting and thus led to a new kind of landscape painting with a permanent character.

In terms of glacier history, the work of Jean-Antoine Linck has the same significance for the Mont Blanc area as that of Caspar Wolf and Samuel Birmann for the central Swiss Alps or that of Thomas Ender for the Austrian Alps in terms of glacier iconography. Linck was therefore both an artist and a glacier historian.

How to cite: Nussbaumer, S. U. and Zumbühl, H. J.: The glacier views of Jean-Antoine Linck - a milestone for the Mont Blanc glacier history from the 18th to the 19th century, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5311, https://doi.org/10.5194/egusphere-egu24-5311, 2024.

X4.14
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EGU24-12440
Christian Rohr, Samuel U. Nussbaumer, Céline Walker, Corina Haller, Tamara T. Widmer, Matthias Fries, Lukas Würsch, and Heinz Zumbühl

Glaciers are excellent climate indicators, and the worldwide glacier retreat serves as a warning signal for the current climate change with its dramatic effects on humans and the environment. Visualizing glacier change by means of images can reach a broad public. Historical glacier images, especially from the so-called Little Ice Age (LIA, approx. AD 1300 to 1850 in the European Alps), show the earlier glacier fluctuations in a particularly impressive way and give us a unique insight into the climatic events of that time. These findings are in turn the key to understand current and possible future climate changes.

The long-term research project "Euro-Climhist" is one of the first projects of its kind worldwide to extract historical documentary data on climate and weather from a wide variety of source types, evaluate the data accordingly, and make it generally accessible in an online database (https://www.euroclimhist.unibe.ch). Until now, the Euro-Climhist database consisted mainly of written sources and measurement data. Within this project, the Euro-Climhist database was conceptually extended to include and secure glacier images in the long term, and to make them accessible to researchers and to the public. Around 500 glacier images were specially prepared for the database and provided with the corresponding metadata, i.e., the name of the artist, the original descriptions as well as supplementary descriptions from the literature, the dating of the images, and the image type. In particular, the assignment to one of five image types - drawing, oil painting, print, photograph, or map - allows conclusions to be drawn about the accuracy of the glacier extents depicted.

Besides written evidence, historical pictorial representations of glaciers allow us to reconstruct glacier extents in the Alps from the early 17th century onwards. Satisfactory quantities of historical material are only available for those glaciers that achieved the necessary degree of fame early on to attract travellers, scientists, and artists. Pictorial representations in painting and graphic arts date back to the early 17th century, but only appear in large numbers with the emerging popularity of Alpine travel during the 18th century. Photographs are available from the end of the 1840s.

How to cite: Rohr, C., Nussbaumer, S. U., Walker, C., Haller, C., Widmer, T. T., Fries, M., Würsch, L., and Zumbühl, H.: Integration of historical glacier images into the Euro-Climhist database, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12440, https://doi.org/10.5194/egusphere-egu24-12440, 2024.

X4.15
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EGU24-10439
Jörg Franke, Andrew Friedman, Noemi Imfeld, and Stefan Brönnimann

The assimilation of early instrumental, documentary, and proxy data into model simulations allows the study of multivariate climate variability from monthly to centennial time scales. The strength of our paleo-reanalysis ModE-RA (Modern Era Reanalysis) lies specifically in the period of the Little Ice Age because the number of assimilated values per year increases from hundreds in the 17th century to thousands in the 18th century to tens of thousands in the 19th century. In addition, recent efforts of weather reconstruction based on early instrumental data even allow for European reconstructions at daily time scales back into the 18th century.

Here, we present a case study of the global climate and European weather anomalies following the Laki eruption in 1783. Most reports have been limited to the European domain and described an unexpectedly warm summer of 1783 and extremely cold winters in the three following years. Our weather reconstruction and ModE-RA support recent model simulations which suggested atmospheric blocking to be the cause of the unexpected warm anomalies in Europe. However, the entire summer of 1783 was not hot, but only a relatively short period in June and July. On the northern hemisphere scale, we find an aerosol-induced cooling. African and Indian Monsoon rainfall is reduced due to a weaker land-sea temperature gradient in line with the response to strong tropical eruptions and an interhemispheric temperature contrast in line with the response to strong extratropical eruptions. In contrast to recent simulations of the Laki eruption, ModE-RA shows a clear boreal winter warming at high latitudes, slightly dampening the hemispheric-scale cooling signal. In the future, monthly paleo-reanalysis or even daily weather reconstructions could be used to drive models of Little Ice Age glacier dynamics.

How to cite: Franke, J., Friedman, A., Imfeld, N., and Brönnimann, S.: The Laki Eruption – studying Weather and Climate during the Little Ice Age with Paleo-Reanalysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10439, https://doi.org/10.5194/egusphere-egu24-10439, 2024.

X4.16
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EGU24-13856
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ECS
Ines Dussaillant, Jacqueline Bannwart, Frank Paul, and Michael Zemp

Glaciers play a fundamental role in the Earth’s water cycles. They are one of the most important freshwater resources for societies and ecosystems and the recent increase in ice melt contributes directly to the rise of ocean levels. For this reasons, they have been declared as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS). Within the Copernicus Climate Change Services (C3S), the global gridded annual glacier mass change dataset provides information on changing glacier resources for the last five decades by combining the glacier outlines from the globally complete Randolph Glacier Inventory with the mass balance and elevation change observations from the Fluctuation of Glaciers database of the World Glacier Monitoring Service (WGMS).

The glacier change product provides a global assessment of annual glacier mass change and related uncertainties (in m w.e. and Gt) and gridded area changes (km2)  since the hydrological year 1975/76 to present, provided in a 0.5°x0.5° (latitude-longitude) global regular grid and in netcdf file format. The new product bridges the gap on spatio-temporal coverage of glacier change observations, providing for the first time in the CDS an annually resolved glacier mass change product using the glacier elevation change sample as calibration. This goal has become feasible at the global scale only recently and thanks to a new globally near-complete (96% of the world’s glaciers) dataset of glacier elevation changes between 2000 and 2020.

The global gridded annual glacier mass change product integrates nicely into the family of the gridded ECV products provided by the C3S CDS. It provides new insights into regional to global glacier mass changes and, hence, has a great potential for contributing to the various state of the climate reports as well as to assessments of the global sea-level budget, the global energy cycle or the global water cycle. Continuation and expansion of the glaciological in-situ observation network is essential for providing the temporal variability of the glacier mass change product. Ensuring the continuation of open source spaceborne datasets with extensive acquisitions tasking planned over glaciated regions is crucial for ensuring the good quality of future glacier products, and one of the greatest gaps in the quality and continuation of the glacier services delivered to C3S.

How to cite: Dussaillant, I., Bannwart, J., Paul, F., and Zemp, M.: Glacier mass change gridded data from 1976 to present derived from the Fluctuations of Glaciers Database - A new product in the Copernicus Service Climate Data Store, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13856, https://doi.org/10.5194/egusphere-egu24-13856, 2024.

X4.17
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EGU24-19324
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ECS
|
Luc Béraud, Fanny Brun, Amaury Dehecq, Laurane Charrier, and Romain Hugonnet

Some glaciers display flow instabilities, among which surge events particularly stand out. Surges are quasi-periodic flow perturbations with an abnormally fast flow over a few months to years. It can result in surface elevation changes of more than 100 m in a few months.

The estimation of the mass transfer and the flow variation can be inferred from the glacier surface elevation and velocities. It is critical data to better understand the dynamics of a surge. While satellite-based DEMs provide useful information for studying surges, their use in previous studies was generally limited to a few DEM differences extending over periods of several years. To date, very few studies have leveraged the full time series of elevation data available since ~2000 which could help quantify the variations of mass transfer during the very short surge phases.

Here, we exploited the high temporal and spatial coverage of the ASTER optical satellite sensor to compute a dense time series of elevation suited for the study of surges. Our case study area is the Karakoram range, in High Mountain Asia. We used non-filtered ASTER digital elevation models (DEMs) of 100 m resolution from Hugonnet et al. (2021). The time series range from about 2001 to 2019, with a median of 56 observations per on-glacier pixel over the whole period. We developed a specific method for filtering the elevation time series that preserves surge signals, as opposed to the original method that tends to reject this behaviour as outliers. A LOWESS method – locally weighted polynomial regression (Derkacheva et al., 2020; Cleveland, 1979) is at the core of this workflow. Then, we predicted the elevation over a regular temporal and spatial grid from filtered data, with the B-spline method ALPS-REML (Shekhar et al., 2021).

In this presentation, we will present the results of this method applied to more than 1000 DEMs covering the Karakoram region to derive elevation time series at 100 m resolution. The filter and the prediction performances will be discussed. The results will be compared with those of other studies, in terms of surge onset and end dates, location or volume transported. Finally, the  elevation data set will be analysed with regard to velocities extracted from ITS_LIVE (Gardner et al., 2024) to validate the approach and highlight the complementarity of both types of observations.

How to cite: Béraud, L., Brun, F., Dehecq, A., Charrier, L., and Hugonnet, R.: An improved dataset of ASTER elevation time series in High Mountain Asia to study surge dynamics, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19324, https://doi.org/10.5194/egusphere-egu24-19324, 2024.

X4.18
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EGU24-2778
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ECS
Mingyang Lv

Glacier surges are prevalent in the Karakoram and often threaten local residents by submerging land and initiating secondary disasters. The Kyagar Glacier is well known for its surge history as it frequently blocked the downstream valley, leading to a series of high-magnitude glacial lake outburst floods. Although the surge dynamics of the Kyagar Glacier have been broadly described in the literature, there remains an extensive archive of remote sensing observations that have great potential for revealing specific surge characteristics and their relationship with historic lake outburst floods. We propose a new perspective on quantifying the surging process using successive digital elevation models (DEMs), which could be applied to other sites where glacier surges are known to occur. Advanced Spaceborne Thermal Emission and Reflection Radiometer DEMs, High Mountain Asia 8-meter DEMs, and the Shuttle Radar Topography Mission DEM were used to characterize surface elevation changes throughout the period from 2000 to 2021.We also used Landsat time series imagery to quantify glacier surface velocities and associated lake changes over the course of two surge events between 1989 and 2021. Using these datasets, we reconstruct the surging process of the Kyagar Glacier in unprecedented detail and find a clear signal of surface uplift over the lower glacier tongue, along with uniformly increasing velocities, associated with the period of surge initiation. Seasonal variations in surface flow are still evident throughout the surge phase, indicating the presence of water at the glacier bed. Surge activity of the Kyagar Glacier is strongly related to the development and drainage of the terminal ice-dammed lake, which is controlled by the drainage system beneath the glacier terminus.

How to cite: Lv, M.: Quantifying the surging process of the Kyagar Glacier in the Karakoram using successive digital elevation models and optical satellite images, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2778, https://doi.org/10.5194/egusphere-egu24-2778, 2024.

X4.19
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EGU24-9745
Christian Casarotto and Mattia Callegari

Direct glaciological measurements are an important dataset of glacier mass balances but remain concentrated on a small number of glaciers. On hydrological years 2019/20 and 2020/21, 318 annual mass-balance observations were compiled based on 169 glaciers worldwide (Zemp et al., 2023). On the other hand, the current climate crisis now requires a description of cryosphere evolution at a larger scale by quantifying annual snow and ice losses on a larger number of glaciers.

A relevant attempt to fill this gap has been provided by Huggonet et al. (2021) where a global dataset of mass balances at a glacier scale have been generated from 2000 to 2020. While being an extremely valuable glacier mass balance dataset, it is limited to provide mass balance estimation with a time scale longer than 5 years, i.e. annual mass balances cannot be considered reliable.

On the other side, the equilibrium line altitude (ELA) method (Rabatel et al., 2016) have been proven to be an effective approach to reconstruct annual glacier mass balance time series as soon as annual estimation of ELA from satellite multispectral images (e.g. Landsat, Sentinel-2) and at least two digital terrain models (DTMs) acquired at different years are available. Typically, highly accurate DTMs (e.g. airborne LiDAR or photogrammetric DTMs), which are only available on a regional scale base, have been employed within the ELA method.

The main objective of this work is to test the ELA method using as input: 1) Landsat and Sentinel-2 estimation of ELA and 2) ASTER DTMs (Hugonnet et al., 2021). In this way, annual mass balances can be retrieved using satellite data only.

We initially tested this approach over the glaciers in Trentino and South Tyrol where seven glaciers have been monitored through glaciological measurements and different airborne DTMs have been acquired during the last 20 years. Our results show that the use of the ELA method with high resolution airborne DTMs can produce mass balance estimations characterized by an error around 0.3 m w.e. with respect to ground measurements. This error value is in line with estimations conducted with the same method in other regions (e.g. Rabatel et al., 2016) and it is in the error range of ground based measurements. The use of ASTER-based 5 years DTM differences as input of the ELA method can produce estimations with a similar error range. Therefore, the combination of ASTER DTM and ELA extracted from Landsat or Sentinel-2 images may be an interesting approach to produce accurate annual mass balance estimations for many glaciers in the world.

 

References :

Hugonnet, R. et al. (2021). Accelerated global glacier mass loss in the early twenty-first century. Nature 592, 726–731

Rabatel, A. et al. (2016). Spatio-temporal changes in glacier-wide mass balance quantified by optical remote sensing on 30 glaciers in the French Alps for the period 1983–2014. Journal of Glaciology62(236), 1153-1166.

Zemp, M. et al. (2023). Global Glacier Change Bulletin No. 5 (2020-2021). WGMS.

How to cite: Casarotto, C. and Callegari, M.: Annual glacier mass balance estimation through ASTER DTMs and snowlines extracted from Landsat and Sentinel-2 images, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9745, https://doi.org/10.5194/egusphere-egu24-9745, 2024.

X4.20
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EGU24-6439
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ECS
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Mhairi Hallford

Extensive databases of satellite imagery are now available and can be used to undertake assessments of the mass balance of glaciers. Previous studies have mapped the end-of-season snowlines (ESS) on glaciers from satellite imagery to find their snowline altitudes (SLA) and used these as proxies for the glacier equilibrium-line altitudes (ELA). This approach is advantageous because it can be implemented at scale and may employ automated methods. The veracity of using remotely measured SLAs as a proxy for in-situ measured ELAs however, has not yet been robustly demonstrated.

This project is undertaking a systematic mapping of ESSs on glaciers with existing measured mass balance records to determine the errors associated with remotely measured SLAs. Glaciers are selected from the World Glacier Monitoring Service (WGMS) Fluctuations of Glacier (FoG) database. For each ELA record, we identify the Landsat image closest in date to the original ELA measurement (where cloud cover is minimal) and the image with the highest altitude snowline for the year. For each image, the snowline is mapped, and its corresponding SLA is extracted from the ASTER Global Digital Elevation Map (ASTERGDEM). The SLAs vs. ELAs of glaciers covering time series greater than 20 years are presented.

How to cite: Hallford, M.: Testing the veracity of satellite-derived end-of-season snowline altitudes as a proxy for the glacier ELA., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6439, https://doi.org/10.5194/egusphere-egu24-6439, 2024.

X4.21
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EGU24-20611
Application of deep learning and remote sensing satellite data to assess glacier retreat for the past three decades in Himachal 
(withdrawn after no-show)
Chander Prakash and Rajat Sharma
X4.22
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EGU24-9700
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ECS
Gabriele Bramati, Florian Hardmeier, Jennifer Susan Adams, Andreas Vieli, and Kathrin Naegeli

Understanding the role and dynamics of debris covering alpine glaciers is complex and multi-faceted. A thin or non-continuous layer (smaller than 2cm) promotes melting, whereas a thicker layer insulates the underlying ice. The response of debris-covered glaciers to climate change is not uniform worldwide. These glaciers not only react to the changing climate, but they are also sensitive to debris-cover evolution. To date, studies analysed limited spatio-temporal data and thus do not describe multi-temporal changes in debris cover thickness. However, these strongly impact long-term glacier evolution as topography changes can lead to ice cliff formation, which is known to considerably speed up glacier melt. Multi-temporal high-resolution remote sensing offers the possibility to fill this gap and monitor changes at a small scale. In this contribution, we apply multi-temporal close-range remote sensing to a debris-covered glacier in the Swiss Alps (Zmuttgletscher, Valais, CH). We make use of Unmanned Aerial Vehicle (UAV) surveys equipped with a dual optical-thermal camera together with manual debris excavations and in-situ meteorological data in different years (2020 and 2023). The thermal surveys are calibrated using supraglacial and proglacial lake water temperatures, combined with debris surface temperature measurements. We explore the debris thickness, morphology, and topography evolution of a portion of the glacier, and discuss it in relation to glacier dynamics and debris transport. The work contributes to the understanding of glacier debris evolution, which is often neglected in debris-covered glacier models and global projections.

How to cite: Bramati, G., Hardmeier, F., Adams, J. S., Vieli, A., and Naegeli, K.: Tapping the potential of multi-temporal thermal infrared UAV over a debris-covered glacier , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9700, https://doi.org/10.5194/egusphere-egu24-9700, 2024.

X4.23
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EGU24-8967
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ECS
Boris Ouvry, Céline Walker, Marin Kneib, Johannes Reinthaler, Francesca Pellicciotti, and Andreas Vieli

Ice cliffs are known to enhance ablation on debris-covered glaciers and surface ablation. The upstream part of debris-covered glacier tongues is often characterised by downstream-widening supraglacial valleys with hummocky topography, arch-shaped ice cliffs alongside incised and meandering supraglacial channels. The incision of supraglacial channels has been suggested as a potentially important process for the formation of ice cliffs; however, the interactions between channel undercutting and ice-cliff formation are poorly understood and remain to be quantified. In particular, the stream undercutting cannot be observed from nadir-based satellite or UAV methods.

In this study, we therefore use a more local approach to investigate these interactions by applying high-resolution terrestrial remote-sensing methods at the example of two debris-covered glaciers: Satopanth Glacier, located in the Indian Himalayas, and Zmutt Glacier in the European Alps. We combined (i) high-density point cloud data from a terrestrial laser scanner, (ii) drone imagery, (iii) time-lapse imagery, and in situ stake measurements of the channel overhangs and the debris and ice-cliff surfaces at daily and fortnightly intervals during the melting season. By differencing the point clouds and DEMs using a Lagragian reference system, we are able to calculate channel incision and melt rates alongside ice-cliff backwasting rates. We further constrain the evolution of these surfaces with the stake measurements and continuous time-lapse imagery of 30 (Zmutt) and 5 (Satopanth) minute intervals.

Our results show that our approach, particularly the acquisition of point cloud data using terrestrial laser-scanning, offers promising perspectives for analysing channel incision and related ice-cliff backwasting. The dominating processes observed for the evolution of the surface morphology are the backwasting of the exposed ice cliff, the erosion of the stream in the undercut below, and the ablation of the debris-covered surface, which are exposed to a range of external factors (e.g., meltwater flow, air temperature, solar radiation, deposition, and debris thickness). We find that the sideway component of the channel incision usually exceeds the downward component and creates, depending on the size of the stream, undercuts of several 10s of cm (Zmutt) to several meters (Satopanth) in width. The related horizontal undercutting rates are generally comparable or more significant than ice-cliff backwasting and sub-debris ablation. However, we note that the incision and ice cliff morphology varies according to their location and orientation along the meandering meltwater stream. For deeply undercut ice overhangs, we are able to detect downward deformation that occasionally leads to a collapse of the ice cliff above and may thereby indirectly further enhance ice cliff backwasting. 

Our results imply that stream incision is the driving process of undercutting and maintaining the ice cliffs, hence a crucial process for their formation and evolution. The integrated use of high-resolution field-based remote-sensing methods thereby contributed successfully towards a better understanding of the morphological evolution of surfaces with relatively thin debris and the related characteristic supraglacial valleys.

How to cite: Ouvry, B., Walker, C., Kneib, M., Reinthaler, J., Pellicciotti, F., and Vieli, A.: Quantifying the morphological evolution and interaction of ice cliffs and supraglacial stream incision on debris-covered glaciers using high-resolution terrestrial lidar and UAV methods, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8967, https://doi.org/10.5194/egusphere-egu24-8967, 2024.

X4.24
|
EGU24-15640
Owen King, Tom Matthews, Marcos Andrade, Juan-Luis Garcia, Claudio Bravo, Wouter Buytaert, Juan Marcos Calle, Alejandro Dussaillant, Tamsin Edwards, Iñigo Irarrazaval, Baker Perry, Emily Potter, Laura Ticona, Bethan Davies, and Jeremy Ely

Climate change has had a significant impact on the behaviour of the high mountain cryosphere, with widespread glacier retreat and mass loss now occurring in most of the planet’s glacierised mountain ranges over multi-decadal timescales. If we are to accurately understand the impacts of deglaciation on freshwater availability to communities downstream, robust modelling of future glacier meltwater yield is paramount. Meteorological observations at glacierised elevations are essential to drive simulations of the energy balance at glacier surfaces, and therefore glacier melt, although such records are sparse in most high mountain regions due to the logistical challenges associated with making even short-term measurements. The scarcity of high-altitude meteorological observations has resulted in only limited understanding of factors such as the spatial and temporal variability of temperature lapse rates, precipitation amounts and phase, and the prevalence of conditions suited to sublimation, all of which have an important influence on glacier mass loss rates at high elevation.

Here we summarise the installation of meteorological and glacier ablation stations in different climatic zones of the South American Andes - the Tropical Andes of Peru (Nevado Ausangate basecamp, 4800 m, (13°48'45.96"S, 71°12'53.18"W) and Bolivia (Laguna Glaciar, 5300 m, 15°50'10.59"S, 68°33'11.30"W), the Subtropical Andes (Glaciar Universidad, Chile, 2540 m, 34°43'10.07"S, 70°20'44.98"W) and Patagonian Andes (Lago Tranquillo, Chile, 280 m, 46°35'47.00"S, 72°47'38.91"W) – as part of the NERC-funded Deplete and Retreat Project. Meteorological station records include time series of air temperature and pressure, relative humidity, wind speed and direction, incoming and outgoing short- and longwave radiation, precipitation amount and phase. Coincident glacier ablation is monitored at each site using ‘Smart Stakes’, recording surface elevation change on-glacier. We describe station situation, installation and preliminary measurements, along with aims and objectives of analyses using the meteorological time series.

How to cite: King, O., Matthews, T., Andrade, M., Garcia, J.-L., Bravo, C., Buytaert, W., Calle, J. M., Dussaillant, A., Edwards, T., Irarrazaval, I., Perry, B., Potter, E., Ticona, L., Davies, B., and Ely, J.: Establishing glacier proximal meteorological and glacier ablation stations in different climatic zones along the South American Andes., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-15640, https://doi.org/10.5194/egusphere-egu24-15640, 2024.

Posters virtual: Fri, 19 Apr, 14:00–15:45 | vHall X4

Display time: Fri, 19 Apr, 08:30–Fri, 19 Apr, 18:00
Chairpersons: Samuel U. Nussbaumer, Frank Paul, Paul Weber
vX4.1
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EGU24-6015
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Highlight
Yingkui Li

High Mountain Asia (HMA) contains the largest glacier inventory outside the polar regions and the melting of these glaciers provides an important freshwater supply for over 250 million people in south, central, and east Asia. Recent studies have quantified glacier changes over the past decades in this area mainly based on the interpretation of satellite imagery, while few studies have investigated the longer-term (centennial-scale) glacier changes due to the lack of mapped outlines and reliable methods to reconstruct the three-dimensional surfaces and volumes of past glaciers. We compiled a dataset of >15,000 mapped glacier outlines during the Little Ice Age (LIA) in the Himalayas, Gangdise, Tanggula, and Tian Shan and reconstructed the ice thickness and volumes of LIA glaciers and their corresponding contemporary glaciers based on a flowline-based GIS model, PalaeoIce. Initial results of 640 LIA glaciers and their corresponding 1466 contemporary glaciers from Tian Shan indicate a total of 47.6% loss of ice volumes since the LIA and the ice volume loss are negatively correlated with glacier area and equilibrium line altitude. This presentation reports the reconstruction of >15,000 LIA glaciers and their corresponding >20,000 contemporary glaciers in the four mountain ranges (Himalayas, Gangdise, Tanggula, and Tian Shan) to examine the spatial pattern of LIA glacier changes and their influencing factors (climate, topography, and debris cover). This work provides important insights into the impacts of glacier changes on water resources in High Mountain Asia in the past 300-500 years.

How to cite: Li, Y.: Patterns and influencing factors of glacier changes in High Mountain Asia since the Little Ice Age, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-6015, https://doi.org/10.5194/egusphere-egu24-6015, 2024.

vX4.2
|
EGU24-6283
Evolution of glaciers in the Northern Greater Caucasus (Elbrus region, Russia) during the Little Ice Age and older Holocene periods based on historical documents, tree-rings and cosmogenic dating
(withdrawn after no-show)
Vincent Jomelli, Olga N. Solomina, Joanna Charton, and Irina S. Bushueva
vX4.3
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EGU24-14469
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ECS
Yadira Curo, Juan de Dios Fernandez, Gladis Celmi, Danny Robles, and Mayra Mejia

Glacier dynamics and the effects of climate change accelerate bedrock erosion and instability of the surrounding topography, causing clean glaciers to be gradually covered by debris, particularly in the ablation zones. While the area of glaciers covered worldwide is increasing, there are few studies on this phenomenon in tropical glaciers and its possible significant effects on glacier melt. In this context, this study analyzes the spatio-temporal evolution of the area of glaciers covered by debris in the Cordillera Blanca from 1962 to 2020. 

To achieve this aim, we used data from the Peruvian National Glacier Inventory for 1962 and 2020. We also identify the covered glaciers through the photo-interpretation of geomorphological features, such as the color and texture of the ground surface, the presence of thermokarst zones, and the formation of small lakes/lagoons observed in the satellite images. In addition, we got the topographic features from the ALOS PALSAR digital elevation model.

The outcomes of this investigation reveal an increase in the number and surface area of glaciers covered, from 33 units (15.41 km2) in 1962 to 173 units (23.06 km2) in 2020. This shows an increase of 49.64% from the glacier area covered by debris. The increase in covered glaciers in the Cordillera Blanca could be because many glaciers identified as debris-free in 1962 were partially or totally covered in 2020; 17.13 km2 of the glacier debris-free area was covered by debris during this period. It has been observed that 93% of the area covered by debris is on slopes greater than 8°. Of these, 25% were in the 24° - 33° range, and 23% were on steeper slopes than 33°. The orientation analysis indicates a predominance of surface covered towards the southwest and south.

Likewise, the areas of glacier retreat covered between 1962 and 2020 were analyzed, identifying 9.45 km2 of glacier surface loss. 18% of the loss areas are on slopes steeper than 8º, mainly from 8º to 17º slope, where 28% of the loss area is located. Meanwhile, a clear retreat trend is observed in those areas with a north orientation of 95% and a northeast orientation of 5%.

These findings suggest a possible association between the higher magnitude slope conditions and the formation of covered glaciers, while the orientation influences the retreat of these glaciers.

How to cite: Curo, Y., Fernandez, J. D. D., Celmi, G., Robles, D., and Mejia, M.: Evolution of the covered glaciers in the Cordillera Blanca during the period 1962 - 2020, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14469, https://doi.org/10.5194/egusphere-egu24-14469, 2024.