The equilibrium line altitudes (ELAs) calculated using the area-altitude-balance-ratio (AABR) 1.6. We reconstructed the extent and ice-surface geometry for 12 palaeo-glaciers in the study area during the Maximal Ice Extent (MIE) which is attributed to LGM. This paper brings forward new geomorphological evidence of marginal glaciation in the Călimani, Suhard, and Gurghiu Mountains which are the southernmost glaciated areas of the NRC. In the Northern Romanian Carpathians (NRC) small Pleistocene cirque glaciers have formed in several isolated mountain massifs exceeding 1800 m asl. Furthermore, new optical data, such as that from Sentinel-2, can be incorporated to further improve the algorithm results.
#Examples of glims manual#
This algorithm can be applied to large regions, such as HMA, to obtain snow line estimates where manual approaches are exhaustive and/or unfeasible. From a regional perspective, the glaciers in the Caucasus, HMA and the Alps yield better results than those in Western Canada.
#Examples of glims series#
The post-2000 SLA values are better than those obtained before 2000 because merging the Landsat series images reduces the temporal resolution, which allows the date of the calculated SLA to be closer to the date of the observed ELA. Furthermore, cloud cover, shadows, and the Otsu method limitation will further affect the SLA calculation.
However, Careser Glacier yields a poor fit between the SLA calculations and ELA observations owing to tremendous surface area changes during the analyzed time series this indicates that glacier surface shape changes due to intense ablation will lead to a misclassification of the glacier surface, resulting in deviations between the SLA and ELA. Furthermore, 10 of these glaciers yield R 2 > 0.5 and the other three glaciers yield R 2 > 0.3 for their respective SLA-ELA relationships, which indicate that the calculated SLA from this algorithm provides a good fit to the ELA observations. Eight of these glaciers yield R 2 > 0.5, and the other five glaciers yield R 2 > 0.3 for their respective SCR-AAR relationships. The SLA accuracy is ~73%, with a mean uncertainty of ☒4 m, for 13 of the reference glaciers. We select 14 reference glaciers from High Mountain Asia (HMA), the Caucasus, the Alps, and Western Canada, which represent four mountainous regions with extensive glacial development in the northern hemisphere. The calculated SCR and SLA values are verified using the observed glacier accumulation area ratio (AAR) and ELA. Here, we present an automated algorithm to classify bare ice and snow cover on glaciers using Landsat series images and calculate the minimum annual glacier snow cover ratio (SCR) and maximum SLA for reference glaciers during the 1985-2020 period in Google Earth Engine. Glacier snow line altitude (SLA) at the end of the ablation season is an indicator of the equilibrium line altitude (ELA), which is a key parameter for calculating and assessing glacier mass balance. These wetter LGM conditions inferred from the paleo-glaciological evidence in Jakupica Mts suggest an enhanced moisture advection in the region. The degree-day model constrained by the pollen-based July paleo-temperature reconstructions yielded an annual total melt at the LGM ELA comparable to or slightly higher than the current mean annual precipitation at the same elevation. The degree-day model was used to calculate the amount of accumulation required to sustain the glaciological equilibrium assuming a certain temperature drop at the ELA. Glacio-climatological modelling was performed for the MIE, which has a well-established LGM age. The samples from the moraine of the penultimate deglaciation phase provided CRE ages with large scatter and biased towards old ages, which is probably the result of inherited cosmogenic nuclide concentrations within the rock. CRE ages from the next moraine generation placed the first phase of deglaciation to 18.2+1.0/-3.0 ka. The ¹⁰Be cosmic ray exposure (CRE) age of this phase was estimated at 19.3+1.7/-1.3 ka, conformable with the Last Glacial Maximum (LGM). The equilibrium line altitude (ELA) of the most extended glacial phase was at 2075⁺³⁷/-25 m asl. The study area comprises six formerly glaciated valleys, five of which were fed by the plateau glacier and one had an independent cirque when local glaciation reached its maximum ice extent (MIE). In the Jakupica Mts a plateau glacier was reconstructed (max.
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