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A valley floor rock glacier in Nautárdalur, eastern Tröllaskagi, northern Iceland, has been investigated since the 1970s. Adjacent valleys are also examined as mountain landsystems. The methodology identifies 'landform elements' (features evident on slopes) on transects that can be identified and mapped from Google Earth imagery. Transects can be compared to show similarities and differences between slopes and valleys and can be used to trace debris and ice/snow flow paths within landsystems. The paper confirms that a glacier ice core is present throughout the Nautárdalur rock glacier. Traces of glacier activity can be found in some neighbouring small valleys but where rock glaciers are not present. Previous field observations, when coupled to current Google Earth imagery, indicate glacier ice formation and deformation over the past 200 years. The quantities and timing of weathered debris from headwall cliffs were sufficient to partly cover small glaciers, thus forming rock glaciers in some, but not all, valleys. The landsystem and transect approach thus indicate glacier origins for the rock glaciers identified. No evidence for 'permafrost creep' in scree slopes that might produce valley-side rock glaciers has been found. [ABSTRACT FROM AUTHOR]

We developed a spatially distributed conceptual melt and runoff model able to cope with debris covered glacier parts. Subdebris melt was calculated based on empirical equations derived from field observations. The model was applied at the Inylchek glaciers. While runoff from Southern Inylchek flows directly into Inylchek River, runoff from Northern Inylchek is blocked by Southern Inylchek and forms Lake Merzbacher. This lake is drained frequently by outburst floods. To calibrate the model, a multi-algorithm, genetically adaptive multi-objective method ( AMALGAM) was used. Daily runoff observations from Inylchek River as well as glacier mass balance gradients from other glaciers in the Tian Shan were used as objective functions in three split samples. Runoff simulations yielded Nash- Sutcliffe coefficients mostly higher than 0.9, and the mass balance gradients were simulated in an acceptable range. The results of the different split samples vary considerably. Considering the used objective functions and additional data such as the equilibrium line altitude, we chose the most promising parameter set to calculate the filling of Lake Merzbacher. This analysis indicated answers to several questions concerning the hydrological system of the lake. Apart from calving at the ice dam formed by Southern Inylchek glacier, the lake seemed so be filled predominantly by meltwater from Northern Inylchek glacier. The lake has a permanent runoff, also during the filling process. After the outburst, the channels seemed to be closed quickly. [ABSTRACT FROM AUTHOR]

Many temperate glaciers in the southeast Tibetan Plateau are covered by supraglacial debris in the ablation area. To evaluate the effect of such debris on summer ablation and mass balance, the surface ablation on the 24K Glacier was measured in the summer of 2008. Mean ablation rates varied from 10 to 52 mm/day, strongly correlated to debris thickness. Synchronous observations of air temperature allowed application of a simple degree-day model to calculate ablation rates. Maximum values of both ablation rate and degree-day factors appeared in the middle area of the glacier where the debris layer thickness was about 1 cm. The simulated daily ablation obtained from the degree-day approach showed that the debris layers significantly affected the total summer ablation. The calculated ablation would be increased by 36% of the total ablation with the actual surface debris cover if glacier surface had been assumed to be entirely debris free. If completely covered by 65 cm thick debris in the ablation area, the glacier would experience a 59% decrease in summer ablation. The presence of a debris cover also leads to a change in the ablation gradient in the ablation zone. [ABSTRACT FROM AUTHOR]

Melt rates of glacier surfaces are strongly influenced by the existence of a debris cover. Dependent on thickness and other physical parameters, the debris layer can enhance or reduce ablation as compared to bare ice conditions. Supraglacial moraines appear very frequently on Central Asian glaciers, greatly affecting water yield from these high mountain regions. In summer 2005, a network of 22 ablation stakes was drilled into locations with varying debris thicknesses on southern Inylchek Glacier in the central Tian Shan. Mean ablation rates varied from 2.8 to 6.7 cm/day, strongly correlated with moraine thickness. Parallel observation of air temperature allowed the application of a simple degree-day approach and the calculation of ablation rates. Efforts to improve calculations of melt rates by incorporating relative air humidity to account for latent heat fluxes failed. This proves that air temperature is already a very good melt indicator. Ice albedo measurements show that reflectivity might be controlled by the occurrence of evaporation or condensation, but this topic needs further investigation. [ABSTRACT FROM AUTHOR]