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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]

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]