(A-F) Conceptual model of the expected time series of erosion rate and sediment production (A and D), sediment discharge and evacuation (B and E), and sediment storage (C and F) over the melt season for the ablation (A-C) and accumulation (D-F) areas. Bedrock erosion in the ablation area occurs in early summer, driven by a pulse of sliding. The erosional products appear in the outlet stream as a pulse of sediment discharge in early to midsummer. The temporary subglacial storage of sediment within the ablation area is exhausted by late summer. In the accumulation area, erosion rates are relatively steady because of steady slow sliding but are lower than ablation area rates because of shielding of the bed by stored sediment (F). Evacuation is also lower (E) because the accumulation area is drained by a less efficient hydrologic system; subglacial conduits do not reach this region. If the rate of erosion and evacuation are equivalent, there is no net change of sediment storage (F). (G and H) Sediment and water discharge in the outlet stream. The relationship between sediment discharge and water discharge (inset in H) is dominated by sediment evacuated from the ablation zone and traces a clockwise hysteresis loop over the summer; this is illustrated using three points in time, labeled 1 – 3. From Riihimaki et al., 2005.
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