Frontal variations

The retreat and advance of glacier fronts has probably been used as a measure of climatic variations as long as humans have lived close to glaciated environments. Climate is constantly changing, with annual fluctuations superimposed on long-term trends. Such climatic changes are reflected in variations in the glacier extent. One example is the growth and decay of the Cenozoic continental ice sheets. Another example is the glacier advances during the 'Little Ice Age' and the subsequent frontal retreat. On a large scale, advances and retreats may be broadly synchronous. On a more detailed scale, however, the

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Cenozoic Continental Glacier Eustatic

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Figure 4.34 The annual (upper panel) and cumulative (lower panel) net mass balance for Maliy Aktru between 1962 and 1997. (Data from WGMS)

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Figure 4.34 The annual (upper panel) and cumulative (lower panel) net mass balance for Maliy Aktru between 1962 and 1997. (Data from WGMS)

picture is more complex. In the same region, some glaciers may be advancing while others are retreating. Differences in local climates, aspect, size, steepness, and speed of individual glaciers may explain the different behaviour. In addition, the effect of a given climatic fluctuation on the glacier mass balance depends on the area-altitude distribution of the glacier. As a result, glaciers in the same area are likely to react differently, or at different rates, to the same mass balance variation (Paterson, 1994).

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