Glacier Accumulation and Ablation

Overview

• Focuses on the processes of glacier accumulation and ablation.
• Examines glaciers as systems with inputs and outputs.

Glacier Accumulation

• Glaciers form from accumulated snow and ice over years.
• Occurs in cold regions where more snow falls than melts.
• Inputs include:
  • Solid precipitation: snow, hail, freezing rain
  • Additional sources: wind-blown snow, avalanches, hoar frost
• Accumulation zone: part of glacier receiving more mass than it loses.
• Transformation Process:
  • Snowflakes compress into granular ice, then firn, and finally glacial ice.
  • Influenced by climate, temperature, and precipitation.
  • Ice cores reveal annual layers, indicating summer and winter cycles.

Glacier Ablation

• Occurs when ice flows into warmer areas or reaches water.
• Processes include:
  • Surface melt in land-terminating glaciers
  • Calving and underwater melt in marine-terminating and lacustrine-terminating glaciers
• Ablation zone: lower part of glacier losing more mass than receives.
• Meltwater streams form from surface melt and flow through glacier beds.

Equilibrium Line Altitude (ELA)

• Separates accumulation and ablation zones.
• Marks altitude where annual accumulation equals annual ablation.

Glaciers as a System

• Glaciers described as viscous fluids, flowing and deforming under weight.
• Systems receive snow/ice and melt as they descend.
• Mass balance:
  • Positive in winter, negative in summer for Winter Accumulation Type Glaciers.
  • Opposite pattern for Summer Accumulation Type Glaciers, such as those influenced by monsoons in the Himalayas.

Further Reading

• Provides resources for deeper understanding:
  • Glaciers online: accumulation and ablation zones
  • Glacier flow and mass balance
  • Glacier hydrology
  • Ice nature and dynamics

References

• Cited works provide foundational knowledge and glossary terms.
  • Cogley et al. (2011)
  • Bakke & Nesje (2011)
  • Naito (2011)
  • Kumar (2011)