Mass balance and equilibrium-line altitudes of glaciers in high-mountain environments

The mass-balance characteristics of glaciers in high-mountain environments complicate the relationship between glacier equilibrium-line altitudes (ELAs) and climatic variables such as precipitation and air temperature. Therefore, methods of ELA reconstruction employed in low-relief environments are commonly not applicable in high mountains, or require some modification. We review the concept of the ELA, with reference to the mass balance of a range of glacier types found in high-mountain regions. We examine the applicability of several commonly used methods of ELA reconstruction for different glacier types, and propose some general principles to guide the choice of appropriate methods.