Term: Equilibrium-line altitude ELA Class:  
 vernacular   (0%)
Created 6 June 2017
Last modified 6 June 2017
Contributed by GCW Glossary


Definition: The spatially averaged altitude of the equilibrium line. The ELA may be determined by direct visual observation, but is generally determined, in the context of mass-balance measurements, by fitting a curve to data representing surface mass balance as a function of altitude (see mass-balance profile). This is often an idealization, because the equilibrium line tends to span a range of altitudes. Many approximations of the ELA have been suggested; the glaciation level and the mid-range altitude are examples. The ELA is understood to be the Annual ELA unless it is qualified as the transient ELA.  IHPGlacierMassBalance