Evolution of a surge-type glacier in its quiescent phase: Kongsvegen, Spitsbergen, 1964-95

Kongsvegen is a 102 km(2) sub-polar (polythermal) surge-type glacier in nor thwest Spitsbergen, Svalbard. It surged just before 1948 and is currently i n its quiescent phase. Measurements of surface geometry since 1966 show a r etreat of the front and strong thinning of up to 75 m in the ablation area, and a build-up, of up to 32 m in the accumulation area. Present-day annual velocities along the glacier are low from 1.4 up to 3.6 m a(-1) The measur ed mean net balance for the period 1987-94 and the balance reconstructed ba ck to 1967 show a weak positive balance of about 0.1 mw.e. The measured act ual ice flux is low and the mass transfer down-glacier at the ELA is only a bout 3-20% of that required for steady state. Thus, the glacier is building up towards a new surge. The total thickening rate on Kongsvegen is somewha t higher than in other cases from Svalbard, but it is small compared with o ther well-studied surge-type glaciers in Alaska and the Pamirs. This relati vely low rate of change is a function of the low accumulation rate and the relatively cold climate compared to other areas and is common for surge-typ e glaciers in Svalbard.