Permafrost and Climatology of a Hawaii Volcano Crater,

Permafrost was discovered in 1969 at an altitude of 4,140 m near the surface of Summit Cone crater on Mauna Kea, a dormant volcano on the island of Hawaii. Although the mean annual air temperature of the nearby Mauna Kea Observatory (alt. ~4,200 m) is well above freezing, the permafrost is at least 10 m thick. Its survival is shown to be associated with the local trapping of radiationally cooled air, a low angle of incidence of sunlight, and a very dry atmosphere. Indications are that it can survive for long periods in the volcanic cones of the dry alpine regions of Hawaii, with a lowering of the mean air temperature immediately over its surface to only a few tenths of a degree below 0°C. The permafrost does not appear to be in thermal equilibrium with the present microclimate of the crater. Though its upper surface shows no signs of degradation during 4 years, the lower surface is probably slowly melting.