Observations of the effect of wind on the cooling of active lava flows

Abstract

We present the first direct observations of the cooling of active lava flows by the wind. We confirm that atmospheric convective cooling processes (i.e., the wind) dominate heat loss over the lifetime of a typical pahochoe lava flow. In fact, the heat extracted by convection is greater than predicted, especially at wind speeds less than 5 m/s and surface temperatures less than 400°C. We currently estimate that the atmospheric heat transfer coefficient is about 45-50 W m-2 K-1 for a 10 m/s wind and a surface temperature ∼500°C. Further field experiments and theoretical studies should expand these results to a broader range of surface temperatures and wind speeds.