© Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License. The Cryosphere Measured and modelled sublimation on the tropical Glaciar

Abstract. Sublimation plays a decisive role in the surface energy and mass balance of tropical glaciers. During the dry season (May–September) low specific humidity and high sur-face roughness favour the direct transition from ice to vapour and drastically reduce the energy available for melting. How-ever, field measurements are scarce and little is known about the performance of sublimation parameterisations in glacier mass balance and runoff models. During 15 days in August 2005 sublimation was measured on the tongue of Glaciar Artesonraju (8◦58 ′ S, 77◦38 ′ W) in the Cordillera Blanca, Perú, using simple lysimeters. Indi-cating a strong dependence on surface roughness, daily to-tals of sublimation range from 1–3 kg m−2 for smooth to 2– 5 kg m−2 for rough conditions. (The 15-day means at that time of wind speed and specific humidity were 4.3 m s−1 an