Bægisárjökull, North-Iceland. Result of glaciological investigations 1967–1968. Part II. The energy balance

The energy budget ierms for a melting glacier were estimaíed for periods in July and August in 1967 and 1968.The turbulent energy fluxes were computed by application of the Monin and Obukhov theory.Evidence showed that this method gave better results than assuming logarithmic profiles of wind, temperature and specific humidity.The relative importance of net radiation, sensible heat, and latent heat in supplying energy at the glacier surface was found to be about 51%, 53% and 16% respectively during the observation period in 1968.For the observation periocl in 1967 the net radiation was found to be responsible for about 57% of the ablation.For a period of 36 days midsumrner in 1968 calculated and measured ablation were found to be in good accordance.By assuming the first one to be representative for the latter, averaged over shorter time intervals, tlie glacier systern response to input of meltwater and rain could be illustrated.Further it is demonstrated that the discrepancy between the results obtainecl using the hydrological method and the glaciological method for mass balance measurements reported by tíjörnsson (1971) might partly be caused by the release of delayed water melled earlier in the summer and was parlly due to an underestimate of the rain volurnes.