Heat balance characteristics during fine periods on the lower parts of the Franz Josef Glacier, South Westland, New Zealand

Abstract

AbstractHeat balance observations were carried out during fine conditions at a site on the lower Franz Josef Glacier in June 1988 and February 1990 and compared with results obtained in August, October, and December 1981. Surface ice melt occurred during all seasons, with the mean melt rate in summer about eight times larger than in winter. The seasonal variation of the various contributions to ice melt was also identified. Sensible heat flux was the dominant heat source, contributing 80 per cent and 55 per cent of the total energy gain in winter and summer, respectively. Latent heat transfer contributed similar amounts in winter (20 per cent) and summer (25 per cent). Net radiation was a heat sink in winter (—13 per cent) and was similar to latent heat transfer in summer at 21 per cent. A newly developed simple method for estimating ice melt using only air temperature is presented and helps to explain the seasonal variations of ice melt.