Energy Balance of High Altitude Glaciarised Basins In The Central Andes: Climatic and Hydrological Aspects
Abstract
The Central Andes of Chile and Argentina can be classified as climatic deserts, yet they support very large populations and a rich agriculture, thanks to melt water from snow melt and glaciers. Meteorological data from one automatic weather station in- stalled on two different glaciers at 3300m and 4600m a.s.l. in the Chilean Andes (700 W, 330 S), are presented and discussed. The relative importance of the terms in the en- ergy balance equation shows substantial differences from that of mid-latitude Alpine glaciers, with turbulent heat transfer accounting for 10 to 20% of the net energy bal- ance. Extremely low relative humidity (up to 8%) and moderate winds result in high evaporation rates. Intense evaporation, together with effective radiative cooling, dew point well below freezing and intense solar radiation favour differential ablation of the snow surface, which results in the formation of snow penitentes, these unique forms result in a further modification of the energy balance. The intense solar radia- tion enhances the effect of the surrounding topography on snow-covered areas, which is modelled using terrain algorithms for digital elevation models. Stable conditions and a clear atmosphere permit effective use of solar radiative models with good re- sults. Remoteness and lack of infrastructures complicate access, which was made us- ing traditional transportation methods in the region: mules! Lack of data and limited budget was partially overcome by developing an alternative simple and economical remote sensing tool for snow cover monitoring and albedo estimation using terrestrial photography. Finally, the output of a distributed snow melt model is compared to dis- charge data from a glacier whose outflow is monitored by the Chilean Water Board, as it is the main source of drinking water for Santiago de Chile.
- Publication:
-
EGS General Assembly Conference Abstracts
- Pub Date:
- 2002
- Bibcode:
- 2002EGSGA..27.4402C