Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.645005
Title: Modelling the energy balance of high altitude glacierised basins in the Central Andes
Author: Corripio, Javier Gonzalez
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2003
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Abstract:
Meteorological data from one automatic weather station installed on two different glaciers at 3335 m and 4667 m in the Chilean Central Andes demonstrate that the relative importance of the terms in the energy balance equation shows substantial differnces from that of mid-latitude Alpine glaciers, with turbulent heat transfer accounting for 10 to 20% of the net energy balance. 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. Stable conditions and a clear atmosphere permit effective incorporation of fully distributed solar radiative models with good results. Melt rates are compared with theoretical models, showing that while evaporation is enhanced in the Andes, surface morphology decreases total ablation. Modelling work suggests that penitentes enhance conservation of snow cover and the consequences of their loss, due to changes in the initial climatic conditions, might be increased ablation over the whole season, decreased glacier mass balance and faster depletion of water resources. To implement distributed energy balance models both at the basin scale and at the microtopography scale, two additional tools where developed. One is a set of algorithms for the computation of terrain parameters from digital elevation models (DEMs) suitable for rough topography. These algorithms, together with those developed for shading and insolation, permit the treatment of overhanging surfaces, such as the penitentes. Another tool is a flexible and inexpensive remote sensing tool for albedo estimation using conventional terrestrial photography. The technique consists in georeferencing oblique photographs to a digital elevation model (DEM), defining a mapping function between the pixel of the image and the corresponding cell on the DEM. Once the image is georeferenced, the reflectance values recorded by the film or digital camera are corrected for topographic and atmospheric influences and for the effect of the photographic process. By comparing these to a surface of known albedo, the spatial distribution of albedos is calculated. The validation of the technique on Alpine terrain shows good agreement with measured values.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.645005  DOI: Not available
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