Relationship between solar radiation and the development and morphology of small cirque glaciers (maladeta mountain massif, central pyrenees, spain)

Abstract

Chueca, J. and Julián, A., 2004: Relationship between solar radiation and the development and morphology of small cirque glaciers (Maladeta Mountain massif, Central Pyrenees, Spain). Geogr. Ann., 86 A (1): 81-89.ABSTRACT. Spatial and temporal variations in radiative fluxes influence glacier mass-balance in mountain areas. The primary goal of this study was to assess differences in solar radiation on three glacial cirques located in the Maladeta Mountain massif (Central Spanish Pyrenees), and analyse their implications on glacier development and morphology. A quantitative approach is adopted to obtain the values of solar radiation (direct, diffuse and global radiation), combining several field data parameters (measured at 55 control-points) with the solar radiation modelling package Ecosim. The data obtained confirm that the morphologies of the glacial bodies developed in the three cirques have a good correlation with the spatial variation on solar radiation inputs, favouring also the conservation (Aneto and Coronas cirques) or total vanishing (Llosás cirque) of the glacial remnants analysed here. The study shows how strongly in this Alpine-Mediterranean context solar radiation -firstly as a function of latitude and time of year, and locally as a function of topographic slope, aspect and shadowing -controls the mass-balance and the spatial distribution of melting in small glaciers, having an effect on the development of their morphologies.

Implications of mountain shading on calculating energy for snowmelt using unstructured triangular meshes

“…In a catchment in the Yukon, Canada, Pomeroy et al (2003) found that on a clear day at midday in the peak snowmelt period, a 20 • south-facing slope received 80% more incoming solar shortwave radiation than a similarly steep, north-facing slope. This spatial variability leads to significant differences in snowmelt timing and magnitude throughout the basin and can limit melt on nested glaciers in shaded cirques (Chueca and Julián, 2004), limit snow melt (Carey and Woo, 1998;Pomeroy et al, 2003), cause changes in surface temperature (Pomeroy et al, 2003), and limit or increase photosynthesis and therefore affect subsequent vegetation patterns (Dymond, 2002). Chueca and Julián (2004) demonstrated that the spatial distribution of small cirque glaciers could be primarily attributed to the differences in incoming shortwave radiation, primarily due to shading.…”

“…This spatial variability leads to significant differences in snowmelt timing and magnitude throughout the basin and can limit melt on nested glaciers in shaded cirques (Chueca and Julián, 2004), limit snow melt (Carey and Woo, 1998;Pomeroy et al, 2003), cause changes in surface temperature (Pomeroy et al, 2003), and limit or increase photosynthesis and therefore affect subsequent vegetation patterns (Dymond, 2002). Chueca and Julián (2004) demonstrated that the spatial distribution of small cirque glaciers could be primarily attributed to the differences in incoming shortwave radiation, primarily due to shading. The spatial variability of topographically driven shortwave radiation is important in even gently rolling terrain, as shown by Pohl et al (2006) in a sub-Arctic tundra river basin.…”

“…This shading changes with time of day, time of year, and latitude. This cycling creates large differences in incident shortwave radiation and can play a principal role in, for example, limiting melt on glaciers that are nested in highly shaded cirques (Chueca and Julián, 2004), snow melt (Carey and Woo, 1998;Pomeroy et al, 2003), surface temperature (Pomeroy et al, 2003), and photosynthesis and subsequent vegetation patterns (Dymond, 2002). In high-relief areas, such as in the Canadian Rocky Mountains, and in low-relief areas with short, steep slopes, the topography can completely block some locations from receiving any direct incoming solar radiation when the sun is low on the horizon.…”

“…It is also necessary to calculate the shortwave radiation that is incident on slopes of various angles and aspects by taking into account selfshading and shading from surrounding topography. The basic geometric equations for estimating shortwave radiation to a slope are well known and have been applied for many years, e.g., Garnier and Ohmura (1968); Dozier et al (1981); Dozier and Frew (1990); Frew (1990); Fu and Rich (1999); Chueca and Julián (2004). However for an algorithm to be widely applicable it must be computationally efficient.…”

Spatial and temporal variability of annual glacier equilibrium line altitudes in the Southern Alps, New Zealand

“…Chueca & Julia´n 2004). Furthermore, where slope is favourable to glacier formation, any convexity in slope will hinder glacier development (Lo´pez-Moreno et al 2006).…”