Javier Chueca

Relationship between solar radiation and the development and morphology of small cirque glaciers (Maladeta Mountain massif, Central Pyrenees, Spain)

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.

Recent evolution (1981-2005) of the Maladeta glaciers, Pyrenees, Spain : extent and volume losses and their relation with climatic and topographic factors

Analysis of aerial photographs, GPS mapping and comparison of digital elevation models have been used to quantify the losses in extent and volume observed (1981-2005) in the glaciers of the Maladeta massif (Spanish Pyrenees). The data are examined in relation to different climatic (temperature, precipitation) and topographic factors that control glacial retreat both at the general and local scales. The evolution observed in the massif is characterized by the remarkable surface and volumetric shrinkage registered in all the glaciers: (1) glacial ice decreased in extent 35.7%, reducing from 240.9 ha to 155.0 ha; (2) losses in total ice volume reached 0.0137 km 3 (75.6mw.e.); (3) mean altitude of the studied glaciers increased 43.5 m. These changes seem to have been forced by climatic change (reduction in the snowfall contributions and increase in the maximum temperatures) during the past few decades in this Pyrenean region. In addition, local variables such as the orientation of each glacier, their altitude and their initial size seem to have induced significant spatial differences in the magnitude of the losses.

Movement of Besiberris Rock Glacier, Central Pyrenees, Spain: Data from a 10-Year Geodetic Survey

Abstract A 10-yr (1993–2003) geodetic survey was conducted at the Besiberris rock glacier, a tongue-shaped, glacigenic rock glacier, located in the eastern-central Spanish Pyrenees (42°35′48″N, 0°49′20″E). Displacement measurements were made on three traverse lines across the rock glacier. Surface horizontal velocity increases from the head to the toe sectors (average values: traverse line A = 8.72 cm yr−1; line B = 10.65 cm yr−1; line C = 13.35 cm yr−1). Velocities are greater at the axis of the rock glacier compared to its lateral margins. In terms of vertical movement, the rock glacier has shown clear thinning of an ice-core. In all three traverse lines, surface lowering has been detected (average values: line A = 5.00 cm yr−1; line B = 7.10 cm yr−1; line C = 5.27 cm yr−1). This general lowering is interpreted as the adjustment of the rock glacier to the climatic amelioration (higher temperature, drier conditions, and reduced snowfall) observed in the Pyrenean region since the end of the Little Ice Age and accentuated in the last few decades.