Identifying links between large-scale atmospheric circulation and local glacier ablation climates in the French Pyrenees

This paper adopts a synoptic climatological approach to elucidate associations between large-scale atmospheric circulation and local summer ablation climates for a small cirque glacier (Taillon Glacier, French Pyrenees), located at the climatically-sensitive southern limit for contemporary European glaciation. The air-mass categories identified possess differential influences on snow and ice melt dependent upon their thermodynamic properties. The observed climate-glacier links are employed to predict the impact of a shift in air-mass type frequency on Pyrenean snowpacks and glaciers. Typically, cyclonic patterns are associated with low ablation whereas high melt is associated with anticylonic systems. An extension of the North African-Mediterranean subtropical ridge with an associated polar shift in the westerlies, as proposed under global warming, would favour an increase in the prevalence of high energy air-masses, thus enhancing Pyrenean ablation climates. Further work is required to extend this air-mass identification scheme over a number of years and to include atmospheric conditions during the accumulation season.