Climatic and geometric controls on the global distribution of surge-type glaciers : implications for a unifying model of surging

Financial support was provided by the ConocoPhillips Lundin Northern Area Program project CRIOS. Controls on the global distribution of surge-type glaciers hold the keys to a better understanding of surge mechanisms. We investigate correlations between the distribution of surge-type glaciers and cli...

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Bibliographic Details
Published in:Journal of Glaciology
Main Authors: Sevestre, H., Benn, Doug I
Other Authors: University of St Andrews. Bell-Edwards Geographic Data Institute, University of St Andrews. School of Geography & Sustainable Development, University of St Andrews. Geography & Sustainable Development
Format: Article in Journal/Newspaper
Language:English
Published: 2016
Subjects:
Energy balance
Glacier surges
Ice and climate
GE Environmental Sciences
3rd-NDAS
BDC
R2C
GE
Journal of Glaciology
Online Access:http://hdl.handle.net/10023/8342
https://doi.org/10.3189/2015JoG14J136
Description
Summary:Financial support was provided by the ConocoPhillips Lundin Northern Area Program project CRIOS. Controls on the global distribution of surge-type glaciers hold the keys to a better understanding of surge mechanisms. We investigate correlations between the distribution of surge-type glaciers and climatic and glacier geometry variables, using a new global geodatabase of 2317 surge-type glaciers. The highest densities of surge-type glaciers occur within an optimal climatic envelope bounded by temperature and precipitation thresholds. Across all regions with both surge-type and normal glaciers, the former are larger, especially at the cold, dry end of the climatic spectrum. A species distribution model, Maxent, accurately predicts the major clusters of surge-type glaciers using a series of climatic and glacier geometry variables, but under-predicts clusters found outside the climatically optimal surge zone. We interpret the results in terms of a new enthalpy cycle model. Steady states require a balance between enthalpy gains generated by the balance flux and losses via heat conduction and meltwater discharge. This condition can be most easily satisfied in cold, dry environments (thin, low-flux glaciers, efficient conductive heat losses) and warm, humid environments (high meltwater discharges). Intermediate conditions correspond to the optimal surge zone, where neither heat conduction nor runoff can effectively discharge enthalpy gains, and dynamic cycling can result. Publisher PDF Peer reviewed

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