000034409 001__ 34409
000034409 037__ $$aARTICLE--2019-005
000034409 041__ $$aEnglish
000034409 100__ $$aBuri, P.
000034409 100__ $$aMiles, E. S.
000034409 100__ $$aSteiner, J. F.
000034409 100__ $$aImmerzeel, W. W.
000034409 100__ $$aWagnon, P.
000034409 100__ $$aPellicciotti, F.
000034409 245__ $$aA physically based 3‐D model of ice cliff evolution over debris‐covered glaciers
000034409 260__ $$c2016
000034409 300__ $$a 
000034409 507__ $$aPatrick Wagnon, ICIMOD staff, peerreviewed, cryosphere
000034409 511__ $$aCrysparticle
000034409 520__ $$aWe use high‐resolution digital elevation models (DEMs) from unmanned aerial vehicle (UAV) surveys to document the evolution of four ice cliffs on the debris‐covered tongue of Lirung Glacier, Nepal, over one ablation season. Observations show that out of four cliffs, three different patterns of evolution emerge: (i) reclining cliffs that flatten during the ablation season; (ii) stable cliffs that maintain a self‐similar geometry; and (iii) growing cliffs, expanding laterally. We use the insights from this unique data set to develop a 3‐D model of cliff backwasting and evolution that is validated against observations and an independent data set of volume losses. The model includes ablation at the cliff surface driven by energy exchange with the atmosphere, reburial of cliff cells by surrounding debris, and the effect of adjacent ponds. The cliff geometry is updated monthly to account for the modifications induced by each of those processes. Model results indicate that a major factor affecting the survival of steep cliffs is the coupling with ponded water at its base, which prevents progressive flattening and possible disappearance of a cliff. The radial growth observed at one cliff is explained by higher receipts of longwave and shortwave radiation, calculated taking into account atmospheric fluxes, shading, and the emission of longwave radiation from debris surfaces. The model is a clear step forward compared to existing static approaches that calculate atmospheric melt over an invariant cliff geometry and can be used for long‐term simulations of cliff evolution and to test existing hypotheses about cliffs' survival.
000034409 650__ $$aCryosphere
000034409 650__ $$aGlaciers
000034409 773__ $$pJournal of Geophysical Research: Earth Surface
000034409 773__ $$v121
000034409 773__ $$n12
000034409 8564_ $$uhttps://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JF004039$$yExternal link (open access)
000034409 8560_ $$fjha.anil4@gmail.com
000034409 8564_ $$uhttp://lib.icimod.org/record/34409/files/physicallyJOGR121-016.pdf
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000034409 980__ $$aICIMODEXT