---
OA_place: publisher
OA_type: hybrid
_id: '19878'
abstract:
- lang: eng
text: Rock debris partially covers glaciers worldwide, with varying extents and
distributions, and controls sub‐debris melt rates by modifying energy transfer
from the atmosphere to the ice. Two key physical properties controlling this energy
exchange are thermal conductivity (k) and aerodynamic roughness length (z0). Accurate
representation of these properties in energy‐balance models is critical for understanding
climate‐glacier interactions and predicting the behavior of debris‐covered glaciers.
However, k and z0 have been derived at very few sites from limited local measurements,
using different approaches, and most model applications rely on values reported
from these few sites and studies. We derive k and z0 using established and modified
approaches from data at three locations on Pirámide Glacier in the central Chilean
Andes. By comparing methods and evaluating melt simulated with an energy‐balance
model, we reveal substantial differences between approaches. These lead to discrepancies
between ice melt from energy‐balance simulations and observed data, and highlight
the impact of method choice on calculated ice melt. Optimizing k against measured
melt appears a viable approach to constrain melt simulations. Determining z0 seems
less critical, as it has a smaller impact on total melt. Profile aerodynamic method
measurements for estimating z0, despite higher costs, are independent of ice melt
calculations. The large, unexpected differences between methods indicate a substantial
knowledge gap. The fact that field‐derived k and z0 fail to work well in energy‐balance
models, suggests that model values represent bulk properties distinct from theoretical
field measurements. Addressing this gap is essential for improving glacier melt
predictions.
acknowledgement: This project received funding from the Swiss National Science Foundation
(Grant 204322, project “REsolving the thickNess Of debris on Earth's glacIers and
its Rate of change,” RENOIR). We thank Lars Groeneveld, Diego Hernández, Alonso
Mejías, Gabriela Reyes and Gabriela Tala for their support during fieldwork. Open
access funding provided by Institute of Science and Technology Austria/KEMÖ.
article_number: e2025JF008360
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Juan Vicente
full_name: Melo Velasco, Juan Vicente
id: 2611dec0-b9c6-11ed-9bea-a81c2b17a549
last_name: Melo Velasco
- first_name: Evan
full_name: Miles, Evan
last_name: Miles
- first_name: Michael
full_name: McCarthy, Michael
id: 22a2674a-61ce-11ee-94b5-d18813baf16f
last_name: McCarthy
- first_name: Thomas
full_name: Shaw, Thomas
id: 3caa3f91-1f03-11ee-96ce-e0e553054d6e
last_name: Shaw
orcid: 0000-0001-7640-6152
- first_name: Catriona Louise
full_name: Fyffe, Catriona Louise
id: 001b0422-8d15-11ed-bc51-cab6c037a228
last_name: Fyffe
- first_name: Adrià
full_name: Fontrodona-Bach, Adrià
id: f06891fd-9f42-11ee-8632-a20971c43046
last_name: Fontrodona-Bach
- first_name: Francesca
full_name: Pellicciotti, Francesca
id: b28f055a-81ea-11ed-b70c-a9fe7f7b0e70
last_name: Pellicciotti
orcid: 0000-0002-5554-8087
citation:
ama: 'Melo Velasco JV, Miles E, McCarthy M, et al. Method dependence in thermal
conductivity and aerodynamic roughness length estimates on a debris‐covered glacier.
Journal of Geophysical Research: Earth Surface. 2025;130(6). doi:10.1029/2025jf008360'
apa: 'Melo Velasco, J. V., Miles, E., McCarthy, M., Shaw, T., Fyffe, C. L., Fontrodona-Bach,
A., & Pellicciotti, F. (2025). Method dependence in thermal conductivity and
aerodynamic roughness length estimates on a debris‐covered glacier. Journal
of Geophysical Research: Earth Surface. Wiley. https://doi.org/10.1029/2025jf008360'
chicago: 'Melo Velasco, Juan Vicente, Evan Miles, Michael McCarthy, Thomas Shaw,
Catriona Louise Fyffe, Adrià Fontrodona-Bach, and Francesca Pellicciotti. “Method
Dependence in Thermal Conductivity and Aerodynamic Roughness Length Estimates
on a Debris‐covered Glacier.” Journal of Geophysical Research: Earth Surface.
Wiley, 2025. https://doi.org/10.1029/2025jf008360.'
ieee: 'J. V. Melo Velasco et al., “Method dependence in thermal conductivity
and aerodynamic roughness length estimates on a debris‐covered glacier,” Journal
of Geophysical Research: Earth Surface, vol. 130, no. 6. Wiley, 2025.'
ista: 'Melo Velasco JV, Miles E, McCarthy M, Shaw T, Fyffe CL, Fontrodona-Bach A,
Pellicciotti F. 2025. Method dependence in thermal conductivity and aerodynamic
roughness length estimates on a debris‐covered glacier. Journal of Geophysical
Research: Earth Surface. 130(6), e2025JF008360.'
mla: 'Melo Velasco, Juan Vicente, et al. “Method Dependence in Thermal Conductivity
and Aerodynamic Roughness Length Estimates on a Debris‐covered Glacier.” Journal
of Geophysical Research: Earth Surface, vol. 130, no. 6, e2025JF008360, Wiley,
2025, doi:10.1029/2025jf008360.'
short: 'J.V. Melo Velasco, E. Miles, M. McCarthy, T. Shaw, C.L. Fyffe, A. Fontrodona-Bach,
F. Pellicciotti, Journal of Geophysical Research: Earth Surface 130 (2025).'
corr_author: '1'
date_created: 2025-06-23T13:54:01Z
date_published: 2025-06-15T00:00:00Z
date_updated: 2025-09-30T13:42:28Z
day: '15'
ddc:
- '550'
department:
- _id: FrPe
doi: 10.1029/2025jf008360
external_id:
isi:
- '001508794200001'
file:
- access_level: open_access
checksum: ca91541516c71d240321630ca42b4dc4
content_type: application/pdf
creator: dernst
date_created: 2025-06-24T06:27:34Z
date_updated: 2025-06-24T06:27:34Z
file_id: '19886'
file_name: 2025_JGREarthSurface_MeloVelasco.pdf
file_size: 3949928
relation: main_file
success: 1
file_date_updated: 2025-06-24T06:27:34Z
has_accepted_license: '1'
intvolume: ' 130'
isi: 1
issue: '6'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '06'
oa: 1
oa_version: Published Version
publication: 'Journal of Geophysical Research: Earth Surface'
publication_identifier:
eissn:
- 2169-9011
issn:
- 2169-9003
publication_status: published
publisher: Wiley
quality_controlled: '1'
scopus_import: '1'
status: public
title: Method dependence in thermal conductivity and aerodynamic roughness length
estimates on a debris‐covered glacier
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 130
year: '2025'
...
---
_id: '12613'
abstract:
- lang: eng
text: 'We 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.'
article_processing_charge: No
article_type: original
author:
- first_name: Pascal
full_name: Buri, Pascal
last_name: Buri
- first_name: Evan S.
full_name: Miles, Evan S.
last_name: Miles
- first_name: Jakob F.
full_name: Steiner, Jakob F.
last_name: Steiner
- first_name: Walter W.
full_name: Immerzeel, Walter W.
last_name: Immerzeel
- first_name: Patrick
full_name: Wagnon, Patrick
last_name: Wagnon
- first_name: Francesca
full_name: Pellicciotti, Francesca
id: b28f055a-81ea-11ed-b70c-a9fe7f7b0e70
last_name: Pellicciotti
citation:
ama: 'Buri P, Miles ES, Steiner JF, Immerzeel WW, Wagnon P, Pellicciotti F. A physically
based 3‐D model of ice cliff evolution over debris‐covered glaciers. Journal
of Geophysical Research: Earth Surface. 2016;121(12):2471-2493. doi:10.1002/2016jf004039'
apa: 'Buri, P., Miles, E. S., Steiner, J. F., Immerzeel, W. W., Wagnon, P., &
Pellicciotti, F. (2016). A physically based 3‐D model of ice cliff evolution over
debris‐covered glaciers. Journal of Geophysical Research: Earth Surface.
American Geophysical Union. https://doi.org/10.1002/2016jf004039'
chicago: 'Buri, Pascal, Evan S. Miles, Jakob F. Steiner, Walter W. Immerzeel, Patrick
Wagnon, and Francesca Pellicciotti. “A Physically Based 3‐D Model of Ice Cliff
Evolution over Debris‐covered Glaciers.” Journal of Geophysical Research: Earth
Surface. American Geophysical Union, 2016. https://doi.org/10.1002/2016jf004039.'
ieee: 'P. Buri, E. S. Miles, J. F. Steiner, W. W. Immerzeel, P. Wagnon, and F. Pellicciotti,
“A physically based 3‐D model of ice cliff evolution over debris‐covered glaciers,”
Journal of Geophysical Research: Earth Surface, vol. 121, no. 12. American
Geophysical Union, pp. 2471–2493, 2016.'
ista: 'Buri P, Miles ES, Steiner JF, Immerzeel WW, Wagnon P, Pellicciotti F. 2016.
A physically based 3‐D model of ice cliff evolution over debris‐covered glaciers.
Journal of Geophysical Research: Earth Surface. 121(12), 2471–2493.'
mla: 'Buri, Pascal, et al. “A Physically Based 3‐D Model of Ice Cliff Evolution
over Debris‐covered Glaciers.” Journal of Geophysical Research: Earth Surface,
vol. 121, no. 12, American Geophysical Union, 2016, pp. 2471–93, doi:10.1002/2016jf004039.'
short: 'P. Buri, E.S. Miles, J.F. Steiner, W.W. Immerzeel, P. Wagnon, F. Pellicciotti,
Journal of Geophysical Research: Earth Surface 121 (2016) 2471–2493.'
date_created: 2023-02-20T08:14:28Z
date_published: 2016-11-22T00:00:00Z
date_updated: 2023-02-24T11:34:54Z
day: '22'
doi: 10.1002/2016jf004039
extern: '1'
intvolume: ' 121'
issue: '12'
keyword:
- Earth-Surface Processes
- Geophysics
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1002/2016JF004039
month: '11'
oa: 1
oa_version: Published Version
page: 2471-2493
publication: 'Journal of Geophysical Research: Earth Surface'
publication_identifier:
eissn:
- 2169-9011
issn:
- 2169-9003
publication_status: published
publisher: American Geophysical Union
quality_controlled: '1'
scopus_import: '1'
status: public
title: A physically based 3‐D model of ice cliff evolution over debris‐covered glaciers
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 121
year: '2016'
...