Direct measurements of meltwater runoff on the Greenland ice sheet surface.
Meltwater runoff from the Greenland ice sheet surface influences surface mass balance (SMB), ice dynamics, and global sea level rise, but is estimated with climate models and thus difficult to validate. We present a way to measure ice surface runoff directly, from hourly in situ supraglacial river d...
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eScholarship, University of California
2017
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Online Access: | https://escholarship.org/uc/item/2jr4d0tr |
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ftcdlib:oai:escholarship.org/ark:/13030/qt2jr4d0tr 2023-05-15T16:28:27+02:00 Direct measurements of meltwater runoff on the Greenland ice sheet surface. Smith, Laurence C Yang, Kang Pitcher, Lincoln H Overstreet, Brandon T Chu, Vena W Rennermalm, Åsa K Ryan, Jonathan C Cooper, Matthew G Gleason, Colin J Tedesco, Marco Jeyaratnam, Jeyavinoth van As, Dirk van den Broeke, Michiel R van de Berg, Willem Jan Noël, Brice Langen, Peter L Cullather, Richard I Zhao, Bin Willis, Michael J Hubbard, Alun Box, Jason E Jenner, Brittany A Behar, Alberto E E10622 - E10631 2017-12-05 application/pdf https://escholarship.org/uc/item/2jr4d0tr unknown eScholarship, University of California qt2jr4d0tr https://escholarship.org/uc/item/2jr4d0tr public Proceedings of the National Academy of Sciences of the United States of America, vol 114, iss 50 climate models fluvial catchment ice sheet meltwater runoff surface mass balance surface water hydrology article 2017 ftcdlib 2021-06-28T17:07:35Z Meltwater runoff from the Greenland ice sheet surface influences surface mass balance (SMB), ice dynamics, and global sea level rise, but is estimated with climate models and thus difficult to validate. We present a way to measure ice surface runoff directly, from hourly in situ supraglacial river discharge measurements and simultaneous high-resolution satellite/drone remote sensing of upstream fluvial catchment area. A first 72-h trial for a 63.1-km2 moulin-terminating internally drained catchment (IDC) on Greenland's midelevation (1,207-1,381 m above sea level) ablation zone is compared with melt and runoff simulations from HIRHAM5, MAR3.6, RACMO2.3, MERRA-2, and SEB climate/SMB models. Current models cannot reproduce peak discharges or timing of runoff entering moulins but are improved using synthetic unit hydrograph (SUH) theory. Retroactive SUH applications to two older field studies reproduce their findings, signifying that remotely sensed IDC area, shape, and supraglacial river length are useful for predicting delays in peak runoff delivery to moulins. Applying SUH to HIRHAM5, MAR3.6, and RACMO2.3 gridded melt products for 799 surrounding IDCs suggests their terminal moulins receive lower peak discharges, less diurnal variability, and asynchronous runoff timing relative to climate/SMB model output alone. Conversely, large IDCs produce high moulin discharges, even at high elevations where melt rates are low. During this particular field experiment, models overestimated runoff by +21 to +58%, linked to overestimated surface ablation and possible meltwater retention in bare, porous, low-density ice. Direct measurements of ice surface runoff will improve climate/SMB models, and incorporating remotely sensed IDCs will aid coupling of SMB with ice dynamics and subglacial systems. Article in Journal/Newspaper Greenland Ice Sheet University of California: eScholarship Greenland Merra ENVELOPE(12.615,12.615,65.816,65.816) |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
climate models fluvial catchment ice sheet meltwater runoff surface mass balance surface water hydrology |
spellingShingle |
climate models fluvial catchment ice sheet meltwater runoff surface mass balance surface water hydrology Smith, Laurence C Yang, Kang Pitcher, Lincoln H Overstreet, Brandon T Chu, Vena W Rennermalm, Åsa K Ryan, Jonathan C Cooper, Matthew G Gleason, Colin J Tedesco, Marco Jeyaratnam, Jeyavinoth van As, Dirk van den Broeke, Michiel R van de Berg, Willem Jan Noël, Brice Langen, Peter L Cullather, Richard I Zhao, Bin Willis, Michael J Hubbard, Alun Box, Jason E Jenner, Brittany A Behar, Alberto E Direct measurements of meltwater runoff on the Greenland ice sheet surface. |
topic_facet |
climate models fluvial catchment ice sheet meltwater runoff surface mass balance surface water hydrology |
description |
Meltwater runoff from the Greenland ice sheet surface influences surface mass balance (SMB), ice dynamics, and global sea level rise, but is estimated with climate models and thus difficult to validate. We present a way to measure ice surface runoff directly, from hourly in situ supraglacial river discharge measurements and simultaneous high-resolution satellite/drone remote sensing of upstream fluvial catchment area. A first 72-h trial for a 63.1-km2 moulin-terminating internally drained catchment (IDC) on Greenland's midelevation (1,207-1,381 m above sea level) ablation zone is compared with melt and runoff simulations from HIRHAM5, MAR3.6, RACMO2.3, MERRA-2, and SEB climate/SMB models. Current models cannot reproduce peak discharges or timing of runoff entering moulins but are improved using synthetic unit hydrograph (SUH) theory. Retroactive SUH applications to two older field studies reproduce their findings, signifying that remotely sensed IDC area, shape, and supraglacial river length are useful for predicting delays in peak runoff delivery to moulins. Applying SUH to HIRHAM5, MAR3.6, and RACMO2.3 gridded melt products for 799 surrounding IDCs suggests their terminal moulins receive lower peak discharges, less diurnal variability, and asynchronous runoff timing relative to climate/SMB model output alone. Conversely, large IDCs produce high moulin discharges, even at high elevations where melt rates are low. During this particular field experiment, models overestimated runoff by +21 to +58%, linked to overestimated surface ablation and possible meltwater retention in bare, porous, low-density ice. Direct measurements of ice surface runoff will improve climate/SMB models, and incorporating remotely sensed IDCs will aid coupling of SMB with ice dynamics and subglacial systems. |
format |
Article in Journal/Newspaper |
author |
Smith, Laurence C Yang, Kang Pitcher, Lincoln H Overstreet, Brandon T Chu, Vena W Rennermalm, Åsa K Ryan, Jonathan C Cooper, Matthew G Gleason, Colin J Tedesco, Marco Jeyaratnam, Jeyavinoth van As, Dirk van den Broeke, Michiel R van de Berg, Willem Jan Noël, Brice Langen, Peter L Cullather, Richard I Zhao, Bin Willis, Michael J Hubbard, Alun Box, Jason E Jenner, Brittany A Behar, Alberto E |
author_facet |
Smith, Laurence C Yang, Kang Pitcher, Lincoln H Overstreet, Brandon T Chu, Vena W Rennermalm, Åsa K Ryan, Jonathan C Cooper, Matthew G Gleason, Colin J Tedesco, Marco Jeyaratnam, Jeyavinoth van As, Dirk van den Broeke, Michiel R van de Berg, Willem Jan Noël, Brice Langen, Peter L Cullather, Richard I Zhao, Bin Willis, Michael J Hubbard, Alun Box, Jason E Jenner, Brittany A Behar, Alberto E |
author_sort |
Smith, Laurence C |
title |
Direct measurements of meltwater runoff on the Greenland ice sheet surface. |
title_short |
Direct measurements of meltwater runoff on the Greenland ice sheet surface. |
title_full |
Direct measurements of meltwater runoff on the Greenland ice sheet surface. |
title_fullStr |
Direct measurements of meltwater runoff on the Greenland ice sheet surface. |
title_full_unstemmed |
Direct measurements of meltwater runoff on the Greenland ice sheet surface. |
title_sort |
direct measurements of meltwater runoff on the greenland ice sheet surface. |
publisher |
eScholarship, University of California |
publishDate |
2017 |
url |
https://escholarship.org/uc/item/2jr4d0tr |
op_coverage |
E10622 - E10631 |
long_lat |
ENVELOPE(12.615,12.615,65.816,65.816) |
geographic |
Greenland Merra |
geographic_facet |
Greenland Merra |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_source |
Proceedings of the National Academy of Sciences of the United States of America, vol 114, iss 50 |
op_relation |
qt2jr4d0tr https://escholarship.org/uc/item/2jr4d0tr |
op_rights |
public |
_version_ |
1766018095443345408 |