The importance of cloud phase when assessing surface melting in an offline coupled firn model over Ross Ice shelf, West Antarctica [in review]
The Ross Ice Shelf, West Antarctica, experienced an extensive melt event in January 2016. We examine the representation of this event by the HIRHAM5 and MetUM high-resolution regional atmospheric models, as well as a sophisticated offline coupled firn model forced with their outputs. The model resul...
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2023
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ftnerc:oai:nora.nerc.ac.uk:536178 2023-12-03T10:13:26+01:00 The importance of cloud phase when assessing surface melting in an offline coupled firn model over Ross Ice shelf, West Antarctica [in review] Hansen, Nicolaj Orr, Andrew Zou, Xun Boberg, Fredrik Bracegirdle, Thomas J. Gilbert, Ella Langen, Peter L. Lazzara, Matthew A. Mottram, Ruth Phillips, Tony Price, Ruth Simonsen, Sebastian B. Webster, Stuart 2023-10-25 http://nora.nerc.ac.uk/id/eprint/536178/ https://tc.copernicus.org/preprints/tc-2023-145/ unknown European Geosciences Union Hansen, Nicolaj; Orr, Andrew orcid:0000-0001-5111-8402 Zou, Xun; Boberg, Fredrik; Bracegirdle, Thomas J. orcid:0000-0002-8868-4739 Gilbert, Ella orcid:0000-0001-5272-8894 Langen, Peter L.; Lazzara, Matthew A.; Mottram, Ruth; Phillips, Tony orcid:0000-0002-3058-9157 Price, Ruth; Simonsen, Sebastian B.; Webster, Stuart. 2023 The importance of cloud phase when assessing surface melting in an offline coupled firn model over Ross Ice shelf, West Antarctica [in review]. The Cryosphere: Discussions. https://doi.org/10.5194/tc-2023-145 <https://doi.org/10.5194/tc-2023-145> Publication - Article PeerReviewed 2023 ftnerc https://doi.org/10.5194/tc-2023-145 2023-11-03T00:03:09Z The Ross Ice Shelf, West Antarctica, experienced an extensive melt event in January 2016. We examine the representation of this event by the HIRHAM5 and MetUM high-resolution regional atmospheric models, as well as a sophisticated offline coupled firn model forced with their outputs. The model results are compared with satellite-based estimates of melt days. The firn model estimates of the number of melt days are in good agreement with the observations over the eastern and central sectors of the ice shelf, while the HIRHAM5 and MetUM estimates based on their own surface schemes are considerably underestimated, possibly due to deficiencies in these schemes and an absence of spin-up. However, the firn model simulates sustained melting over the western sector of the ice shelf, in disagreement with the observations that show this region as being melt-free. This is attributed to deficiencies in the HIRHAM5 and MetUM output, and particularly a likely overestimation of nighttime net surface radiative flux. This occurs in response to an increase in nighttime downwelling longwave flux from around 180–200 W m-2 to 280 W m-2 over the course of a few days, leading to an excessive amount of energy at the surface available for melt. Satellite-based observations show that this change coincides with a transition from clear-sky conditions to clouds containing both liquid-water and ice-water. The models capture the initial clear-sky conditions but seemingly struggle to correctly represent the ice-to-liquid mass partitioning associated with the cloudy conditions, which we suggest is responsible for the radiative flux errors. Article in Journal/Newspaper Antarc* Antarctica Ice Shelf Ross Ice Shelf The Cryosphere The Cryosphere Discussions West Antarctica Natural Environment Research Council: NERC Open Research Archive West Antarctica Ross Ice Shelf |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
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ftnerc |
language |
unknown |
description |
The Ross Ice Shelf, West Antarctica, experienced an extensive melt event in January 2016. We examine the representation of this event by the HIRHAM5 and MetUM high-resolution regional atmospheric models, as well as a sophisticated offline coupled firn model forced with their outputs. The model results are compared with satellite-based estimates of melt days. The firn model estimates of the number of melt days are in good agreement with the observations over the eastern and central sectors of the ice shelf, while the HIRHAM5 and MetUM estimates based on their own surface schemes are considerably underestimated, possibly due to deficiencies in these schemes and an absence of spin-up. However, the firn model simulates sustained melting over the western sector of the ice shelf, in disagreement with the observations that show this region as being melt-free. This is attributed to deficiencies in the HIRHAM5 and MetUM output, and particularly a likely overestimation of nighttime net surface radiative flux. This occurs in response to an increase in nighttime downwelling longwave flux from around 180–200 W m-2 to 280 W m-2 over the course of a few days, leading to an excessive amount of energy at the surface available for melt. Satellite-based observations show that this change coincides with a transition from clear-sky conditions to clouds containing both liquid-water and ice-water. The models capture the initial clear-sky conditions but seemingly struggle to correctly represent the ice-to-liquid mass partitioning associated with the cloudy conditions, which we suggest is responsible for the radiative flux errors. |
format |
Article in Journal/Newspaper |
author |
Hansen, Nicolaj Orr, Andrew Zou, Xun Boberg, Fredrik Bracegirdle, Thomas J. Gilbert, Ella Langen, Peter L. Lazzara, Matthew A. Mottram, Ruth Phillips, Tony Price, Ruth Simonsen, Sebastian B. Webster, Stuart |
spellingShingle |
Hansen, Nicolaj Orr, Andrew Zou, Xun Boberg, Fredrik Bracegirdle, Thomas J. Gilbert, Ella Langen, Peter L. Lazzara, Matthew A. Mottram, Ruth Phillips, Tony Price, Ruth Simonsen, Sebastian B. Webster, Stuart The importance of cloud phase when assessing surface melting in an offline coupled firn model over Ross Ice shelf, West Antarctica [in review] |
author_facet |
Hansen, Nicolaj Orr, Andrew Zou, Xun Boberg, Fredrik Bracegirdle, Thomas J. Gilbert, Ella Langen, Peter L. Lazzara, Matthew A. Mottram, Ruth Phillips, Tony Price, Ruth Simonsen, Sebastian B. Webster, Stuart |
author_sort |
Hansen, Nicolaj |
title |
The importance of cloud phase when assessing surface melting in an offline coupled firn model over Ross Ice shelf, West Antarctica [in review] |
title_short |
The importance of cloud phase when assessing surface melting in an offline coupled firn model over Ross Ice shelf, West Antarctica [in review] |
title_full |
The importance of cloud phase when assessing surface melting in an offline coupled firn model over Ross Ice shelf, West Antarctica [in review] |
title_fullStr |
The importance of cloud phase when assessing surface melting in an offline coupled firn model over Ross Ice shelf, West Antarctica [in review] |
title_full_unstemmed |
The importance of cloud phase when assessing surface melting in an offline coupled firn model over Ross Ice shelf, West Antarctica [in review] |
title_sort |
importance of cloud phase when assessing surface melting in an offline coupled firn model over ross ice shelf, west antarctica [in review] |
publisher |
European Geosciences Union |
publishDate |
2023 |
url |
http://nora.nerc.ac.uk/id/eprint/536178/ https://tc.copernicus.org/preprints/tc-2023-145/ |
geographic |
West Antarctica Ross Ice Shelf |
geographic_facet |
West Antarctica Ross Ice Shelf |
genre |
Antarc* Antarctica Ice Shelf Ross Ice Shelf The Cryosphere The Cryosphere Discussions West Antarctica |
genre_facet |
Antarc* Antarctica Ice Shelf Ross Ice Shelf The Cryosphere The Cryosphere Discussions West Antarctica |
op_relation |
Hansen, Nicolaj; Orr, Andrew orcid:0000-0001-5111-8402 Zou, Xun; Boberg, Fredrik; Bracegirdle, Thomas J. orcid:0000-0002-8868-4739 Gilbert, Ella orcid:0000-0001-5272-8894 Langen, Peter L.; Lazzara, Matthew A.; Mottram, Ruth; Phillips, Tony orcid:0000-0002-3058-9157 Price, Ruth; Simonsen, Sebastian B.; Webster, Stuart. 2023 The importance of cloud phase when assessing surface melting in an offline coupled firn model over Ross Ice shelf, West Antarctica [in review]. The Cryosphere: Discussions. https://doi.org/10.5194/tc-2023-145 <https://doi.org/10.5194/tc-2023-145> |
op_doi |
https://doi.org/10.5194/tc-2023-145 |
_version_ |
1784260195232251904 |