Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography)
Microtopography can be a key driver of heterogeneity in the ground thermal and hydrological regime of permafrost landscapes. In turn, this heterogeneity can influence plant communities, methane fluxes, and the initiation of abrupt thaw processes. Here we have implemented a two-tile representation of...
Published in: | Geoscientific Model Development |
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Online Access: | http://nora.nerc.ac.uk/id/eprint/532934/ https://nora.nerc.ac.uk/id/eprint/532934/1/N532934JA.pdf https://doi.org/10.5194/gmd-15-3603-2022 |
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ftnerc:oai:nora.nerc.ac.uk:532934 2023-05-15T17:54:26+02:00 Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography) Smith, Noah D. Burke, Eleanor J. Schanke Aas, Kjetil Althuizen, Inge H.J. Boike, Julia Christiansen, Casper Tai Etzelmüller, Bernd Friborg, Thomas Lee, Hanna Rumbold, Heather Turton, Rachael H. Westermann, Sebastian Chadburn, Sarah E. 2022-05-06 text http://nora.nerc.ac.uk/id/eprint/532934/ https://nora.nerc.ac.uk/id/eprint/532934/1/N532934JA.pdf https://doi.org/10.5194/gmd-15-3603-2022 en eng EGU https://nora.nerc.ac.uk/id/eprint/532934/1/N532934JA.pdf Smith, Noah D.; Burke, Eleanor J.; Schanke Aas, Kjetil; Althuizen, Inge H.J.; Boike, Julia; Christiansen, Casper Tai; Etzelmüller, Bernd; Friborg, Thomas; Lee, Hanna; Rumbold, Heather; Turton, Rachael H.; Westermann, Sebastian; Chadburn, Sarah E. 2022 Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography). Geoscientific Model Development, 15 (9). 3603-3639. https://doi.org/10.5194/gmd-15-3603-2022 <https://doi.org/10.5194/gmd-15-3603-2022> cc_by_4 CC-BY Earth Sciences Publication - Article PeerReviewed 2022 ftnerc https://doi.org/10.5194/gmd-15-3603-2022 2023-02-04T19:53:25Z Microtopography can be a key driver of heterogeneity in the ground thermal and hydrological regime of permafrost landscapes. In turn, this heterogeneity can influence plant communities, methane fluxes, and the initiation of abrupt thaw processes. Here we have implemented a two-tile representation of microtopography in JULES (the Joint UK Land Environment Simulator), where tiles are representative of repeating patterns of elevation difference. Tiles are coupled by lateral flows of water, heat, and redistribution of snow, and a surface water store is added to represent ponding. Simulations are performed of two Siberian polygon sites, (Samoylov and Kytalyk) and two Scandinavian palsa sites (Stordalen and Iškoras). The model represents the observed differences between greater snow depth in hollows vs. raised areas well. The model also improves soil moisture for hollows vs. the non-tiled configuration (“standard JULES”) though the raised tile remains drier than observed. The modelled differences in snow depths and soil moisture between tiles result in the lower tile soil temperatures being warmer for palsa sites, as in reality. However, when comparing the soil temperatures for July at 20 cm depth, the difference in temperature between tiles, or “temperature splitting”, is smaller than observed (3.2 vs. 5.5 ∘C). Polygons display small (0.2 ∘C) to zero temperature splitting, in agreement with observations. Consequently, methane fluxes are near identical (+0 % to 9 %) to those for standard JULES for polygons, although they can be greater than standard JULES for palsa sites (+10 % to 49 %). Through a sensitivity analysis we quantify the relative importance of model processes with respect to soil moisture and temperatures, identifying which parameters result in the greatest uncertainty in modelled temperature. Varying the palsa elevation between 0.5 and 3 m has little effect on modelled soil temperatures, showing that using only two tiles can still be a valid representation of sites with a range of palsa elevations. Mire ... Article in Journal/Newspaper palsa permafrost Natural Environment Research Council: NERC Open Research Archive Jules ENVELOPE(140.917,140.917,-66.742,-66.742) Stordalen ENVELOPE(7.337,7.337,62.510,62.510) Iškoras ENVELOPE(25.369,25.369,69.297,69.297) Geoscientific Model Development 15 9 3603 3639 |
institution |
Open Polar |
collection |
Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
English |
topic |
Earth Sciences |
spellingShingle |
Earth Sciences Smith, Noah D. Burke, Eleanor J. Schanke Aas, Kjetil Althuizen, Inge H.J. Boike, Julia Christiansen, Casper Tai Etzelmüller, Bernd Friborg, Thomas Lee, Hanna Rumbold, Heather Turton, Rachael H. Westermann, Sebastian Chadburn, Sarah E. Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography) |
topic_facet |
Earth Sciences |
description |
Microtopography can be a key driver of heterogeneity in the ground thermal and hydrological regime of permafrost landscapes. In turn, this heterogeneity can influence plant communities, methane fluxes, and the initiation of abrupt thaw processes. Here we have implemented a two-tile representation of microtopography in JULES (the Joint UK Land Environment Simulator), where tiles are representative of repeating patterns of elevation difference. Tiles are coupled by lateral flows of water, heat, and redistribution of snow, and a surface water store is added to represent ponding. Simulations are performed of two Siberian polygon sites, (Samoylov and Kytalyk) and two Scandinavian palsa sites (Stordalen and Iškoras). The model represents the observed differences between greater snow depth in hollows vs. raised areas well. The model also improves soil moisture for hollows vs. the non-tiled configuration (“standard JULES”) though the raised tile remains drier than observed. The modelled differences in snow depths and soil moisture between tiles result in the lower tile soil temperatures being warmer for palsa sites, as in reality. However, when comparing the soil temperatures for July at 20 cm depth, the difference in temperature between tiles, or “temperature splitting”, is smaller than observed (3.2 vs. 5.5 ∘C). Polygons display small (0.2 ∘C) to zero temperature splitting, in agreement with observations. Consequently, methane fluxes are near identical (+0 % to 9 %) to those for standard JULES for polygons, although they can be greater than standard JULES for palsa sites (+10 % to 49 %). Through a sensitivity analysis we quantify the relative importance of model processes with respect to soil moisture and temperatures, identifying which parameters result in the greatest uncertainty in modelled temperature. Varying the palsa elevation between 0.5 and 3 m has little effect on modelled soil temperatures, showing that using only two tiles can still be a valid representation of sites with a range of palsa elevations. Mire ... |
format |
Article in Journal/Newspaper |
author |
Smith, Noah D. Burke, Eleanor J. Schanke Aas, Kjetil Althuizen, Inge H.J. Boike, Julia Christiansen, Casper Tai Etzelmüller, Bernd Friborg, Thomas Lee, Hanna Rumbold, Heather Turton, Rachael H. Westermann, Sebastian Chadburn, Sarah E. |
author_facet |
Smith, Noah D. Burke, Eleanor J. Schanke Aas, Kjetil Althuizen, Inge H.J. Boike, Julia Christiansen, Casper Tai Etzelmüller, Bernd Friborg, Thomas Lee, Hanna Rumbold, Heather Turton, Rachael H. Westermann, Sebastian Chadburn, Sarah E. |
author_sort |
Smith, Noah D. |
title |
Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography) |
title_short |
Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography) |
title_full |
Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography) |
title_fullStr |
Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography) |
title_full_unstemmed |
Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography) |
title_sort |
explicitly modelling microtopography in permafrost landscapes in a land surface model (jules vn5.4_microtopography) |
publisher |
EGU |
publishDate |
2022 |
url |
http://nora.nerc.ac.uk/id/eprint/532934/ https://nora.nerc.ac.uk/id/eprint/532934/1/N532934JA.pdf https://doi.org/10.5194/gmd-15-3603-2022 |
long_lat |
ENVELOPE(140.917,140.917,-66.742,-66.742) ENVELOPE(7.337,7.337,62.510,62.510) ENVELOPE(25.369,25.369,69.297,69.297) |
geographic |
Jules Stordalen Iškoras |
geographic_facet |
Jules Stordalen Iškoras |
genre |
palsa permafrost |
genre_facet |
palsa permafrost |
op_relation |
https://nora.nerc.ac.uk/id/eprint/532934/1/N532934JA.pdf Smith, Noah D.; Burke, Eleanor J.; Schanke Aas, Kjetil; Althuizen, Inge H.J.; Boike, Julia; Christiansen, Casper Tai; Etzelmüller, Bernd; Friborg, Thomas; Lee, Hanna; Rumbold, Heather; Turton, Rachael H.; Westermann, Sebastian; Chadburn, Sarah E. 2022 Explicitly modelling microtopography in permafrost landscapes in a land surface model (JULES vn5.4_microtopography). Geoscientific Model Development, 15 (9). 3603-3639. https://doi.org/10.5194/gmd-15-3603-2022 <https://doi.org/10.5194/gmd-15-3603-2022> |
op_rights |
cc_by_4 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/gmd-15-3603-2022 |
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Geoscientific Model Development |
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15 |
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9 |
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3603 |
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3639 |
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