Convective heat transfer of spring meltwater accelerates active layer phase change in Tibet permafrost areas
Convective heat transfer (CHT) is one of the important processes that control the near-ground surface heat transfer in permafrost areas. However, this process has often not been considered in most permafrost studies, and its influence on freezing–thawing processes in the active layer lacks quantitat...
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ftdoajarticles:oai:doaj.org/article:e62d4d4b2bd0419f9bdf4b51b4587a40 2023-05-15T13:02:51+02:00 Convective heat transfer of spring meltwater accelerates active layer phase change in Tibet permafrost areas Y. Zhao Z. Nan H. Ji L. Zhao 2022-03-01T00:00:00Z https://doi.org/10.5194/tc-16-825-2022 https://doaj.org/article/e62d4d4b2bd0419f9bdf4b51b4587a40 EN eng Copernicus Publications https://tc.copernicus.org/articles/16/825/2022/tc-16-825-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-825-2022 1994-0416 1994-0424 https://doaj.org/article/e62d4d4b2bd0419f9bdf4b51b4587a40 The Cryosphere, Vol 16, Pp 825-849 (2022) Environmental sciences GE1-350 Geology QE1-996.5 article 2022 ftdoajarticles https://doi.org/10.5194/tc-16-825-2022 2022-12-31T01:40:24Z Convective heat transfer (CHT) is one of the important processes that control the near-ground surface heat transfer in permafrost areas. However, this process has often not been considered in most permafrost studies, and its influence on freezing–thawing processes in the active layer lacks quantitative investigation. The Simultaneous Heat and Water (SHAW) model, one of the few land surface models in which the CHT process is well incorporated into the soil heat–mass transport processes, was applied in this study to investigate the impacts of CHT on the thermal dynamics of the active layer at the Tanggula station, a typical permafrost site on the eastern Qinghai–Tibet Plateau with abundant meteorological and soil temperature and soil moisture observation data. A control experiment was carried out to quantify the changes in active layer temperature affected by vertical advection of liquid water. Three experimental setups were used: (1) the original SHAW model with full consideration of CHT, (2) a modified SHAW model that ignores CHT due to infiltration from the surface, and (3) a modified SHAW model that completely ignores CHT processes in the system. The results show that the CHT events occurred mainly during thaw periods in melted shallow (0–0.2 m) and intermediate (0.4–1.3 m) soil depths, and their impacts on soil temperature at shallow depths were significantly greater during spring melting periods than summer. The impact was minimal during freeze periods and in deep soil layers. During thaw periods, temperatures at the shallow and intermediate soil depths simulated under the scenario considering CHT were on average about 0.9 and 0.4 ∘ C higher, respectively, than under the scenarios ignoring CHT. The ending dates of the zero-curtain effect were substantially advanced when CHT was considered due to its heating effect. However, the opposite cooling effect was also present but not as frequently as heating due to upward liquid fluxes and thermal differences between soil layers. In some periods, the advection flow ... Article in Journal/Newspaper Active layer temperature permafrost The Cryosphere Directory of Open Access Journals: DOAJ Articles The Cryosphere 16 3 825 849 |
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Directory of Open Access Journals: DOAJ Articles |
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English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
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Environmental sciences GE1-350 Geology QE1-996.5 Y. Zhao Z. Nan H. Ji L. Zhao Convective heat transfer of spring meltwater accelerates active layer phase change in Tibet permafrost areas |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
description |
Convective heat transfer (CHT) is one of the important processes that control the near-ground surface heat transfer in permafrost areas. However, this process has often not been considered in most permafrost studies, and its influence on freezing–thawing processes in the active layer lacks quantitative investigation. The Simultaneous Heat and Water (SHAW) model, one of the few land surface models in which the CHT process is well incorporated into the soil heat–mass transport processes, was applied in this study to investigate the impacts of CHT on the thermal dynamics of the active layer at the Tanggula station, a typical permafrost site on the eastern Qinghai–Tibet Plateau with abundant meteorological and soil temperature and soil moisture observation data. A control experiment was carried out to quantify the changes in active layer temperature affected by vertical advection of liquid water. Three experimental setups were used: (1) the original SHAW model with full consideration of CHT, (2) a modified SHAW model that ignores CHT due to infiltration from the surface, and (3) a modified SHAW model that completely ignores CHT processes in the system. The results show that the CHT events occurred mainly during thaw periods in melted shallow (0–0.2 m) and intermediate (0.4–1.3 m) soil depths, and their impacts on soil temperature at shallow depths were significantly greater during spring melting periods than summer. The impact was minimal during freeze periods and in deep soil layers. During thaw periods, temperatures at the shallow and intermediate soil depths simulated under the scenario considering CHT were on average about 0.9 and 0.4 ∘ C higher, respectively, than under the scenarios ignoring CHT. The ending dates of the zero-curtain effect were substantially advanced when CHT was considered due to its heating effect. However, the opposite cooling effect was also present but not as frequently as heating due to upward liquid fluxes and thermal differences between soil layers. In some periods, the advection flow ... |
format |
Article in Journal/Newspaper |
author |
Y. Zhao Z. Nan H. Ji L. Zhao |
author_facet |
Y. Zhao Z. Nan H. Ji L. Zhao |
author_sort |
Y. Zhao |
title |
Convective heat transfer of spring meltwater accelerates active layer phase change in Tibet permafrost areas |
title_short |
Convective heat transfer of spring meltwater accelerates active layer phase change in Tibet permafrost areas |
title_full |
Convective heat transfer of spring meltwater accelerates active layer phase change in Tibet permafrost areas |
title_fullStr |
Convective heat transfer of spring meltwater accelerates active layer phase change in Tibet permafrost areas |
title_full_unstemmed |
Convective heat transfer of spring meltwater accelerates active layer phase change in Tibet permafrost areas |
title_sort |
convective heat transfer of spring meltwater accelerates active layer phase change in tibet permafrost areas |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/tc-16-825-2022 https://doaj.org/article/e62d4d4b2bd0419f9bdf4b51b4587a40 |
genre |
Active layer temperature permafrost The Cryosphere |
genre_facet |
Active layer temperature permafrost The Cryosphere |
op_source |
The Cryosphere, Vol 16, Pp 825-849 (2022) |
op_relation |
https://tc.copernicus.org/articles/16/825/2022/tc-16-825-2022.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 doi:10.5194/tc-16-825-2022 1994-0416 1994-0424 https://doaj.org/article/e62d4d4b2bd0419f9bdf4b51b4587a40 |
op_doi |
https://doi.org/10.5194/tc-16-825-2022 |
container_title |
The Cryosphere |
container_volume |
16 |
container_issue |
3 |
container_start_page |
825 |
op_container_end_page |
849 |
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