Dynamics of Freezing/Thawing Indices and Frozen Ground from 1961 to 2010 on the Qinghai-Tibet Plateau
Freezing/thawing indices are important indicators of the dynamics of frozen ground on the Qinghai-Tibet Plateau (QTP), especially in areas with limited observations. Based on the numerical outputs of Community Land Surface Model version 4.5 (CLM4.5) from 1961 to 2010, this study compared the spatial...
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ftmdpi:oai:mdpi.com:/2072-4292/15/14/3478/ 2023-08-20T04:09:11+02:00 Dynamics of Freezing/Thawing Indices and Frozen Ground from 1961 to 2010 on the Qinghai-Tibet Plateau Xuewei Fang Anqi Wang Shihua Lyu Klaus Fraedrich agris 2023-07-10 application/pdf https://doi.org/10.3390/rs15143478 EN eng Multidisciplinary Digital Publishing Institute Atmospheric Remote Sensing https://dx.doi.org/10.3390/rs15143478 https://creativecommons.org/licenses/by/4.0/ Remote Sensing; Volume 15; Issue 14; Pages: 3478 freezing/thawing indices permafrost dynamics Community Land Surface Model Qinghai-Tibet Plateau Text 2023 ftmdpi https://doi.org/10.3390/rs15143478 2023-08-01T10:48:51Z Freezing/thawing indices are important indicators of the dynamics of frozen ground on the Qinghai-Tibet Plateau (QTP), especially in areas with limited observations. Based on the numerical outputs of Community Land Surface Model version 4.5 (CLM4.5) from 1961 to 2010, this study compared the spatial and temporal variations between air freezing/thawing indices (2 m above the ground) and ground surface freezing/thawing indices in permafrost and seasonally frozen ground (SFG) across the QTP after presenting changes in frozen ground distribution in each decade in the context of warming and wetting. The results indicate that an area of 0.60 × 106 km2 of permafrost in the QTP degraded to SFG in the 1960s–2000s, and the primary shrinkage period occurred in the 2000s. The air freezing index (AFI) and ground freezing index (GFI) decreased dramatically at rates of 71.00 °C·d/decade and 34.33 °C·d/decade from 1961 to 2010, respectively. In contrast, the air thawing index (ATI) and ground thawing index (GTI) increased strikingly, with values of 48.13 °C·d/decade and 40.37 °C·d/decade in the past five decades, respectively. Permafrost showed more pronounced changes in freezing/thawing indices since the 1990s compared to SFG. The changes in thermal regimes in frozen ground showed close relations to air warming until the late 1990s, especially in 1998, when the QTP underwent the most progressive warming. However, a sharp increase in the annual precipitation from 1998 began to play a more controlling role in thermal degradation in frozen ground than the air warming in the 2000s. Meanwhile, the following vegetation expansion hiatus further promotes the thermal instability of frozen ground in this highly wet period. Text permafrost MDPI Open Access Publishing Remote Sensing 15 14 3478 |
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MDPI Open Access Publishing |
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ftmdpi |
language |
English |
topic |
freezing/thawing indices permafrost dynamics Community Land Surface Model Qinghai-Tibet Plateau |
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freezing/thawing indices permafrost dynamics Community Land Surface Model Qinghai-Tibet Plateau Xuewei Fang Anqi Wang Shihua Lyu Klaus Fraedrich Dynamics of Freezing/Thawing Indices and Frozen Ground from 1961 to 2010 on the Qinghai-Tibet Plateau |
topic_facet |
freezing/thawing indices permafrost dynamics Community Land Surface Model Qinghai-Tibet Plateau |
description |
Freezing/thawing indices are important indicators of the dynamics of frozen ground on the Qinghai-Tibet Plateau (QTP), especially in areas with limited observations. Based on the numerical outputs of Community Land Surface Model version 4.5 (CLM4.5) from 1961 to 2010, this study compared the spatial and temporal variations between air freezing/thawing indices (2 m above the ground) and ground surface freezing/thawing indices in permafrost and seasonally frozen ground (SFG) across the QTP after presenting changes in frozen ground distribution in each decade in the context of warming and wetting. The results indicate that an area of 0.60 × 106 km2 of permafrost in the QTP degraded to SFG in the 1960s–2000s, and the primary shrinkage period occurred in the 2000s. The air freezing index (AFI) and ground freezing index (GFI) decreased dramatically at rates of 71.00 °C·d/decade and 34.33 °C·d/decade from 1961 to 2010, respectively. In contrast, the air thawing index (ATI) and ground thawing index (GTI) increased strikingly, with values of 48.13 °C·d/decade and 40.37 °C·d/decade in the past five decades, respectively. Permafrost showed more pronounced changes in freezing/thawing indices since the 1990s compared to SFG. The changes in thermal regimes in frozen ground showed close relations to air warming until the late 1990s, especially in 1998, when the QTP underwent the most progressive warming. However, a sharp increase in the annual precipitation from 1998 began to play a more controlling role in thermal degradation in frozen ground than the air warming in the 2000s. Meanwhile, the following vegetation expansion hiatus further promotes the thermal instability of frozen ground in this highly wet period. |
format |
Text |
author |
Xuewei Fang Anqi Wang Shihua Lyu Klaus Fraedrich |
author_facet |
Xuewei Fang Anqi Wang Shihua Lyu Klaus Fraedrich |
author_sort |
Xuewei Fang |
title |
Dynamics of Freezing/Thawing Indices and Frozen Ground from 1961 to 2010 on the Qinghai-Tibet Plateau |
title_short |
Dynamics of Freezing/Thawing Indices and Frozen Ground from 1961 to 2010 on the Qinghai-Tibet Plateau |
title_full |
Dynamics of Freezing/Thawing Indices and Frozen Ground from 1961 to 2010 on the Qinghai-Tibet Plateau |
title_fullStr |
Dynamics of Freezing/Thawing Indices and Frozen Ground from 1961 to 2010 on the Qinghai-Tibet Plateau |
title_full_unstemmed |
Dynamics of Freezing/Thawing Indices and Frozen Ground from 1961 to 2010 on the Qinghai-Tibet Plateau |
title_sort |
dynamics of freezing/thawing indices and frozen ground from 1961 to 2010 on the qinghai-tibet plateau |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2023 |
url |
https://doi.org/10.3390/rs15143478 |
op_coverage |
agris |
genre |
permafrost |
genre_facet |
permafrost |
op_source |
Remote Sensing; Volume 15; Issue 14; Pages: 3478 |
op_relation |
Atmospheric Remote Sensing https://dx.doi.org/10.3390/rs15143478 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/rs15143478 |
container_title |
Remote Sensing |
container_volume |
15 |
container_issue |
14 |
container_start_page |
3478 |
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1774721984272269312 |