Retrieving Soil Moisture in the Permafrost Environment by Sentinel-1/2 Temporal Data on the Qinghai–Tibet Plateau
Soil moisture (SM) products presently available in permafrost regions, especially on the Qinghai–Tibet Plateau (QTP), hardly meet the demands of evaluating and modeling climatic, hydrological, and ecological processes, due to their significant bias and low spatial resolution. This study developed an...
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ftmdpi:oai:mdpi.com:/2072-4292/14/23/5966/ 2023-08-20T03:59:05+02:00 Retrieving Soil Moisture in the Permafrost Environment by Sentinel-1/2 Temporal Data on the Qinghai–Tibet Plateau Zhibin Li Lin Zhao Lingxiao Wang Defu Zou Guangyue Liu Guojie Hu Erji Du Yao Xiao Shibo Liu Huayun Zhou Zanpin Xing Chong Wang Jianting Zhao Yueli Chen Yongping Qiao Jianzong Shi agris 2022-11-25 application/pdf https://doi.org/10.3390/rs14235966 EN eng Multidisciplinary Digital Publishing Institute Atmospheric Remote Sensing https://dx.doi.org/10.3390/rs14235966 https://creativecommons.org/licenses/by/4.0/ Remote Sensing; Volume 14; Issue 23; Pages: 5966 soil moisture SAR retrieval algorithm high spatial resolution permafrost Text 2022 ftmdpi https://doi.org/10.3390/rs14235966 2023-08-01T07:30:25Z Soil moisture (SM) products presently available in permafrost regions, especially on the Qinghai–Tibet Plateau (QTP), hardly meet the demands of evaluating and modeling climatic, hydrological, and ecological processes, due to their significant bias and low spatial resolution. This study developed an algorithm to generate high-spatial-resolution SM during the thawing season using Sentinel-1 (S1) and Sentinel-2 (S2) temporal data in the permafrost environment. This algorithm utilizes the seasonal backscatter differences to reduce the effect of surface roughness and uses the normalized difference vegetation index (NDVI) and the normalized difference moisture index (NDMI) to characterize vegetation contribution. Then, the SM map with a grid spacing of 50 m × 50 m in the hinterland of the QTP with an area of 505 km × 246 km was generated. The results were independently validated based on in situ data from active layer monitoring sites. It shows that this algorithm can retrieve SM well in the study area. The coefficient of determination (R2) and root-mean-square error (RMSE) are 0.82 and 0.06 m3/m3, respectively. This study analyzed the SM distribution of different vegetation types: the alpine swamp meadow had the largest SM of 0.26 m3/m3, followed by the alpine meadow (0.23), alpine steppe (0.2), and alpine desert (0.16), taking the Tuotuo River basin as an example. We also found a significantly negative correlation between the coefficient of variation (CV) and SM in the permafrost area, and the variability of SM is higher in drier environments and lower in wetter environments. The comparison with ERA5-Land, GLDAS, and ESA CCI showed that the proposed method can provide more spatial details and achieve better performance in permafrost areas on QTP. The results also indicated that the developed algorithm has the potential to be applied in the entire permafrost regions on the QTP. Text Active layer monitoring permafrost MDPI Open Access Publishing Remote Sensing 14 23 5966 |
institution |
Open Polar |
collection |
MDPI Open Access Publishing |
op_collection_id |
ftmdpi |
language |
English |
topic |
soil moisture SAR retrieval algorithm high spatial resolution permafrost |
spellingShingle |
soil moisture SAR retrieval algorithm high spatial resolution permafrost Zhibin Li Lin Zhao Lingxiao Wang Defu Zou Guangyue Liu Guojie Hu Erji Du Yao Xiao Shibo Liu Huayun Zhou Zanpin Xing Chong Wang Jianting Zhao Yueli Chen Yongping Qiao Jianzong Shi Retrieving Soil Moisture in the Permafrost Environment by Sentinel-1/2 Temporal Data on the Qinghai–Tibet Plateau |
topic_facet |
soil moisture SAR retrieval algorithm high spatial resolution permafrost |
description |
Soil moisture (SM) products presently available in permafrost regions, especially on the Qinghai–Tibet Plateau (QTP), hardly meet the demands of evaluating and modeling climatic, hydrological, and ecological processes, due to their significant bias and low spatial resolution. This study developed an algorithm to generate high-spatial-resolution SM during the thawing season using Sentinel-1 (S1) and Sentinel-2 (S2) temporal data in the permafrost environment. This algorithm utilizes the seasonal backscatter differences to reduce the effect of surface roughness and uses the normalized difference vegetation index (NDVI) and the normalized difference moisture index (NDMI) to characterize vegetation contribution. Then, the SM map with a grid spacing of 50 m × 50 m in the hinterland of the QTP with an area of 505 km × 246 km was generated. The results were independently validated based on in situ data from active layer monitoring sites. It shows that this algorithm can retrieve SM well in the study area. The coefficient of determination (R2) and root-mean-square error (RMSE) are 0.82 and 0.06 m3/m3, respectively. This study analyzed the SM distribution of different vegetation types: the alpine swamp meadow had the largest SM of 0.26 m3/m3, followed by the alpine meadow (0.23), alpine steppe (0.2), and alpine desert (0.16), taking the Tuotuo River basin as an example. We also found a significantly negative correlation between the coefficient of variation (CV) and SM in the permafrost area, and the variability of SM is higher in drier environments and lower in wetter environments. The comparison with ERA5-Land, GLDAS, and ESA CCI showed that the proposed method can provide more spatial details and achieve better performance in permafrost areas on QTP. The results also indicated that the developed algorithm has the potential to be applied in the entire permafrost regions on the QTP. |
format |
Text |
author |
Zhibin Li Lin Zhao Lingxiao Wang Defu Zou Guangyue Liu Guojie Hu Erji Du Yao Xiao Shibo Liu Huayun Zhou Zanpin Xing Chong Wang Jianting Zhao Yueli Chen Yongping Qiao Jianzong Shi |
author_facet |
Zhibin Li Lin Zhao Lingxiao Wang Defu Zou Guangyue Liu Guojie Hu Erji Du Yao Xiao Shibo Liu Huayun Zhou Zanpin Xing Chong Wang Jianting Zhao Yueli Chen Yongping Qiao Jianzong Shi |
author_sort |
Zhibin Li |
title |
Retrieving Soil Moisture in the Permafrost Environment by Sentinel-1/2 Temporal Data on the Qinghai–Tibet Plateau |
title_short |
Retrieving Soil Moisture in the Permafrost Environment by Sentinel-1/2 Temporal Data on the Qinghai–Tibet Plateau |
title_full |
Retrieving Soil Moisture in the Permafrost Environment by Sentinel-1/2 Temporal Data on the Qinghai–Tibet Plateau |
title_fullStr |
Retrieving Soil Moisture in the Permafrost Environment by Sentinel-1/2 Temporal Data on the Qinghai–Tibet Plateau |
title_full_unstemmed |
Retrieving Soil Moisture in the Permafrost Environment by Sentinel-1/2 Temporal Data on the Qinghai–Tibet Plateau |
title_sort |
retrieving soil moisture in the permafrost environment by sentinel-1/2 temporal data on the qinghai–tibet plateau |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2022 |
url |
https://doi.org/10.3390/rs14235966 |
op_coverage |
agris |
genre |
Active layer monitoring permafrost |
genre_facet |
Active layer monitoring permafrost |
op_source |
Remote Sensing; Volume 14; Issue 23; Pages: 5966 |
op_relation |
Atmospheric Remote Sensing https://dx.doi.org/10.3390/rs14235966 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/rs14235966 |
container_title |
Remote Sensing |
container_volume |
14 |
container_issue |
23 |
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5966 |
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