Evaluation of aMetOp ASCAT-Derived Surface Soil Moisture Product in Tundra Environments
Satellite-derived surface soil moisture data are available for the Arctic, but detailed validation is still lacking. Previous studies have shown low correlations between in situ and modeled data. It is hypothesized that soil temperature variations after soil thaw impact MetOp ASCAT satellite-derived...
Published in: | Journal of Geophysical Research: Earth Surface |
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Online Access: | https://doi.org/10.1029/2018JF004658 |
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ftzenodo:oai:zenodo.org:2636627 2024-09-15T17:58:16+00:00 Evaluation of aMetOp ASCAT-Derived Surface Soil Moisture Product in Tundra Environments Högström, Elin Heim, Birgit Bartsch, Annett Bergstedt, Helena Pointner, Georg 2018-11-12 https://doi.org/10.1029/2018JF004658 eng eng Zenodo https://zenodo.org/communities/nunataryuk https://zenodo.org/communities/eu https://doi.org/10.1029/2018JF004658 oai:zenodo.org:2636627 info:eu-repo/semantics/openAccess Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode Journal of Geophysical Research: Earth Surface, (2018-11-12) info:eu-repo/semantics/article 2018 ftzenodo https://doi.org/10.1029/2018JF004658 2024-07-26T03:46:02Z Satellite-derived surface soil moisture data are available for the Arctic, but detailed validation is still lacking. Previous studies have shown low correlations between in situ and modeled data. It is hypothesized that soil temperature variations after soil thaw impact MetOp ASCAT satellite-derived surface soil moisture (SSM) measurements in wet tundra environments, as C band backscatter is sensitive to changes in dielectric properties. We compare in situ measurements of water content within the active layer at four sites across the Arctic in Alaska (Barrow, Sagwon, Toolik) and Siberia (Tiksi), taken in the spring after thawing and in autumn prior to freezing. In addition to the long-term measurement fields, where sensors are installed deeper in the ground, we designed a monitoring setup for measuring moisture very close to the surface in the Lena River Delta, Siberia. The volumetric water content (VWC) and soil temperature sensors were placed in the moss organic layer in order to account for the limited penetration depth of the radar signal. ASCAT SSM variations are generally very small, in line with the low variability of in situ VWC. Short-term changes after complete thawing of the upper organic layer, however, seem to be mostly influenced by soil temperature. Correlations between SSM and in situ VWC are generally very low, or even negative. Mean standard deviation matching results in a comparably high root-mean-square error (on average 11%) for predictions of VWC. Further investigations and measurement networks are needed to clarify factors causing temporal variation of C band backscatter in tundra regions. Article in Journal/Newspaper Barrow lena river Tiksi Tundra Alaska Siberia Zenodo Journal of Geophysical Research: Earth Surface 123 12 3190 3205 |
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language |
English |
description |
Satellite-derived surface soil moisture data are available for the Arctic, but detailed validation is still lacking. Previous studies have shown low correlations between in situ and modeled data. It is hypothesized that soil temperature variations after soil thaw impact MetOp ASCAT satellite-derived surface soil moisture (SSM) measurements in wet tundra environments, as C band backscatter is sensitive to changes in dielectric properties. We compare in situ measurements of water content within the active layer at four sites across the Arctic in Alaska (Barrow, Sagwon, Toolik) and Siberia (Tiksi), taken in the spring after thawing and in autumn prior to freezing. In addition to the long-term measurement fields, where sensors are installed deeper in the ground, we designed a monitoring setup for measuring moisture very close to the surface in the Lena River Delta, Siberia. The volumetric water content (VWC) and soil temperature sensors were placed in the moss organic layer in order to account for the limited penetration depth of the radar signal. ASCAT SSM variations are generally very small, in line with the low variability of in situ VWC. Short-term changes after complete thawing of the upper organic layer, however, seem to be mostly influenced by soil temperature. Correlations between SSM and in situ VWC are generally very low, or even negative. Mean standard deviation matching results in a comparably high root-mean-square error (on average 11%) for predictions of VWC. Further investigations and measurement networks are needed to clarify factors causing temporal variation of C band backscatter in tundra regions. |
format |
Article in Journal/Newspaper |
author |
Högström, Elin Heim, Birgit Bartsch, Annett Bergstedt, Helena Pointner, Georg |
spellingShingle |
Högström, Elin Heim, Birgit Bartsch, Annett Bergstedt, Helena Pointner, Georg Evaluation of aMetOp ASCAT-Derived Surface Soil Moisture Product in Tundra Environments |
author_facet |
Högström, Elin Heim, Birgit Bartsch, Annett Bergstedt, Helena Pointner, Georg |
author_sort |
Högström, Elin |
title |
Evaluation of aMetOp ASCAT-Derived Surface Soil Moisture Product in Tundra Environments |
title_short |
Evaluation of aMetOp ASCAT-Derived Surface Soil Moisture Product in Tundra Environments |
title_full |
Evaluation of aMetOp ASCAT-Derived Surface Soil Moisture Product in Tundra Environments |
title_fullStr |
Evaluation of aMetOp ASCAT-Derived Surface Soil Moisture Product in Tundra Environments |
title_full_unstemmed |
Evaluation of aMetOp ASCAT-Derived Surface Soil Moisture Product in Tundra Environments |
title_sort |
evaluation of ametop ascat-derived surface soil moisture product in tundra environments |
publisher |
Zenodo |
publishDate |
2018 |
url |
https://doi.org/10.1029/2018JF004658 |
genre |
Barrow lena river Tiksi Tundra Alaska Siberia |
genre_facet |
Barrow lena river Tiksi Tundra Alaska Siberia |
op_source |
Journal of Geophysical Research: Earth Surface, (2018-11-12) |
op_relation |
https://zenodo.org/communities/nunataryuk https://zenodo.org/communities/eu https://doi.org/10.1029/2018JF004658 oai:zenodo.org:2636627 |
op_rights |
info:eu-repo/semantics/openAccess Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode |
op_doi |
https://doi.org/10.1029/2018JF004658 |
container_title |
Journal of Geophysical Research: Earth Surface |
container_volume |
123 |
container_issue |
12 |
container_start_page |
3190 |
op_container_end_page |
3205 |
_version_ |
1810434667847876608 |