Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution
The Topographic Wetness Index (TWI) is a commonly used proxy for soil moisture. The predictive capability of TWI is influenced by the flow-routing algorithm and the resolution of the Digital Elevation Model (DEM) that TWI is derived from. Here, we examine the predictive capability of TWI using 11 fl...
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American Geophysical Union
2022
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ftunivhelsihelda:oai:helda.helsinki.fi:10138/351631 2024-01-07T09:40:47+01:00 Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution Riihimaki, H. Kemppinen, J. Kopecky, M. Luoto, M. BioGeoClimate Modelling Lab Department of Geosciences and Geography Doctoral Programme in Geosciences Helsinki Institute of Sustainability Science (HELSUS) 2022-12-13T10:11:04Z 21 application/pdf http://hdl.handle.net/10138/351631 eng eng American Geophysical Union 10.1029/2021WR029871 The authors thank Annina Niskanen, Panu Lammi, Akseli Toikka, Aino-Maija Maattanen and Pekka Niittynen for their contribution to the field data and the staff at the Kilpisjarvi Biological research station for their support. They also acknowledge the National Land Survey of Finland for the LiDAR data and Jacquelin DeFaveri for proof-reading the manuscript. H. Riihimaki and J. Kemppinen were funded by the Doctoral Programme in Geosciences at the University of Helsinki. J. Kemppinen was also funded by the Arctic Interactions at the University of Oulu and Academy of Finland (project 318930, Profi 4). M. Kopecky was funded by the Czech Academy of Sciences (project RVO 67985939). The field research was funded by the Academy of Finland (project 286950). Permission to carry out fieldwork was granted by Metsahallitus. Riihimaki , H , Kemppinen , J , Kopecky , M & Luoto , M 2021 , ' Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution ' , Water Resources Research , vol. 57 , no. 10 , ARTN e2021WR029871 . https://doi.org/10.1029/2021WR029871 ORCID: /0000-0001-7521-7229/work/103098359 ORCID: /0000-0001-6203-5143/work/108863588 08b9425e-07ea-439f-92d6-dcec3a8e5572 http://hdl.handle.net/10138/351631 000711970600030 unspecified openAccess info:eu-repo/semantics/openAccess 1172 Environmental sciences Article publishedVersion 2022 ftunivhelsihelda 2023-12-14T00:02:05Z The Topographic Wetness Index (TWI) is a commonly used proxy for soil moisture. The predictive capability of TWI is influenced by the flow-routing algorithm and the resolution of the Digital Elevation Model (DEM) that TWI is derived from. Here, we examine the predictive capability of TWI using 11 flow-routing algorithms at DEM resolutions 1-30 m. We analyze the relationship between TWI and field-quantified soil moisture using statistical modeling methods and 5,200 study plots with over 46 000 soil moisture measurements. In addition, we test the sensitivity of the flow-routing algorithms against vertical height errors in DEM at different resolutions. The results reveal that the overall predictive capability of TWI was modest. The highest r(2) (23.7%) was reached using a multiple-flow-direction algorithm at 2 m resolution. In addition, the test of sensitivity against height errors revealed that the multiple-flow-direction algorithms were also more robust against DEM errors than single-flow-direction algorithms. The results provide field-evidence indicating that at its best TWI is a modest proxy for soil moisture and its predictive capability is influenced by the flow-routing algorithm and DEM resolution. Thus, we encourage careful evaluation of algorithms and resolutions when using TWI as a proxy for soil moisture. Peer reviewed Article in Journal/Newspaper Arctic HELDA – University of Helsinki Open Repository |
institution |
Open Polar |
collection |
HELDA – University of Helsinki Open Repository |
op_collection_id |
ftunivhelsihelda |
language |
English |
topic |
1172 Environmental sciences |
spellingShingle |
1172 Environmental sciences Riihimaki, H. Kemppinen, J. Kopecky, M. Luoto, M. Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution |
topic_facet |
1172 Environmental sciences |
description |
The Topographic Wetness Index (TWI) is a commonly used proxy for soil moisture. The predictive capability of TWI is influenced by the flow-routing algorithm and the resolution of the Digital Elevation Model (DEM) that TWI is derived from. Here, we examine the predictive capability of TWI using 11 flow-routing algorithms at DEM resolutions 1-30 m. We analyze the relationship between TWI and field-quantified soil moisture using statistical modeling methods and 5,200 study plots with over 46 000 soil moisture measurements. In addition, we test the sensitivity of the flow-routing algorithms against vertical height errors in DEM at different resolutions. The results reveal that the overall predictive capability of TWI was modest. The highest r(2) (23.7%) was reached using a multiple-flow-direction algorithm at 2 m resolution. In addition, the test of sensitivity against height errors revealed that the multiple-flow-direction algorithms were also more robust against DEM errors than single-flow-direction algorithms. The results provide field-evidence indicating that at its best TWI is a modest proxy for soil moisture and its predictive capability is influenced by the flow-routing algorithm and DEM resolution. Thus, we encourage careful evaluation of algorithms and resolutions when using TWI as a proxy for soil moisture. Peer reviewed |
author2 |
BioGeoClimate Modelling Lab Department of Geosciences and Geography Doctoral Programme in Geosciences Helsinki Institute of Sustainability Science (HELSUS) |
format |
Article in Journal/Newspaper |
author |
Riihimaki, H. Kemppinen, J. Kopecky, M. Luoto, M. |
author_facet |
Riihimaki, H. Kemppinen, J. Kopecky, M. Luoto, M. |
author_sort |
Riihimaki, H. |
title |
Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution |
title_short |
Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution |
title_full |
Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution |
title_fullStr |
Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution |
title_full_unstemmed |
Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution |
title_sort |
topographic wetness index as a proxy for soil moisture : the importance of flow-routing algorithm and grid resolution |
publisher |
American Geophysical Union |
publishDate |
2022 |
url |
http://hdl.handle.net/10138/351631 |
genre |
Arctic |
genre_facet |
Arctic |
op_relation |
10.1029/2021WR029871 The authors thank Annina Niskanen, Panu Lammi, Akseli Toikka, Aino-Maija Maattanen and Pekka Niittynen for their contribution to the field data and the staff at the Kilpisjarvi Biological research station for their support. They also acknowledge the National Land Survey of Finland for the LiDAR data and Jacquelin DeFaveri for proof-reading the manuscript. H. Riihimaki and J. Kemppinen were funded by the Doctoral Programme in Geosciences at the University of Helsinki. J. Kemppinen was also funded by the Arctic Interactions at the University of Oulu and Academy of Finland (project 318930, Profi 4). M. Kopecky was funded by the Czech Academy of Sciences (project RVO 67985939). The field research was funded by the Academy of Finland (project 286950). Permission to carry out fieldwork was granted by Metsahallitus. Riihimaki , H , Kemppinen , J , Kopecky , M & Luoto , M 2021 , ' Topographic Wetness Index as a Proxy for Soil Moisture : The Importance of Flow-Routing Algorithm and Grid Resolution ' , Water Resources Research , vol. 57 , no. 10 , ARTN e2021WR029871 . https://doi.org/10.1029/2021WR029871 ORCID: /0000-0001-7521-7229/work/103098359 ORCID: /0000-0001-6203-5143/work/108863588 08b9425e-07ea-439f-92d6-dcec3a8e5572 http://hdl.handle.net/10138/351631 000711970600030 |
op_rights |
unspecified openAccess info:eu-repo/semantics/openAccess |
_version_ |
1787421578381754368 |