Local-scale heterogeneity of soil thermal dynamics and controlling factors in a discontinuous permafrost region
In permafrost regions, the strong spatial and temporal variability in soil temperature cannot be explained by the weather forcing only. Understanding the local heterogeneity of soil thermal dynamics and their controls is essential to understand how permafrost systems respond to climate change and to...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | Environmental Research Letters |
| Subjects: | |
| Online Access: | https://doi.org/10.1088/1748-9326/ad27bb |
| _version_ | 1827340658160959488 |
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| author | Chen Wang Ian Shirley Stijn Wielandt John Lamb Sebastian Uhlemann Amy Breen Robert C Busey W Robert Bolton Susan Hubbard Baptiste Dafflon |
| author_facet | Chen Wang Ian Shirley Stijn Wielandt John Lamb Sebastian Uhlemann Amy Breen Robert C Busey W Robert Bolton Susan Hubbard Baptiste Dafflon |
| author_sort | Chen Wang |
| collection | DOAJ |
| description | In permafrost regions, the strong spatial and temporal variability in soil temperature cannot be explained by the weather forcing only. Understanding the local heterogeneity of soil thermal dynamics and their controls is essential to understand how permafrost systems respond to climate change and to develop process-based models or remote sensing products for predicting soil temperature. In this study, we analyzed soil temperature dynamics and their controls in a discontinuous permafrost region on the Seward Peninsula, Alaska. We acquired one-year temperature time series at multiple depths (at 5 or 10 cm intervals up to 85 cm depth) at 45 discrete locations across a 2.3 km ^2 watershed. We observed a larger spatial variability in winter temperatures than that in summer temperatures at all depths, with the former controlling most of the spatial variability in mean annual temperatures. We also observed a strong correlation between mean annual ground temperature at a depth of 85 cm and mean annual or winter season ground surface temperature across the 45 locations. We demonstrate that soils classified as cold, intermediate, or warm using hierarchical clustering of full-year temperature data closely match their co-located vegetation (graminoid tundra, dwarf shrub tundra, and tall shrub tundra, respectively). We show that the spatial heterogeneity in soil temperature is primarily driven by spatial heterogeneity in snow cover, which induces variable winter insulation and soil thermal diffusivity. These effects further extend to the subsequent summer by causing variable latent heat exchanges. Finally, we discuss the challenges of predicting soil temperatures from snow depth and vegetation height alone by considering the complexity observed in the field data and reproduced in a model sensitivity analysis. |
| first_indexed | 2024-03-07T21:23:44Z |
| format | Article |
| id | doaj.art-3decea7f28e74d8da577344645d5cf4a |
| institution | Directory Open Access Journal |
| issn | 1748-9326 |
| language | English |
| last_indexed | 2024-03-07T21:23:44Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Environmental Research Letters |
| spelling | doaj.art-3decea7f28e74d8da577344645d5cf4a2024-02-27T07:27:34ZengIOP PublishingEnvironmental Research Letters1748-93262024-01-0119303403010.1088/1748-9326/ad27bbLocal-scale heterogeneity of soil thermal dynamics and controlling factors in a discontinuous permafrost regionChen Wang0https://orcid.org/0000-0001-9508-7425Ian Shirley1https://orcid.org/0000-0002-2229-1414Stijn Wielandt2https://orcid.org/0000-0002-2672-2998John Lamb3Sebastian Uhlemann4https://orcid.org/0000-0002-7673-7346Amy Breen5https://orcid.org/0000-0002-1109-3906Robert C Busey6https://orcid.org/0000-0001-9538-1122W Robert Bolton7https://orcid.org/0000-0002-4282-242XSusan Hubbard8https://orcid.org/0000-0003-2966-5631Baptiste Dafflon9https://orcid.org/0000-0001-9871-5650Lawrence Berkeley National Laboratory , Berkeley, CA, United States of AmericaLawrence Berkeley National Laboratory , Berkeley, CA, United States of AmericaLawrence Berkeley National Laboratory , Berkeley, CA, United States of AmericaLawrence Berkeley National Laboratory , Berkeley, CA, United States of America; Department of Earth System Science, Stanford University , Stanford, CA, United States of AmericaLawrence Berkeley National Laboratory , Berkeley, CA, United States of AmericaInternational Arctic Research Center, University of Alaska , Fairbanks, AK, United States of AmericaInternational Arctic Research Center, University of Alaska , Fairbanks, AK, United States of AmericaInternational Arctic Research Center, University of Alaska , Fairbanks, AK, United States of America; Oak Ridge National Laboratory , Oak Ridge, TN, United States of AmericaLawrence Berkeley National Laboratory , Berkeley, CA, United States of America; Oak Ridge National Laboratory , Oak Ridge, TN, United States of AmericaLawrence Berkeley National Laboratory , Berkeley, CA, United States of AmericaIn permafrost regions, the strong spatial and temporal variability in soil temperature cannot be explained by the weather forcing only. Understanding the local heterogeneity of soil thermal dynamics and their controls is essential to understand how permafrost systems respond to climate change and to develop process-based models or remote sensing products for predicting soil temperature. In this study, we analyzed soil temperature dynamics and their controls in a discontinuous permafrost region on the Seward Peninsula, Alaska. We acquired one-year temperature time series at multiple depths (at 5 or 10 cm intervals up to 85 cm depth) at 45 discrete locations across a 2.3 km ^2 watershed. We observed a larger spatial variability in winter temperatures than that in summer temperatures at all depths, with the former controlling most of the spatial variability in mean annual temperatures. We also observed a strong correlation between mean annual ground temperature at a depth of 85 cm and mean annual or winter season ground surface temperature across the 45 locations. We demonstrate that soils classified as cold, intermediate, or warm using hierarchical clustering of full-year temperature data closely match their co-located vegetation (graminoid tundra, dwarf shrub tundra, and tall shrub tundra, respectively). We show that the spatial heterogeneity in soil temperature is primarily driven by spatial heterogeneity in snow cover, which induces variable winter insulation and soil thermal diffusivity. These effects further extend to the subsequent summer by causing variable latent heat exchanges. Finally, we discuss the challenges of predicting soil temperatures from snow depth and vegetation height alone by considering the complexity observed in the field data and reproduced in a model sensitivity analysis.https://doi.org/10.1088/1748-9326/ad27bbpermafrostthermal dynamicsheterogeneitysoil temperaturesnowvegetation |
| spellingShingle | Chen Wang Ian Shirley Stijn Wielandt John Lamb Sebastian Uhlemann Amy Breen Robert C Busey W Robert Bolton Susan Hubbard Baptiste Dafflon Local-scale heterogeneity of soil thermal dynamics and controlling factors in a discontinuous permafrost region Environmental Research Letters permafrost thermal dynamics heterogeneity soil temperature snow vegetation |
| title | Local-scale heterogeneity of soil thermal dynamics and controlling factors in a discontinuous permafrost region |
| title_full | Local-scale heterogeneity of soil thermal dynamics and controlling factors in a discontinuous permafrost region |
| title_fullStr | Local-scale heterogeneity of soil thermal dynamics and controlling factors in a discontinuous permafrost region |
| title_full_unstemmed | Local-scale heterogeneity of soil thermal dynamics and controlling factors in a discontinuous permafrost region |
| title_short | Local-scale heterogeneity of soil thermal dynamics and controlling factors in a discontinuous permafrost region |
| title_sort | local scale heterogeneity of soil thermal dynamics and controlling factors in a discontinuous permafrost region |
| topic | permafrost thermal dynamics heterogeneity soil temperature snow vegetation |
| url | https://doi.org/10.1088/1748-9326/ad27bb |
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