The global distribution of Earth's critical zone and its controlling factors
Abstract The near‐surface layer of Earth which provides essential elements for supporting life is now recognized as the critical zone (CZ). This study provides the first global assessment of the CZ thickness (CZT) and its controlling factors by combining data sets of climate, vegetation height (VH),...
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| Format: | Article |
| Language: | English |
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Wiley
2017-04-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1002/2017GL072760 |
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| author | Xianli Xu Wen Liu |
| author_facet | Xianli Xu Wen Liu |
| author_sort | Xianli Xu |
| collection | DOAJ |
| description | Abstract The near‐surface layer of Earth which provides essential elements for supporting life is now recognized as the critical zone (CZ). This study provides the first global assessment of the CZ thickness (CZT) and its controlling factors by combining data sets of climate, vegetation height (VH), water table depth (WTD), groundwater thickness (GWT), topography, and lithologic data. The analysis shows that CZT ranges from 0.7 to 223.5 m with an average value of 36.8 m across continental areas; CZT is thickest in midlatitudes (subtropical to temperate zones). The proportion of aboveground part (VH) to CZT is 19.9 ± 16.7% (mean ±one standard deviation), while it is 80.1 ± 16.7% for the underground part (WTD + GWT). A generalized linear model shows that compound topographic index (ln(a/tan(b)), where a is the upslope contributing area and b is the slope degree of the landscape) and potential evapotranspiration are the first two major controlling factors on the variations in CZT. This study opens opportunities for further advancing CZ science by providing one of its most important properties—its thickness. |
| format | Article |
| id | doaj-art-a5dbbc403e274302bfec44445c790336 |
| institution | Kabale University |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2017-04-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-a5dbbc403e274302bfec44445c7903362025-08-20T03:49:46ZengWileyGeophysical Research Letters0094-82761944-80072017-04-014473201320810.1002/2017GL072760The global distribution of Earth's critical zone and its controlling factorsXianli Xu0Wen Liu1Key Laboratory for Agro‐ecological Processes in Subtropical Region, Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha ChinaCollege of Resources and Environmental Sciences Hunan Normal University Changsha ChinaAbstract The near‐surface layer of Earth which provides essential elements for supporting life is now recognized as the critical zone (CZ). This study provides the first global assessment of the CZ thickness (CZT) and its controlling factors by combining data sets of climate, vegetation height (VH), water table depth (WTD), groundwater thickness (GWT), topography, and lithologic data. The analysis shows that CZT ranges from 0.7 to 223.5 m with an average value of 36.8 m across continental areas; CZT is thickest in midlatitudes (subtropical to temperate zones). The proportion of aboveground part (VH) to CZT is 19.9 ± 16.7% (mean ±one standard deviation), while it is 80.1 ± 16.7% for the underground part (WTD + GWT). A generalized linear model shows that compound topographic index (ln(a/tan(b)), where a is the upslope contributing area and b is the slope degree of the landscape) and potential evapotranspiration are the first two major controlling factors on the variations in CZT. This study opens opportunities for further advancing CZ science by providing one of its most important properties—its thickness.https://doi.org/10.1002/2017GL072760ecohydrologysoil erosionsoil hydrology/hydropedologyclimate changelandscape ecologyvegetation distribution |
| spellingShingle | Xianli Xu Wen Liu The global distribution of Earth's critical zone and its controlling factors Geophysical Research Letters ecohydrology soil erosion soil hydrology/hydropedology climate change landscape ecology vegetation distribution |
| title | The global distribution of Earth's critical zone and its controlling factors |
| title_full | The global distribution of Earth's critical zone and its controlling factors |
| title_fullStr | The global distribution of Earth's critical zone and its controlling factors |
| title_full_unstemmed | The global distribution of Earth's critical zone and its controlling factors |
| title_short | The global distribution of Earth's critical zone and its controlling factors |
| title_sort | global distribution of earth s critical zone and its controlling factors |
| topic | ecohydrology soil erosion soil hydrology/hydropedology climate change landscape ecology vegetation distribution |
| url | https://doi.org/10.1002/2017GL072760 |
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