Root‐zone soil moisture variability across African savannas: From pulsed rainfall to landcover switches
The main source of soil moisture variability in savanna ecosystems is pulsed rainfall. Rainfall pulsing impacts water‐stress durations, soil moisture switching between wet‐to‐dry and dry‐to‐wet states, and soil moisture spectra as well as derived measures from it such as soil moisture memory. Rainfa...
| Autores principales: | , , , , , , , , , , , |
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| Formato: | Journal Article |
| Lenguaje: | Inglés |
| Publicado: |
Wiley
2020
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| Materias: | |
| Acceso en línea: | https://hdl.handle.net/10568/108250 |
| _version_ | 1855542368487342080 |
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| author | Räsänen, M. Merbold, Lutz Vakkari, V. Aurela, M. Laakso, L. Beukes, J.P. Zyl, P.G. van Josipovic, M. Feig, G. Pellikka, P. Rinne, J. Katul, G.G. |
| author_browse | Aurela, M. Beukes, J.P. Feig, G. Josipovic, M. Katul, G.G. Laakso, L. Merbold, Lutz Pellikka, P. Rinne, J. Räsänen, M. Vakkari, V. Zyl, P.G. van |
| author_facet | Räsänen, M. Merbold, Lutz Vakkari, V. Aurela, M. Laakso, L. Beukes, J.P. Zyl, P.G. van Josipovic, M. Feig, G. Pellikka, P. Rinne, J. Katul, G.G. |
| author_sort | Räsänen, M. |
| collection | Repository of Agricultural Research Outputs (CGSpace) |
| description | The main source of soil moisture variability in savanna ecosystems is pulsed rainfall. Rainfall pulsing impacts water‐stress durations, soil moisture switching between wet‐to‐dry and dry‐to‐wet states, and soil moisture spectra as well as derived measures from it such as soil moisture memory. Rainfall pulsing is also responsible for rapid changes in grassland leaf area and concomitant changes in evapotranspirational (ET) losses, which then impact soil moisture variability. With the use of a hierarchy of models and soil moisture measurements, temporal variability in root‐zone soil moisture and water‐stress periods are analysed at four African sites ranging from grass to miombo savannas. The normalized difference vegetation index (NDVI) and potential ET (PET)‐adjusted ET model predict memory timescale and dry persistence in agreement with measurements. The model comparisons demonstrate that dry persistence and mean annual dry periods must account for seasonal and interannual changes in maximum ET represented by NDVI and to a lesser extent PET. Interestingly, the precipitation intensity and soil moisture memory were linearly related across three savannas with ET/infiltration ∼ 1.0. This relation and the variability of length and timing of dry periods are also discussed. |
| format | Journal Article |
| id | CGSpace108250 |
| institution | CGIAR Consortium |
| language | Inglés |
| publishDate | 2020 |
| publishDateRange | 2020 |
| publishDateSort | 2020 |
| publisher | Wiley |
| publisherStr | Wiley |
| record_format | dspace |
| spelling | CGSpace1082502025-09-29T06:20:47Z Root‐zone soil moisture variability across African savannas: From pulsed rainfall to landcover switches Räsänen, M. Merbold, Lutz Vakkari, V. Aurela, M. Laakso, L. Beukes, J.P. Zyl, P.G. van Josipovic, M. Feig, G. Pellikka, P. Rinne, J. Katul, G.G. soil moisture rain savannas The main source of soil moisture variability in savanna ecosystems is pulsed rainfall. Rainfall pulsing impacts water‐stress durations, soil moisture switching between wet‐to‐dry and dry‐to‐wet states, and soil moisture spectra as well as derived measures from it such as soil moisture memory. Rainfall pulsing is also responsible for rapid changes in grassland leaf area and concomitant changes in evapotranspirational (ET) losses, which then impact soil moisture variability. With the use of a hierarchy of models and soil moisture measurements, temporal variability in root‐zone soil moisture and water‐stress periods are analysed at four African sites ranging from grass to miombo savannas. The normalized difference vegetation index (NDVI) and potential ET (PET)‐adjusted ET model predict memory timescale and dry persistence in agreement with measurements. The model comparisons demonstrate that dry persistence and mean annual dry periods must account for seasonal and interannual changes in maximum ET represented by NDVI and to a lesser extent PET. Interestingly, the precipitation intensity and soil moisture memory were linearly related across three savannas with ET/infiltration ∼ 1.0. This relation and the variability of length and timing of dry periods are also discussed. 2020-07 2020-05-14T21:04:00Z 2020-05-14T21:04:00Z Journal Article https://hdl.handle.net/10568/108250 en Open Access Wiley Räsänen, M., Merbold, L., Vakkari, V., Aurela, M., Laakso, L., Beukes, J.P., Zyl, P.G. van, Josipovic, M., Feig, G., Pellikka, P., Rinne, J. and Katul, G.G. 2020. Root‐zone soil moisture variability across African savannas: From pulsed rainfall to landcover switches. Ecohydrology |
| spellingShingle | soil moisture rain savannas Räsänen, M. Merbold, Lutz Vakkari, V. Aurela, M. Laakso, L. Beukes, J.P. Zyl, P.G. van Josipovic, M. Feig, G. Pellikka, P. Rinne, J. Katul, G.G. Root‐zone soil moisture variability across African savannas: From pulsed rainfall to landcover switches |
| title | Root‐zone soil moisture variability across African savannas: From pulsed rainfall to landcover switches |
| title_full | Root‐zone soil moisture variability across African savannas: From pulsed rainfall to landcover switches |
| title_fullStr | Root‐zone soil moisture variability across African savannas: From pulsed rainfall to landcover switches |
| title_full_unstemmed | Root‐zone soil moisture variability across African savannas: From pulsed rainfall to landcover switches |
| title_short | Root‐zone soil moisture variability across African savannas: From pulsed rainfall to landcover switches |
| title_sort | root zone soil moisture variability across african savannas from pulsed rainfall to landcover switches |
| topic | soil moisture rain savannas |
| url | https://hdl.handle.net/10568/108250 |
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