Deep desiccation of soils observed by long-term high-resolution measurements on a large inclined lysimeter
| Autor: | Markus Merk, Nadine Goeppert, Nico Goldscheider |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Hydrology and Earth System Sciences, Vol 25, Pp 3519-3538 (2021) Hydrology and earth system sciences, 25 (6), 3519–3538 |
| ISSN: | 1607-7938 |
| DOI: | 10.5194/hess-2020-274 |
| Popis: | Availability of long-term and high-resolution measurements of soil moisture is crucial when it comes to understanding all sorts of changes to past soil moisture variations and the prediction of future dynamics. This is particularly true in a world struggling against climate change and its impacts on ecology and economy. Feedback mechanisms between soil moisture dynamics and meteorological influences are key factors when it comes to understanding the occurrence of drought events. We used long-term high-resolution measurements of soil moisture on a large inclined lysimeter at a test site near Karlsruhe, Germany. The measurements indicate (i) a seasonal evaporation depth of over two meters. Statistical analysis and linear regressions indicate (ii) a significant decrease in soil moisture levels over the past two decades. This decrease is most pronounced at the start and the end of the vegetation period. Furthermore, Bayesian change point detection revealed (iii), that this decrease is not uniformly distributed over the complete observation period. Largest changes occur at tipping points during years of extreme drought, with significant changes to the subsequent soil moisture levels. This change affects not only the overall trend in soil moisture, but also the seasonal dynamics. A comparison to modeled data showed (iv) that the occurrence of deep desiccation is not merely dependent on the properties of the soil but is spatially heterogeneous. The study highlights the importance of soil moisture measurements for the understanding of soil moisture fluxes in the vadose zone. |
| Databáze: | OpenAIRE |
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