Root‐zone soil moisture variability across African savannas : from pulsed rainfall to land‐cover switches

dc.contributor.authorRasanen, Matti
dc.contributor.authorMerbold, Lutz
dc.contributor.authorVakkari, Ville
dc.contributor.authorAurela, Mika
dc.contributor.authorLaakso, Lauri
dc.contributor.authorBeukes, J. Paul
dc.contributor.authorVan Zyl, Pieter G.
dc.contributor.authorJosipovic, M.
dc.contributor.authorFeig, Gregor Timothy
dc.contributor.authorPellikka, Petri
dc.contributor.authorRinne, Janne
dc.contributor.authorKatul, Gabriel G.
dc.date.accessioned2020-10-20T05:02:57Z
dc.date.available2020-10-20T05:02:57Z
dc.date.issued2020-07
dc.description.abstractThe 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.en_ZA
dc.description.departmentGeography, Geoinformatics and Meteorologyen_ZA
dc.description.librarianhj2020en_ZA
dc.description.sponsorshipNational Science Foundation; European Commission; Bundesministerium für Bildung und Forschung; Academy of Finland.en_ZA
dc.description.urihttp://wileyonlinelibrary.com/journal/ecoen_ZA
dc.identifier.citationRäsänen, M., Merbold, L., Vakkari, V., et al. Root-zone soil moisture variability across African savannas: From pulsed rainfall to land-cover switches. Ecohydrology. 2020;13:e2213. https://doi.org/10.1002/eco.2213.en_ZA
dc.identifier.issn1936-0584 (print)
dc.identifier.issn1936-0592 (online)
dc.identifier.other10.1002/eco.2213
dc.identifier.urihttp://hdl.handle.net/2263/76546
dc.language.isoenen_ZA
dc.publisherWileyen_ZA
dc.rights© 2020 The Authors. Ecohydrology published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License.en_ZA
dc.subjectMemoryen_ZA
dc.subjectPersistenceen_ZA
dc.subjectPrecipitation intensityen_ZA
dc.subjectSavannaen_ZA
dc.titleRoot‐zone soil moisture variability across African savannas : from pulsed rainfall to land‐cover switchesen_ZA
dc.typeArticleen_ZA

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