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The root-zone soil moisture spectrum in a mediterranean ecosystem

Publication ,  Journal Article
Corona, R; Katul, G; Montaldo, N
Published in: Journal of Hydrology
June 1, 2022

Storage of water within soil pores of the root zone introduce memory effects in the dynamics of soil moisture that are considerably longer than the integral timescale of many atmospheric processes. Thus, hydro-climatic states can be “sustained” through land-surface heat and water vapor fluxes primarily because they can “feed off” on this long-term soil moisture memory. Root-zone soil moisture memory is only but one feature characterizing the spectrum of soil moisture dynamics, which is analyzed here using a combination of long-term measurements and models. In particular, the spectrum of root-zone soil moisture content in a Mediterranean ecosystem is examined using 14-years of half-hourly measurements. A distinguishing hydro-climatic feature in such ecosystems is that sources (mainly rainfall) and sinks (mainly evapotranspiration) of soil moisture are roughly out of phase with each other. For over 4 decades of time scales and 7 decades of energy, the canonical shape of the measured soil moisture spectrum is shown to be approximately Lorentzian determined by the soil moisture variance and its memory but with two exceptions: the occurrences of a peak at diurnal-to-daily time scales and a weaker peak at near annual time scales. Model calculations and spectral analysis demonstrate that diurnal and seasonal variations in hydroclimate forcing responsible for variability in evapotranspiration had minor impact on the normalized shape of the soil moisture spectrum. However, their impact was captured by adjustments in the temporal variance. These findings indicate that precipitation and not evapotranspiration variability dominates the multi-scaling properties of soil moisture variability consistent with prior climate model simulations. Furthermore, the soil moisture memory inferred by the annual peak of soil moisture (340 d) is consistent with climate model simulations, while the memory evaluated from the loss function of a linearized mass balance approach leads to a smaller value (50 d), highlighting the effect of weak non-stationarity on soil moisture variability.

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Published In

Journal of Hydrology

DOI

ISSN

0022-1694

Publication Date

June 1, 2022

Volume

609

Related Subject Headings

  • Environmental Engineering
 

Citation

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Corona, R., Katul, G., & Montaldo, N. (2022). The root-zone soil moisture spectrum in a mediterranean ecosystem. Journal of Hydrology, 609. https://doi.org/10.1016/j.jhydrol.2022.127757
Corona, R., G. Katul, and N. Montaldo. “The root-zone soil moisture spectrum in a mediterranean ecosystem.” Journal of Hydrology 609 (June 1, 2022). https://doi.org/10.1016/j.jhydrol.2022.127757.
Corona R, Katul G, Montaldo N. The root-zone soil moisture spectrum in a mediterranean ecosystem. Journal of Hydrology. 2022 Jun 1;609.
Corona, R., et al. “The root-zone soil moisture spectrum in a mediterranean ecosystem.” Journal of Hydrology, vol. 609, June 2022. Scopus, doi:10.1016/j.jhydrol.2022.127757.
Corona R, Katul G, Montaldo N. The root-zone soil moisture spectrum in a mediterranean ecosystem. Journal of Hydrology. 2022 Jun 1;609.
Journal cover image

Published In

Journal of Hydrology

DOI

ISSN

0022-1694

Publication Date

June 1, 2022

Volume

609

Related Subject Headings

  • Environmental Engineering