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Title: Radiative and precipitation controls on root zone soil moisture spectra

Here, we present that temporal variability in root zone soil moisture content (w) exhibits a Lorentzian spectrum with memory dictated by a damping term when forced with white-noise precipitation. In the context of regional dimming, radiation and precipitation variability are needed to reproduce w trends prompting interest in how the w memory is altered by radiative forcing. A hierarchy of models that sequentially introduce the spectrum of precipitation, net radiation, and the effect of w on evaporative and drainage losses was used to analyze the spectrum of w at subtropical and temperate forested sites. Reproducing the w spectra at long time scales necessitated simultaneous precipitation and net radiation measurements depending on site conditions. The w memory inferred from observed w spectra was 25–38 days, larger than that determined from maximum wet evapotranspiration and field capacity. Finally, the w memory can be reasonably inferred from the Lorentzian spectrum when precipitation and evapotranspiration are in phase.
Authors:
ORCiD logo [1] ;  [2] ;  [3] ;  [4] ;  [3] ;  [5] ;  [4]
  1. Nagoya University (Japan). Hydrospheric Atmospheric Research Center; University of Alaska, Fairbanks, AK (United States)
  2. Nagoya University (Japan). Hydrospheric Atmospheric Research Center; Duke Univ., Durham, NC (United States). Nicholas School of the Environment and Department of Civil and Environmental Engineering
  3. Nagoya University (Japan). Graduate School of Bioagricultural Sciences
  4. Nagoya University (Japan). Hydrospheric Atmospheric Research Center
  5. University of Tokyo (Japan). Graduate School of Agricultural and Life Science
Publication Date:
Grant/Contract Number:
SC0006967; SC0011461
Type:
Accepted Manuscript
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 41; Journal Issue: 21; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Research Org:
Duke Univ., Durham, NC (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; soil moisture spectra; soil moisture memory; decay time scale; evaporative damping time scale; red-noise; black-noise
OSTI Identifier:
1454924

Nakai, Taro, Katul, Gabriel G., Kotani, Ayumi, Igarashi, Yasunori, Ohta, Takeshi, Suzuki, Masakazu, and Kumagai, Tomo'omi. Radiative and precipitation controls on root zone soil moisture spectra. United States: N. p., Web. doi:10.1002/2014GL061745.
Nakai, Taro, Katul, Gabriel G., Kotani, Ayumi, Igarashi, Yasunori, Ohta, Takeshi, Suzuki, Masakazu, & Kumagai, Tomo'omi. Radiative and precipitation controls on root zone soil moisture spectra. United States. doi:10.1002/2014GL061745.
Nakai, Taro, Katul, Gabriel G., Kotani, Ayumi, Igarashi, Yasunori, Ohta, Takeshi, Suzuki, Masakazu, and Kumagai, Tomo'omi. 2014. "Radiative and precipitation controls on root zone soil moisture spectra". United States. doi:10.1002/2014GL061745. https://www.osti.gov/servlets/purl/1454924.
@article{osti_1454924,
title = {Radiative and precipitation controls on root zone soil moisture spectra},
author = {Nakai, Taro and Katul, Gabriel G. and Kotani, Ayumi and Igarashi, Yasunori and Ohta, Takeshi and Suzuki, Masakazu and Kumagai, Tomo'omi},
abstractNote = {Here, we present that temporal variability in root zone soil moisture content (w) exhibits a Lorentzian spectrum with memory dictated by a damping term when forced with white-noise precipitation. In the context of regional dimming, radiation and precipitation variability are needed to reproduce w trends prompting interest in how the w memory is altered by radiative forcing. A hierarchy of models that sequentially introduce the spectrum of precipitation, net radiation, and the effect of w on evaporative and drainage losses was used to analyze the spectrum of w at subtropical and temperate forested sites. Reproducing the w spectra at long time scales necessitated simultaneous precipitation and net radiation measurements depending on site conditions. The w memory inferred from observed w spectra was 25–38 days, larger than that determined from maximum wet evapotranspiration and field capacity. Finally, the w memory can be reasonably inferred from the Lorentzian spectrum when precipitation and evapotranspiration are in phase.},
doi = {10.1002/2014GL061745},
journal = {Geophysical Research Letters},
number = 21,
volume = 41,
place = {United States},
year = {2014},
month = {10}
}