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Nocturnal evapotranspiration in eddy-covariance records from three co-located ecosystems in the Southeastern U.S.: Implications for annual fluxes

Publication ,  Journal Article
Novick, KA; Oren, R; Stoy, PC; Siqueira, MBS; Katul, GG
Published in: Agricultural and forest meteorology.
September 2009

Nocturnal evapotranspiration (ET N ) is often assumed to be negligible in terrestrial ecosystems, reflecting the common assumption that plant stomata close at night to prevent water loss from transpiration. However, recent evidence across a wide range of species and climate conditions suggests that significant transpiration occurs at night, frustrating efforts to estimate total annual evapotranspiration (ET) from conventional methods such as the eddy-covariance technique. Here, the magnitude and variability of ET N is explored in multiple years of eddy-covariance measurements from three adjacent ecosystems in the Southeastern U.S.: an old grass field, a planted pine forest, and a late-successional hardwood forest. After removing unreliable data points collected during periods of insufficient turbulence, observed ET N averaged 8-9% of mean daytime evapotranspiration (ET D ). ET N was driven primarily by wind speed and vapor pressure deficit and, in the two forested ecosystems, a qualitative analysis suggests a significant contribution from nocturnal transpiration. To gapfill missing data, we investigated several methodologies, including process-based multiple non-linear regression, relationships between daytime and nighttime ET fluxes, marginal distribution sampling, and multiple imputation. The utility of the gapfilling procedures was assessed by comparing simulated fluxes to reliably measured fluxes using randomly generated gaps in the data records, and by examining annual sums of ET from the different gapfilling techniques. The choice of gapfilling methodology had a significant impact on estimates of annual ecosystem water use and, in the most extreme cases, altered the annual estimate of ET by over 100mmyear⁻¹, or ca. 15%. While no single gapfiling methodology appeared superior for treating data from all three sites, marginal distribution sampling generally performed well, producing flux estimates with a site average bias error of <10%, and a mean absolute error close to the random measurement error of the dataset (12.2 and 9.8Wm⁻², respectively).

Duke Scholars

Published In

Agricultural and forest meteorology.

DOI

ISSN

0168-1923

Publication Date

September 2009

Volume

149

Issue

9

Start / End Page

1491 / 1504

Related Subject Headings

  • Meteorology & Atmospheric Sciences
  • 37 Earth sciences
  • 31 Biological sciences
  • 30 Agricultural, veterinary and food sciences
  • 07 Agricultural and Veterinary Sciences
  • 06 Biological Sciences
  • 04 Earth Sciences
 

Citation

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MLA
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Novick, K. A., Oren, R., Stoy, P. C., Siqueira, M. B. S., & Katul, G. G. (2009). Nocturnal evapotranspiration in eddy-covariance records from three co-located ecosystems in the Southeastern U.S.: Implications for annual fluxes. Agricultural and Forest Meteorology., 149(9), 1491–1504. https://doi.org/10.1016/j.agrformet.2009.04.005
Novick, K. A., R. Oren, P. C. Stoy, M. B. S. Siqueira, and G. G. Katul. “Nocturnal evapotranspiration in eddy-covariance records from three co-located ecosystems in the Southeastern U.S.: Implications for annual fluxes.” Agricultural and Forest Meteorology. 149, no. 9 (September 2009): 1491–1504. https://doi.org/10.1016/j.agrformet.2009.04.005.
Novick KA, Oren R, Stoy PC, Siqueira MBS, Katul GG. Nocturnal evapotranspiration in eddy-covariance records from three co-located ecosystems in the Southeastern U.S.: Implications for annual fluxes. Agricultural and forest meteorology. 2009 Sep;149(9):1491–504.
Novick, K. A., et al. “Nocturnal evapotranspiration in eddy-covariance records from three co-located ecosystems in the Southeastern U.S.: Implications for annual fluxes.” Agricultural and Forest Meteorology., vol. 149, no. 9, Sept. 2009, pp. 1491–504. Epmc, doi:10.1016/j.agrformet.2009.04.005.
Novick KA, Oren R, Stoy PC, Siqueira MBS, Katul GG. Nocturnal evapotranspiration in eddy-covariance records from three co-located ecosystems in the Southeastern U.S.: Implications for annual fluxes. Agricultural and forest meteorology. 2009 Sep;149(9):1491–1504.
Journal cover image

Published In

Agricultural and forest meteorology.

DOI

ISSN

0168-1923

Publication Date

September 2009

Volume

149

Issue

9

Start / End Page

1491 / 1504

Related Subject Headings

  • Meteorology & Atmospheric Sciences
  • 37 Earth sciences
  • 31 Biological sciences
  • 30 Agricultural, veterinary and food sciences
  • 07 Agricultural and Veterinary Sciences
  • 06 Biological Sciences
  • 04 Earth Sciences