Guidelines for Validating Bowen Ratio Data

J. O. Payero, C. M.U. Neale, J. L. Wright, R. G. Allen

Research output: Contribution to journalReview articlepeer-review

61 Scopus citations


For a variety of reasons, the measurement of latent heat flux using the Bowen ratio method can sometimes result in erroneous data. This study provides guidelines for detecting erroneous Bowen ratio data and illustrates the application of these guidelines by comparing Bowen ratio and lysimeter data collected over grass and alfalfa in southern Idaho. Errors in net radiation were detected by comparing measured with theoretical values. However, it was found that good theoretical procedures to validate soil heat flux data are lacking. Only empirical equations mainly used for remote sensing applications to obtain estimates close to noontime are available. Extremely inaccurate latent heat fluxes were easily filtered out by rejecting data when the calculated Bowen ratio (β) values were close to -1. A simplified procedure was proposed to reject fluxes with the wrong sign, and three different equations were used successfully to detect the occurrence of condensation inside the type of measurement system used in the study. Guidelines to assure adequate fetch are provided. Fetch did not affect the measured fluxes in this study, which may have been due to the similarity in surface properties between the crops under study and those in the surrounding fields.

Original languageEnglish (US)
Pages (from-to)1051-1060
Number of pages10
JournalTransactions of the American Society of Agricultural Engineers
Issue number4
StatePublished - Jul 2003
Externally publishedYes


  • Alfalfa
  • Bowen ratio
  • Energy balance
  • ET
  • Evapotranspiration
  • Grass
  • Latent heat flux
  • Lysimeter
  • Soil heat flux

ASJC Scopus subject areas

  • Agricultural and Biological Sciences (miscellaneous)


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