HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sauer, T. J. Articles by Horton, R. Search for Related Content PubMed Articles by Sauer, T. J. Articles by Horton, R. GeoRef GeoRef Citation Agricola Articles by Sauer, T. J. Articles by Horton, R. Related Collections Agroclimatology Soil Methods/Instrumentation Soil Thermal Properties

SPECIAL SECTION - ADVANCES IN MEASUREMENT AND MONITORING METHODS

Errors in Heat Flux Measurement by Flux Plates of Contrasting Design and Thermal Conductivity

^a USDA-ARS, National Soil Tilth Laboratory, 2150 Pammel Dr., Ames, IA 50011-4420
^b USDA-ARS, Soil and Water Management Research Unit, St. Paul, MN 55108
^c Dep. of Physics and Astronomy, Drake University, Des Moines, IA 50311
^d Dep. of Agronomy, Iowa State University, Ames, IA 50011
^* Corresponding author (sauer{at}nstl.gov).

Received 13 March 2003.

The thermal conductivity () of soils may vary by a factor of about 4 for a range of field soil water contents. Measurement of soil heat flux (G) using a heat flux plate with a fixed distorts heat flow through the plates and in the adjacent soil. The objectives of this research were to quantify heat flow distortion errors for soil heat flux plates of widely contrasting designs and to evaluate the accuracy of a previously reported correction. Six types of commercially available heat flux plates with varying thickness, face area, and thermal conductivity (_m) were evaluated. Steady-state laboratory experiments at flux densities from 20 to 175 W m^-2 were completed in a large box filled with dry or saturated sand having of 0.36 and 2.25 W m^-1 K^-1. A field experiment compared G measured with pairs of four plate types buried at 6 cm in a clay soil with G determined using the gradient technique. The flux plates underestimated G in the dry sand by 2.4 to 38.5% and by 13.1 to 73.2% in saturated sand while in moist clay plate performance ranged from a 6.2% overestimate to a 71.4% underestimate. Application of the correction generally improved agreement between plate estimates and independent G measurements, especially when > _m, although most plate estimates were still significantly lower than the actual G. Limitations of the correction procedure indicate that renewed effort should be placed on innovative sensor designs that avoid or minimize heat flow distortion and/or provide direct, in situ calibration capability.

This article has been cited by other articles:

				F. Zvomuya, F. J. Larney, S. M. McGinn, A. F. Olson, and W. D. Willms Surface Albedo and Soil Heat Flux Changes Following Drilling Mud Application to a Semiarid, Mixed-Grass Prairie Soil Sci. Soc. Am. J., September 1, 2008; 72(5): 1217 - 1225. [Abstract] [Full Text] [PDF]

				T. J. Sauer and P. J. Pinter Jr. Introduction to the Symposium "Progress in Radiation and Energy Balance Measurement Systems" Agron. J., January 1, 2007; 99(1): 238 - 239. [Full Text] [PDF]

				T. J. Sauer, T. E. Ochsner, and R. Horton Soil Heat Flux Plates: Heat Flow Distortion and Thermal Contact Resistance Agron. J., January 1, 2007; 99(1): 304 - 310. [Abstract] [Full Text] [PDF]

				T. E. Ochsner, T. J. Sauer, and R. Horton Field Tests of the Soil Heat Flux Plate Method and Some Alternatives Agron. J., June 5, 2006; 98(4): 1005 - 1014. [Abstract] [Full Text] [PDF]