Premium
Systematic errors in ground heat flux estimation and their correction
Author(s) -
Gentine P.,
Entekhabi D.,
Heusinkveld B.
Publication year - 2012
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2010wr010203
Subject(s) - heat flux , forcing (mathematics) , soil thermal properties , environmental science , energy balance , flux (metallurgy) , sensible heat , surface layer , soil science , atmosphere (unit) , heat transfer , soil water , atmospheric sciences , remote sensing , meteorology , mechanics , materials science , geology , physics , layer (electronics) , thermodynamics , metallurgy , field capacity , composite material
Incoming radiation forcing at the land surface is partitioned among the components of the surface energy balance in varying proportions depending on the time scale of the forcing. Based on a land‐atmosphere analytic continuum model, a numerical land surface model, and field observations we show that high‐frequency fluctuations in incoming radiation (with period less than 6 h, for example, due to intermittent clouds) are preferentially partitioned toward ground heat flux. These higher frequencies are concentrated in the 0–1 cm surface soil layer. Subsequently, measurements even at a few centimeters deep in the soil profile miss part of the surface soil heat flux signal. The attenuation of the high‐frequency soil heat flux spectrum throughout the soil profile leads to systematic errors in both measurements and modeling, which require a very fine sampling near the soil surface (0–1 cm). Calorimetric measurement techniques introduce a systematic error in the form of an artificial band‐pass filter if the temperature probes are not placed at appropriate depths. In addition, the temporal calculation of the change in the heat storage term of the calorimetric method can further distort the reconstruction of the surface soil heat flux signal. A correction methodology is introduced which provides practical application as well as insights into the estimation of surface soil heat flux and the closure of surface energy balance based on field measurements.