A new method to estimate sensible heat fluxes from wavelet analysis of semi-high frequency radiometric canopy temperature Dr. Nicolas Bambach University of California, Davis, USA

Wavelet analysis was applied to high frequency canopy infrared radiometric temperature to derive sensible heat flux density (H). We found that plant canopy temperature traces show ramp-like features such as those observed from air temperature measured above canopies. We propose that the mean resistance to heat transfer is implicitly resolved by deriving the magnitude and time of ramp-like canopy temperatures over periods of times commonly used to derived H by other techniques (e.g about 30 minutes in eddy covariance and surface renewal analysis). We compare estimates of H from this new approach to eddy covariance and surface renewal. The method was assessed using data collected on a variety of crop surfaces: alfalfa, almonds, and grapevines. We found that H estimates using this new method strongly correlate with estimations derived from standard micrometeorological methods. These results suggest a path for more practical and cost-effective ground-based estimations of evapotranspiration based on energy budget approaches.