Intercomparison of Sensible Heat Flux Measurement based on Eddy Covariance and Small Aperture Scintillometer above the Forest Canopy

Eddy covariance and scintillometer techniques are effective ways to measure the sensible heat flux at local and regional scales.As part of ChinaFLUX,continuous sensible heat flux was measured by using the Eddy Covariance(EC) technique at two and three canopy heights of a subtropical pinus plantation on the red earth hilly region in southeastern China.Meanwhile,continuous sensible heat flux was also measured by Small Aperture Scintillometer(SAS),which was installed in the direction of east by south,with about 70m distance between the laser emitter and receiver.There were consistence between the EC systems at two and three canopy heights and SAS system.At the diurnal and seasonal scales,sensible heat flux by SAS was higher than that by the EC systems at two and three canopy heights.However,sensible heat flux by SAS was lower than that by the EC systems at two and three canopy heights.There showed the strongest correlation in the direction of from south to south by west and from north by east to east by north,which were perpendicular to the dominating wind direction.During the daytime,the correlation of sensible heat flux between the EC systems at two and three canopy heights and SAS system were higher than that during the nighttime.The difference of sensible heat flux between the EC systems at two and three canopy heights and SAS system were related with the disparity in their footprint and disadvantages.