TITLE:
Reciprocal Analysis of Sensible and Latent Heat Fluxes in a Forest Region Using Single Height Temperature and Humidity Based on the Bowen Ratio Concept
AUTHORS:
Toshisuke Maruyama, Manabu Segawa
KEYWORDS:
Bowen Ratio, Eddy Covariance, Reciprocal Determination, Estimation of Evapotranspiration, Canopy Surface Temperature and Humidity
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.8 No.7,
June
20,
2016
ABSTRACT: Evapotranspiration in forests has been researched
for a long time because it serves an important role in water resource issues
and biomass production. By applying the reciprocal analysis based on the Bowen
ratio concept to the canopy surface, the sum result of sensible and latent heat
fluxes, i.e., actual
evapotranspiration (ET), is estimated
from engineering aspect using the net radiation (Rn) and heat flux into the ground (G). The new method uses air temperature and humidity at a single
height by determining the relative humidity (rehs) using the canopy temperature (Ts). The validity of the method is confirmed by the latent heat
flux (lE) and sensible heat flux (H) observed by mean of eddy covariance method.
The heat imbalance is corrected by multiple regression analysis. The temporal
change of lE and H at the canopy surface is clarified using hourly and yearly data.
Furthermore, the observed and estimated monthly evapotranspiration of the sites
are compared. The research is conducted using hourly data and the validation of
the method is conducted using observed covariance at five sites in the world
using FLUXNET.