CO2 and water vapor flux evaluations by modified gradient methods over a mangrove forest

Two types of the modified gradient method for CO2 and water vapor flux estimation, in which the eddy correlation is applied only to the sensible heat flux, are presented. One type uses the eddy diffusivity for the sensible heat flux, and the other establishes the flux-gradient relation in the form of the product f sub m f sub n as a function of the gradient Richardson number. The latter method can be used even in heavy rains. In order to confirm the applicability of these methods, the dimensionless profile relations for momentum, sensible heat, latent heat and CO2 are estimated over a mangrove forest. Although these dimensionless profiles indicate smaller values than the Businger-Dyer representation under stable conditions, they indicate similar tendency with each other. The two modified gradient methods agree with each other although the scatter in the individual comparison is large.