Field observations of heat budget on a tidal flat

In order to investigate the heat budget on a tidal flat, systematic measurements of wind velocity, air, water and soil temperatures, air humidity and radiation fluxes were made on Wajiro tidal flat at the east side of Hakata Bay in Kyushu Island, Japan. The observations were carried out in both summer and winter of 1997. The relationship between the albedo and water depth, the properties of radiation fluxes and the budget among sensible, latent and subsurface heat fluxes have been revealed. In the daytime, the net radiation to the tidal flat is nearly equal to the net solar radiation and is distributed to the latent heat flux and the subsurface one. As the net radiation in the nighttime becomes almost zero, the subsurface heat flux is balanced against the latent one.