Abstract
The sea breeze has thermal moderation effects on leeward areas. Because evapotranspiration from leaf surfaces is functionally similar to that from water surfaces in relation to thermal budgets on earth surface, the existence of a temperature fall in proportion to the amount of evapotranspiration in a forest and of the earth surface temperature moderation phenomena influencing the earth surface of a leeward area can be expected. Let us assume that the temperature difference ((c-Tf)) between the intercept c of the temperature axis and the average forest temperature Tf in the expression of relationship between Tf and the normalized vegetation index NVI means evapotranspiration, and the gradient ((c-Tf)) /NVI, which Nemani et al. once tried to relate to the canopy resistance, is assumed to represent the normalized evapotranspiration excluding the effect of NVI. Then, factors influencing the gradient ((c-Tf))/NVI and the temperature difference ((c-Tf)) has been analyzed using Matsue Weather Bureau data. Following results were obtained. Forest evapotranspiration ((c-Tf)) and normalized evapotranspiration of forests ((c-Tf))/NVI are mainly controled by the canopy temperature and the product u(qs-q) of the wind velocity u and the saturation deficit (qs-q). Solar radiation and air temperature are not governing factors for evapotranspiration of forests on nine days of fine weather condition.
