Abstract
Ozone impact on the forest in the Tanzawa Mountains has been recognized for many years. In order to understand the forest decline, the hourly stomatal O3 flux and the accumulated Phytotoxic Ozone Dose (PODy: y means a threshold) were estimated using two numerical models. The numerical models (meteorological model: MM5 and air quality model: CMAQ) were executed to estimate the hourly O3 concentration and the meteorological elements (air temperature, specific humidity, insolation and wind speed) from April to October including the leafing time to the leaf-fall time. We compared the POD1（ 26.2 mmol/m2 ）based on observation and the POD1 ( 27.7 mmol/m2 ) based on the output of numerical models at the Inukoeji station in the Tanzawa Mountains, and these POD1 values were comparable. It shows the possibility of an application of numerical models for an O3 impact study in the Tanzawa Mountains. The horizontal distribution of the POD1 showed that the POD1 exceeded the critical level in the Tanzawa Mountains. The POD1 depends on the altitude and reaches higher values at the top of the mountains, because the stomatal O3 conductance parameters on temperature and humidity depend on the altitude and are higher values on top of the mountains.
