Changes in heat balance characteristics of ponded shallow water in Japan under the current and future climates were investigated using a simple physical model for estimating water temperature with climatic data and the future climate scenario. The most notable results from the simulations were that the latent heat loss from the shallow water in the period June to August under the doubled CO2-climate would become larger by about 2.0MJ m-2day-1, compared with that under the present climate conditions. The increase in the latent heat loss under the doubled CO2-climate may lead to concomitant decrease in sensible heat loss from the shallow water to air under the doubled CO2-climates. The changes in the heat balance characteristics resulted in a decrease in the Bowen ratio of the ponded shallow water under the doubled CO2-climate conditions.
The tundra ecosystem contains a large amount of organic matter in the seasonally thawed layer and permafrost which might be a source of greenhouse effect gases due to global warming. This study was carried out to determine whether or not the tundra ecosystem has become a source of greenhouse effect gases. The micrometeorology of the Arctic coastal tundra ecosystem near Barrow, Alaska was measured during the summer of 1993, in order to make clear the characteristics of the heat budget in relation to the global warming phenomena. Over this Arctic coastal tundra, the heat budget components changed remarkably due to air mass conditions. Cold and moist wind from the Polar Sea brought high levels of sensible heat flux H and the air temperature did not increase. Warmer and drier wind on clear days from inland tundra increased air and soil temperatures and reduced the relative humidity and H. The cold and moist wind was observed frequently in June and early July, and the warmer and drier wind was after late July. The ratio of sensible heat flux to net radiation H/Rn, increased with wind speed but that of latent heat flux lE to net radiation lE/Rn did not, when the tundra surface was dry. Analyses of lE/Rn and H/Rn showed that each active surface level of heat flux was different between lE and H under dry conditions. After heavy rain the surface of the tundra ecosystem turned into standing water conditions. That made the active surface levels the same for lE and H, which increased of lE/Rn with wind speed. The Arctic coastal tundra ecosyatem is characterized by a thick moss carpet whose diffusion resistance (canopy resistance rc) was examined. The canopy resistance for latent heat flux was larger under drier tundra conditions than under standing water conditions. Drying of the tundra ecosystem makes the contribution of sensible heat flux H/Rn larger which might affect greenhouse effect gas fluxes of CO2 and CH4, and will accelerate global warming.
Air pollution by SO2 at Tonghua city is one of the serious air pollution problems in China. In order to investigate the characteristics of the air pollution and occurrence of high SO2 cencentration in this area, atmospheric SO2 concentration at ground level was examined by comparing simulation by diffusion models and observation, and the types of air pollution were classified with fuzzy cluster analysis. (1) Fairly reasonable agreement on SO2 concentration was obtained between the simulation and observation (r2=0.65). The Hanna-Gifford and the Pasquill models were useful to estimate the ground surface concentration. (2) The contribution of area-souces, e.g. low chimneys, to total ground surface SO2 concentration was about 77.1%, which clearly indicated the importance of air pollution from area-sources in this area. (3) The highest SO2 concentration occurred under F-type of atmospheric stability (strong stable atmospheric condition) and SSW wind direction in cold period. These highest SO2 episodes occurred at the meshes of NO. 8, which is close to a power plant, and No. 29, which is densely populated with high consumption of coal. (4) The difference between the maximum and minimum SO2 concentrations in a year was more than 13 folds. (5) The characteristics of SO2 air pollution were classified into three types. Differences of the three types were based on the type of pollution sources, amount of coal consumption, and the difference between SO2 concentration in 1990 and that in 1993. This method of analysis was clearly useful to evaluate the types of the air pollution objectively and quantitatively.