Studies on Atmospheric Ozone at Tokyo

[摘要] The amount of atmospheric ozone was measured at Tokyo during the period from January 1951 to September 1952, using a chromium photo-electric tube and glass filters (R. Stair's method).According to the results of observation, the amount of atmospheric ozone shows a marked seasonal variation having the maximum value in late spring (about 0.28cm) and the minimum value in fall (about 0.22cm). This agrees fairly well with the results obtained by other observers in similar latitudes.Relations between the deviation of the ozone amount and the surface high and low pressure systems are studied. The positive ozone deviation is found near and in front of a surface migratory anticyclonic center and the negative one is generally found near the center of surface low pressure. An example illustrating the changes of ozone deviation during the passage of a migratory anticyclone (April 24_??_27, 1951) is presented here. By the above observation, the maximum deviation of ozone amount is observed on the day preceding the passage of the anticyclonic center. The large variation in the ozone deviation during the said period can be explained more clearly by considering the change of the air temperature or potential temperature in the lower stratosphere rather than by considering the change of the height of tropopause.A close correlation seems to exist between the wind direction (observed at a single station) in the lower stratosphere and the ozone deviation.In general, as to the vertical motion in the atmosphere, there are upward or downward motions of air in front of or at the rear of a trough at 500 millibar level, and reversed motions are assumed to exist in the lower stratosphere. Using the above mentioned result, the authors studied the relation between the ozone deviation and the vertical motion in the lower stratosphere. According as the observing station is situated in front of or at the rear of a trough on the 500 millibar weather map, the ozone deviation seems to become positive or negative, respectively.

[学科分类] 大气科学