On the Variation of the Atmospheric Potential Gradient due to the Smokecloud caused by the Air-Raid Fire of Yokahama

[摘要] The smoke cloud of the air-raid fire of Yokohama covered the area beyond Mito. The Kakioka Magne_??_ic Observatory was also covered by this cloud and the Benndorf's electrograph recorded the variation o the atmospheric potential gradient due to the cloud. The potential gradient was about 17 V/M at first. When the tip of the cloud reached the zen_??_th the gradient began to decrease, and after about half an hour, when the sky was covered with dense black smoke-cloud it reached about O V/M. The height of the top and the ba e of the cloud was estimated about 1300 m and 700 m at Mt. Tsukuba Observatory.The density of the spa e-charge in the smoke-cloud is estimates at 0.0075 esu/m3. And it is also estimated that it is about 0.3 esu/m3 at Yokohama. It is about he same degree of magnitude with that in the case of the cloud of smoke of the Volcano Asama, the dust storm, the snowstorm and the smoke of the locomotive.

[学科分类] 大气科学