On the drought of the winter of 1923-1924 in Tokyo

[摘要] The records of spell of dry days in Tokyo since 1911 are tabulated in the table p. 52. As dry days the days without precipitation and those with precipitation less than 0, 7mm and not occur on successive two days are taken. The longest spell occurred on 1917 and it continued 39 days. The next longest happened this year and it was 34 days. Fine days prevail in this district when the general distribution of pressure belongs to so called West-high East-low type as already named by Prof. Okada, and also when the high pressure belt covers Japan proper from West to East or when the belt situates a little south of Japan Proper so that South or Southwest breezes prevail in the district. The West-high East-low occurs cyclically and hence in normal winters fine days is interrupted by rain or snow-fall nearly once a week or, once in 5 or 6 days. But when the high pressure belt takes position mentioned above, it persists rather long, during which the weather is kept dry. The former cyclic phenomenon superposes with this, so that we have cloudiness or week shower once in 5, 6 or 7 days even in this period. To know the cause of the movement of high pressure zone is most important for long range forecast, but it is not yet discovered. (S. F.).

[学科分类] 大气科学