(Tenki is the bulletin journal of the Meteorological Society of Japan in Japanese.)
TENKI, Vol. 66, No. 2, pp. 141-160, 2019
A lot of information, such as correlation and sensitivity between the heavy rainfall and the environments, which cannot be obtained by a deterministic forecast, is expected to be obtained by many predicted scenarios of ensemble forecasts, when the ensemble forecast-analysis system is used in the analysis of the heavy rainfall. In this paper, the rainfall system, which caused the heavy rainfall on 19-20th August 2014 and recorded the heaviest rainfall amount during the observation periods over southern Hiroshima, was reproduced. The relation between the precipitation amount and the atmospheric environment, especially the low-level inflow from the south was investigated with the reproduced scenarios of the ensemble forecasts. The following 4 features were obtained from this investigation. (1) The intense southerly flow reached from Iyo-Nada to southern Hiroshima caused the heavy rainfall. (2) The more intense southerly flow produces the more-organized rainfall system, of which rainfall amount was heavier. (3) The water vapor flux of low-level inflow and the mixing ratio of precipitation in Hiroshima City correlated positively when the storm relative helicity at the inflow side of the system was large, and the correlation became larger when the time lag due to the advection of the air mass was considered. (4) In this case, the correlations between the instability indices, such as CAPE, and the rainfall amount are greatly fluctuated and becomes smaller than that of (3). These findings imply that it is difficult to use these instability indices in the discussion on the relation with the rainfall amounts, in this case.
(Tenki is the bulletin journal of the Meteorological Society of Japan in Japanese.)
TENKI, Vol. 66, No. 2, pp. 113-140, 2019
From the beginning of the Sino-Japanese War in 1937 to the end of the WWII in 1945, Japanese military occupied wide areas in East and Southeast Asia and the Western Pacific. Along with the extension of the front, Japanese military's weather surveys replaced existed local ones and interrupted their continual observation. In addition to ground observation, it carried out upper-air observation with pilot-balloon and radiosonde to support its air forces on the basis of the extended survey network. As for the data accumulated up to the end of the WWII by Japanese military, however, it has been believed that they were lost in the disturbances of war and to restore this wartime discontinuity is almost impossible.
Scrutinizing book stocks of several institutions at home and in the United States, such as the Library of Congress, the author found not a few unused materials, in which wartime weather data had been recorded. In this paper, following up the wartime vicissitudes of Japanese weather survey, he reviewed instructive cases, where such materials had been rescued successfully, in order to promote the efficient search of buried data in the near future.
(Tenki is the bulletin journal of the Meteorological Society of Japan in Japanese.)
TENKI, Vol. 66, No. 8, pp. 513-527, 2019
Using Vital Statistics data of the Ministry of Health, Labour and Welfare of Japan, regional and temporal features of cold mortality were analyzed with relation to temperature variations. For 16,573 deaths from "exposure to excessive natural cold (X31)" that is based on the Tenth International Classification of Diseases (ICD-10), mortality in each of the 47 prefectures was calculated after adjusting for differences in the age structure among prefectures and years. It was found that cold mortality is higher by about 12% in a prefecture where climatic-mean winter (December-March) temperature was 1ßC lower. For seasonal and interannual variations, the four months from December to March account for 78% of the annual cold mortality, and a winter of 1ßC lower mean temperature (December-March) has a higher cold mortality by about 20%. On a daily time scale, cold mortality is found to increase by about 15% for a 1ßC difference of daily mean temperature. These results indicate that cold mortality is dependent on climatological and meteorological conditions in each region and on a daily to yearly time scales, although the dependence is weaker than that of heat-stroke mortality.