(Tenki is the bulletin journal of the Meteorological Society of Japan in Japanese.)
TENKI, Vol. 61, No. 1, pp. 23-29, 2014
To research the distribution of air temperature in the city of Tajimi, Gifu prefecture, a total of 15 thermometers were placed at the schools and parks in the city of Tajimi, and the city of Kasugai, Aichi prefecture in August 2010. From the distribution of monthly average air temperature, air temperature at the center of Tajimi city was higher than the suburbs. Also, the days of daily minimum air temperature more than or equal to 25¡C and daily maximum air temperature more than or equal to 35¡C at the elementary school near the center of Tajimi city was more than those at other schools. This tendency appeared more clearly on the days of daily minimum air temperature more than or equal to 25¡C. Also, the air temperature near the center of the city was higher than that of the suburbs in the early morning. Thus, it was indicated that the air temperature was hard to decrease as the bottom of the basin. From these results, the influence of urbanization to the formation of the daily minimum temperature in Tajimi city was indicated.
(Tenki is the bulletin journal of the Meteorological Society of Japan in Japanese.)
TENKI, Vol. 61, No. 2, pp. 81-90, 2014
Data at 92 stations for 1951 to 2010 were used to examine large-scale distribution of extreme-value parameters of precipitation in Japan on the basis of L-moments. Annual maximum values of daily, hourly, and ten-minute precipitations were found to show statistically significant negative correlation to latitude, and positive correlation to warm-season total precipitation (P). For hourly and ten-minute precipitation, L-CV has positive and negative correlations to latitude and P, respectively, and L-skewness has positive correlation to latitude. These facts indicate a tendency of reduced sporadicity at stations in low latitude and/or with large warm-season precipitation amount, so that extreme short-term precipitation of long return periods tends to show reduced dependence on latitude and P. Although L-CV and L-skewness have variations among stations, those of L-skewness are within a range of statistical variability expected for a single GEV function. This situation raises doubts about the need of specifying shape parameters of extreme-value functions station by station, since L-skewness is related to the shape of extreme-value distribution.
(Tenki is the bulletin journal of the Meteorological Society of Japan in Japanese.)
TENKI, Vol. 61, No. 7, pp. 525-540, 2014
The present study analyzed the relationship between the stagnation or passage of the nocturnal local wind front and the atmospheric pressure field in surroundings. We used the atmospheric pressure data observed at the JMA observatories located in and around the central Tokyo, and that observed by the METROS network which had been installed in the Tokyo wards area. We focused on the period from July to August 2004 which was a hot summer. The results of the present study can be summarized as follows:
1) At midnight with weak wind when UHI developed, it was shown that local wind fronts advanced toward the central Tokyo from the inland side. The local wind fronts are grouped into two types from the behavior. One is "stagnation type" of which the front stagnates near the central Tokyo and does not head out to the sea. Another is "passage type" of which the front heads out to the sea as time passes.
2) In the case of the stagnation type, the front stagnates near the surface low pressure area in the central Tokyo, and the local wind system which advances from inland side and the southern wind which prevails on Tokyo Bay converges into the central Tokyo.
3) On the other hand, in the case of the passage type, the influence of the atmospheric pressure depression in the central Tokyo due to the UHI is weaker than in the case of the stagnation type. The local wind system which advances from inland converges with the southerly weak wind on Tokyo Bay.
4) Both types of the fronts were found when the atmospheric pressure gradient in surroundings was small. In this condition, the stagnation type front was found when the atmospheric pressure field in surroundings was higher in southern area. On the other hand, the passage type front was found when that in surroundings was higher in northern area. The present study showed that a minor difference in the atmospheric pressure field in surroundings greatly influenced the behavior of the local wind system and the stagnation or passage of the local wind front.