This study was undertaken to clarify the secular variation in the occurrence rate of convective rainfall across the Kanto district during summer. The data used for this study were hourly precipitation (108 locations) from AMeDAS observation sites in July and August between 1980 and 2009, and daylight hours and wind direction/speed (73 locations).

First, 850 sunny days were selected for which synoptic-scale disturbances in and around the target study area were not analyzed with the data from the 00UTC weather chart and AMeDAS daylight hour data. The rainfall occurring on these sunny days was considered to be due to a convective system accompanying the solar heating of the ground surface.

There are three types of secular variation in the occurrence of convective rainfall. When there was an increase in the occurrence rate of type-I convective rainfall, there was a secular decrease in the occurrence of type III. Consequently, a negative correlation between types I and III was confirmed. When the geographic distribution of each type was compared by quantity, type I was distributed in the northern Kanto mountain ranges, while types II and III were distributed the foothills of the northern mountains and southern Kanto. An increase in the occurrence rate of convective rainfall and secular tendencies were confirmed for type I. In contrast, for type III, while the intensity and frequency of convective rainfall both decreased, the intensity of overall rainfall increased.

In conclusion, this study highlights the importance of discussing the secular variability in the occurrence of rainfall in southern Kanto including the Tokyo metropolitan area in relation to secular variation on the Kanto district scale. Furthermore, the variability should be analyzed while taking the speed of land and sea breezes into account, along with synoptic-scale disturbances in rainfall intensity.

While the World Heritage Convention is aimed at the evaluation and protection of natural and cultural heritage registration on the World Heritage List is also utilized as an effective means for tourism development in local areas. Many examples of the transformation of tourism have been reported at World Heritage Sites after registration. Especially when areas were underdeveloped as popular tourist sites, registration as World Heritage Sites can change not only the number of visitors but also their type from allocentric to psychocentric. Cases of remote islands isolated from urban areas are good examples.

The purpose of this study was to examine the qualitative as well as quantitative transformation of tourists visiting the Ogasawara Islands, oceanic islands located approximately 1,000 km from the main islands of Japan, before and after World Heritage registration in 2011. As methods for the measurement of the qualitative transformation, tourists' characteristics and behavior before and after registration were compared, focusing on the frequency at which they had visited Ogasawara in the past, the length of stay on a single trip, and places visited during the stay, as well as their age and occupation.

The number of tourists not only increased after the Ogasawara Islands became well known but also several marked changes in their characteristics and behavior were seen after registration. Before registration, many tourists in Ogasawara felt strongly attracted to and had a special feeling toward the islands, and repeaters, single travelers, and long-term stay travellers were typical. This showed that allocentric tourists to Ogasawara were more common than psychocentric ones before registration, probably because the locational feature of the islands meant that a relatively long time was necessary for a visit. After registration, however, single travelers and repeaters decreased in number as well as in rate, and the percentage of psychocentric or mass tourists who stay for shorter times and take part in many guided tours increased. Meanwhile, because a single visit still requires at least several days, much of the increase in tourists comprise students and the elderly. Considering the limitations of accommodation and transportation, it is not yet clear whether these tendencies will continue and expand in the future. However, tourism in the Ogasawara Islands could change fundamentally depending on corresponding changes on the receiving side such as tourism agents and local administration.