In this study, the retailing system in Kushiro City was investigated separately in the daytime and in the morning and nighttime in 1988, and the relationships between these two urban retailing systems is discussed. In order to clarify this urban retailing system, a classification of retail areas was made according to the models presented by Kiji (1975, 1988). First, retail areas were classified in terms of the trade type within each area. Second, retail areas were classified in terms of the process of modernization within each area. Finally, the relationships between the two classifications was examined. The results obtained from the analysis are summarized as follows:
1. As a result of the grouping of retail trade type in the daytime, five groups were derived: highorder functions; middle-order functions; low-order functions; fresh-food functions; and automobile row and gasoline stations. Next, as a result of the grouping of retail areas in terms of trade type, four groups were derived: the high-level centers; the low-level centers; the group characterized by freshfood functions, urban arterial functions, automobile row functions and high-order functions; and the group which is characterized by automobile row functions and gasoline stations. The former two groups are collectively regarded as a “nucleated” set, and the latter two as “ribbons.” As a result of the grouping of retail areas in terms of operating variables, the most modernized level, the intermediate level, and the traditional level groups were derived.
2. In a comparison with the classification of retail areas in terms of trade type and the classification of retail areas in terms of operating variables, the final classifications of the modernized nucleated centers, the traditional nucleated centers, the neighborhood centers, the modernized ribbons, and the traditional ribbons were derived in the daytime. Kushiro's urban retailing system in the daytime is discussed in the following. The modernized nucleated centers, the traditional nucleated centers and the neighborhood centers may be functionally compared with nucleated centers. Meshes that belong to the neighborhood centers are very small in number. The modernized nucleated centers are most frequently observed in the CBD where ten type 1 large-scale retail stores and many multiples are located and high-order and middle-order functions are dominant. The traditional nucleated centers, which are characterized by the smallest and unincorporated retailing and the high-order and middle-order functions, are widely distributed throughout the old built-up areas except for the CBD. The modernized ribbons extend continuously along Route 38 in the western parts of Kushiro. These modernized ribbons may be compared with “automobile rows.” Meanwhile, the traditional ribbons are located continuously in the northern parts of the built-up areas.
3. As a result of the grouping of retail trade type in the morning and nighttime, four groups were derived: high-order functions; low-order functions; fresh-food functions; and automobile row functions and gasoline stations. Next, as a result of the grouping of retail areas in terms of the trade types, three groups were derived: the group compared with nucleated centers; the group characterized by fresh-food functions; and the group characterized by automobile row functions and gasoline stations. As a result of the grouping of retail areas in terms of operating variables, the most modernized level, the intermediate level, and the traditional level groups were set up.

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The simplest expression of the urban surface is alternation of buildings and streets. The space above a street between buildings is called an urban canyon. Air circulation in an urban canyon, which affects the behavior of air pollutants emitted by motor vehicles, is a significant factor in investigating the urban environment. However, because of the difficulty in installing observation equipment, few observational studies on air circulation have been conducted in actual urban canyons. In the present study, in order to detect three-dimensional air circulation in an urban canyon quantitatively, three wind vector components were measured using interval camera and tracer balloons with a known ascending rate. The three-dimensional position of the tracer balloons was determined by microscopic measurements of the position and diameter of the balloons on the negatives taken at an interval of two seconds (Fig. 2, Photo 1). Thereafter, wind vectors that drive the tracer balloons were calculated by subtracting the ascending rate of the respective balloons from the vectors of balloon movement. The direction and length of the target canyon, located on the former campus of Hiroshima University in Hiroshima City, are NNW-SSE and about 80m, with canyon height and width of about 18m and 25m, respectively (Fig. 1). During the observation periods, wind at 3m above the rooftop level blew obliquely to the canyon direction, and wind velocity ranged from 1.6 to 2.3m/s (Table 2).
The results of observations can be summarized as follows:
1) Measurement of air circulation using tracer balloons and interval camera is a simple method for the setup of observation equipment, and can be used without serious error (Table 1). Therefore, this method is applicable to actual urban canyons.
2) Although there were marked contrasts in the distribution of air and surface temperatures in a canyon, no significant difference was observed in air circulation between approximately noon and during the afternoon (Fig. 4). Therefore, the air circulation detected in this study could be induced mechanically by downward air motion due to the blocking effect of leeward buildings. Air flow parallel to the canyon direction was in a spiral stream (Fig. 3). Moreover, the intensity of circulation defined as wind vorticity (Fig. 5) in the cross-section of the canyon correlated positively and significantly with the wind component perpendicular to the canyon direction at 3 m above the rooftop level (Fig. 6).
3) Wind velocity parallel to the canyon direction increased toward the leeward canyon direction (Fig. 3 (b), (c)). The increase in the wind component rate parallel to the canyon direction was nealy proportional to the downward wind velocity at the canyon top (Fig. 7), i.e., the net downward air flow from the canyon top should accelerate wind velocity in the canyon along the canyon direction.
In conclusion, it was observationally confirmed that air circulation in the urban canyon spirals with descending and ascending motions on the leeward and windward sides of the canyon versus to the wind aloft, respectively. Moreover, the intensity of air circulation varies according to the wind velocity aloft, and wind velocity parallel to the canyon direction is accelerated by net inflow from the canyon top. Since the wind conditions in the present observation were rather limited, further observations are needed for various wind velocities and directions.

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The objective of this study is to trace in detail the relocation process of households within a metropolitan area. Here relocation is defined, under the methodological perspective, with reference to the life cycle of each household. The empirical data set is based on the results of a questionnaire focusing on married households, which were surveyed in Kawagoe City, Saitama prefecture, in 1990 and 1992.
As the first step, a certain general trend was detected with regard to the frequency and period of each household's residential relocation. It centered around once and/or twice in frequency, concentrating on the “child-bearing” stage. Moreover, it tended to overlap with the period of initial home ownership, and its mobility also showed a tendency for a sudden decline after that period.
Secondly, a correlation was found between the style of ownership and household relocation. The three dominant patterns of house ownership change were as follows: 1) from “rented” to “rented, ” 2) from “rented” to “owner-occupied, ” and 3) from “owner-occupied” to “owner-occupied.” These correspond approximately to the respective changes in the phases of family life. The distance moved showed the maximum within the 20km range. In case 2), however, another peak in frequency was found between 20 and 30km; this may be called “leap-frogging” moving. There was no clear-cut tendency in direction in cases of 1) and 3), which are moves without status change. Case 3), for ownership acquisition, also suggested an underlying tendency in direction.
The residential mobility of each household had a fairly low score in general, except for such limited involuntary factors as a second marriage, the death of a partner and/or a change in job location or of the job itself. This indicates the relative “durability” of the term of home occupancy in the house acquired up to the stage of family expansion or child-rearing. There also exists a sharp distinction between a random move within a certain limited distance and a rather spatially biased one that encompasses a fairly wide area; that is, the former corresponds to moves without a change in ownership status in the pre-child or child-rearing family stage, and the latter to moves at the stage of the first house ownership acquisition. All the findings in this study support the following sequential process: 1) the residential location at the household stage of pre-house ownership works as a robust factor constraining the location of the houses of initial acquisition; and hence 2) the “locus” of initial acquisition constrains the relocation process of household residential behavior after that stage.

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