Many theories of climatic classification and of division of climatic regions of the world have been presented in general books on climatology and on physical geography. However, few reports trace the current of thoughts synthetically from the very root of studies up to the present. In the present paper the author has an object to follow the development of thoughts successively and point out how the thoughts of significance had been exploited and developed further. This paper consists of three parts ; namely, an examination of effective methods, a discussion of the problem of humid and arid boundary, and an examination of genetic methods.
Effective methods since the 1840's are examined. Some earlier works by Hult, Supan, Köppen, de Martonne, Philipsson etc. were followed by several modern works by Blair, Trewartha, Creutzburg Troll, etc. Special attention is paid to make clear the current of thoughts, regarding representative standards for clamatic classification and for objective divisions into climatic regions.
Then, the problem of the boundary between humid and arid regions are reviewed and examined. The concept of effective humidity originated in Linssers's earlier work has been developed by various successors, in order to make clear the water budget or the limit of arid region, indirectly. Physiogeographic consideration by A. Penck was a pioneer work of importance. After genealogic consideration of various methods for evaluating aridity of climate (indices such as Regenfaktor, indice d'aridité, quotient pluviothermique, precipitation effectiveness etc.) and their applicability to distinguish humid and arid climates, the author examines concisely the approach to the rational classification of climate introduced by Thornthwaite, and developed by his successors.
It is also pointed out that there are two currents of thoughts regarding the main division of climatic regions of the world. One is to divide, except for the polar region, the world into humid and arid regions, then to subdivide the former into thermal zones and the latter into regions depending upon the degree of aridity. The other is, on the contrary, to divide the world into several thermal zones, and then to subdivide them into subregions, based upon the degree of aridity or humidity of climate. The standpoint of these approachs, therefore, are different to each other.
Finally, genetic methods of classification of climate and their applicability to the presentation of climatic regions are examined. The root of such a current could be found in the early works on wind systems or windregions of the world introduced by Mühry, Wojeikof, Köppen, Hettner etc. during the latter half of the last century and the first half of this

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Though the need for demand management is emphasized for solving the water supplydemand problems in Japan, there is little detailed information about actual conditions of water use. The objective of the present study is to clarify the residential water demand structure in the Ashida river basin, located in the eastern part of Hiroshima prefecture, with a drainage area of 900 km² (Fig. 1), by using individual data. Water demands for municipal and industrial sectors have been rapidly increased with urbanization and industrialization since 1960. In 1975, Fukuyama city had a total population of 330, 000 and a total amount of water use of 1.3 ×10⁸m³.
A questionnaire survey of 3, 200 households is conducted to obtain information on the factors which have any effects on residential water use. The monthly or bi-monthly water use series of individual households are transcribed from meter books of each municipality for the 1975, 1976 and 1977 fiscal years.
In the present study, the following three types of residential water demand models are tested using linear equations. Model A with income variable is used for all of the households which offer the available sets of data (Sample f) . Models B and C, which contain dummy variables on water-saving, and income and price variables, are used for the households utilizing their water only for residential purposes (Samples pi and V).
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where Rw is the amount of municipal water use in m3/household/year, Np the number of persons in household, Nb the number of babies (less than two years old) in household, In the income in million yen/household/year, Pr the average price of water in yen/m³, and others are dummy variables except of regression coefficients, ai, bi, and ci (Table 1). Regression coefficients of a₃, b₂, b₃, b₄, c₂ and c₆ are expected to be negative, and all of other regression coefficients with the exception of constant termsa₀, b₀, and c₀ are expected to be positive.
The results of a sample survey are summarized as follows ;
1. The mean values of Pw (public water supply), Gw (ground water use), and Tl (flushtoilet use) show the wide regional differences, but there are no remarkable differences in the mean values of other variables (Table 3). The seasonal variations for residential water use show a minimum of 78% to 87% in winter and a maximum of 114% to 130% in summer.
2. The regression analyses using Models A, B and C are listed in Tables 4, 5, and 6. Each equation is the “best” one that yields the expected signs of regression coefficients and no longer explains a significant amount of the remaining unexplained variation by adding another variable, among all equations having every possible combination of explanatory variables. A significant portion of the variation in residential water use can be explained by the variables of the number of persons in household (Np), and the presences or absences of ground water use (Gw), of flush-toilet use (Tl), and of non-domestic water uses around the house (Nr and Ot). The obtained results agree entirely with the previous study of Tachikawa city (Shimmi, 1977).
Table 7 shows the household-size, income, and price elasticities evaluated at the mean of respective variables by using individual data. The household-size elasticities are in the ranges of 0.41 to 0.45 for Sample i, of 0.30 to 0.73 for Sample JV, and of 0.38 to 0.51 for Sample V. These ranges are consistent with the previous estimates. The income elasticities range from 0.01 to 0.22 for Sample III, and from 0. 01 to 0. 11 for Sample V.

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The main purpose of the present study is to clarify the profile of air flow in the canopy layers. In a study of the atmospheric boundary layers, under neutral stabilities, the following basic equations are given in the canopy layers by Takeda (1965):
where τ is the vertical transfer of momentum, ρ the air density, C the constant proportional to the drag coefficient of the individual roughness element, F the leaf-area parameter, u the wind speed, K the eddy diffusivity and α the constant. F denotes the degree of the growth density of vegetation, being assumed to take the value between 0 (without vegetation) and 1 (completely dense growth). From the above equations following secondorder differential equation is obtained:

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