In the earlier paper (Nakagawa, 1977), the author has published the optimum Brunt type experimental formula for atmospheric radiation from a cloudless sky at Tateno based on theoretical calculations;
_??_
where ε₀=R_A/σT₀⁴ is the apparent atmospheric emissivity, R_A is downward flux of atmospheric radiation from the sky, 6 is Stefan-Boltzmann constant, To is absolute surface air temperature, and e₀ is surface water vapor pressure in mb. In reality, the sky is, however, nearly always cloudy. If clouds are present, the amount of downward longwave radiation from clouds is greatly increased and the cooling of the ground is correspondingly reduced. Consequently, when using the experimental formula for estimating atmospheric radiation, it is general practice to introduce the influence of cloudiness.
The general solution for the equation of longwave radiation transfer in the atmosphere is given by _??_ where B_v (T) is Planck's function, _??__f is the transmission function of a slab, v is wave number, n_i and T_i are, respectively, apparent fractional cloudiness and cloud base temperature of the i-th cloud layer. Subscription ∞ represents the top of the atmosphere. In the special case of n₁=n₂=n₃=0, which denotes a cloudless sky condition, the numerical calculation scheme of the solution has been established (Nakagawa, 1977). Therefore, it is of importance to determine n_i and T_i. In this paper, n_i is determined from the result of surface visual observation of clouds, T_l is assumed to be equal to the temperature of the convective condensation level, and T₂ and T₃, follow Katayama (1966). Values computed with the program developed in this paper are in good agreement with directly observed values at Tateno (see Fig. 1).
At four points in Japan, atmospheric radiation is calculated everyday in 1975 (see Fig. 2). After parameterizing the computed values, a new type experimental formula is determined as follows ;
_??_
The coefficient a_ij is determined by the least square method (see Table 2). These formulae explain more than 99% of total variance. Consequently, whichever formula may be used, the resulting estimated values are about the same. Since the above equation contains several layers of clouds, it is necessary to obtain cloudiness at several layers for the calculation of the emissivity ε_n. In practice, the accurate data of multiple layer cloudiness are not available, for this reason, the above equation is not suitable for the climatological studies. Another type formula with a use of total cloud cover is determined as follows;
_??_
The coefficient a_ij determined is given in Table 3. The values of percent of reduction decrease, these formulae explaining from 96 to 90% of total variance. This formula derived from data at Tateno or Kagoshima systematically underestimates downward flux of atmospheric radiation during winter at Wakkanai or Wajima which is located in the districts along the Japan Sea. If only one formula is applied throughout the country, one for Wajima is the most appropriate.
With a use of the formula for Wajima, monthly normals of net longwave radiation at 78 points in Japan are estimated (see Table 4). The isolines in the distribution map of annual normals of net longwave radiation (see Fig. 6) run parallel to the central mountain range, having a tendency to decrease from the districts along the Japan Sea to ones along the Pacific Ocean.

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The Arima-Takatsuki Tectonic Line (ATL), located on the northwestern rim of the Kinki Triangle, is an active fault zone developed along the geologic boundary separating the Tanba Zone of Paleozoic rocks to the north and the Ryoke Zone of granite to the south. Along the middle and eastern parts of this tectonic line, limiting the northern border of the Osaka Plain, displacements of terrain features, mainly terrace surfaces (dissected fans), due to fault activities can be clearly observed. The writer has investigated these displaced topographies and attempted to elucidate the nature of fault activities of the middle and eastern parts of the ATL. The findings can be summarized as follows.
1) Faults in this area, trending either E-W or ENE-WSW, can be classified into three types, those having: 1) displaced terrace surfaces vertically, and valleys cutting these surfaces dextrally, such as Kiyoshikojin and Satsukioka Faults; 2) formed shallow depression zones such as Hanayashiki, Koyaike and Ibaraki Depressions in the E-W direction on the terrace surfaces; and 3) cut through and displaced valleys in the mountains on the north, such as Ishizumitaki, Satsukioka, Minoo and Nyoidani Faults. 2) Rates of displacements have been computed by estimating ages of the terrace sur-faces and valleys dissecting these surfaces; for type 1), 0.5-1.5m/10³ years dextrally and 0.06-0.2m/10³ years vertically, and for type 2), a maximum of 0.8m/10³ years in vertical direction.
3) The active fault system of the Rokko Mountains is continuous to that of the study area. Active faults of both regions are distributed in the shape of E-W extending wedge, with the tip pointing to the eastern end of the study area. These fault systems have been active in the second half of the Quaternary under the stress field of E-W compression. Accordingly, NE-SW trending faults have greater amounts of vertical displacements than ENE-WSW trending faults, with both having dextral movements.
4) The Median Tectonic Line (MTL), bordering the base of the Kinki Triangle, is also an E-W trending geologic boundary. Along active faults associated with the MTL, the rates of displacements both in vertical and dextral directions are twice as great as those found for the active faults of the ATL. Distribution of type 3) faults of the ATL is similar to that of the MTL in the sense that both are located on the northern side of geologic boundaries.

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This paper analyses the composition of channel network, especially parameters of Horton's laws, and discusses the characteristics of drainage basins in Japan. Basic data are collected from 180 partial drainage basins in the whole country and 19 full drainage basins in Hokkaido.
Horton's laws of drainage net composition hold well in drainage basins of Japan as well as in drainage basins of other countries. Parameters of Horton's laws vary slightly from area to area and from geology to geology. Ranges of values of the bifurcation ratio, the drainage area ratio, and the stream fall ratio are about the same between the partial drainage basins and full drainage basins. There are some differences in the ranges of values of the stream length ratio and the stream slope ratio between the partial drainage basins and the full drainage basins. These values of the full drainage basins are greater than those of the partial drainage basins. It is considered that these differences are due to more frequent meandering of rivers in middle and lower parts of drainage system. The linear relation is found between the bifurcation ratio and the drainage area ratio, and the slope of its regerssion equation is nearly 1.0. It is interesting that the drainage area ratio is always about 0.4 greater than the bifurcation ratio.
The average of the bifurcation ratio of drainage basins in Japan is 4.24, which is greater than a theoretical value of 4.0. The average of the stream fall ratio is about 1.0 for drainage basins in Japan. Drainage basins are considered, in general, to be in the stage of maturity in stream channel development in Japan. As the stream channel is liable to develop on an originally inclined land surface, the frequency of excess stream is greater in Japan than in other continental countries. Although the stream bed is nearly in dynamic equilibrium, it tends to be slightly aggraded, especially in fresh volcanic rocks areas.

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