In order to make clear the influnce of a shelter-hedg on the sensible heat transfer from the surface of a greenhouse, experiments were carried out in field and in a wind tunnel, respectively.
The geometries of the greenhouse and the shelter-hedge are shown in Fig. 1. Similarity problem between field measurement and model test was examined by using the data of heat transfer at the outersurface of greenhouses which were protected from wind by the shelter-hedge. The results of the model test in the wind tunnel were in well accordance with those from field measurements (Fig. 3).
The effects of shelter-hedge on sensible heat transfer from the greenhouse were studied more minutely by using a model house in the wind tunnel. The results obtained are summerized as follows:
1) The average heat transfer coefficients of greenhouses with and without the shelter-hedge were calculated from eq. 5, respectively. Fig. 4 indicates the wind dependence of h_F/h_o (where h_F and h_o denote respectively the average heat transfer coefficients for greenhouses with and without the shelter-hedge).
The ratio h_F/h_o decreased firstly with wind velocity, reached the minimum at wind velocity of 2m/sec, increased secondary with wind velocity and became nearly constant in the wind range over 8m/sec.
2) The experiments were carried out under conditions that x=1·C, V_N=3.7 and 12.8m/sec and CL=60 and 50% (where z denotes the distance between the greenhouse and the shelter-hedge, C the height of greenhouse, V_N the wind velocity and CL the closeness of shlter-hedge) to find out the influence of height of shelter-hedge upon the heat transfer from the greenhouse. Experimental results indicate that the shelter-hedge higher than that of greenhouse is more effective from the standpoint of greenhouse heating (Fig. 5).
3) The infuluence of shelter-hedge on the heat transfer from the greenhouse was found to change with the distance between the greenhouse and the shelter-hedge, as can be seen in Fig. 6. These relations were approximated by concave curves. The minimum value of ratio h_F/h_o was found in the range from x=2·H to x=3·H.

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Transmission of solar radiation into greenhouses is an important factor in greenhouse design. Factors which influence the solar irradiation in a greenhouse can be divided into three groups. They are external, structual, and internal factors (see Fig. 1).
This paper describes an analytical method for calculating the direct solar irradiation in an isolated gable roofed greenhouse. The effect of the first and second order internal reflection in a greenhouse is taken into consideration. The effect of incident angle on the reflectivity and the decrease of the solar radiation due to the shading effects of the structural elements have also been taken into account in the computational model. But the thickness of the structural elements, the decrease of transmissivity due to flirts on covering materials, and diffuse transmission (reflection) due to water droplets condensed on them are neglected. The calculation, therefore, may include some overestimations for an actual greenhouse.
The computatianal procedure was prograammed for a computer, and was applied to four types of East-West oriented greenhouse: one of which is a usual glasshouse and the others are a glasshous with reflective mirror on the wall and/or roof. Calculations were made for the winter solstice at 35° latitude for use at Tokyo and smilar latitudes. The total direct solar radiation received by the floor of the house is assessed by summing the primary (or straight) and secondary (or reflected) direct solar radiation contributed by each wall and roof suface separately (see Fig. 2).
The following onoclusions were obtained:
1. The ratio of the daily integrated secondary solar irradiation on the floor to the direct irradiation outside is about 0.1 for a usual glasshouse placed in East-West orientation. But its distribution on the floor is not uniform.
2. The average total direct solar irradiation on the floor in an East-West oriented glasshouse with reflective mirror on the north side wall is more than the direct solar irradiation outside.

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The author observed the profiles of the wind velocity and of the snow temperature above a sea ice near Syowa Station in Antarctica.
The energy budget was expressed by the simple equation (1), as the sun rose scarcely above the horizon for all day long in winter (June and July). The turbulent heat transfer (Q_e) was calculated from the energy budget. The turbulent heat flux (Q_W) was obtained by the equation(2) including the wind component. The values obtained by two different methods coincided well, as the sun rose scarcely above the horizon. But, it was impossible to calculate the turbulent heat transfer in August and September, because the sunshine influenced the heat budget on the surface of a sea ice and the values of evaporation and sublimation became not negligible.

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The cocfficient of water-vapor transfer from the leaf interior to the surrounding air was evaluated in relation to wind speed and stomatal aperture, and the relation between transpiration rate and wind speed was quantitatively interpreted, after the simulation of the heat-budget of a leaf. The change in tht transpiration rate in the range of low wind speed was revealed, since the effect of transfer by free convection for the heat and water-vapor transfer over a leaf was added to that by forced convection. Moreover, the boundarylayer transfer coefficients including the factors of temperture variation on a leaf surface and the turbulence within a plant canopy were used for the calculation.
From a plant leaf, water is transported through stomates and cuticle, and then across the boundary layer on a leaf surface. Using the internal coefficient for internal transfer of vapor, D_L, and the external one for the bouneary layer, D_B, the transpiration rate, w, is expressed as follows;
w=2D_L⋅D_B/D_L+D_BΔ_cL, D_TR=D_L⋅D_B/D_L+D_B,
where DTR is called “transpiration-transfer-coefficient”.
D_B=D_n+D_f,
D_n and D_f are the water-vapor transfer coefficients for free and forced convections, respectively. D_n is given from the following formula,
Dn=A⋅f(Gr, Sc)d/l,
where f (Gr, Sc) is a graphical function of Gr·Sc, Gr; Grashof number decided from leaf-air temperature difference and vapor-concentration departure of the leaf interior from the ambient air, Sc; Schmidt number, d; molecular diffusivity of water vapor to air, l; characteristic length of a leaf.
D_f is written as follows,
D_f=Bu^0.5,
where u is wind speed, A and B; numerical coefficients.
Δ_cL is difference in water-vapor concentration between the leaf interior on the mesophyll cell walls and the ambient air outside the boundary layer, Δ_cL is expressed as follows, Δ_cL=C_L-r_A⋅C_A,
where C_L and C_A are the saturated concentration of water-vapor at temperatures of leaf and air, respectively, r_A; relative humidity of the air.
In still air, the transpiration-transfer-coefficient has a value determined from the internal vapor transfer coefficient and the external one for free convection.
In flowing air, increasing wind speed causes an increase in transpiration-transfer-coefficient. The increasing rate of the coefficient is large in the range of low wind speed and becomes gradually smaller with an increase in wind speed, until the coefficient approaches asymptotically to the value of the internal coefficient. The effect of wind speed on the increase in transpiration-transfer-coefficient is fairly large as stomatLs open.

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In this paper are presented results of numerical study of the humidity change of air-mass, which moves from the sea into inland. Simultaneous differential equations (see Eqs. 1-3) as nonstationary two-dimensional diffusion of heat and water vapor in the lower atmosphere and of heat in the soil layer were numerically integrated by the difference method on an electronic computer. Profiles of turbulent diffusivity were estimated on the basis of KEYPS equation, in which is considered the effect of stability of lower air layer on the turbulent diffusivity of earch physical quantity. In numerical experiments soil moisture condition is parameterized by μ(=e_s/e(T_o)). The sets of physical parameters used in the experiments are presented in Table 1.
The results obtained can be summarized as follows:
1) Numerical experiments indicate that a mean K-profile calculated at the fetch of 7km can be used in investigating the air-mass transformation as representative one with acceptable error, although the turbulent diffusivity changes initialy some what rapid in both the profile and abosolute values, as air-mass moves over land (see Fig. 3).
2) The height at which the difference of humidity (Δq=q(x, z)-q(o, z)) becomes 0, 1g/kg is adopted for characterizing (Z_H) the thickness of internal boundary layer developing over the surface Fig. 7 shows the fetch dependence of boundary layer thickness. These relationships can be approximated by (Z_H/L)=2.86×[(Kx/L²U)^1/2]^1.27, μ=0.4
strong wind (Z_H/L)=1.06×[(Kx/L²U)^1/2]^2.0, μ=0.25
weak wind (Z_H/L)=20.1×[(Kx/L²U)^1/2]^1.17, μ=0.6
(Z^H/L)=0.9×[(Kx/L²U)^1/2]^1.42, μ=0.4
The thickness of internal boundry layer is thicker for weak wind conditions than for strong wind conditions. With increasing surface wetness, the humidity boundary layer becomes thicker due to intensive supply of water vapor from the ground surface.
3) The part of diurnal changes of specific humidity, of temperature and of turbulent diffusivity are sensitive to the variation in thermal stability near the ground as shown in Fig. 10.
Mean values of turbulent diffusivity (case-1) are greater for dry surface than for wet surface (case-5) from 1.1 to 1.5 times, indicating that increased thermal instability under dry surface conditions causes more strong turbulent mixing.
4) Fig. 11 shows the variation in heat balance structure with the fetch. In the case of dry surface, total heat amount stored into layer during the daylight period was found to incease proportionally with the fetch.
On the other hand, total heat amount transferred from the ground surface into air layer as sensible heat flux during the daylight period decreased somewhat, mainly because of decrease of temperature difference between air layer and the ground surface. It appeared that the heat balance structure at the wet ground surface did not very change with the fetch.

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