The diurnal variation of the wind and temperature fields in the Ekman layer is studied by solving the equation of motion and of heat conduction. Eddy diffusivity is assumed to take the values which are evaluated by the extrapolated use of a modified KEYPS equation to the Ekman layer. With regard to the boundary conditions, the standard lapse-rate is assumed at the upper boundary and a constant temperature is assumed at the lower boundary which is set up in the soil. In this kind of study, hitherto, the constant flux layers near the surface are assumed in order to avoid a large amount of calculation, but in the present work, the original prognaustic equations of the whole layer are directly integrated by use of the matrix method for finite difference equations. Computation is carried out until cyclic solutions of one day period are obtained.The computed results are compared with observations available to us at present.

Assuming a steady and horizontal flow and thermal stratification in the Ekman layer, it is investigated how the wind structure in the layer is affected by thermal stratification. For this purpose an extrapolated application of the turbulent transfer relations, which hold in the lowest tens meters, to the entire layer is made. The wind and stress vectors and exchange coefficient are calculated numerically as functions of height, thermal stratification and roughness parameter. It is found that the shape of the Ekman spiral is affected by thermal stratification in such a way that the wind component normal to isobar increases generally with increase of stability. It is also found that the magnitude of the stress decreases with increase of stability, that the wind speed in the lower layer decreases with increase of stability, and that the height of the Ekman layer increases with increase of instability. Comparison of the calculated results with observed data is made on the surface values, indicating fairly good agreement._

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The turbulent exchange coefficient