In the first part of the present inquiry, we calculated the, effective (outgoing) radiation in the free atmosphere at any level above the ground. confining ourselves to the case in which the sky is clear (Tab. 4). The result of this computation seems to be in accordyance with what is reached by the common sense; for example, the effective. radiation increases in proportion as the temperature grows or in approaching the ground from the higher level. At some level lower than 1km, it seems that there exists a layer of inversion with respect to the outgoing radiation, but the detail of which was not examined in this preliminary report. From the result of this computation, the geographical distribution of the outgoing radiation was calculated and shown in Fig. 3 and Fig. 4.
In the second part of this paper, the foregoing theory was extended to the case of the overcast sky (Tab. 5 and Figs. 5-10). From these Tabs. and Figs.. we can draw the following evidences:-
(i) In the atmosphere between the ground and the cloud sheets, the outgoing radiation diminishes as we go up from the ground toward the upper layer, regardless of the height of the cloud sheets. The ratio of this decrease incrases in proportion as the temperature at the ground grows.
(ii) When the height of the cloud sheet is fixed, the radiation at any level is also nearly proportional to the temperature near the ground.
(iii) At any fixed level above the ground, the radiation is nearly proportional to the height of the cloud sheet, the ratio of this increasing, and hence the difference of radiations at two different levels, is greater in proportion as the airtemperature grows coming nearer the ground.
(iv) When temperature is fixed, the distance between the two sheets of cloud which corresponds to the constant difference of radiation is almost independent of the height of level under consideration.
(v) The distance between the two levels in the atmosphere which corresponds to some constant difference of radiations generally diminishes with the temperature near the ground. Higher the temperature, the more remarkable is the variation of outgoing radiation with respect to the vertical distance, but when the temperature is fixed at a certain point, the ratio, of this variation is almost independent of the height of the cloud sheet.
In the third part, the results of the investigations in the two preceeding cases-clear skies and overcast skies-are combined, and the general cases in which the sky is partly covered by the cloud, were investigated. The mean cloud amount for the respective zone of latitude was taken from Brook's Table, and assuming the mean height of the cloud over the whole earth to be 5km, the geographical distribution of the terrestrial radiation at the ground was computed and shown in Fig. 11. From this Tab. or Fig., we can see that the radiation (outgoing) equator moves from latitude 0° (in winter) to about 30°N (in summer), just the same as the seasonal movements of the thermal equator of the temperature of the air.
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