The evaporation of raindrops in a sub-cloud layer and the change in the state of the layer by it were treated by numerical calculation. The layer is assumed to be uniform in the horizontal. In the model 1 air is assumed to be at rest and in the model 2 vertical airflow with constant velocity is assumed. Following conclusions were obtained. The amount of evaporated-water in the sub-cloud layer is large beyond expectation. The stability is changed by the cooling due to evapora tion. Pressure dome under a thunder cloud may be explained by the evaporation of raindrops in the sub-cloud layer. The size-spectrum of raindrops gives a significant influence on the changes in the state of the layer. There is considerably large difference between the amount of evaporated-water in updraft and that in downdraft.
This is continuance from previous papers by the authorl), 2). Fig. 3 shows the horizontal distribution of snow crystals during the snowfall on January 25, 1961. Photomicrographs of plastic replicas of these crystals are shown in Photos. 1-4. Characteristic of this snowfall was that the snow crystals fell from two cloud-layers ; that is, plate, stellar and column crystals fell from the upper layer, and needle crystals fell from the lower one. As seen in Photos. 5-7, the plate and column crystals from the upper layer developed along the c-axis during their drifting in the lower layer suitable for needle evelopment.
Electric charges generated by breaking of a piece of single crystal ice, polycrystalline ice including numerous bubbles, and polycrystalline ice including few bubbles were measured by the use of electrometers. The charge generated was only 5×10-3 e. s. u, cm-2 in single crystal ice, while in polycrystalline ice 1 e. s. u. cm-2 charge was obtained. It was found that in case the polycrystalline ice including numerous bubbles under temperature gradient was broken in two pieces, the warmer part was charged negatively and the colder part positively.
This study aims to obtain characteristics of some indices of solar activity and relations among them. First the following relation between sunspot number S and international magnetic character-figure C was obtained : C=α+S/(βS+γ) This equation holds good in both cases of annual and monthly means. Next the sunspot number was analyzed from the standpoint of view that the tide-generating forces of the planets affect the sunspot activity. In both cases of the earth and Jupiter, the revolution-period and its half period were detected in the variation of spot number. These variations differ at the increasing stage of sunspot from at the decreasing stage. Instead of individual analysis concerning with Mercury or Vienus, the combined effects of 4 planets were examined. As the result, 88.9-, 142.3-, 178-year period and other periods were brought to light.
The polar cap absorption (PCA) especially in twilight condition is considered taking into account of negative ion O- which is possibly formed through the charge transfer process, O-2+O→O2+O-+1.2eV(6) and it follows the negative ion in the upper mesosphere is not O-2 but O- in general, [O-]/[O-2]_??_α6/d(O-)[O] where α6 be presumably 10-11 cm3 sec-1 or so. Then the screening effect of O3 Chappuis bands absorption becomes important.