The adsorption of water vapor was measured at several constant temperatures from 0°to -15°C on the oxides of zinc, cadmium, nickel and copper by weighing method. The isotherms obtained are all of the sigmoid nature, but with some step-wise discontinuities. The heats of adsorption were calculated from the isotherms, those of the first to second layer being found higher than those of next few layers which approached the heat of condensation of water vapor. The data have been discussed in terms of two-dimensional transitions of state, taking into consideration the interaction effects between adsorbed water olecules together with the adsorption forces of the solid surface toward the layers of adsorbed water molecules.
Measurements of electric charge on a riming probe (an ice-coated metal rod) were made during the collision of supercooled droplets and ice particles with the probe under various condition in a cold chamber. It was found that the most important factors in the electrification of the probe were temperature, temperature difference between the probe and ice particles, and rate of riming. As the mechanism of the electrification, the following points were considered. 1. When the riming rate is high under favourable conditions, tearing off of fine structures of rime from the probe's surface is significant. 2. When temperature is relatively warm, e.g., warmer than about -10°C, tearing off of liquid-like film from the riming surface is effective. In the light of these mechanisms, local positive space charge in the lower part of thunderclouds and field pattern of wave type were explained.
Vertical profiles of the electric potential near the surface of snow cover were observed in drifting snow weather at Mt. Teine. From the profiles, the following vertical distribution of space charge near the surface was ascertained: a large positive space charge was distributed just near the surface, a negative space charge was distributed at about 80cm above the surface and further a small positive charge existed at levels higher than 1m. It is considered that these space charges resulted from the impact of snow pellets on one another, and that the space charges of the three categories were carried on larger snow pellets, smaller snow pellets and ions respectively from near the surface to the higher levels. These observations seem to be serviceable in explaining the confused discrepancies among the results obtained hitherto by Simpson, Kahler and Dorno, Yoshida and Ota.
A study of the vertical tilt of the planetary waves by means of the so-called 2-level, quasi-geostrophic model is performed. As the levels of modeling research, 250 mb and 750 mb levels are selected, the vertical p-velocity being zero at 0 mb and 1000 mb levels. Assuming the zonal basic current in the baroclinic channel, the simple sinusoidal disturbances are superimposed on each level. Since the vertical tilt of disturbances is roughly proportional to the zonally averaged value of the northward transport of sensible heat, the time evolution of the zonally averaged value of the transport of sensible heat is treated theoretically and the stability criterion for the development of disturbances is obtained. In case of the large amplitude of disturbances the different stability criterion is given, compared with that obtaind from the discussion of the linearized perturbation equation. The motion of the vertical tilt of disturbances with time is pseudo-periodic type, having a tilt to the east or west in the westerlies. When the upper trough moves faster than the lower one at the initial time, we expect the slowing down of the movement of the upper trough later and the lower trough moves relatively faster than the upper one. The pseudoperiod mentioned above is 3-15 days and it depends on the vertical shear of the zonal basic currents and also the intensity of disturbances.
The northward transport of sensible heat in the baroclinic atmosphere is examined in relation with the non-adiabatic heating such as the heat supply into the atmosphere from the ocean and also the condensation effect. The theoretical results mentioned above are compared in good agreement with the numerical experiments in two-level model which are performed as the modeling research. As the actual example of the treatment of non-adiabatic heating over the sea surface, the cyclogenesis over the Sea of Japan in winter season is discussed. Numerical forecast by making use of 4-level geostrophic model is shown. As another example of non-adiabatic heating due to the condensation effect, the numerical forecasts by using the actual data are discussed comparing with cases where the motion is adiabatic. It is also shown that the retardation of movement of lower trough or cyclone at the 1000mb level, which is generally expected near Japan from the forecast in case of adiabatic motion, is improved considerably.
Basic data are arranged to explain the author's newly proposed practical rules for predicting some chief characteristics of Bai-u in West Japan by the aerological data at MarcusIsland one month before. The rules are as follows : (i) Setting in of Bai-u for any year occurs 31 days after the appearance of phase " I ", i.e. the day from which onward the upper wind at 18km height over Marcus changes from westerly to easterly, and ending of Bai-u also occurs 31 days after the appearance of phase " S ", i.e. the day from which the easterly wind velocity at 18km height over Marcus becomes to exceed 10m sec-1 for at least 5 days. Accordingly, the days between phase "I" and "S" give the period of Bai-u for any year. (ii) The 31st day after the appearance of the peak (maximum) in T curve, i. e. a curve showing the day to day change of tropopause height at Marcus during phase I-S, corresponds to the principal rainy day of West Japan. Here the principal rainy day (PRD) is defined as follows : when the rainfall terminates in a day, its day is PRD, while, when the rainfall continues over two days, a day of the largest daily amount is PRD. (iii) If the easterly wind blows continuously during phase I-S, the rainy season of land rain and low temperature can be expected, and the dry rainy eason may correspond to a few occurrence of the easterly wind. And the other case corresponds to the rainy season of shower and high temperature. (iv) The larger range among mean wind velocity less than 10m sec-1 at 12Z of each day and that more than 10m sec-1 of the easterly wind during phase I-S, gives the largest amount of rainfall during Bai-u period. (v) The daily amount of heavy rainfall during the Bai-u period can be expected 31 days after the appearance of HR type i. e. the peak of T curves at Marcus Island corresponding to the trough at 100mb and 200mb levels.
Weather radar has played a significant role in detection of precipitation area, however, it has a weak point that its detectability lowers according as the distance to the precipitation increases. The lowering of detectability is due mainly to the following four factors. 1) Spread of microwave with its propagation 2) Attenuation of microwave by atmospheric gases, clouds and precipitation 3) Increasing of beam height with distance 4) Decreasing of “fraction of beam filled” with distance Among the above factors, 3) and 4) are difficult to examine, related to the three dimentional reflectivity distribution within target storm. Then the author tries to estimate statistically the effect of the respective factors on the lowering of detectability. It seems likely that the effect of “increasing of beam height with distance” is negligible within ca. 130km (the minimum attainable beam height of 2000m) on an average. And it would seem that within ca. 130km the lowering of detectability is due mainly to the effects of “spread of microwave” and “attenuation by atmospheric gases ”.