Journal of the Meteorological Society of Japan. Ser. II
Online ISSN : 2186-9057
Print ISSN : 0026-1165
ISSN-L : 0026-1165
Volume 21, Issue 5
Displaying 1-6 of 6 articles from this issue
• Y. Takahasi
1943 Volume 21 Issue 5 Pages 225-246
Published: 1943
Released on J-STAGE: February 05, 2009
JOURNAL FREE ACCESS
• S. Sakuraba, K. Maki
1943 Volume 21 Issue 5 Pages 246-251
Published: 1943
Released on J-STAGE: February 05, 2009
JOURNAL FREE ACCESS
The computation of vertically labile energy widely applied in the adiabatic chart starts from the assumption that one and only one element of air rises in some manner through the stationary environment, and this is called the parcel method in S. Petterssen's terminology. Actually the integrated effect of the large number of particles making up the air column should be considered (slice method).
Developing Margules' classical theory on the energy of storm, one(1) of the authors recently calculated one example of “feuchtlabile” energy, taking into account both the ascending and the descending currents and found that the moistlabile energy is very small even in a layer of lapse-rate 3/4_??_, where _??_ is the dry adiabatic lapserate. This is because the descending current consumes the greater part of condensational energy in the atmosphere of conditional instability.
The result is very important and further investigation is desirable. Thus the present authors intend to discuss the potential energy of vertical air column unstably stratified, adopting the slice method of energy computation.
First, consider a heavy cold mass of air 1, above a potentially warmer mass 2. Each dry mass has a uniform lapse-rate smaller than the dry adiabatic and the temperature is discontinuou only at the surface of separation of the two masses. Thus the entropy increases upwards uniformly in each mass and makes a jump at the boundary of the two masses.
The interchange of the masses should occur in the form of vertical mixing, because there exists a relation that the entropy of mass 1 at pressure p1, is equal to that of mass 2 at pa.
The result of numerical evaluation is as follows.
The above table shows that the available energy decreases with the stability of the layer.
The problem of moist-labile energy will be reserved for the second part.
• S. Sakuraba, K. Maki
1943 Volume 21 Issue 5 Pages 251-259
Published: 1943
Released on J-STAGE: February 05, 2009
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Consider a vertical air column of depth h. The pressure is p0 at the ground and pn, at the top. The lower part from p0 to pi (pn<pi<p0) is saturated and ascends wet-adiabatically, while the upper part from pi to pn descends dry-adiabatically. A constant lapse-rate α is assumed, and at the boundary pi there exists no discontinuity of temperature, therefore the energy releasable by such an overturning, if any, is nothing but the moist-labile (feuchtlabile) energy.
The energy equation has been derived and the result of numerical evaluation is as follows:
It is seen here that the moist-labile energy is generally very small in the atmosphere of conditional instability.
• M. Ota
1943 Volume 21 Issue 5 Pages 259-263
Published: 1943
Released on J-STAGE: February 05, 2009
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Some measurements were made on the electricity of snow at the Observatory on Mt. Fuji (3776m). The results were as follows:
(1) Most of the snow particles, drifted by wind from the surface on fine days, were charged positively, and had the mean charge of 7.4×10-4 e. s. u. per particle.
(2) The snow particles scooped at random from the snow surface were all charged positively, and had the mean charge of 4.7×10-4 e. s. u.
(3) The snow flakes (nucleus) were all charged positively. The nuclei were 0.2_??_1mm long and had a charge of 1_??_4×10-4 e. s. u.
Soft hails had both kinds of electricity, the ratio of the numbers of each was 1.4 and the mean charges were +28, -33×10-4 e. s. u. (max. reached +67, -80×10-4 e. s. u.)
(4) On rubbing snow particles against each other, it was found that a large quantity of electricity was easily obtained in this way. In this experiment, negatively charged particles were often observed, and we could not reach any conclusion on the mechanism of electrification.
• S. Kasahara
1943 Volume 21 Issue 5 Pages 263-266
Published: 1943
Released on J-STAGE: February 05, 2009
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When the rain drop falls through the atmosphere, it always meets with air resistance, and gradually condenses or evaporates. Then the falling velocity of the water drop varies with time. The equation of the motion of the water drop is as follows where σ, is the density of the water drop.
p, the density of the air. φ, the coefficient of air resistance. I have solved the equation by means of the Bessel function and have calculated numerically.
• M. Furuiti
1943 Volume 21 Issue 5 Pages 267-271
Published: 1943
Released on J-STAGE: February 05, 2009
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Recently, it is often found that the regulating weight of the float of Dines' anemometer, changes gradually from its certificated value. To search for its cause, I have done experiments on the following two cases.
(1) The effect of the weight of water which condenses on the surface of the float above water level. I have confirmed that, about ten days after a Dines' anemometer was set up, 0.4 gramme of water has condensed on the surface of the float above water level. On the other hand, experiments showed that the water remaining on the surface of the float after being sprinkled on it amounted only to 2-3 grammes.
Accordingly, condensed water will not exceed 4 grammes on the outer and inner surfaces of the float above water level.
(2) The effect of water temperature on buoyancy.
I have experimented so that, for example, the regulating weight should increase about 8 grammes by water temperature descent from 28°C to 10°C.
Of the two causes, the latter is larger.
Thus, in reality, the regulating weight varies mainly owing to the above-mentiored two causes.