In this note are described a device of measuring the transmission of light through lake water, and some r_??_ults of test observations made in Lake Kawaguti and Lake Saiko of the Fuji Lake District toward the end of August, 1935. Beside, in the scheme of our work are inc_??_uded some other physical as well as chemical observations. The transmission apparatus consists of two cylindrical metal vessels which contain an electric lamp and a photo-cell respectively, sealed waterlight and rigidly co_??_nected each other by means of four brass rods having a free space between the windows at the ends of the _??_ylinders. The cell and lamp are connected to a microamme_??_er and to a battery respectively by means of cables so as to enable us to read the photo-cur_??_ent intensity at any moment when the light is switched on, the whole instrument being hung down into the water up to a desired depth. Though the instrument gave incredibly high values of transmission coefficient of water, it is thought to serve for determining the general character of the distribution of turbidity. The observations were confined to the middle part of each lake. In each series of observations an abnormally turbid layer was found at a certain depth which corresponds to the layer of the maximum gradient of temperature. its existence is attribu'ed to the possible invasion of colder shore water creeping under the warmer surface water brought down along the mountain slope after being precipitated. The authors also describe a plan of improvements of the instrument which seems to be necessary in giving more reliable values of transmission coefficients. At the same time, some chemical constituents of water were determined and meteorological effects upon the chemical composition were discussed. There was found no apparent relation between the change, with depth, of the light transmission and that of chemical composition.
Heavy rainfall was experienced in Kwantô district from 21st to 26th September, 1935, when the precipitation amounted more than 600mm in mountainous region. 1) Heavy rainfall of the first period: A line of discontinuity laid in the offing of Kwantô and Tôkaidô from 21st to 23rd, which had the structure of warm front, but scarcely changed its location throughout the period. In this case the rainfall limited on the northern side of the line of discontinuity and the amount of precipitation decreased according the distance from the line 2) Heavy rainfall of the second period: The second line of discontinuity, which extended from northeast to south-west and swept over Kwantoô toward north-westwards, accompanied by heavy squall going ahead it. The first squall (A group) broke out near Suruga Bay and advanced east-north-eastwards with velocity 47km per hour. This direction seemed to run rather parallel to the line of discontinuity and did not coincide with the upper air current. The second squall (B1 group) broke out in the south-eastern part of Kwantô district along the line, parallel to and ahead the line of discontinuity. This squall advanced north-westwards. 3) Heavy rainfall of the third period: After the passage of second line of discontinuity, heavy rainfall accompanied by thunder storm occurred in the mountainous region of the western and north-western parts of Kwantô. This heavy rain seemed to occur excited by the ascending current, due to the orographic effect of the mountain on the south eastern tropical maritime air mass. 4) The inclination of the first surface of discontinuity was 15', which had been determined by the observation on the earth's surface and Mt Ibukiyama. On the other hand the inclination of the second one was about 1°, determined by the vertical distribution of equivalent potential temperature. 5) A relation is calculated between the intensity of rainfall ds/dt, horizontal wind velocity in the upper warm air of the surface of discontinuity υ, inclination of the surface of discontinuity ε1, the height of upper warm air /H, and the density of air ρ1, mixing ratio w1, and temperature of /T1 at the lowest part of warm air respectively. The relation is as follows: where β is the lapse rate, R is the gas constant, g is the acceralation of gravity and log10b is 2308. The numerical values within the blacket of the equation were calculated in a table, for every values H and T1. 6) The vertical velocities of the warm air of the second surface of discontinuity, calculated from the maximum intensity of rainfall observed at twelve stations by the method of above mentioned, does not exceed 1 meter per second, with the assumption that the upper limit of the warm air is 8km from the sea level. 7) The mechanism of the first surface of discontinuity is the common one which appeared in many text books of meteorology. But the mechanism of the second surface of discontinuity, which is also a kind of warm front, is very complicated, compared with the former, for the sake of the steep inclination of the surface of discontinuity, and heavy squall advancing parallel and perpendicular to the line of discontinuity, which suggests the existence of violent vertical current within the warm air. 8) The vertical structure of the cold air is very stable while the warm air is conditionally unstable and has abundant humidity. Therefore it should be able to cause the heavy rainfall. 9) The mechanism of the advancement of the heavy squall seems to be, that the breakage of instability occurred at some place, propagates to the direction of more u stable structure, and never propagates according with direction of the upper air current. Explanation of the Illustrations.
On the 24-25th Sept. 1935 the warm front was observed in the KwantÔ distric_??_and brough_??_ there the heavy rainfall. (See T. Ootani and K. Sone's paper). In this paper the present authors have investigated on the characteristic features of the line of discontinuity which was caused at the warm front. It was found that the line of discontinuity marched to NW-wards to the KwantÔ district from the SE-ern sea with a velocity about 3-4m/sec and went up generally the river Tone forming a wedge-like line. The inclination of the surface of discontinuity was found to be about 40'.
It is a well-known fact that the coefficicnt of the molecular viscosity in air is found to increase with air temperature. For instance, an empirical formula given by Grindy and Gibson is as follows1); η=0.0001702(1+0.00329θ+0.0000070θ2) in c. g. s. units, where θ is the temperature in Centigrades. Afterware's, some analogous empirical formulae have been obtained by Rankine2), Millikan(3) and others. Correspondingly, it will be seen that the coefficient of the eddy viscosity increases with air temperature. On both theoretical and observational grounds, L. F. Richardson(1) believes that, eddy viscosity depen_??_s on the temperature difference between ground and air and on the wind velocity. In order to determine approximate'y the quanti ative relationship from the pilot-balloon observations with single theodolite; H. M. Treloar(2) has expressed it as follows: ν=70(1+0.1T)V, in which V is the wind velocity at a height of 50 meters, T the difference of temperature in Fahr. between surface soil an_??_ air at 10 feet. Here, the basis of his method rests on the assumption that the coefficient of surface friction is a universal cons ant. In this paper, we determined the eddy viscosity from an empirical formula of the ascending velocity of the pilot-balloon. When the compres-sibility of air has to be allowed, for the total resistance to the translation through an air of the balloon, in the corresponding directions, we are led by consideration of dimensions to a formula where α is the radius of balloon, ν is the kinematic coefficient of eddy viscosity, κ denotes the elasticity, viz. κ=ρ dp/dp. V is the ascending velocity of the balloon, and ρ the air density. Also, ζ is a numerical constant depending on the nature of the surface of the balloon, and n and m are the constants to be determined. Here, the force Qg is the excess of the gravity of the balloon over its total lift of the hydrogen gas, viz. where Ρ denotes the density of air, σ the hydrogen gas in the balloon, and g the acceleration of gravity. Let Lg denote the free lift of the balloon and W the weight of it, hence we have R=(Q-W)g=Lg at any height, where the balloon balanees between its resistance force and lift. It follows, substituting from (1) and (2) the coefficient of the kinematic eddy viscosity gives By using the boserved pilot-balloon's data from the double theodorite made at Haneda branch station of the C. M. O. located in the compoun 1 of the Tokyo Air-port from Sept. to Dec. in 1934, the values of n and m were found viz. n=1, m=1.591.(1) At the stational state of the atmosphere, we may put ∂p/∂z=- ρg and T=Ts-δz, hence we have dp/dρ=g/g-δR_??_RT in which R is the gas constant and δ the lapse rate of the atmospheric temperature. Wherefore, on making these substitutions, the expression (3) becomes From the data obtained by the observations made with the double theodolites from July 1932 to August 1933 at Haneda, (2) we found the value of_??_as the function of the surface air temperature (ts). This empirical relation may be written in the form in c. g. s. units and ts is in Centigrade. Let us put v0 as the value of ν when p=760mm, ts=0 and at the ground z=0, we shall have in c. g. s. units. Now we may neglect the small terms of the developed equation of (4) for obtaining a first approximation, and by the substitution of (5) in (4), we get the equation of the coefficien of the kinematic eddy viscosity in c. g. s. units;
The author has treated the effect of the stable vortices caused by a semicylindrical mountain range on a flat plain upon the wave length, amplftude and frequency of the Helmholtz wave. The wave length K is expressed by the amplitude L by L=1/H, and frequencies of stable wave length and amplitude of the Helmholtz wave by x=1/K, x=H if we consider those of infinite as unit. The conclusion drawn is as follows:- Behind the stable vortex the stable wave length and amplitude of the Helmholtz wave are respectively minimum and maximum, upon the stable vortex they are entirely opposite and in the winlward they take middle in the former and the latter places. The frequencies of stable wave length and amplitude of the Helmholtz wave are reciprocally proportional to stable wave length and amplitude of Helmholtz wave respectively. In other wards the stable Helmholtz Wave wi_??_h large amplitude and short wave length is frequent in the region behind the stable vortex, next in the windward and the unstable Helmholtz wave with short wave length and small amplitude is probable in the domain upon the stable vortex. The above effects depend upon the strength of the stable vortex, that is, the position of it. The stronger the strength of it, the larger the effects and the ampler the affected domain, especially these influence extends to far distance in the sea-side of it.
There are at present two dominant theories of essentially differnet mechanism on the existence of the high pressure belt of subtrooical latitude (subtropische Hochdruckgürtel, for brevity hereafter will be call “subtropical high”), whose development and decaying of intensity and migration of the location in the course of year have unseparably intimate relation with our climatic circumstances, in conjunction with the high and low pressure system developing over the continent and ocean (High and Low of Monsoons). This is the very reason why we n_??_me it “the active center of the atmosphere”. Thus it is one of the most important problem in the the_??_ry of the general circulation of the atmosphere to investigate the mechanism of subtropical high. One of them is the theory inheren from W. Ferrel, in which he assumes the conservation of angularmomentum referred to the rotation axis of the earth in spetially fixed coordinate and the complete rest of the atmosphere relative to the rotating earth at a certain stage of the earth's history. In this theory the effect of friction is discar_??_el. Indeel W. Ferrel succeeded in determining the location of subtropical high, but his hypothetical conditions are generally unrealizable on our globe. (This throry will be named “dynamical theory, dynamische Theorie” in the present paper). The other is the theory by Oberbeck and others, in which the distribution of air temperature constitutes the cssential factor in deciding the subtropical high (This theory will be named “thermic theory, thermische Theorie”). In this paper the latter thermic theory is supported, and finally the mechanism of subtropical high and that of high and low pressure system accompanying monsoon wind are condcluded to be essentially the same. Next, in order to explain the mechanism of monsoon high and low has seen introduced the term “Cyclo-and Anticyclogenesis of Oberbeck's type”, in consideration of the analogy with that in the theory of air mass. This means “in the northern hemisphere, the current system of warm air in the south and cold air in the north results in the formation of anticyclonic motion and that of cold air in the south and warm in the north result in the formation of cyclonic motion (This result has been derived in my previous pa_??_er. On the Effect of the Distribution of Continent and Ocean upon the Geaeral Circulation of the Atmosphere and the Theory and the Theory of Monsoons, Geophys. Mag. Vol. IX).” The above theme is the generalized one of Oberbeck's theory. Here warm and cold air mean that of positive and negative deviation from normal temperature respectively, viz. in the problem of planetary circulation the normal temperature denotes the equilibrium temperature and in the problem of non-planetary circulation the normal temperature has to be replaced by the temperature corresponding to the planetary circulation. As annual mean, in the tropical region the air temperature ove the continent is higher than that over the ocean on the same hatitude and reversed in higher latitude, the critical latitude being supposed to be about 45°, as is evident from, say, Spitaler's formula. Such a distribution of non-planetary temperature constitutes the essential factor in determining the high and low pressure system developing over continent and ocean, namely on the continent warm air exists in the south and cold air in the north, the location of juxtaposition of both currents being at latitude 45°. This distribution of current system corresponds to anticyclogenesis of Oberbeck's type and may be compared to the Siberian High in win'er seasons. The same is said of cyclonic motion over the ocean.