bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Geomagnetic Fluctuations
Authors: Haraldson Stig
Published: January 2012

The article presents an investigation of VLF-oscillations (0.2—200 c/s) in the earth’s magnetic field. The measurements were made in the archipelago of Stockholm (59’ N) during the period July 1957—June 1959. The oscillations were recorded by two different instruments : a high-speed Heiland oscillograph and a low-speed Esterline-Angus recorder. In the Esterline-Angus diagrams a morning minimum at about 8 o’clock local time was found. In the Heiland oscillograms three different features were found: 1. Frequent occurrence of sinusoidal fluctuations presenting a few very narrow bands; 2. Oscillations in the H- and Z-component are sometimes simultaneous, sometimes not ; 3. The amplitudes in the Z-component are smaller than in the H-component. It has not been possible to find a correlation between the fluctuations investigated here and other geophysical phenomena. A possible mechanism for generation of the sinusoidal oscillations is discussed.
Forecasting Thunderstorms and Showers by the Slice Method
Authors: Shishkin N. S.
Published: January 2012

The author gives a further development of the slice method proposed by J. Bjerknes in 1938. The formulae obtained use data from aerological soundings to compute the vertical thickness of convective clouds, their optimum amount, and the velocity of vertical development. The paper deals with the way of forecasting thunderstorms and showers based on the slice method.
A Mountain Wave Theory including the Effect of the Vertical Variation of Wind and Stability
Authors: Döös Bo R.
Published: January 2012

The motion over an infinitely long mountain ridge has been studied. The scale of the motion is assumed to be so small that the influence of the earth's rotation can be neglected. It is assumed further that the motion is non-viscous, laminar, steady and isentropic. The resulting wave equation is solved under the assumption that the coefficient which contains the vertical variation of the wind and temperature can be approximated by the function: α0 exp(– λz) + α1.
The wavelengths and amplitudes are evaluated in four actual cases when lee wave clouds have been observed. The agreement between the observed and computed distances between the piles of lee wave clouds is good.
In these four cases comparison is also made with the simple method to compute the wavelength obtained by considering the oscillation of an air parcel in a stable atmosphere.
A Preliminary Study of the Dynamics of Transient, Planetary Waves in the Atmosphere
Authors: Wiin-Nielsen A.
Published: January 2012

Recent studies of the planetary waves in the atmosphere have suggested that the vorticity equation assumes a quasi-stationary character for motions whose scale is comparable to the radius of the earth. These tentative results are adopted as a working hypothesis, and a preliminary study is made of the stability and structure of the waves which are possible in an atmospheric model which is formulated on the basis of the working hypothesis.
It is shown that the assumed stationary form of the vorticity equation acts as a filter which eliminates the Rossby type waves from the solution of the linearized equations in the two-parameter case. The wave-solutions in a linearized form of a three-parameter model are next found and investigated. The major results are that only slowly moving waves are possible and that unstable wave-solutions will appear for sufficiently large vertical wind-shears. A modified form of the model in which horizontal advection of vorticity is also included is analyzed, and it is shown that a wave-length of maximum instability occurs.
A prediction model which can be used in studies of the planetary waves is formulated. Since the model will apply to planetary scales only, it can be used to study the importance of nonlinear interactions between the planetary scales and smaller scales.
Numerical Tests of a Method for Dynamic Analysis in Regions of Poor Data Coverage
Authors: Richardson Norman N.
Published: January 2012

This paper describes a series of numerical experiments which were done to test a theoretical method for dynamic analysis in regions of poor data coverage. Theoretically, if vorticity were conserved, the exact vorticity field in such a region could be determined by Lagrangian advection of vorticity from areas of known data. The technique was applied to a field of rather dense data where a “hole” was created by withholding all observations within a given area.

The first experiments, assuming the atmosphere to be purely barotropic, resulted in a field within the hole that closely approached, after a reasonable time, the field obtained by a barotropic forecast using all the data. The remaining experiments, under simulated operational conditions, tested the effects of: 1) baroclinic processes, 2) size of hole, 3) frequency of observation, and 4) allowing a single strip of data across the hole. The results were much as predicted by the theory and reasonably accurate analyses were obtained.
The Tiros II Radiation Experiment
Authors: Hanel R. A. , Stroud W. G.
Published: January 2012

The TIROS II meteorological satellite, containing two television cameras and a family of electro-magnetic radiation experiments, was placed into orbit on November 23, 1960. The medium resolution radiometer is a cluster of five sensors, their optical axes inclined at 45° to the spin axis of the satellite. The spin of TIROS provides the scanning motion. Channels are sensitive to the following spectral bands: (1) 6 to 6.5, (2) 8 to 12, (3) 0.2 to 6, (4) 8 to 30, and 0.55 to 0.75 microns.
Indirect evidence of the importance of water-soluble continentally derived aerosols
Authors: Gambell, Jr. A. W.
Published: January 2012

The Ca++/Cl– ratio is a logical index of the predominance of continental or marine water-soluble aerosols in precipitation. Use of this ratio and others indicates that, excluding immediate coastal areas, continental aerosols constitute a large majority of the soluble material brought down in precipitation over land. The correlation of the concentrations of various ions in precipitation with the regional distribution of these elements in the soil presents further support for this conclusion.
Some numerical calculations of the vertical velocity field in hurricanes
Authors: Krishnamurti T. N.
Published: January 2012

The commonly observed crescent-shaped geometry of the tangential wind field in hurricanes is imposed on the primitive equations of atmospheric motion, and solutions for the vertical velocity field are obtained. It is shown that the numerically computed vertical motion field exhibits a spiral form, very similar to what is observed in radar pictures in individual hurricanes.

Aircraft flight data from the National Hurricane Research Project are utilized to carry out the numerical calculations in several hurricanes over the Atlantic.

An attempt is made to obtain an analytic solution for the same complete system of equations for a generalized Rankine vortex with a prescribed crescent-shaped geometry. It is shown that the analytic solution has an interesting spiral form. This solution for the Rankine vortex is compared with the corresponding finite difference solution to estimate the errors in the finite difference solution.
Establishment of a scheme stable in initial data to compute meteorological elements by means of solving thermohydrodynamic equations
Authors: Nemchinov S. V. , Sadokov V. P.
Published: January 2012

The stability of prognostic schemes obtained by means of the solution of primitive equations is studied. Three possible schemes are examined among which only one scheme is stable in Richtmyer’s sense. The relationship between time step and grid step depends essentially on the least characteristic number λ1 of a matrix A as follows: Δt/Δs ⩽ √6·λ1. The order of the matrix A is equal to the number of levels considered in the prognostic sheme.
Objective analysis of the vorticity field within a region of no data
Authors: Smith F. B.
Published: January 2012

Objective methods for estimating meteorological fields within so-called “data-holes” are compared. In particular, if Ψ is the streamfunction, a solution of the biharmonic equation ▽4Ψ = 0 subject to specified values of Ψ and δΨ/δn around the boundary of the hole is shown to provide a field whose mean square wind velocity error is comparable to that obtained by RICHARDSON (1961) for a hole 1200 km square using THOMPSON’S (1961) technique of sequential Lagrangian advection of known vorticity into the hole from outside. A scheme is suggested, combining certain advantages of both methods, which involves the Lagrangian advection of vorticity and periodic adjustment of the vorticity field to conform with the known changes in Ψ and δΨ/δn around the boundary.
Natural radioactive isotopes in the atmosphere at Kodiak and Wales, Alaska
Authors: Lockhart, Jr. Luther B.
Published: January 2012

The concentrations of natural radioisotopes of the radon and thoron series in the air in Alaska have been determined from data collected by NRL air-monitor equipment operated at Kodiak (1950–1960) and Wales (1953–1959). Seasonal variations in the concentrations of these activities at both sites have been observed; the average concentrations are compared with those at other sites where similar measurements have been made.
Dynamic instability in barotropic flow
Authors: Haltiner G. J. , Song Lt. R. T.
Published: January 2012

The dynamic stability of single-jet and double-jet zonal currents is investigated for several quasi-barotropic models by a finite difference method and by means of finite Fourier series.

The two methods give generally similar results, but some moderate differences occur when the mesh length is decreased or the number of Fourier components is increased. Also the stability characteristics of single-jet and double-jet profiles differ considerably.
On the temperature dependence of the lower wavelength cutoff of a series of Schott glass filters
Authors: Hickey J. R. , Brett D. A. , Drummond A. J.
Published: January 2012

The authors have extended the work of Ångström & Drummond concerning the temperature dependence of the three meteorological standard filters (Schott OG 1, RG2 and RG8) and here give values of the temperature coefficient of the center of lower cutoff for seven other Schott sharp cutoff filters. The results demonstrate that there is a definite relationship between the normalized cutoff wavelength and this coefficient, the coefficient increasing semi-logarithmically with wavelength over the region 440–920 millimicrons.
Baroclinic instability in two layer systems
Authors: Pedlosky Joseph
Published: January 2012

The stability properties of the two layer baroclinic model with arbitrary horizontal shear are discussed. Necessary conditions for instability are derived and show that the potential vorticity gradient must be both positive and negative. Bounds are placed on the propagation speed and growth rate of unstable waves by showing that the complex phase speed must lie in a certain semi-circle in the complex velocity plane. Sufficient conditions for instability are also discussed for a certain clam of flows.
A dynamical theory of spiral rain band in tropical cyclones
Authors: Yamamoto Ryozaburo
Published: January 2012

Elastoid waves and elastoid-gravoid waves ere treated for a horizontal circular vortex or a simple model of tropical cyclones. The dynamical possibility for a banded or spiral region of upward motion is shown.
The effect of wind on the propagation rate of acoustic-gravity waves
Authors: Clarke R. H.
Published: January 2012

A method is described for deriving acoustic-gravity wave velocity in the presence of wind shear. It is used to calculate numerical weighting factors for a few special cases of two and three layer model atmospheres. These show that the wind velocity in a cold layer between two warm layers has a predominant positive influence on group velocity, and the wind at higher levels a negative influence, while phase velocity is quite differently affected.

The theory is illustrated by world-wide data relating to the Russian megaton explosion of 30 October 1961, and a study of global winds at the time. It was found possible to account for world-wide variations in wave propagation rate largely by a simple regression on the sine of the explosion longitude, which made possible estimates of effective wind over various ray path lengths. This was found, on the global scale, to be the mean of the wind in the 9-16 km layer, that is, approximately the mean wind in the “sound channel”. Negative weightings at higher levels predicted by the model appear to be incorrect, and due to its inadequacy. The data strongly suggest that the “level of effective mean wind” is approximately that of the tropopause in middle latitudes.
Finite difference approximations for the determination of dynamic instability
Authors: Haltiner G. J.
Published: January 2012

Approximate forms of the vorticity and thermal equations are linearized and combined to yield a second-order partial differential equation for the amplitude of harmonic perturbations. Finite-difference approximations for the derivatives yield a homogeneous system of algebraic equations; and the condition that its determinants vanish for a non-trivial solution yields the “frequency” equation, which may be solved to give the phase velocities of the harmonic waves. Solutions are obtained for zonal currents in which the wind varies vertically and horizonally and for a variety of conditions with respect to grid distances, latitude and current width. Generally speaking, the computations showed that decreasing the latitude and shear and increasing the static stability were all destabilizing influences, not without some exceptions, however. In addition, very short waves were found to be stable; however, instability was found for very long waves, including a retrogressive unstable mode. Moreover, multiple unstable modes were found for many wavelengths.

Calculations based on actual observations of the jet stream in December show it to be dynamically unstable, both baroclinically and barotropically, with one mode of maximum instability at a wavelength of about 3000 to 4000 km and a secondary maximum at about 10,000 km.
The mathematical equivalence of multi-level and vertically integrated numerical forecasting models
Authors: Berkofsky Louis
Published: January 2012

It is shown that, if the equations for an n-level model are averaged, the resulting equations have mathematical forms which, under certain conditions, are identical with those of the vertically integrated n-parameter model. The implications for the temperature and ɷ-profiles are discussed in order to achieve exact mathematical equivalence. A physically consistent vertically integrated model yields temperature and w-profiles which depart from those required for mathematical exactness, yet appears to lead to more realistic results.
On the cooling of the sea surface by evaporation and heat exchange
Authors: Hasse Lutz
Published: January 2012

Differences between surface and subsurface water-temperature are causcd by evaporation, long-wave radiation and exchange of sensible heat. The relative importance of these three components is discussed, especially with aid of observations under neutral conditions. Evaporation as well as hack radiation contributes to a cooling of the surface of 0.1 to 0.2 centigrade under neutral conditions, while under diahatic conditions greater surface temperature deviations are caused by heat exchange.
Simulation of ring patterns observed with noctilucent cloud particles
Authors: Skrivanek R. A. , Soberman R. K.
Published: January 2012

Laboratory simulation of the ring or halo patterns which were found in the electron microscopic examination of noctilucent cloud particles has been attempted. This was done by impacting ice coated nickel particles on collecting surfaces similar to those used in the 1962 rocket sampling of the clouds. Ring patterns similar to those observed on the rocket sampling surfaces have been produced. From the condition necessary to produce these patterns, a formation mechanism is inferred.
Atmospheric stratification revealed by twilight scattering
Authors: Bigg E. K.
Published: January 2012

The uses and limitations of the twilight method of detecting aerosol layers are discussed and an experimental modification capable of checking the reliability of the results is described. The data from several sequences of measurements are shown to give average distributions of stratospheric aerosols in good agreement with those determined by direct sampling.

The stratification revealed by the experiments is very variable. Simultaneous observations at different latitudes show that the aerosol distributions often have the same form over distances of 300 km, but that the degree of similarity decreases rapidly with increasing separations. There are preferred heights for layers showing intense scattering, which on the average, slope upwards towards the equator. Some features show a surprisingly high degree of persistence in time and some curious changes in apparent height.
Computations of the eddy heat and density transports across the Gulf Stream
Authors: Oort Abraham H.
Published: January 2012

Data of the current velocity, temperature and density of the Gulf Stream, collected during 200 crossings of the current in cruises off Onslow Bay, Jacksonville (30° N) and Cape Hatteras, are used to compute the eddy fluxes of heat and density across the mean current. In each cruise an eddy transport of heat is observed, which is directed from the colder coastal water to the Sargasso Sea in the surface layers. The meanders in the stream appear to increase the thermal contrast across the so-called Gulf Stream front and thus violate the ordinary diffusion laws by not transporting heat from the warm to the cold source. The transport of density across the stream is, in general, towards the shore, reflecting mostly the influence of the temperature on the density.

WEBSTER (1961b) has shown in an earlier study that there is a surface flow of kinetic energy and momentum from the meanders to the mean flow of the Gulf Stream. Since the meanders of the scale considered in these studies appear to speed up the Gulf Stream and do not feed upon, but actually build up the thermal contrast near the surface, these eddies must be forced.

More measurements of the kind described in this paper, are needed to verify the observed abnormal heat and density fluxes in the Gulf Stream.
A direct method of stream-function computation
Authors: Endlich R. M. , Mancuso R. L.
Published: January 2012

An iterative method is described that fits a stream function (Ψ) to wind observations. The technique was designed for use in tropical regions where errors in height data and other difficulties preclude use of the geostrophic or balance equations to obtain y; however, the technique is believed to be sufficiently general to have other applications. Since the calculations may be carried out rapidly by an electronic computer, the technique might serve as a replacement for the laborious streamline-isotach method of tropical analysis.

The equations basic to the computations are given. If the stream function is defined to have the units of height (i.e., meters), it is convenient to use observed heights as the initial-guess field. Several iterations are made until the computed values of Ψ stabilize within a pre-determined limit. Explicit calculations of vorticity and of boundary values of Ψ, as required in a stream function obtained by solution of a Poisson equation, are not needed. Analyses of computed values of Ψ in the Caribbean are compared with independent, subjective analyses of the same data, and show excellent agreement. Autocorrelations show that computed values of stream function were considerably more persistent than height data for the period studied.
La corrélation d’espace du géopotentiel du niveau moyen
Authors: Pantchev St.
Published: January 2012

The statistical structure of the fluctuations of local changes in geopotential is studied using the equation gz = RT valid at the level of the so-called mean energy level of the atmosphere, which is also the level of geostrophic advection. It is shown that the two-dimensional random scalar field H(x, y) is anisotropic horizontally, that is to say, the correlation moment BHH of two points depends not only upon the distance r between them, but also upon the orientation of the straight line joining the two points in the horizontal plane. The explicit form of this dependence is given.In order to evaluate the contribution of the non-linear term, one must introduce the advection equation and the assumption of quasi-normality, generally accepted in turbulence theory.Finally, the particular case of a gaussian correlation function for the geopotential BHH(r) is envisaged.
A measure of form difference and its application to the study of turbulent motions
Authors: Groen P.
Published: January 2012

The aim of the present paper is twofold, viz., on one hand, to introduce a measure of form difference between two configurations of a given number of points as a tool for studying the effect of turbulent motions upon the deformation and spreading of point clusters, and, on the other hand, to derive a statistical relationship between the deformations of triangles of a given size, formed by triads of points in a field of random motions, and the properties of that field (eddy diffusivity as a function of size).As a geometrical by-product, a systemetics of triangle forms is found, which represents the set of all possible triangle forms by means of the points of a sphere. In this representation the form difference, as defined in this paper, appears to be equivalent with the angular distance on the sphere between the points representing the forms of the triangles.
Editorial
Authors: None None
Published: January 2012

none
Soviet Antarctic Expedition. Information Bulletin, Vol. III Elsevier Publishing Comp. Amsterdam, London, New York, 1965
Authors: Schytt Valter
Published: January 2012

None
Corrigendum
Authors: Schytt Valter
Published: January 2012

None
A climatological study of persistency and probability of precipitation in Sweden
Authors: Eriksson Bertil
Published: January 2012

Time series consisting of wet and dry days have been studied regarding persistency properties. The conditional probabilities calculated show that the time series approximately behave like simple Markov chains. Using the Markov model some probabilities regarding precipitation have been computed and the results are compared with empirical probabilities.
A computation of the evaporation in Southern Sweden during 1957
Authors: Nyrerg Alf
Published: January 2012

The monthly evaporation during 1957 from a region in Southern Sweden has been computed by means of studies of the precipitation and the net influx of water vapour into the area. Upper air charts have been used and from the geostrophic winds and humidity values the net flux has been computed twice a day. Various sources of error have been discussed, among them the effect of the ageostrophic component of the wind which for various reasons had to be neglected. No definite conclusion as to the importance of the ageostrophic component has been reached, but it seems likely that the errors caused are not very large in this area.The method seems useful even over the rather small area studied, but an improved network with denser observations is desirable. The evaporation was largest during July and August and smallest during the winter months. The contribution to the run-off was largest during July-October. During April and May the evaporation was even larger than the precipitation.The yearly value of evaporation agreed well with estimates from hydrologic studies.
Significance of statistical relations derived from geophysical data
Authors: Nordø Jack
Published: January 2012

Most geophysical phenomena have typical interrelations in time and space. But these restrictions are frequently forgotten by investigators processing data in order to verify, or to detect, the laws of nature. For example, the claimed relations between geophysical events and eosmical data are numerous, but rather few such relationships survive the next decade. One main reason for this is certainly the use of random sampling techniques when investigating geophysical data, in spite of the fact that statistics of related terms were studied by Markov half a century ago.If long series of records are available, the sampling complications due to serial correlation can be removed by selecting dates separated by a proper interval of time. But in most cases we have data only for relatively short intervals, and we are therefore forced to use all data to get optimum determination of the statistical parameters. The significance of these parameters then depend very much on the serial correlations involved.The purpose of this paper is to derive tests of significance, which may be applicable to a variety of such investigations when serial correlations are present in the data.
The Norwegian-Swedish-British Antarctic Expedition
Authors: Ahlmann Hans Wson
Published: January 2012

This expedition, the financial backing of which has now been secured, is planned
to leave Norway in November 1949 for the Western parts of Queen Maud Land, in about
long. 0°, to spend two winters there and return to Europe in 1952. As this district was
claimed by Norway in January 1939, and recognized as a dependency of that country in
June 1948, and as Norway is paying far more towards the expedition than either of the
other countries, the expedition will sail under the Norwegian flag, and its leader will
be Professor H. U. SVERDRUP, the Director of “Norsk Polarinstitutt”. The wintering group
will consist of 14 men, of whom 6 are scientific experts, 2 from each country. This
expedition was first proposed by me in Oslo and London in May 1946, and committees
appointed for that purpose by the three countries have since been cooperating in working
out the plans.
An Aerological Study of Large-Scale Atmospheric Disturbances
Authors: Nyberg Alf
Published: January 2012

Pressure change areas in the 500 mb level move with 60% of the speed of the wind
in that level. Advection of cold (warm) air at upper isobaric levels is followed by
geopotential falls (rises) at the same levels. The prognostic usefulness of this rule is
much higher in the 500 mb level than in the 700 mb level. – There are strong indications
of dynamic interaction between flow patterns in distant regions on the hemisphere. A
deepening of one upper trough will in special cases lead to a second deepening
downstream. – In a deepening trough the cold tropospheric air is shown to be sinking at
the same time as the jet stream increases and the front becomes sharper. Models of the
distribution of vertical motion and divergence in the frontal zones are given.
The Geochronology of the Deep Ocean Bed
Authors: Pettersson Hans
Published: January 2012

In this article different lines of approach to a geochronology of the deep ocean
bed, as revealed by sediment cores, are indicated.
Adiabatic Perturbation Equations for a Zonal Atmospheric Current
Authors: Queney P.
Published: January 2012

By a proper choice of coordinates and variables, a simple and quasi-symmetrical
system of differential equations is obtained for the infinitesimal adiabatic
perturbations of the most general continuous zonal air-flow. The coordinate surfaces are
those of the orthogonal system built up with the isentropic surfaces and the meridians,
and the variables are the displacements of the fluid in the directions of the coordinate
lines, and the local disturbance of the pressure. From these perturbation equations a
differential equation for the pressure disturbance alone is derived in the case of a
wave, and it is then shown that this wave equation can be always greatly simplified if
account is taken of the order of magnitude of the various parameters. Simplified
expressions are also given for the components of the vibration (fluid displacement).
More particular equations and formulae are then derived for short-period, middle-period
and long-period waves successively, this classification being made according to the
value of the orbital frequency compared to the coefficient of hydrostatic stability and
Coriolis parameter, and special cases are also considered where the wave equation
reduces to one with constant coefficients (elastic, gravitational, Rossby's waves).
Finally some incorrect recently published results are discussed.
Ueber die allgemeine atmosphärische Zirkulation während der diluvialen
Vereisungsperioden
Authors: Viete Gänter
Published: January 2012

The range of polar cold air over the northern hemisphere was increased during the
glacial periods primarily due to the extension of the large ice shields. Particulary in
the northatlantic region the atmospheric centers of action and the storm tracks were
shifted southwards, the meridional temperature gradient was strengthened and
consequently the general circulation increased. This intensification of the large scale
exchange of air does not contradict the recent increase of the general circulation and
its consequences, since during the glacial periods the increase was of a compulsory and
secondary nature caused by the ice extension itself. On the contrary the atmospheric
circulation at the beginning of the glaciation must have been decreased. However, the
continued extension of the Scandinavian ice shields, as well as the creation of the
Keewatin and Labrador shields in North America and the North Asian glaciation, occurred
during periods of secondarily increased circulation. An examination of the most
important Ice age theories shows that the primary weakening of the circulation may be
satisfactorily explained only by assuming a decrease of the earth's solar radiation
supply. The astronomical Ice age theory is applicable only in connection with the
assumption of an uplift of the Iceland-Faerisland submarine ridge.
Experimental Studies of a Polar Vortex I
Authors: Fultz Dave
Published: January 2012

A description is given of experiments carried out during 1949 and early 1950 that
were designed to produce some phenomenon exhibiting effects of the resultant horizontal
Coriolis force on a symmetrical vortex that results from the latitude variation of the
Coriolis force. A circular cap of dense liquid at the base of a small hemispherical
shell filled with liquid was forced to rotate about a vertical axis independently of the
rate of rotation of the remaining fluid and containing vessels. Within the ranges of 20
to 150 r.p.m. for the vessel and 0 to 120 relative r.p.m. for the cap vortex, the center
of mass of the polar cap never showed appreciable displacements away from the polar axis
exept for a range of sufficiently high relative rotations when the vortex was
anticyclonic in sense. Numerical checks are given with a simplified calculation in
spherical coordinates of the torque equilibrium for the vortex as a whole.
Some Aspects of Argentine Rainfall
Authors: Olascoaga M. J.
Published: January 2012

This report investigates at first what percentage of the number of days with rain accounts for most of the rainfall in widely separated climatic provinces of Argentina. It turns out that this percentage, which may be termed the relative precipitation intensity, is a constant in space and time. Then the frequency distribution of natural rainfall periods (rainstorms) is analysed in relation to the rainfall derived from these disturbances. It is found that the same percentage of the rainstorms accounts for the same large fraction of total rainfall regardless of season or geographical effects.
Sporadic E Movements on 21 June 1949
Authors: Gerson N. C.
Published: January 2012

An interesting instance of sporadic E reflections occurred on 21 June 1949 over North America. These reflections, reported by radio amateurs operating in the 50 mc/s band during the hours of 0000-0400 GMT, are portrayed in figures 1–5. The various radio amateurs report whenever a radio contact is made by means of sporadic E. Such contacts are carefully screened to insure that propagation by means of the ground wave or the F2 ionospheric layer is not involved.
Le mouvement des tourbillons atmosphériques
Authors: Van Mieghem J.
Published: January 2012

The force which acts on an atmospheric vortex depends on its intensity, on the Coriolis parameter and the latitude effect on this parameter. The zonal, meridional and vertical components of this force are linear functions of two correlations: one between the corresponding component of the air velocity and the horizontal divergence of the current and the other, between this same first component and the meridional component of the velocity.
Aeromagnetic Survey of Vertical Intensity over the Sound with Apparatus of the BMZ Type
Authors: Lundbak Asger
Published: January 2012

An attempt was made to measure the magnetic vertical intensity over a sea area and, in part, over land with an apparatus of the BMZ-type suspended in a special way in an aircraft. Some control measurements were made, and the conclusion was drawn that under certain conditions, which can easily be complied with, an accuracy of the individual measurements of about ± 20 gammas can be obtained.
Das Phänomen »Blaue Sonne»
Authors: Jenne Werner
Published: January 2012

The phenomenon “Blue Sun” could be observed in Scotland September 26, 1950, in other parts of Europe, for instance in Sweden and Germany, on the following day. An attempt was made approximately to fix the probable geographical limits, inside of which the bluish colour of the sun could be seen. The investigation deals also with the explanation of the phenomenon from the point of view of theoretical physics.
Optical Measurement of Particle Distribution in the Sea
Authors: Jerlov N. G.
Published: January 2012

A method has been developed for studying the distribution of suspended particles in the sea. The intensity of the light from a Tyndall beam scattered in the water samples is measured. Essential precautions in the study of clear ocean water are given. The method is illustrated by the particle distribution found off the Nile estuary and in the Strait of Gibraltar. The possibilities offered by the method suggest that it should be more widely employed for characterizing water masses and for studying horizontal and vertical movements in the sea. Other pertinent problems, re the settling of suspensoids near land and the flushing of harbours, may also be investigated in this way.
Die Feldkomponentenmühle: Ein Gerät zur Messung der drei Komponenten des luftelektrischen Feldes und der Flugzeugeigenladung bei Flugzeugaufstiegen
Authors: Kasemir H.-W.
Published: January 2012

Recording the atmosperic-electric potential gradient from an aeroplane it is very useful to get all the three field-components. This is the case especially in investigations in greater altitudes and in thunderclouds. In this paper an apparatus is described working on the principle of the ‘Feldmühle’ (field strength meter) and giving simultaneous recording of the atmospheric-electric potential gradient separated in the three rectangular components of the field. Furthermore a method is pointed out to separate the field of the own charge of the aeroplane and to record this one separately. This enables the ‘Feldkomponentenmühle’ (field component meter) to be used in motor driven aeroplanes.
Experiments on Non-Laminar Flow of Mercury in Presence of a Magnetic Field
Authors: Lehnert B.
Published: January 2012

Two examples are given of non-laminar motion in an electrically conducting liquid in the presence of an external magnetic field.
Theory of Development and of Thickness Patterns
Authors: McVittie G. C.
Published: January 2012

The equations of motion, of continuity, of vorticity and of heat-transfer are transformed from coordinates (x, y, z) to coordinates (x, y, p) without the use of the hydrostatic equation in the vertical. An approximation based on the empirical fact that the isobaric surfaces are slightly inclined to the horizontal together with the use of dimensionless variables, gives the hydrostatic equation and simplifies the fundamental equations by the rejection of many of their terms. Thereafter definitions of certain types of geostrophic and nongeostrophic motions lead, respectively, to (a) Rossby's potential-vorticity equation; (b) the development and thickness-patterns theory of R. C. Sutcliffe, which is discussed in detail; and (c) J. G. Charney's (1949) treatment of the equivalent barotropic atmosphere. These models of atmospheric motions are compared and contrasted.
Localization of Aurorae with 10 m High Power Radar Technique, using a Rotating Antenna
Authors: Hellgren Gösta , Meos Johan
Published: January 2012

The paper describes the 10 m high power recorder with a rotating antenna that is used since May 1951 for the localization of aurorae at the Radio Wave Propagation Laboratory of the Kiruna Geophysical Observatory (67.8° N, 20.5° E). Continuous observations during the time May 1951–March 1952 have disclosed periods of auroral activity. The preliminary results from these observations indicate that there is a good correlation between the auroral activity, the magnetic activity, and the appearance of the NI-layer, a special type of sporadic E ionization often appearing in connection with magnetic bays and supposed to be caused by the same ionizing agent as the aurora. The distribution in range and bearing of the recorded aurorae agrees with the simple theory that most of the radio wave scattering comes from those points where the radar beam is perpendicular to the surface of the auroral discharges. The calculated height distributions of the reflection centres have maxima around 120 km.
Electron-Microscope Study of Cloud and Fog Nuclei
Authors: Ogiwara S. , Ōkita T.
Published: January 2012

Droplets of clouds on a mountain and of fog in an urban area were captured and the form, nature and size of their nuclei were studied by means of an electron-microscope and by a chamber of constant humidity. These nuclei have similar form and nature to the hygroscopic particles in haze and to the artificially produced combustion particles. No sea-salt nuclei were found in our observations, therefore sea-spray appears to be an insignificant source of condensation nuclei. It was found that both the cloud and the fog nuclei originated in combustion products which were the mixture of hygroscopic and non-hygroscopic substances, and that the greater part of the nuclei did not contain pure sulfuric acid.
Two Years of Momentum Flux Data for 31° N
Authors: Starr V. P. , White R. M.
Published: January 2012

At various times during the past two years, the authors have had occasion to report upon the results of an investigation of the angular momentum balance of the atmosphere as deduced from actual wind measurements dis- tributed over the northern hemisphere (STARR and WHITE 1951, 1952a, 1952b). The nieteoro- logical implications of the results of these studies have been discussed in these papers. A further investigation for a period of one additional year has n ow been completed for 31′ N, in order to verify the previous conclu- sions with independent data. A continuous two-year period has thus been analysed and represents a concluded phase of the investiga- tion for this latitude.
On the Content of Nitrogen in Atmospheric Precipiation in Sweden II
Authors: Ångström Anders , Högberg Linus
Published: January 2012

In the present paper an attempt is made to give a general idea of the geographical distribution of fixed nitrogen (NH4-N) transferred to the soil through precipitation in Sweden. Further a map is given showing the distribution of α, a quantity proportional to the nitrogen concentration in the precipitation at the beginning of a rain and, it is assumed, representative for the content of fixed nitrogen in the atmosphere before the rain is falling.
A discussion of different causes of the concentration of fixed nitrogen in precipitation is presented and a photochemical process is suggested, which would explain the almost constant ratio between NH4-N and NO3-N frequently found within the temperate zones. It is evident, however, that other causes also are at work, especially at lower latitudes. The need of laboratory experiments is emphasized.
Expectancy of Clear Days in the Central Zone of the Total Eclipse of the Sun June 30, 1954, in Sweden
Authors: Lindholm F.
Published: January 2012

The occurrence of the total solar eclipse in 1954, visible in southern Sweden, has raised the question regarding the cloudiness conditions which may be expected in this part of the country at the time of the eclipse. A detailed investigation of the average sunshine conditions at Swedish stations situated along the track of the totality has therefore been made. From this is concluded that the coastal regions are decidedly more favourable than the inland. A comparison between the western and eastern coasts leads to the conclusion that the average cloudiness at 14h, the hour of observation nearest to the totality, is slightly higher on the West coast than at locations on northern Öland and southern Gotland. Regarding the number of clear sky days at different places the coasts are also more favourable than the inland, and of those the northern part of Öland seems to be considerably more favourable even than the outer part of the West coast. The statistics refer to observations at 14h June 20—July 10 in the years 1931–1950.
On the Fields of Wind and Temperature over Japan and Adjacent Waters during Winter of 1950–1951
Authors: Mohri Keitaro
Published: January 2012

First, a mean cross section along the meridian 140° E during three months (Dec. 1950–Feb. 1951) is discussed. The main characteristics are:

An extremely strong subtropical jet (75 m sec-1) situated at 33° N near 190 mb;

A semi-stationary sloping surface which divides almost barotropic warm tropical air in the south from more or less baroclinic temperate air situated in the north;

A slight indication of a polar-front jet situated near 230 mb at 41° N; the weak intensity of this jet depends upon the strong variability in position of the polar front.

Much warmer temperature in the upper troposphere to the south, and much colder temperature in the lower troposphere north of the subtropical jet, as compared with mean conditions at 76° E and 80° W.

The computed mean winds at 140° E are combined with the mean isotachs given by Yeh over China, at the 12-km level. Using the acceleration determined from the isotach pattern, the mean angle of cross-contour flow at 200 mb is determined to be about 8° (between longitudes 110° and 140° E), with a mean cross-contour component of 8 in sec–1 toward lower heights, in the center of the mean jet stream.

Second, daily meridional cross sections through Japan are presented for the period 8 to 15 December 1950. These show an extremely strong individual jet stream in which the observed maximum wind speed reached a velocity of more than 110 m sec–1, with near-zero absolute vorticity to the south. An associated nearly-isothermal layer underneath is much deeper (up to 4 and even 6 km) than in other parts of the globe. It is suggested that this unusual depth results from a combination of a stable layer associated with the semi-stationary subtropical jet, and the polar front, when the latter moves southward in east Asia. The behavior of the tropopause in the intermediate atmosphere south of the polar front during this series suggests subsidence of the tropopause and its transformation into the lower boundary of a deep stable layer which is transformed into some kind of front separating the real tropical air from a more temperate air moving in from the regions north of the Himalayas.
Meteorological Conference in Helsingfors, Finland, 18–22 May 1953
Authors: Bolin B.
Published: January 2012

During the last four or five years Scandinavian meteorologists have met once or twice a ycar to discuss basic meteorological problems under investigation in the Scandinavien countries. In most cases also a few scientists from countries outside Scandinavia have been invited to present their work and to exchange ideas with their Scandinavian colleagues. The experiences gained during previous meetings in Bergen, Copenhagen, Oslo and Stockholm have been exceedingly valuable. Hence, between May 18 and 22 of 1953, a similar meeting was held in Helsingfors at the invitation of the Geophysical Society of Finland and of the Institute of Meteorology at the University of Helsingfors. The very successful meeting was led by professor E. Palmfn and professor V. Vaiala. Professor Palmin acted a general chairman and was assisted by Dr. L. Vuorela as general secretary.
A Critical Examination of Theories of Charge Generation in Thunderstorms
Authors: Mason B. J.
Published: January 2012

A concise review is presented of the more important features of the meteorological and electrical behaviour of thunderstorms from which the main conditions to be fulfilled by any satisfactory theory of charge generation, are enumerated. The various theories are then examined, as far as possible from a quantitative point of view, in the light of these requirements. None is found to be entirely satisfactory. It is concluded that the mechanism which most accords with the observed facts is the charge generation and separation which, according to the results of laboratory experiments, will be associated with the growth of graupel pellets in the supercooled region of the thundercloud.
Identification of Sunspots
Authors: Alfvén H.
Published: January 2012

According to the magneto-hydrodynamic theory of sunspots there should be a correlation between the spots on one hemisphere during a certain cycle and spots on the opposite hemisphere during the following cycle. This has been statistically confirmed by Galvenius and Wold, and by Whittle. It is pointed out that individual sunspot groups may be reproduced at the opposite hemisphere during the following cycle. An analysis of the sunspots between – 4° and + 4° seems to support this conclusion, and a number of sunspots are “identified” as being produced by the same original disturbance in the solar core.
Transport and Production of Vorticity in the Atmosphere
Authors: Van Mieghem J.
Published: January 2012

The classical form of the vorticity equation is transformed into an equation of balance from which the vorticity transport and the rate of vorticity production are deduced. Transport and production are given for 1) an arbitrary component of the absolute vorticity, 2) the absolute vorticity vector, 3) the absolute vorticity flux through a surface, 4) the total absolute vorticity within a volume. Special consideration is given to the absolute vertical vorticity, the absolute vorticity component normal to the isentropic surfaces and the total absolute vertical vorticity of the atmosphere. The influence of vertical motions and of heating and cooling on the vorticity transport is discussed. The sign of the meridional vorticity transport is tentatively determined.
Observations of Lee Wave Clouds in the Jämtland Mountains, Sweden
Authors: Larsson Lennart
Published: January 2012

An account is presented of three years of observations of lee-wave clouds in the Jämtland mountains, Sweden, with detailed descriptions of some individual cases. Wind and stability conditions in connection with the occurrence of the clouds are given. A brief discussion of the agreement between observed conditions and theoretical results is attempted.