bluuebunny/crossref_metadata_2025 huggingface dataset:
A software tool for simulating practical chemistry
Authors: Povey David , Bennett James
Published: January 2012

The field of 'active learning' is growing rapidly in many areas and high-quality software that allows the student to interact with a particular environment is now becoming commonplace. Chemistry is no exception and one area that has seen extensive development is the use of computer simulations of laboratory procedures used either as a preparation for laboratory work or to carry out a virtual investigation. In the former case, Nicholls (1999) describes a range of software providing pre-laboratory support for a range of firstyear undergraduate inorganic chemistry experiments. Using these computer programs, students work at their own rate on material presented through graphics, animations, simple calculations, tests and questions prior to carrying out the actual laboratory exercise. It is claimed that this approach'encourages students to evaluate critically procedures and results by ensuring that they think beforehand about the tasks they will be performing subsequently in the actual laboratory class. Garratt (1997) describes a different approach, predominantly in the areas of physical chemistry and biochemistry, giving students the opportunity to design 'virtual investigations' and to process and interpret the resulting data. For example, students are asked to choose a set of experimental parameters to allow the kinetics of a particular enzyme (randomly generated from 150,000 hypothetical examples) to be investigated.DOI:10.1080/0968776000080205
The specification and design of an interactive virtual environment for use in teacher training
Authors: French Fiona , Cumpson Ian , Wood Ruth
Published: January 2012

The original concept was to create a 'simulation' which would provide trainee teachers, specializing in Information and Communications Technology (ICT) with the opportunity to explore a primary school environment. Within the simulation, factors affecting the development and implementation of ICT would be modelled so that trainees would be able to develop the skills, knowledge and understanding necessary to identify appropriate strategies to overcome the limitations. To this end, we have developed Allsorts Primary - the prototype of a simulated interactive environment, representing a typical primary school.DOI:10.1080/09687760108656775
Editorial -Time for an experiment
Authors: Conole Gráìnne
Published: January 2012

This issue of the journal contains six very different papers exploring the issues around the use of learning technologies, which reflect the growing diversity of research interests and activities in this area. Oliver, Bradley and Boyle describe a project that is concerned with the development of online courses as part of a pan-European virtual university. The issues raised by the paper are timely given the current national initiative to develop a UK euniversity. McSporran and Young consider the impact of gender issues on online learning and contend that there is evidence to suggest that women achieve better results than men and that it is the loner male that is disadvantaged by distance learning. Condron reports on a TLTP (Teaching and Learning Technology Programme) 3 project and in particular on the use of electronic resources to support dialogue in small-group teaching. Campbell, Littlejohn and Duncan also look at resources but from the perspective of encouraging the reuse of academic resources as part of an initiative to develop a Scottish electronic staff development library. Shaikh and Macaulay report on a study of the use of groupware to support collaborative learning. Finally, Davies and Denning identify six conceptual areas which they suggest are of relevance and significance for online behaviour.DOI:10.1080/0968776010090201
Reviews
Authors: Barker Philip , Frank Andrea , Jones Chris , Pearson Elaine , Jordan Gillian , Traxler John , Clark Linda
Published: January 2012

The theme of this year's International Simulation and Gaming Yearbook - 'Transition and Change' - addresses the topical discourse on the improvement of pedagogy by the introduction of active and student-centred learning in UK higher education. Although the value of 'learning-by-doing' and experiential learning is well recognized by researchers in education, many subjects and university courses continue to employ teaching methods (such as lectures) that favour a passive reproduction of information rather than the fostering of student understanding. In this regard, simulations and games are powerful tools that not only promote an active, student-centred approach to learning but have the potential to help realize government policies to improve the quality of teaching and learning in higher education institutions in the UK.DOI:10.1080/0968776010090208
Courseware in academic library user education: a literature review from the GAELS Joint Electronic Library Project
Authors: Joint Nick , Kemp Bob , Ashworth Susan
Published: January 2012

The GAELS project (Glasgow Allied Electronically with Strathclyde) is a library-based project intended to promote a culture shift among engineering researchers at Glasgow and Strathclyde Universities. Our intention is to decrease researchers' dependence on separately held local print collections in favour of collaboratively held networked electronic resources. To support this aim, GAELS (1999) has created a courseware package to teach researchers the different information retrieval skills required to use such networked resources.DOI:10.1080/0968776010090304
Reviews
Authors: Barker Philip , Jordan Gillian , Hanson Janet , Hartley Roger
Published: January 2012

This is another in the long list of '500 Tips' series, published by Kogan Page. Phil Race, the author, is a well-known name in learning and teaching and has published extensively. The presentation of advice in this way is clearly a well-tested formula and, judging by the copies from the series in my own institution's library, these are frequently borrowed books, but I wonder whether this format is now a little overused? Advice from a guru can be very valuable, but in an era of evidence-based practice it is even better if the advice is backed up with references to facilitate the reader's further research in the area. Unfortunately in this book references are few and far between. There is a short list of suggested further reading but, for example, in the section on being a group member, where the work of Belbin is referred to, this is not referenced and Belbin does not appear in the subsequent reading list.DOI:10.1080/0968776010090308
An Economical Net Radiometer
Authors: Suomi V. E. , Kuhn P. M.
Published: January 2012

A net radiometer of moderate accuracy but of simple construction and very low cost is described. The value of net radiation is obtained from the difference of fourth power temperatures of the upper and lower radiating surfaces. Conduction losses are held to a low value by employing a good insulating material and ventilation losses above and below are kept to a low value by two layers of thin polyethylene film. Field tests, calibration data, and applications are described.
An Experiment in Numerical Prediction with two Non-Geostrophic Barotropic Models
Authors: Bring A. , Charasch E.
Published: January 2012

The result of a test with two simple non-geostrophic barotropic models are discussed. One of these models is based on ideas presented in a previous article (Charash 1957). The forecasts obtained are found to differ significantly from forecasts obtained with the quasi-geostrophic model. Both non-geostrophic models appear to be free from one major weakness of the non-geostrophic model, i.e. the hypertrophy of anticyclones. It is suggested that the disappointing forecasting performance of baroclinic models hitherto to a considerable degree springs from a similar weakness as exposed here in the quasi-geostrophic barotropic model.
Some Observations Relating to the Stability of Warm Cumuli
Authors: Squires P. , Twomey S.
Published: January 2012

Simultaneous observations of giant sea-salt nuclei and droplet spectra in cumuli have shown that variations in the concentration of these nuclei have no direct effect on the microstructure of cumuli.
On Pyrheliometric Measurements
Authors: Angström Anders
Published: January 2012

Pyrheliometric measurements are now introduced in the meteorological practice to an extent which makes a condensed survey over the present status desirable.

In the following I have combined the main content of the survey on the pyrheliometric scales, given by the International Radiation Commissions, with a description of the present modernized type of the Ångström Pyrheliometer. I have added a critical examination of its function and the sources of error which ought to be avoided at its operation. A detailed survey of its construction seems justified by the fact that it is the only standard instrument at present available in the market, where institutes can easily determine its physical constants, thus controlling the basis for absolute measurements of solar radiation. I have added an Annex containing a simple theory of the “edge effect” in the pyrheliometer. The main content of the annex coincides practically with the theory I gave already in 1914, but I repeat it here with some minor corrections together with a discussion of the factors influencing the effect and also of the results of practical experiments.

The important result is derived, that the edge correction is to some extent dependent on the internal convection within the pyrheliometer, and may from this reason vary between about 1.3 and 3.8 percent of the measured radiation. In the new constructions, now available in Sweden, this error is eliminated.
Some Comments on the Numerical Integration of the Vorticity Equation and Related Equations
Authors: Benton George S.
Published: January 2012

It is shown that if the streamfunction is specified over an Eulerian region R (x, y) at t=0, and on the boundaries of R (x, y) at t > 0, a solution of the vorticity equation which satisfies certain conditions of continuity will be unique. If vorticity is also specified at the inflow boundary, such a solution is excluded. In the latter case, an internal discontinuity propagates into the region along a material surface, and in principle solutions should be obtained separately for each sub-region and “matched” kinematically and dynamically at the interface. The associated analytical or numerical problems are prohibitive.

The problem of obtaining stable methods of numerical integration, specifying only the stream function on the boundary, is considered. Numerical integrations of a non-linear first order differential equation indicate that such stable methods may exist, in contradiction to linear theory.

The integration of the vorticity and associated equations for the first time-step is also considered. A method is presented which is not only simple to apply, but also maintains the same accuracy as succeeding time-steps for which centered difference techniques are used.
Study of Cosmic Ray Produced Short-Lived P32, P33, Be7, and S35 in Tropical Latitudes
Authors: Goel P. S. , Narasappaya N. , Prabhakara C. , Thor Rama , Zutshi P. K.
Published: January 2012

The fall-out rate of four short-lived isotopes P32, P33, Be7 and S35, produced in the collisions of cosmic ray particles with air nuclei, has been measured at a number of stations in India and compared with the calculated rate of production. In the case of Be7, the agreement between the calculated and measured values is good. The fall-out rates of P32 and P33 are not inconsistent with the calculated values; that of S35, however, is about five times higher than expected.

The absolute concentrations of an individual isotope in various rain falls have been found to vary by more than a factor of forty; relative concentrations of the different isotopes, however, stayed within fairly narrow limits. The ratio of the concentration of the isotope Be7 to that of the isotope P32 in individual rain samples has been used to find out the periods for which various air masses had been irradiated in the interval between two successive precipitations. The mean period of irradiation is found to be about thirty-five days.

Our results are consistent with the view that, in these tropical latitudes, intrusions of stratospheric air into the troposphere are either rare or weak in intensity.

The method seems capable of further development as a tool for studying meteorological problems.
C. F. Richter, Elementary Seismology, W. H. Freeman and Co.
Authors: Cooley Duane S.
Published: January 2012

In conclusion, therefore, the relatively small importance of advective terms in the statistical scheme described is a measure not of their importance in the dynamic equations, but rather of some average rate of change of the wind field during the forecast period.
Some Computations of Water Heights and Currents in the Baltic
Authors: Svansson Artur
Published: January 2012

The Skagerack, the Kattegatt, the Danish Sounds and the Baltic, all together here called the Trans-Baltic, are treated as a one-dimensional channel with homogenous water. Water heights and velocities are computed from the linear hydrodynamical equations, including terms of acceleration, wind stress, air pressure and friction. It is made numerically with help of the electronic computor BESK. The computations are mainly concentrated to a case 5/12–12/12 1932. The same treatment is also made for a closed basin consisting of the Baltic proper + the Gulf of Finland, altogether here called the Eastsea.
The Evaporation-Precipitation Cycle of the Trades
Authors: Kraus E. B.
Published: January 2012

The area distribution of surface wind strengths between 30° S and 30° N is expressed as a function of the median velocity, on the basis of climatological data. This is used to obtain estimates of evaporation and energy dissipation over the same area.

The main energy supply of the trade circulation is due to condensation in the equatorial trough. It depends partly on evaporation into the trade winds at some earlier time. A study of the energy balance shows that this may lead to oscillations with a period of about 3 weeks; corresponding to the mode of the time which elapses between the evaporation and the precipitation of the same vapour molecules.

Disturbances or fluctuations in the direct meridional circulation of the sub-tropics may be initiated by changes in the infra-red cooling rate and by changes in the height of the tropopause. It is suggested tentatively that this could be caused by changes in the ozone distribution above the tropical tropopause.
Further Statistics Concerning the General Circulation
Authors: Starr Victor P.
Published: January 2012

During the past few years it has become increasingly clear that the newer outlook upon the fundamental processes of the general circulation continues to flourish and prosper. It bids fair to become the essential starting point for all rational discussion of the large motions of the atmosphere, as indeed it must if its principal ideas are correct.
Isotopic Composition of Sulfur in Precipitation and Sea-Water
Authors: Östlund Göte
Published: January 2012

As an attempt to approach the question of the origin of airborne sulfur, it was intended to make measurements of natural S35 and determine the S32/S34-ratio of sulfur in rain-water. For different reasons the S35 counting had to be omitted, but the S32/S34-ratio, and the sulfur contents of a number of samples of precipitation and sea-water were made.
Integration of Four-Level Prognostic Equations over the Hemisphere
Authors: Kuo H. L. , Nordö Jack
Published: January 2012

The three-dimensional quasi-nondivergent prognostic equation derived previously by Kuo is integrated over the hemisphere, the vertical distribution being represented by four levels. The effects of the mean radiational heating, friction and heating from the ground, and that of the turbulent diffusion have been included in this investigation. The initial disturbance considered is a random combination of ten wave components in x and seven wave components in y. The result of the integration is that at the end of the fourth day at 850 mb, three closed lows have been formed, all around latitude 60°, while the pole is occupied by a high. These lows have the dimensions of the semi-permanent lows in winter.
Changes in the Radioactivity Regime during the Passage of a Cold Front over The Netherlands
Authors: Bleichrodt J. F. , Bleeker W. , Schmidt F. H.
Published: January 2012

Artificial radioactivity in rainwater was measured during the passage of a cold front over The Netherlands. The specific radioactivity of the frontal rain increased considerably after the frontal veering of the wind. Concurrently the “age” of the fission products decreased from 45 to 17 days, indicating a supply of atomic debris from recent nuclear explosions in arctic regions. The specific radioactivity of the air increased considerably on the day of the frontal passage. Trajectories of pre-frontal and post-frontal air indicate that the pre-frontal air comes from a source region in the Mediterranean and the post-frontal air from the arctic regions. The diagram of the frontal passage is analysed.
A Study of the Composition of Marine Atmospheres
Authors: Lodge, Jr. James P. , Mac Donald, Jr. A. J. , Vihman Eero
Published: January 2012

Data on trace substances in air, obtained in mid-Pacific during two summers, are summarized. Particulate matter was analyzed for chloride, sulfate and nitrate; tests were performed for ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide. The results give information concerning the composition of marine air which can assist in evaluating possible natural contributions to urban pollution on the West Coast of the United States during the summer months, in addition to the geochemical value of the work.
The Daily Variation of the Cosmic Ray Nucleonic Component at Murchison Bay and Uppsala
Authors: Sandström Arne Eld , Dyring Eric , Lindgren Stig
Published: January 2012

In both places the monitors were of the standard pattern with 12 proportional counters filled with 97 per cent enriched B10F8. The first and second harmonics of the mean daily variation have been determined both for yearly periods and for each sun rotation period. Vector sum diagrams for the first harmonics in the latter case are given covering the intervals 31 Aug. 1956 to 15 Aug. 1959 for Uppsala and 13 Sept. 1957 to 29 April 1959 for Murchison Bay. In some instances a considerable phase shift has taken place from one sequence of sun rotation periods to another. These phase shifts were not contemporary at the two stations. The first harmonic of the 12-month means displays a high degree of constancy with only a small secular phase shift. The amplitudes of the second harmonics are very small. Conditions are especially favourable concerning the deviation in the earth’s magnetic field of the particles registered by the Murchison Bay monitor. Accordingly it has been possible to determine the direction of the anisotropy with a fairly good accuracy. The Murchison Bay records do not show any prominent phase shift with the Kp index. Concerning Uppsala, days with [Kp]max ≤  1+ have a later time of maximum than other days. The influence of single days with an abnormal daily variation is discussed.
On the Appearance of Ninhydrinpositive Substances in the Atmosphere
Authors: Munczak F.
Published: January 2012

This report is part of a larger work (entered at the Austrian Academy of Sciences on 20th June, 1959) which appears here without significant alteration and translated into English; it deals with the investigation of atmospheric organic nitrogen compounds. On some days in the course of these investigations the appearance of ninhydrinpositive substances could be established an at least some of them could be identified with great probability as amino acids. Observations are made about the appearance of these substances in relation to meteorological factors, and about the sizes in which particles of these substances may appear. Some remarks are added about their possible origin and the influence their appearance may have on life.
Phase Changes in the Daily Variation of the Cosmic Ray Nucleonic Component
Authors: Parsons N. R.
Published: January 2012

Results of the analysis of solar daily variations in the cosmic ray nucleonic component at nine stations during the International Geophysical Year are presented. Examination of month to month phase behaviour leads to the conclusion that there is an important component variation synchronized in Universal Time at all stations, and its origin is discussed. Its effects on inferences about the primary anisotropy responsible for the main part of the daily variation and on various characteristics of the observed variation are also discussed.
On the Frequency of Lightning Flashes to High Objects A Study on the Gulf of Bothnia
Authors: Müller-Hillebrand D.
Published: January 2012

The space-charge calculation of a lightning stroke according to Golde resultsin a simple geometrical relation between the area within which a flash strikes an object and its height. A comparison between the number of lightning strokes to chimneys and thenumber of lightning downstrokes per km2 shows, that the statistical attraction distance of a 70 m high chimney is more than 250 m and thereby more than the leader’s step-length after Schonland. An explanation may be the space-charge plume, which leaves the lightning rod in a thunderstorm field and may conduct a lightning discharge to the chimney from some hundreds of meters’ distance.
Advection over Sweden of Radioactive Dust from the First French nuclear Test Explosion
Authors: Lindblom Gunnar
Published: January 2012

An examination of the occurrence over Sweden of radioactive debris from the first French nuclear test in February 1960 has been undertaken. The distribution of radioactive deposit was uneven. The time of arrival of debris can be determined accurately, and a comparison is made with meteorological parameters. Special autoradiographical and gammaspectrometrical examinations have been carried out, which suggest fractionation effects to be present in the scavenging processes.
On the Angular Momentum Balance in the Equatorial Trough Zone of the Eastern Hemisphere
Authors: Berson F. A. , Troup A. J.
Published: January 2012

A study has been made of the conditions for seasonal balance of zonal angular momentum, during Southern summer, in the troposphere overlying the equatorial (monsoonal) Westerlies. The observational data are not adequate to determine the finer details of balance. It is shown that by and large it can be accounted for by zonal pressure gradients and meridional transport of Earth’s angular or Ω-momentum (a Coriolis effect). Zonal and meridional stresses due to advective and eddy transports of relative zonal or ū-momentum as well as the surface frictional stresses are of considerably smaller magnitude. This confirms for a monsoonal region the conclusions of Palmer (1958), from observations in the North Pacific in June, that quasi-geostrophic equilibrium occurs down to very low latitudes above the planetary friction layer. The high-level easterly jet stream is shown to play an important part in two aspects of balance.
Radiation to Actinometric Receivers in Its Dependence on Aperture Conditions
Authors: Ångström Anders
Published: January 2012

After an introduction on basic conceptions, concerning the influence of aperture conditions on the readings of actinometers, a short review is given on recent results as regards the arcumsolar sky radiation. The combined effect of aperture and sky radiation on pyrheliometric readings, in the case of point receivers, is discussed. Conclusions are drawn as regards the influence of aperture conditions on (a) solar constant determinations and (b) on the difference between readings with aid of different pyrheliometers. The principles which ought to be applied in the construction of pyrheliometers for different kind of use, are briefiy discussed.
Measurements of the Water Vapour, Tritium and Carbon-14 Content of the Middle Stratosphere over Southern England
Authors: Brown F. , Goldsmiths P. , Green H. F. , Holt A. , Parham A. G.
Published: January 2012

Measurements of the water vapour, tritium and carbon-14 content of the stratosphere at heights of between 80,000 and 100,00 feet, made over England during the years 1956 to 1960, are described.

The tritium and carbon-14 concentrations are greater than those expected from natural production due to the cosmic radiation. The bulk of these two isotopes, at present in the stratosphere, has been injected there during the course of thermonuclear explosions.

Mass spectrometric analyses show that the deuterium/hydrogen ratio of the water and the carbon-13/carbon-12 and oxygen-16/oxygen-18 ratios of the carbon dioxide collected at these heights were the same, within the accuracy of measurement, as those for samples collected near the ground.

The concentration of tritium at the heights of the measurements has not fallen since the termination of thermonuclear weapon testing in autumn 1958. There is poor correlation between the tritium concentration at 90,000 feet and that of particulate caesium-137 at 47,000 feet measured over the sampling period. The humidity above 80,000 feet is found to be greater than that in the lower stratosphere.

It is concluded from these humidity and tritium results that the large scale meridional circulation in the stratosphere, first postulated by Brewer and Dobson, does not reach heights of 90,000 feet over temperate latitudes.
Note on the Propagation of Baroclinic Waves in a Zonal Ocean Current
Authors: Welander Pierre
Published: January 2012

In a zonal ocean current one sees Stationary or slowly moving baroclinic waves, with a wavelength of 1,000 km or more. These waves may be equivalent to a type of very long waves studied earlier in the atmospheric case. The wave speed is independent of the wave number but depends on the speed of the basic current, the stratification etc. For the case of a zonal current with exponential vertical profile, stationary waves are found for an eastward current. The wave perturbation normally decays downward in an exponential way. The parameter that decides the nature of the waves is λ = β/f2 ΔAp0/U0 where U0 is the amplitude of the basic current, ΔA the vertical variation of the specific volume, p0 the scale pressure (the pressure variation that corresponds to the scale depth of the basic current), and f the Coriolis parameter. For a westward current travelling neutral waves exist but only for special values of λ that are not normally expected in the oceans.
A Dynamical Method of Analyzing Meteorological Data
Authors: Thompson Philip Duncan
Published: January 2012

This paper deals with the problem of reconstructing meteorological conditions in “holes”-i.e., large regions from which no data are received, but which are surrounded by regions in which the frequency and density of observations are fairly high. The method proposed here is a combination of numerical procedures of analysis and prediction, by which one can generate a series of increasingly exact analyses in a hole. It is shown that the error of this method approaches a definite lower limit which depends on: The size and shape of a hole The average time required for individual particles to travel across the hole. The average absolute rate of flow across the boundary of the hole, and A statistical measure of the inaccuracies inherent in the prediction system. Numerical estimates of the accuracy attainable by this method indicate that dynamical methods are significantly better than conventional methods based on pure interpolation and smoothing. Finally, some aspects of the problem of network design are reviewed in the light of our present results.
On the Geostrophic Flow at the Surface of the Pacific Ocean with Respect to the 1,000-decibar Surface
Authors: Reid, Jr. Joseph L.
Published: January 2012

The geopotential anomaly at the surface of the Pacific Ocean with respect to the 1,000-decibar surface is computed. Horizontal variations in geopotential at greater depth are shown to be smaller and are neglected. The geostrophic flow at the sea surface with respect to the 1,000-decibar surface is shown to agree in general with the averages of currents estimated from the set and drift of vessels and tabulated in various atlases. The major gyres of the ocean are clearly shown and one new feature, a South Equatorial Countercurrent, is revealed in the western Pacific.

Since there is meridional flow in the ocean, the flow is not entirely geostrophic and the contours of geopotential anomaly may lie at some angle to the streamlines. This is most evident where the contours intersect the coast and cross the equator. A qualitative consideration of wind stress indicates that where wind and current are in the same direction geopotential anomaly will rise along a streamline and where they are opposed geopotential anomaly will decrease along a streamline. This effect can at least qualitatively account for the rise of geopotential anomaly to the west in the region of the trades and toward the east in the northern hemisphere westerlies.
Statistical studies of the performance of cosmic ray recording instruments
Authors: Dyring Eric
Published: January 2012

A method is presented to determine the variance of statistical fluctuations in cosmic ray data derived from the neutron monitor, the duplex cubical counter telescope and the directional telescopes. The standard deviation of the error distribution from instruments at the cosmic ray stations at Uppsala, Murchison Bay and Mt. Wellington is estimated by the method. The results are compared with the Poisson distribution and it is stressed that the use of the Poisson distribution will give an underestimate. The results offer standard error calculations of cosmic ray data.
Spectral considerations in two-dimensional incompressible flow
Authors: Pedlosky Joseph
Published: January 2012

The spectrum of two-dimensional incompressible motion is studied with particular attention paid to non-linear interactions. Conditions for the absence of direct interactions between high and low wave numbers are developed. The non-linear tendency of an initial spectrum is computed to illustrate these points. The importance of the angular distribution of the spectrum is illustrated in a spectral stability problem for an isotropic stream function spectrum. Finally, a special inertial equilibrium spectrum is derived exhibiting the properties of an energy barrier in wave number space.
On baroclinic instability in filtered and non-filtered numerical prediction models
Authors: Wiin-Nielsen Aksel
Published: January 2012

The criterion for baroclinic instability in a two level model of the large-scale motion in the atmosphere is computed and compared for the following cases: (1) A quasigeostrophic model with constant static stability. (2) A quasi-geostrophic model with a horizontal variation of static stability. (3) A primitive equation model with constant static stability. (4) A primitive equation model with horizontal variation of static stability.

It is found that the models containiig a horizontal variation of the static stability have a maximum instability at shorter wavelengths than the models with constant static Stability; that only small differences are observed in the amplification rate of baroclinic disturbances in models with the aame variation of static stability but with different basic equations 88 long as the variation of the meteorological parameters are in the observed range; but that large differences in the amplification rate occur when the Richardson number is small, i.e. for smell mean static stabilities and/or large vertical wind shears.

The structure of the baroclinically unstable disturbances are computed and compared for the four models mentioned above. The variation of the ageostrophic wind and the static stability through the wave is of special importance. It tuns out that the maximum ageostrophic wind at the upper level is about 15 % of the maximum wind, while the corresponding number at the lower level is 20 %. The distribution of the ageostrophic wind at the upper level is such that the wind is supergeostrophic around the ridge in the geopotential with a maximum close to the maximum geopotential and subgeostrophic around the trough in the geopotential. The distribution of static stability in the developing baroclinic wave is such that the air becomes more stable than the average between the ridge and trough (looking downstream), but more unstable between the trough and the ridge.
Vortex flows normal to a flat surface
Authors: Schwiderski Ernst W. , Lugt Hans J.
Published: January 2012

Numerical results of axisymmetric vortex flows normal to a flat surface are presented for a variety of Reynolds numbers. The results are based on an extension of Prandtl’s boundary layer theory, which permits a reduction of the Navier-Stokes equations to an ordinary boundary value problem that is transformed to a set of nonlinear Volterra integral equations. The solutions are compared with phenomena observed in hurricanes.
The stability of nongeostrophic perturbations in a baroclinic zonal flow
Authors: Árnason Geirmundur
Published: January 2012

The stability of a baroclinic zonal flow is studied by means of the method of small perturbations without imposing geostrophic balance on the perturbations. In other respects the present treatment of the stability problem is within the same framework as most other studies on the subject. The removal of the geostrophic aasumption makes the results applicable to low latitudes and provides thereby some insight into the conditions under which tropical disturbances may form. The theory leads to increased understanding of conditions favoring deviations from geostrophic flow and explains why observed perturbations are for the most part quaaigeostrophic. Furthermore, it reconciles results of some previous studies which within the narrower framework of geostrophic theory appeared unconnected. Two cases of generalization of previous results by other investigators are studied. The first of these extend results of EADY (1949) and FJÖRTOFT (1950), the second cam extends results obtained by CHARNEY (1947), HOLMBOE (1959), and ÁRNASON (1961). Based on these two cases general stability criteria are proposed.
On representative observations
Authors: Petersen Daniel P. , Middleton David
Published: January 2012

The traditional concept of a “representative observation” is examined and the need for a rigorous and objective definition is discussed in the light of the advancing technology of numerical weather analysis and prediction. Recent advances in the theory of sampling and filtering of multi-dimensional stochastic processes now make meaningful the following definition: a representative observation is a datum pertaining to a particular point and time, which is the result of an optimum filtering operation on the continuous raw data field, under the criterion of minimum average mean square error of reconstruction from the subsequent sampled values on a given space/time lattice.
In many cases of interest, the applicable filter weighting functions can be determined without complete knowledge of the wave-number spectra of the “signal” and “noise” processes. While the required operations can only be approximated in the case of conventional surface and upper air observations, in two important areas—radar and satellite instrumentation—simple and elegant mechanization may be feasible. In addition, the development yields usable insight into such questions as the density and arrangement of observation networks, numerical smoothing of discrete data, and approximations to derivatives used in numerical analysis and prediction.
Currents induced by tides and gravity waves
Authors: Hunt J. N. , Johns B.
Published: January 2012

Two-dimensional oscillatory potential flow was shown by Rayleigh and Schlichting to give rise to a steady second-order streaming at the outer edge of a laminar boundary layer. Their method is here extended to a three-dimensional Oscillatory flow which may be represented at a plane boundary by two harmonic oscillations (U, V) of frequency σ/2π in perpendicular horizontal directions.

The resulting second-order mean velocity components are interpreted in terms of bottom currents induced by tidal motion in shallow sew, or by doubly modulated gravity waves. These currents depend critically on the relative magnitudes of U, V and f/σ, where f is the Coriolis parameter.

It is suggested that on the tidal scale, such currents may contribute to the circulation within the North Sea, while on the gravity wave scale they contribute to the formation of offshore sandbars around the coasts.
The problem of deducing the climate from the governing equations
Authors: Lorenz Edward D.
Published: January 2012

The climate of a system is identified with the set of long-term statistical properties. Methods of deducing the climate from the equations which govern the system are enumerated. These methods are illustrated by choosing a first-order quadratic difference equation in one variable as a governing equation. The equation contains a single parameter. Particular attention is given to the climatic mean of the single variable.

Analytic methods yield the climate in some cases where the system varies periodically, but generally fail when the system varies nonperiodically. Numerical integration yields a value of the climatic mean for any individual value of the parameter. Additional analytic reasoning is needed to determine the nature of the climatic mean as a function of the parameter.

The progression from steady-state to periodic to nonperiodic behavior, as the parameter increases, is compared to the progression from steady-state to periodic to irregular flow in the rotating-basin experiments, as the rate of rotation increases.
On the formation and development of layer clouds
Authors: Matvejev L. T.
Published: January 2012

Empirical results indicating similar turbulent transfer for cloud droplets and for water vapour or sensible heat have been used in order to derive a set of prognostic equations for the total moisture content and for the equivalent potential temperature. With given external conditions, especially imposed vertical velocity the equations can be used for forecasting the formation and development of layer clouds. An example of practical application is discussed.
On Rossby waves in spiral galaxies
Authors: Dickinson Robert E.
Published: January 2012

Galactostrophic eddy velocities are used to eliminate the dependence of the potential vorticity equation on the velocities. The resultant time dependent equation involves the mass densities alone.
On the airflow over mountains with gentle slopes
Authors: Petkovšek Z . , Ribarič M.
Published: January 2012

The nonlinear equations for the two-dimensional small scale steady-state flow of a compressible fluid are put in a form appropriate for the treatment of streamlines with gentle slopes. For the limiting case when the slopes of the streamlines are negligibly small, these equations are solved numerically and the obtained results compared with the solutions of the linearized equations to determine the limits within which the linearization is permissible. Few numerical examples are given, to demonstrate the difference between solutions obtained by linearized and nonlinearized models of the atmosphere. It was found that the restriction that the total velocity of the wind be positive plays a decisive role in determining the maximum thickness of the air layer which is able to pass over a mountain of certain height.
Wind conditions in situations of patternform and non-patternform cumulus convection
Authors: Plank Vernon G.
Published: January 2012

Comparisons were made between the wind and wind shear profiles pertaining to pattern- form (clouds in rows) and non-patternform cumulus convection. No unique or consistent differences were found. The directional correspondence of the cumulus rows and wind was also investigated. The rows were found to be most frequently oriented about 3° to the left of the surface wind and about 15° to the left of the wind at the cloud base level.
Local Climatological Studies of the Temperature Conditions in an Urban Area
Authors: Sundborg Å.
Published: January 2012

The following article deals with an investigation of the local variations in the horizontal temperature distribution in the Uppsala district during different times of the year, of the day and under changing weather conditions. The article treats mainly the methods of investigation, especially the choice of observation stations, but also comments briefly upon some of the results. An attempt is made to place the established temperature contrasts in relation with simple climatological elements such as cloudiness, wind velocity, temperature and absolute humidity. The article is a preliminary report of an investigation, the complete results of which are shortly to be published in Geographica (Papers from the Geographical Institute, University of Uppsala, No. 22).
Variations in the Density of Small-Ions Caused by the Accumulation of Emanation
Exhaled from the Soil
Authors: Norinder Harald , Siksna Reinhards
Published: January 2012

Observations indicate that the density of ions increases during meteorologically
undisturbed summer nights. This typical increase is discussed and it is suggested that
the probable cause is to be found in the accumulation of emanation exhaled from the
ground. The accumulation occurs in weather situations which weaken or suppress
convection.
Numerical Integration of the Barotropic Vorticity Equation
Authors: Charney J. G. , Fjörtoft R. , Von Neumann J.
Published: January 2012

A method is given for the numerical solution of the barotropic vorticity equation over a limited area of the earth’s surface. The lack of a natural boundary calls for an investigation of the appropriate boundary conditions. These are determined by a heuristic argument and are shown to be sufficient in a special case. Approximate conditions necessary to insure the mathematical stability of the difference equation are derived. The results of a series of four 24-hour forecasts computed from actual data at the 500 mb level are presented, together with an interpretation and analysis. An attempt is made to determine the causes of the forecast errors. These are ascribed partly to the use of too large a space increment and partly to the effects of baroclinicity. The rôle of the latter is investigated in some detail by means of a simple baroclinic model.
Some Results of a Multiple Ship Survey of the Gulf Stream
Authors: Fuglister F. C. , Worthington L. V.
Published: January 2012

The first multiple ship survey of the Gulf Stream Area between Cape Hatteras and the Grand Banks of Newfoundland took place during the period from the 6th to the 23rd of June 1950. The survey was given the code name “Operation Cabot” by the U. S. Navy Hydrogra hic Office which acted as headquarters the planning and operational phases of the survey. The civilian scientist in charge of the technical phases of the program was Dr RICHARD H. FLEMING, Director, Division of Oceanography, U. S. Navy Hydrographic Office.
The Meridional Flux of Sensible Heat over the Northern Hemisphere
Authors: White Robert M.
Published: January 2012

The meridional eddy flux of sensible heat is examined by means of finite difference integration methods from northern hemisphere charts for the winter 1945–46. The eddy sensible heat flux is shown to occur principally in the lowest layers of the atmosphere and to decrease with elevation. The magnitude of the eddy sensible heat transports are compared with the total poleward energy flux required by the radiation balance, and are shown to comprise a very large fraction of this flux.
Note on Cooperative Research Projects
Authors: Rossby C.-G.
Published: January 2012

During the last few years, while the writer has served as professor of meteorology at the University of Stockholm, attempts have been made in Sweden to develop an informal type of international cooperation in meteorological research, similar to that which flourished in Europe before the outbreak of the Second World War, but at the same time adapted to meet the needs of the vastly enlarged scope and responsibilities of the meteorology of today.
Note on the Numerical Integration of the Equations of Meteorological Dynamics
Authors: Sawyer J. S. , Bushby F. H.
Published: January 2012

The work of CHARNEY (1949 a, 1949 b and 1950) and his collaborators on the numerical integration of the equations of meteorological dynamics is of considerable theoretical interest and of potential practical importance. In view of the promising nature of Charney’s earlier results an independent examination has been carried out in the Forecasting Research Division of the Meteorological Office at Dunstable. The purpose of the present note is to report the results of some calculations performed dong the lines of those of CHARNEY (1949 a, 1949 b) and also to indicate the results of experience which we have gained from some small-scale computational experiments with a baroclinic model used by SUTCLIFFE (1947) and now being studied by CHARNEY (1950).
The Geostrophic Poleward Flux of Angular Momentum in the Month of January 1949
Authors: Mintz Yale
Published: January 2012

From sea level, 700, 500, 300 and 200 mb daily synoptic charts over the whole of the northern hemisphere and 100 mb charts over three fourths of the hemisphere, the mean geostrophic poleward flux of angular momentum is computed for January 1949. A northward total flux is found in all latitudes, with the maximum at latitude 32 1/2° N of 5.4 × 1016 t m2 s–2. Four fifths of this flux occurs between the 500 and 100 mb levels. From the meridional convergence of the flux, the mean zonal surface stress is computed. The sign of this derived stress is found to be in good agreement with the distribution of the surface zonal wind: its average magnitude, in the region of the surface westerlies, is 1.2 dynes cm–2.
Forecasting Minimum Temperatures
Authors: Reuter Heinz
Published: January 2012

Two causes for a coloured sun are discussed, namely refraction and absorption. The importance of integrating the refraction effects arising from different parts of the sun’s disk as light sources is emphasized. It is shown that by such integration of ring phenomena around the sun, many observed peculiarities may be explained. Important conditions for that some types of coloured suns shall arise are homogeneity of the particles of the scattering medium, and also that the particles shall be large enough to give rise to rings of sufficiently small radius. Transfer of air masses at long distances but without a sideward mixture taking place is in favour of the creation of dust sheets of homogeneous character, as the vertical sedimentation has then time to come into action.
Height Variations in the Concentration of Ions Near the Ground During Quiet Summer Nights at Uppsala
Authors: Norinder Harald , Siksna Reinhards
Published: January 2012

Results of measurements of the concentration of small- and large-ions at different heights near the ground during quiet summer nights at Uppsala are given. Characteristic shapes for the variation of the concentration of ions are illustrated. At the ground the concentration of small ions increases more than at higher levels, where also an enhanced content of small ions can be observed during the stated weather conditions. The number of large ions descreases after sunset reaching a minimum at sunrise, after sunrise a comparatively rapid increase follows. It seems that the concentration of large ions near the ground is actually a little below that at the higher levels. Preliminary explanations of the variations are outlined.
A Comparison between Observed and Computed Winds with Respect to their Applicability for Vorticity Computations
Authors: Hovmöller Ernest
Published: January 2012

The insufficiency of computed height values for computations of derivatives such as vorticity and convergence, at least for the 300-mb and higher levels, is illustrated by theoretical and practical examples, and it is recommended to make more extensive use of observed winds. This gives a possibility to take into account the cyclostrophic and other non-geostrophic wind components for the vorticity computation which is the first step in the numerical forecasting methods (CHARNEY 1951).