bluuebunny/crossref_metadata_2025 huggingface dataset:
Monthly charts of evaporation from the N. Indian Ocean (including the Red Sea and the Persian Gulf)
Authors: Privett D. W.
Published: February 2007

Monthly values of the rate of evaporation from each 5‐degree square of the N. Indian Ocean and from the Red Sea and the Persian Gulf have been obtained by using a modified form of Jacobs's formula and climatic data supplied by the Meteorological Office.
Similarity theory in the relation between fluxes and gradients in the lower atmosphere
Authors: Taylor R. J.
Published: February 2007

Available data on wind and temperature profiles and heat and momentum fluxes in the lower atmosphere have been examined in the light of the similarity theory of Monin and Obukhov (1954) and, except in conditions of very strong lapse where some doubt remains, reasonable agreement is found.

The ‘log + linear’ profile form is investigated and it is shown that, in lapse conditions, it is applicable only to a very limited range of stability corresponding approximately with forced convection conditions. The constant, α, which enters into this profile is about 6 and thus considerably larger than the value proposed by Monin and Obukhov. The discrepancy is due to these authors' having applied the profile to a larger range of stability than is justified.

Subject to the reservation expressed for the case of very strong lapse conditions, the similarity scheme has been shown to extend to free convection conditions where a – ⅓ power form of profile is more appropriate. The relevant constants are estimated.
The summer circulation of the arctic stratosphere below 30 km
Authors: Hare F. Kenneth
Published: February 2007

The summer circulation of the arctic stratosphere is examined in the light of climatological data and daily synoptic analysis. The Ferrel westerlies are shown to extend to about 20 km (50 mb) immediately above the jet axis. The middle stratospheric easterlies above them descend to 15 km at the pole in midsummer. The easterlies flow round the flanks of a flat‐centred anticyclone near the pole, and are almost devoid of perturbations. The lower stratosphere (tropopause to 20 km) has a disturbed thermal regime due to vertical motion associated with waves in the Ferrel westerlies or with cold lows within the westerly ring.
The carbon‐dioxide flux over a field of sugar beet
Authors: Monteith J. L. , Szeicz G.
Published: February 2007

The difference of CO2 concentration at two heights above a sugar beet crop was measured with a sensitive infra‐red gas analyser. The ratio of evaporation to humidity gradient and of total heat flux to wet‐bulb temperature gradient gave a transport number for calculating CO2 flux, assumed proportional to CO2 gradient and wind speed. In August and September 1958 there was often a constant upward flux at night (mean 0·05 mg cm−2 hr−1) attributed to respiration by plants and soil micro‐organisms; but during daylight, photosynthesis gave a downward flux varying with solar radiation and reaching a maximum of 0·4 mg cm−2 hr−1. From 31 July to 11 September the net downward flux of atmospheric CO2 was 158 ± 29 mg cm−2 compared with an uptake of 217 ± 38 mg cm−2 estimated from dry matter increase of sampled plants. During October there was a net upward flux of 4·9 mg cm−2 day−1 attributed to a striking increase in amount of CO2 produced in the soil.
The use of the Campbell‐Stokes sunshine recorder as an integrating actinometer
Authors: Estrada I. G. Galindo , D'Albe E. M. Fournier
Published: February 2007

A simple method is described to evaluate the daily total direct solar radiation, by measuring the weight of paper burnt in the Campbell‐Stokes sunshine recorder.
The accuracy of determination of the vertical distribution of atmospheric ozone from emission spectrophotometry in the 1,043 cm−1 band at high resolution
Authors: Walshaw C. D.
Published: February 2007

A method is outlined for obtaining the vertical distribution of atmospheric ozone from ground‐level measurements of the downcoming thermal radiation in the region of the 1,043 cm−1 (9·6 μ) band. The emission measurements are such as may be made with a grating spectrometer of the Goody type; the slit width is about 2·5 cm−1, enabling interference from water vapour and carbon‐dioxide lines to be eliminated.

Estimates are made of the various sources of error, using a model atmosphere having three ozone variables (which are the ozone contents of the layers 1,000–600, 600–300 and 300–50 mb), and basing the analysis on four combinations of wave number and zenith angle of observation.

It is concluded that results of useful accuracy may be obtained for the two tropospheric layers, but that the method is not sufficiently sensitive to give significant information on the upper layer. The continuous absorption over the region lowers the accuracy appreciably but does not affect the main conclusion.
The variation in composition of sea‐salt nuclei with mode of formation
Authors: Oddie B. C. V.
Published: February 2007

It is shown that at coastal stations, while the coarser spray has a composition close to that of sea water, the smaller droplets (diameters less than about 25 microns) have a much higher proportion of potassium. The rapid decrease in the Na: K ratio with increasing distance from the sea is principally due to the settling out of the coarser spray. The result is consistent with Wilson's hypothesis that salt nuclei are formed largely from an extremely thin surface layer very rich in organic matter, which contains a high proportion of potassium.
Some notes on the stratospheric winds at Canton Island and Christmas Island
Authors: Ebdon R. A.
Published: February 2007

Stratospheric wind data for Canton and Christmas Islands show a fluctuation with a period of about 24 to 28 months in the zonal component. Christmas Island data also show that the fluctuation exists from below 60 mb to 10 mb (the highest level for which data are available) and that the amplitude of the fluctuation increases with height. The change in wind direction from W to E, or vice versa, is evident first at the higher levels and appears to work gradually downwards; at 60 mb the reversal of wind direction is evident about six months after that at 25 mb, and about twelve months after that at 10 mb.

Attempts to connect events in the equatorial stratosphere with events in the equatorial troposphere were not successful.
Project Jet Stream Research Flight No. 30, April 1957
Authors: Reiter E. R.
Published: February 2007

An analysis is made of Project Jet Stream Research Flight No. 30, conducted on 8 April 1957. This flight made several traverses through a pronounced jet stream over the New England States. The fields of wind speed, potential temperature, vorticity and divergence are presented in vertical cross‐sections. Special reference is made to the differences between geostrophic and actual vertical wind shear in the vicinity of the jet core.
Measurements of evaporation and heat transfer in the lower atmosphere by an automatic eddy‐correlation technique
Authors: Dyer A. J.
Published: February 2007

Following the development of an automatic instrument for the determination of evaporation and sensible‐heat transfer by the eddy‐correlation technique, a large number of measurements of these eddy fluxes have been made over level pasture‐land. The observations, taken at a height of 4 m, are in excellent agreement with the energy balance. Individual measurements, of 5‐min duration, are distributed about a strict energy balance with a standard deviation of 31 per cent, due mainly to horizontal gradients of wind, temperature, and humidity below 4 m height. Over a period of several hours these gradients average out to negligible values.

The short response time of the sensing equipment (∽ 0·3 sec) ensures that, for conditions of moderate and high instability, significant deficiencies in eddy‐flux measurements occur only with winds exceeding 10 m sec−1.

A quantity ϵ, the ‘evaporation fraction,’ i.e., the ratio of evaporation to evaporation plus sensible‐heat transfer, is found to increase markedly after rain, and to gradually decrease during the succeeding dry period. This increase can be quantitatively related to the amount of rain. The average value of ϵ during February‐March 1960 was 0·56, whilst a value of 0·54 can be computed from annual totals of precipitation and net day‐time radiation income.
Design of interference filters for the observation of infra‐red emission from atmospheric carbon dioxide by an earth satellite
Authors: Smith S. D.
Published: February 2007

Detailed proposals are made for the design of a high‐order Fabry‐Perot type interference filter in which the transmission bands of the filter are exactly matched to 15 lines of the R‐branch of the CO2 spectrum near 15 μ. The striking energy advantages of such an interferometer are discussed and it is shown that use of an optically worked high‐index germanium spacer leads to a further considerable increase in light grasp. It is concluded that technical problems are not severe and a calculation of the energy that can be collected by the proposed system suggests that a detector of area 9 mm2 with a noise‐equivalent‐power of 10−10 watts (i.e. comparable with a standard Golay cell) can provide adequate sensitivity.
Atmospheric observations of line intensity and half‐width in the rotation and ν2 vibration‐rotation bands of water vapour
Authors: Saiedy F.
Published: February 2007

Curves of growth have been measured in the solar spectrum between 8 and 13 μ on five atmospheric water‐vapour lines, three in the rotation band and two in the ν2 vibration‐rotation band. The water vapour in the path, from radiosonde data, was never less than 1 g cm–2, so that it was possible to measure S0 (the line intensity at T0 = 273°K) and α0 (the half‐width at p0 = 1,000 mb) separately only for the weak line at 914.03 cm–1, with errors of approximately 3 and 5 per cent respectively. For four strong lines at 871.32, 878.61, 1106.74 and 1111.53 cm–1 only the product S0 α0 could be obtained, with an estimated error of 8 per cent. The results of the rotation lines show reasonable agreement with theoretical values. Using theoretical values of α0, the normalizing factor n̈ for the two n̈2 lines are 0·0165 for 1106·74 and 0·0126 for 1111·53 cm–1, which differ considerably from the overall normalizing factor 0·005 given for this band by Benedict et al. (1952) and show a slight dependence on the rotational quantum number J.
Vertical series of sea and air temperatures close to the surface, taken aboard the yacht Petula in the tropical Atlantic
Authors: Evans F. , Dickson C. N. , Kove N. A. G.
Published: February 2007

Sea and air temperatures were taken at a number of points within 2 m of the surface. In general, both sea and air temperature profiles were almost isothermal at more than 1 m from the surface. Air temperatures gave some indication of a change from neutral to stable conditions above about 55 cm. There was little confirmation of an earlier suggested similarity between profiles of wind, temperature and humidity under near‐neutral conditions.
Point discharge from natural and artificial points (Pt. II)
Authors: Milner J. W. , Chalmers J. Alan
Published: February 2007

Measurements have been made of the point‐discharge current through an artificial point at about tree‐top height, the potential gradient at the ground nearby and the wind speed. The results are similar in form to those for an isolated point at greater height and do not show the square‐law relation between current and potential gradient that has previously been found when wind‐speed has not been taken into account. The current flowing down a living tree has also been measured and obeys a similar relation with potential gradient.
The effect of sampling and averaging on the spectrum of turbulence
Authors: Smith F. B.
Published: February 2007

The dual effect of averaging wind‐fluctuation data and subsequent sampling over periods of specified duration modifies the full spectrum of turbulence at both high frequencies and low frequencies. The nature of the wave filtering so implied has been known and used for some years, but apparently the derivation of the mathematical form of this filter so far has not been set down in the literature in a completely satisfactory form. This note is an attempt to meet this need.
A note on the equation of mean motion as used in numerical prediction
Authors: Jones D. E. , Graystone P.
Published: February 2007

An investigation is made into the behaviour of the individual terms in the vertically averaged vorticity equation. It is shown that certain minor terms are biased in sign, and that their inclusion may lead to gross errors in a numerical forecast. The separate terms are also shown to increase in magnitude in the course of a numerical forecast but at differing rates.
Evidence of geostrophic motion in the equatorial stratosphere
Authors: Reed R. J.
Published: February 2007

The characteristics of the temperature oscillation associated with the recently discovered 26‐month oscillation of the zonal wind component in the equatorial stratosphere are inferred from the thermal wind relationship. Computations based on actual wind data predict an amplitude of 2·5°C for the temperature oscillation near the equator and a phase difference of one to two months between wind and temperature cycles at 20 km increasing to seven months at 24 km. The close correspondence between predicted and observed characteristics supports the hypothesis that the 26‐month oscillation is in geostrophic equilibrium.

The hypothesis is also supported by a consideration of relative sizes of the local wind acceleration and Coriolis force which indicates that the acceleration becomes an order of magnitude less than the Coriolis force at a distance of 40 km from the equator.
Gravity waves in the atmosphere as a three‐dimensional problem
Authors: Sawyer J. S.
Published: February 2007

An equation is derived (see Eq. (10)) for the vertical variation of the amplitude of standing waves when the wind direction varies with height and the wave is periodic both in the x‐ and y‐directions. The equation is solved numerically for specified two‐ and three‐layer atmospheres to determine possible wavelengths in the x and y directions for lee‐waves. The lee‐wave pattern is calculated for an isolated hill in specified cases.
The radar equation in meteorology
Authors: Probert‐Jones J. R.
Published: February 2007

While meteorologists can obtain much useful information by using radar in a qualitative manner, great benefit can be derived by obtaining quantitative measurements. However, these measurements have been found, in general, to be below values calculated from radar theory by a factor of between two and five, and there has been no satisfactory explanation for this discrepancy. In this paper, the radar equation for a meteorological target is derived, particular attention being devoted to the effect of the shape of the main lobe of the beam, and of the radiation outside it. It is shown that previous theoretical expressions for both the gain and the echoing volume have been too large, and hence that previous equations overestimated the received power. The present equation gives good agreement with all the experimental data.
Transfer through the tropopause and within the stratosphere
Authors: Newell R. E.
Published: February 2007

The evidence for tropospheric‐stratospheric mass exchange is reviewed. A large fraction of the exchange appears to occur in the vicinity of the middle latitude tropopause discontinuity and the concomitant jet stream. Calculations of the flux of radioactive substances in the troposphere support this view. Computations of the horizontal flux of ozone in the lower stratosphere are presented for the I.G.Y. period divided into three‐month seasons. Indications are that the large‐scale quasi‐horizontal transient eddies can transport ozone polewards in sufficient quantities to account for the spring build‐up of ozone. Such large‐scale mixing, as opposed to mean meridional motions, also allows explanation of the distribution of radioactive tungsten in the stratosphere. Transports appear to be polewards and downwards between latitudes 20° and 60°. Independent meteorological evidence, in the form of isentropic cross‐sections and values of the covariance between the meridional and vertical components of the wind, support the mixing scheme. The observed counter‐gradient eddy flux of heat can be explained from the model. Distributions of certain other trace substances are not at variance with the model. From a preliminary examination of the angular momentum transport processes up to 60 km it appears that transient eddies are also important to these levels but there is not yet sufficient global coverage to evaluate the contributions due to mean motions and standing eddies.
Measurements of the vertical distribution of atmospheric ozone at Nairobi
Authors: Griggs M.
Published: February 2007

Measurements of the vertical distribution of atmospheric ozone at Nairobi (2°S) are presented.
Long‐wave radiation from clear skies
Authors: Swinbank W. C.
Published: February 2007

Analysis of the observations of long‐wave radiation from clear skies, R, made by Dines at Benson, yields a correlation coefficient of 0·99 between R and the black‐body radiation at the corresponding screen temperature T. A new series of measurements over wider ranges of temperature and humidity confirms this, with the same value for the correlation between R and σT4, the regression equation being: R = −17·195 σT4 (milliwatt cm−, T °K).

An alterlative representation of equals accuracy is R = 5·31.10−14 T−6 (Milliwatt cm−2, T°K) The latter formulation is probably better founded physically, and brings out the temperature dependence of the ‘effective emissivity’ ϵ (i.e. R/σT4), which the atmosphere must exhibit. Either expression provides an estimate of R in terms of T with a probable error less than 0·5 mw cm−2.

The present analysis omits any explicit reference to the influence of vapour pressure e on R, and so differs essentially from those due to Brunt and Angström. Re‐appraisal of these latter suggests that the relationships established therein between * and e result basically from a correlation between temperature and humidity. Both the nature and the degree of the correlation between RσT4 and e for a given locality would then depend on the temperature‐humidity regime occurring there. The wide variations from place to place, both in the values of the coefficients occurring in the Brunt and Angström equations, and in the degree of correlation found between R/σT4 and the corresponding function of e, are thereby explained.
Vertical temperature profiles over adjacent land and lake stations
Authors: Munn R. E. , Richards T. L.
Published: February 2007

A comparison is made between vertical temperature profiles obtained concurrently from land and lake stations about one‐half mile apart. Tethered balloons were used to support modified radiosondes up to 1,000ft. The results of 46 ascents are time‐grouped to show significant differences between the profiles throughout most of the 24 hours. These differences are mostly obviously consistent with the difference in thermal properties of the underlying surfaces, but in some respects a more complex relation, associated with the lake breeze, may be involved.
A note on determining the scale of turbulence
Authors: Pasquill F. , Butler H. E.
Published: February 2007

Recent observations of wind inclination near the ground in stationary conditions, are shown to possess properties consistent with an effectively complete description of the turbulence on the low‐frequency side. The results are therefore particularly suitable for determining the conventional time‐scale of turbulence, and the values obtained are found to be appreciably greater than many previous estimates. The results are then used to examine the accuracy of estimating the scale from data which are less complete on the low‐frequency side (shorter sampling duration), by making assumptions about the shape of the whole spectrum, and it is seen that assumptions which have hitherto seemed reasonable for this purpose can in fact lead to a two‐fold or greater underestimation of the scale. It is inferred that for adequate low‐frequency specification (hence reliable estimation of scale) the sampling duration over which measurements should be made and repeated many times must be at least 40 times the time‐scale.
The electrification of snowstorms and sandstorms
Authors: Latham J.
Published: February 2007

An analysis is made of available observations on the electrical properties of natural and artificial snowstorms. an explanation for this electrification is given in terms of a theory of charge transfer associated with temperature gradients in ice, which has been shown earlier to provide a tenable theory of thunderstorm electrification. Further analysis shows that sandstorms exhibit similar electrical effects to those of snowstorms, and it is suggested that the temperature gradient effect may provide an explanation for sandstorm electrification.
Trees and climatic history in scotland
Authors: Lamb H. H.
Published: February 2007

Scotland constitutes a gap in our information about the Early Middle Ages warm epoch (circa 1000–1300 A.D.). Evidence has been sought from vegetational history as well as documentary records.

A sample tree found lying in a peat bog at an exposed part of the north‐west coast where trees no longer grow was discussed in the Quarterly Journal, 1945, when it was thought to have grown there in the Middle Ages or later. the result of a radiocarbon dating test on this tree contradicts all the opinions then expressed about its age. the tree and other remains from the same bog are now shown to have belonged to the latter part of the post‐glacial climatic optimum before 2000 B.C., and there is no tangible evidence that trees have grown at the point in question at any time since 1000 B.C. This compels a re‐assessment of the other evidence, of what we may hope to learn from it and how much we know so far about the climatic history of Scotland in medieval and post‐medieval times.

Documents of the times concerned, already used but not so far quoted in this connexion by various historians, have yielded the most promising indications to date. the isolated facts and impressions gained from these sources seem most simply explained by assuming that Scotland shared the general experience in northern lands of a warm epoch, accompanying the period of high culture, from 1070 A.D. or earlier, to around 1300 and that the subsequent deterioration had serious effects upon the economy. the evidence from Scotland, as opposed to that from neighbouring countries, of frequent bad seasons and deteriorating condition of the land, is so far, however, almost entirely indirect and in itself inconclusive. Only after 1550 are enough facts known to make the latter stages of the decline culminating in the dire years of the 1690's reasonably clear and unmistakable.
A tentative model of the 26‐month oscillation in tropical latitudes
Authors: Reed R. J.
Published: February 2007

A model of the three‐dimensional wind and temperature fields in the 26‐month oscillation is presented, based in part on empirical data concerning the temperature behaviour and its relationship to the zonal wind behaviour and in part on theoretical deductions from the thermodynamic energy and continuity equations.

The empirical data show that equatorward of 16° latitude highest temperatures precede the west wind maximum by intervals varying from 4–5 months at the 20 mb level to 0–1 months at the 80 mb level. Near the Equator the amplitude of the temperature oscillation is approximately 2°C and varies little with height in the foregoing altitude range. In the subtropics the phase of the temperature cycle is nearly opposite to that at the Equator, lowest temperatures preceding the maximum (relative) westerlies. the amplitude at these latitudes increases from a fraction of a degree at 80 mb to about 1°C at 20 mb. the features of the temperature and zonal wind behaviours are shown to be consistent with the thermal wind relationship.

The theoretical results indicate that the vertical velocity has a maximum amplitude of about 0·01 cm sec−1 at the Equator and that the phase of the vertical velocity oscillation reverses near 15° latitude. Maximum subsidence precedes highest temperatures by about one month. Meridional velocities are strongest near 15° latitude where they reach values of 1–2 cm sec−1. Maximum northerly winds follow maximum subsidence by about one‐quarter cycle.

The observed quasi‐biennial oscillation of total ozone amount is shown to be qualitatively consistent with the model, and near the Equator, to be in quantitative agreement with the theoretical results.

It is speculated that the 26‐month oscillation possesses two superposed modes: a tropical mode characterized by a vertically‐propagating wave and a hemispheric mode consisting of a Pole to Equator standing wave. Finally, it is proposed that the oscillation has its origin in a subharmonic response to the annual heating cycle.
The ‘southern oscillation’
Authors: Troup A. J.
Published: February 2007

An attempt is made to obtain a coherent picture of the extent and mode of operation of the ‘southern oscillation.’ This term is used here, following Sir Gilbert Walker, to describe a standing fluctuation of opposed pressure anomalies in both eastern and western hemispheres. The existence of this opposition has been verified, using more recent data, for stations in the Indian and Pacific Ocean regions; results show the oscillation was less marked in recent decades.

The representativeness and physical meaning of the index devised by Walker to characterize the state of the oscillation are considered. The geographical extent of the phenomenon is examined using correlation and regression charts of pressures with Walker's index. The temperature and rainfall anomalies associated with it may be derived qualitatively from the pressure anomalies.

Recent data are used to verify persistence and lag correlations between station pressures; while there has again been some decline, the lag correlations of elements with previous South America pressures still hold good. The decline in these various quantities is indicative of a minor secular change commencing in the 1920's, which is also evident in a decrease in the variability of pressure.

What ‘periodicities’ appear to exist in elements affected by the southern oscillation may well be an outcome of sampling fluctuations in (often persistent) random series. This is suggested by the variety of supposed ‘periods’ reported, and their evanescence in space and time. An example of this evanescence in time is provided from the Darwin pressure record.

A mechanism for the oscillation is proposed in terms of variations in a direct toroidal circulation between warmer eastern and cooler western hemispheres. These variations are attributed, (following a model by Palmer of the synoptic climatology of the tropical Pacific) to variations in the south‐east trades in the South Pacific and the consequent variations in cyclonic vortex generation in the West Pacific. The persistence of anomalies is then due to the extent of ocean areas in the south‐east Pacific where the sea temperature is lower than the air temperature. The lag correlations observed may be due to this persistence and to a transmission of anomalies along the trades through air‐sea interaction.
The computation of infra‐red cooling rate in planetary atmospheres
Authors: Rodgers C. D. , Walshaw C. D.
Published: February 2007

A scheme is described for the calculation of the atmospheric infra‐red radiative cooling rate which is suitable for use at all levels. It uses the Curtis matrix method together with the Curtis‐Godson approximation in a form which includes the influence of temperature on line intensity. Doppler effect is included. Because of its simplicity the Goody random model is used for all the absorption bands considered (H2O rotation and 6.3μ, CO2 15μ, O3 9.6μ); the use of more accurate models as they become available presents no fundamental difficulty and in any case many of the topics investigated are not particularly sensitive to the spectral model used. A method of reducing the number of spectral intervals is described and its accuracy demonstrated. An accurate method of dealing with diffuse radiation is used to test the diffuse approximation, with the result that the constant factor 1.66 originally proposed by Elsasser is found to be quite adequate for most purposes. Cooling rate errors caused by the following factors are estimated: (1) random and systematic errors in the initial temperature and humidity profiles; (2) the size of the vertical step used in computation; (3) neglecting the temperature dependence of the Curtis matrix; (4) non‐linear effects in forming climatological means. It is shown that the easily computed ‘cooling to space’ is often a good approximation. All the error investigations are based on direct calculations of the cooling profile. Some comparisons with other techniques are presented and a number of examples of meteorological interest are used to illustrate the versatility of the computing scheme.
Isentropic relative‐flow analysis and the parcel theory
Authors: Green J. S. A. , Ludlam F. H. , McIlveen J. F. R.
Published: February 2007

A discussion is given of the justification and usefulness of analysing on isentropic charts observations of the flow relative to a mature large‐scale motion system under the assumption that the system is in a steady state. It appears that trade wind air may rise over a front into a jet stream and that by an extension of the parcel theory into three dimensions the speed of a jet stream may be related to an area on the aerological diagram.
The role of deformation in the large‐scale dispersion of clusters
Authors: Djuric D.
Published: February 2007

A study is made of the deformation of fluid bodies in horizontal flow in the absence of small‐scale turbulent diffusion. On the basis of a kinematic model, formulae for the increase of the separation of pairs of particles and of the dispersion of particles from the centre of gravity of each cluster of particles are given. The results are compared with statistical data from the dispersion of air trajectories in a barotropic model corresponding to the development of the flow in the Northern Hemisphere over a period of 8 days.

The dispersion of clusters by deformation is used to demonstrate how the diffusion coefficient increases with the scale of motion.
A new method for the prediction of typhoon movement using the 700 mb chart
Authors: Tse S. Y. W.
Published: February 2007

Storm tracks which crossed the area between the Equator and 35°N, 105°E and 160°E, during the period 1957 to 1960 have been analysed. For each storm position values of the 700 mb contour height (geopotential metres) He, Hw, Hs and Hn, were extracted at four selected grid points labelled as E, W, S and N respectively. E and W were at distances of 10° longitude east and west of the storm centre, S and N at distances of 10° latitude south and north of the storm centre. The differences (He − Hw) = ΔϕH and (Hs − Hn) = ΔϕH were computed for 516 storm positions and used as predictors. The subsequent 24‐hr meridional and zonal displacements of the storm in degrees latitude and longitude, Δϕ and Δλ, were chosen as predictands. The over‐all synoptic pattern at 700 mb was then introduced as an additional criterion. Regression lines corresponding to a few easily recognized synoptic patterns were derived from scatter diagrams of ΔϕH versus Δϕ and ΔλH versus Δλ. A nomogram was constructed to give Δϕ and Δλ for values of ΔϕH and ΔλH respectively.

The method, tested in 44 forecasts on 8 storms during May to September 1961, gave an average error of 87 nautical miles; this compares favourably with other objective methods.
Local differences in the attenuation of solar radiation over Britain
Authors: Monteith J. L.
Published: February 2007

In relation to other British stations, radiation totals at Aberporth on the Welsh coast are anomalously high. On the basis of recorded sunshine, the annual mean intensity of direct radiation at Aberporth is 31 mw cm−2 compared with 25 mw cm−2 elsewhere. Allowing for the change of extra‐terrestrial radiation with latitude, the effective transmission of the atmosphere is greatest at Aberporth and Lerwick, less at Eskdale‐muir, and least at Kew, consistent with differences of air pollution. Measurements at a station installed near Aberystwyth suggest that the relatively clean air over Aberporth may be confined to a very narrow coastal strip.

At Kingsway, the direct radiation per hour of sunshine increased from 21 mw cm−2 in 1957 to 26 mw cm−2 in 1963 consistent with the decrease of smoke in central London. Kingsway and Kew now record about the same intensity of radiation attenuated at roughly 1 per cent per 10 μg m−3 of smoke.

Applying this analysis to the radiation balance of Britain, previous estimates of potential evaporation in north Scotland were raised from 13 to 17 inches per year, removing most of the difference in estimated evaporation over Britain.
Features of Transvaal hailstorms
Authors: Carte A. E.
Published: February 2007

Hailstorms in the vicinity of Johannesburg and Pretoria, South Africa, are being studied mainly by means of a dense network of voluntary observers. The storms have shown great variability. A characteristic of sustained storms is their tendency to move to the left of the mid‐tropospheric winds, whereas in the Northern Hemisphere movement is to the right. One of these storms appeared to be multicellular at a stage when hailstones up to 6 cm diameter were falling. Another produced large spongy hailstones along part of its path.
The melting of small ice spheres and cones
Authors: Drake J. C. , Mason B. J.
Published: February 2007

The times of complete melting of small ice spheres in airstreams of controlled temperature, humidity and velocity were measured and compared with the values computed from theory. The theory, which allows for heat transfer to the ice particle by conduction through the air and by condensation upon its surface, agrees quite well with the observations if allowance is made for the heat content of the water retained by the particle during the melting process. The melting times of small ice cones of various shapes did not differ from those of spheres of equivalent volume by more than 10 per cent. It was demonstrated both theoretically and experimentally that an evaporating ice sphere will acquire the same surface temperature as the ice‐coated junction of a thermocouple psychrometer placed in the same airstream provided that the radiation and conduction errors of the latter are rendered negligible by good design.
Annual variation of ozone in Antarctica
Authors: Dobson G. M. B.
Published: February 2007

Observations of the total ozone at Halley Bay (75°S) during the I.G.Y. showed that the annual variation there was very different from that found at a similar northern latitude. Later observations now available show similar characteristics. Further, recent measurements at the South Pole and at Byrd (80°S) give similar results to those at Halley Bay, indicating that this type of annual variation is probably characteristic of Antarctica generally.
Objective analysis of the 100 mb level
Authors: Woodroffe A.
Published: February 2007

This paper describes an objective technique for the analysis of 100 mb contour charts. The method is basically an extension of a procedure that has proved successful at lower levels. The problems associated with the analysis of contour heights at 100 mb and above are discussed briefly and a sample analysis is shown. It is considered that the objective analyses are of similar standard to those produced by an analyst using conventional methods.
A new dimensional approach to the problem of flux‐gradient relationships near the ground
Authors: Bernstein A. B.
Published: February 2007

Application of the dimensional method of vector lengths to the continuity equations for momentum, heat, and any conservative scalar property whose mass concentration is S, yields a flux‐gradient relationship of the form \documentclass{article}\pagestyle{empty}\begin{document}$ \[ \frac{{K_z }} {{r_\omega S\sigma S}}\frac{{\partial \overline S }} {{\partial z}} = f_S \left\{ {\frac{{KgzH}} {{\rho c_p T\sigma _{\omega ^3 } }}} \right\} \] $\end{document}

Which is identical to the Monin‐Obukhov relationship except that the governing parameter u* is replaced by σω and the governing parameter S* is replaced by γωS σS. This formulation cannot be adequately tested with existing data due to a systematic underestimation of the rapid‐response statistics under non‐neutral conditions. This underestimation is the result of improper choice of sampling period and interval between successive measurements. While a satisfactory correction may be applied to the stress, permitting examination of the Monin‐Obukhov formulation, no such correction procedure is possible with respect to γωS σS and σω.
The free‐convection temperature profile
Authors: Deardorff J. W. , Willis G. E.
Published: February 2007

Measurements of horizontally averaged temperature within a convection chamber suggest that as the Rayleigh number is increased, there is a tendency for Priestley's constant H∗︁ of the free‐convection temperature profile to approach the atmospheric value. An extrapolation of this trend implies that an atmospheric layer in which the temperature gradient varies as z−4/3 is truly representative of free convection and is not influenced by very small values of mean wind shear.

In Townsend's open‐box convection experiment, the downdraught which persisted at the location of temperature measurements is considered here to have suppressed the appearance of a — 4/3 power region and perhaps to have caused an extended — 2 power region in the temperature gradient.

A small‐scale field experiment is proposed to settle the controversy of the power dependence of the free‐convection temperature gradient in windless conditions.
A theoretical study of the ice accretion process
Authors: Macklin W. C. , Payne G. S.
Published: February 2007

A theoretical study has been made of the assumptions underlying the simple heat balance relations which have been used so far to predict the surface temperatures of ice deposits being formed by the accretion of supercooled water droplets. Calculations have been made of the freezing and subsequent cooling times of a thin water film on the surface of a ventilated sphere initially at a uniform temperature. It is demonstrated that this effectively simulates hailstone growth. The calculations show that both the freezing and cooling processes are dominated by the sphere temperature although, during freezing, the temperature of the water film may rise to a value close to 0°C. They also show that, except at sphere temperatures within a few degrees of 0°C, the freezing time of the water film is short compared with the total time taken to remove the latent heat of fusion by the forced convection process. The reason for this is that the heat of fusion is first conducted rapidly into the sphere, and then more slowly dissipated through the air boundary layer on the surface of the sphere to the environment.

Values of the freezing and subsequent cooling times of the water film are presented for various values of the ambient temperature, sphere radius and film thickness. Film thicknesses have been related to the radii of the cloud droplets by a semi‐empirical relation. The liquid water concentrations required to maintain a sphere at a steady temperature have been computed and found to compare well with those given by the simple heat balance relation for a spherical hailstone. Thus, although the simple heat balance relations completely ignore the physical processes involved in the accretion of individual droplets, they are useful for predicting values for the mean temperatures of an accreting surface in a steady state situation.
Continuous regular pressure oscillations in the atmosphere at night
Authors: Shrestha K. L.
Published: February 2007

Continuous and very regular pressure oscillations with periods ranging from 15 to 120 sec and having magnitudes of 1 to 6 μ bar were observed on clear and calm nights at two of the three microbarograph stations near Brisbane, Australia. Their dependence on the topography and the stability of the lower atmosphere resembles that for lee waves observed behind ridges.
Characteristics of vertical velocity fluctuations observed on a 430‐m tower
Authors: Kaimal J. C. , Haugen D. A.
Published: February 2007

During the summer of 1963, sonic anemometers were mounted at 46, 137, 229 and 320 metres on a 430 metre tower to measure turbulent fluctuations in the vertical velocity component. Mean horizontal wind speeds and temperatures were measured at 12 levels on the tower.

Characteristic behaviour of power spectra for four typical stability conditions are described. Evidence of an inertial subrange is found at all levels regardless of stability. Analysis of the rate of dissipation, ϵ, indicates that there is no simple relationship which can describe its behaviour with height for all conditions. Its behaviour is shown to change with thermal stratification; ϵ remains relatively constant with height during well‐established convection but decreases rapidly above 46 m when the temperature gradient is stable. It is also shown that ϵ is roughly proportional to the product of the third power of the standard deviation of the vertical velocity component and the wave number of its logarithmic spectral peak.

The data from the sonic anemometers provide some additional information on the structure of convection during very unstable lapse conditions. Analyses of coherence between successive levels indicate the presence of a second generation of convective elements above the plume convection generally observed near the ground. The transition layer is estimated to be in the vicinity of 100 m. The scale of turbulence for the top three levels shows an initial increase with increasing instability followed by a decrease. It is conjectured that this decrease is a consequence of the fact that the second‐generation convective elements move faster than the wind speeds indicated at the level of instrumentation.
Energy‐preserving integrations of the primitive equations on the sphere
Authors: Grimmer M. , Shaw D. B.
Published: February 2007

Long‐term global integrations of the primitive equations for the free‐surface model are performed using spherical polar co‐ordinates. Two methods are used to overcome the computational drawback of excessive resolution near the poles. In the first, time‐steps vary latitudinally on a grid with constant angular increments. Stable integrations result, in which the evolutions closely match (save for phase‐truncation due to divergence) those of the analytic solution of the non‐divergent vorticity equation for initial data in which non‐linear interactions vanish. In the second set of integrations zonal resolution varies latitudinally, and the resulting differential phase‐truncation causes spurious interactions which lead to rapid departure from the analytic solution. In both cases finite difference approximations are used which preserve domain sums of mass and of total energy (kinetic plus potential), in analogy with properties of the continuous equations. The space‐differencing method, together with the time‐smoothing inherent in the variable time‐step scheme, may have helped to suppress non‐linear instability in the first set of integrations.
An analysis of the chemical composition of rain‐water and air over the British Isles and Eire for the years 1959–1964
Authors: Stevenson Catherine M.
Published: February 2007

The results of an analysis of the chemical composition of precipitation and air over the British Isles and Eire are presented. Tables are given showing the median concentrations of S, Cl, Na, K, Ca and nitrogen in ammonia and nitrate, and maps are presented to indicate the variations in sources for different chemicals. The errors in the sampling technique are discussed.
The white box: The mean mechanics of the cumulus cycle
Authors: Fraser A. B.
Published: February 2007

A region surrounding a cumulus cloud is defined in such a way that (when virtual temperature effects are neglected) there is no sensible heat transfer across the boundaries of the region. This simplifies the discussion of the interaction between the cumulus and its environment. A model of the region, which is called the white box, is developed and an estimate is made of the net vertical mass transport within it as a function of height. Rain and cloud radiation have the effect of modifying this transport and may be described in terms of it. If the requirements of continuity are satisfied by means of an alteration of the wind profile of the environment downstream, the wind near the base of the cloud downstream is increased. It is shown that cumulus convection can destabilize as well as stabilize its environment.
A pressure oscillation in a 10‐level atmospheric model
Authors: Benwell G. R. R. , Bretherton F. P.
Published: February 2007

A pressure oscillation in the 10‐level primitive equation model of Bushby and Timpson (1967) has been diagnosed as a standing inertio‐gravitational wave in the external mode. A small modification to the linearized balance equation used to define the initial state has resulted in its elimination. Although the broad development of the pressure field is unaffected, significant changes have appeared in the rainfall. The speed of propagation of external gravity waves in the model is about 285 m/s, substantially less than for a comparable continuous atmosphere.
The regions of formation of atmospheric ozone
Authors: Brewer A. W. , Wilson A. W.
Published: February 2007

The nature and magnitude of the source of the natural ozone of the atmosphere is discussed and the results of calculations of the local rates of production in the periods January‐February and July‐August are given. The effect of different assumptions and models on the deduced source regions and source strengths is demonstrated. It is concluded that the most satisfactory result is obtained using solar ultraviolet intensities recently measured in the stratosphere. It is possible that there may be some catalytic destruction of ozone by water vapour, but below 35 km the effect must be small.
Transport of gases to and from surfaces with bluff and wave‐like roughness elements
Authors: Chamberlain A. C.
Published: February 2007

Wind tunnel experiments have been done on the transport of a radio‐active vapour of thorium B, and water vapour, to and from surfaces with spherical, cylindrical and wave‐like roughness elements. The results are analysed in terms of the dimensionless number B of Owen and Thomson.

For values of the roughness parameter u* z0 v−1 between 10 and 1,000, the results were found to conform approximately to Owen and Thomson's empirical formula
\documentclass{article}\pagestyle{empty}\begin{document}$ \[B^{ - 1} = \alpha \left({\frac{{u_* h}}{\nu }} \right)^m \left({\frac{\nu }{D}} \right)^n \] $\end{document}

Where h (= 30 z0) is the equivalent sand roughness, D the diffusivity of the vapour, and α, m and n are constants with values 0·5, 0·45 and 0·8 respectively. Experiments with aerodynamically smooth surfaces give results in accordance with von Kármán's equation.

Wind profiles over large bodies of water imply rather small values of the roughness length and u* z0 v−1 generally lies in the range 0·1 to 10. In this region, the bluff‐body effect on momentum transport is small, and is counteracted by the fact that D for water vapour is greater than v. As a result, B−1 is small, and the resistances to transport of momentum and water vapour are nearly the same. Experiments on the rate of evaporation of water in a tank in the wind tunnel give values of the bulk evaporation coefficient, referred to a height 5 cm above the surface, in good agreement with theory.