bluuebunny/crossref_metadata_2025 huggingface dataset:
Governing desertification in Mediterranean Europe: The challenge of environmental policy integration in multi‐level governance contexts
Authors: Briassoulis H.
Published: July 2010

Successfully combating desertification has proven to be a demanding endeavour. Fifteen years since the UNCCD was signed, its implementation record remains poor worldwide and in Mediterranean Europe. Desertification is a complex socio‐environmental problem, which requires long‐term efforts towards integrating environmental concerns in sectoral and development policies, coordination among sectors, policies, agencies and programmes as well as efficient and effective multilevel collaboration arrangements. It is not accidental that Environmental Policy Integration (EPI) and multi‐level governance (MLG) are central notions in the UNCCD neither that it's poor implementation record may partly be due to the difficulties of responding to these challenges. This study explores the role of EPI in combating desertification in MLG contexts. First, it briefly negotiates desertification and the UNCCD emphasizing the EPI and MLG provisions. After presenting the conceptual and methodological framework employed, it offers a broad‐brush assessment of the integration of desertification concerns into development policies at the international, EU and Mediterranean member state level and the role of governance and MLG. It concludes that the state of integrating desertification concerns in development policies at all levels is poor and the current mode of governance and MLG are far from the UNCCD ideal of ‘good governance’. The low political priority of desertification, several context‐specific factors, the general and sectoral mode of governance and the complexities of contemporary MLG contexts explain this poor integration. Future research directions are suggested to advance the state of knowledge on promoting EPI in MLG contexts and provide policy support for combating desertification. Copyright © 2010 John Wiley & Sons, Ltd.
Preparation of Highly Stable Biodegradable Polymer Micelles by Coating with Polyion Complex
Authors: Ohya Yuichi , Takeda Shinya , Shibata Yosuke , Ouchi Tatsuro , Maruyama Atsushi
Published: July 2010

Positively charged core/shell type polymer micelles were prepared from a biodegradable amphiphilic block copolymer, poly(L‐lysine)‐block‐poly(L‐lactide). Polyanion‐coated biodegradable polymer micelles were then prepared via polyion complex (PIC) formation with polyanionic hyaluronic acid (HA) on the positively charged micelles. Characterization of the acquired HA‐coated micelles was carried out via dynamic light scattering, atomic force microscopic observation and ζ‐potential measurements. The HA‐coated micelles exhibited extremely high stability against dilution and colloidal stability. The PIC‐coated micelle system with high stability would be a useful drug delivery vehicle able to survive long‐term circulation in the bloodstream.

magnified image
A fully automatic and highly efficient navigator gating technique for high‐resolution free‐breathing acquisitions: Continuously adaptive windowing strategy
Authors: Jhooti P. , Keegan J. , Firmin D. N.
Published: July 2010

A fully automatic and highly efficient free‐breathing navigator gated technique, continuously adaptive windowing strategy (CLAWS), is presented. Using a novel and dynamic acquisition strategy that ensures all potential navigator acceptance windows are possible, CLAWS acquires an image with the highest possible efficiency regardless of variations in the respiratory pattern. Unnecessary prolongation of scan durations due to respiratory drift or navigator acceptance window adjustments are avoided. As CLAWS requires no setting of the acceptance window, nor monitoring of the navigator traces during the scan, operator dependence is minimized and ease of use improved. CLAWS was compared against a standard accept/reject algorithm (ARA) and an end‐expiratory following ARA (EE‐ARA) in 20 healthy subjects and 10 patients (ARA only). The respiratory efficiency was compared against the retrospectively determined best possible respiratory efficiency for each acquisition. On average, the difference between CLAWS scan times and best possible scan times was 0.6% (±1.3%). For the ARA and EE‐ARA techniques, mean differences were 14.4% (±20.9%) and 32.6 ± 10.9%, respectively. Had the CLAWS algorithm been used with the ARA and EE‐ARA traces, mean differences would have been 0.2% (±1.1%) and 0.5% (±1.7%), respectively. Image quality was the same for all techniques: respiratory gating, motion artifacts, navigator, and coronary artery imaging. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
International variations in bronchial responsiveness in children: Findings from ISAAC phase two
Authors: Büchele Gisela , Genuneit Jon , Weinmayr Gudrun , Björkstén Bengt , Gehring Ulrike , von Mutius Erika , Priftanji Alfred , Stein Renato T. , Addo‐Yobo Emmanuel O. , Priftis Kostas N. , Shah Jayant R. , Forastiere Francesco , Svabe Vija , Crane Julian , Nystad Wenche , García‐Marcos Luis , Saraçlar Yıldız , El‐Sharif Nuha , Strachan David P. ,   the ISAAC Phase Two Study Group
Published: July 2010

Rationale

Bronchial responsiveness is an objectively measurable trait related to asthma. Its prevalence and association with asthma symptoms among children in many countries are unknown.

Objectives

To investigate international variations in bronchial responsiveness (BR) and their associations with asthma symptoms and atopic sensitization.

Methods

Bronchial challenge tests were conducted in 6,826 schoolchildren (aged 8–12 years) in 16 countries using hypertonic (4.5%) saline. FEV1 was measured at baseline and after inhalation for 0.5, 1, 2, 4, and 8 min. BR was analyzed both as a dichotomous (bronchial hyperreactivity, BHR, at least 15% decline in FEV1) and as a continuous variable (time–response slope, BR slope, individual decline in FEV1 per log(min)).

Results

Prevalence of wheeze last year ranged from 4.4% in Tirana (Albania) to 21.9% in Hawkes Bay (New Zealand) and of BHR from 2.1% in Tirana to 48% in Mumbai (India). The geometric mean BR slope varied between 3.4%/log(min) in Tirana and 12.8%/log(min) in Mumbai and Rome (Italy). At the individual level, BHR was positively associated with wheeze during the past 12 months both in affluent countries (OR = 3.6; 95% CI: 2.7–5.0) and non‐affluent countries (OR = 3.0; 1.6–5.5). This association was more pronounced in atopic children. There was a correlation (ρ = 0.64, P = 0.002) between center‐specific mean BR slope and wheeze prevalence in atopic, but not in non‐atopic children.

Conclusions

BR to saline in children varied considerably between countries. High rates of BR were not confined to affluent countries nor to centers with high prevalences of asthma symptoms. The association between wheeze and BHR at the individual level differed across centers and this heterogeneity can be largely explained by effect modification by atopy. Pediatr. Pulmonol. 2010; 45:796–806. © 2010 Wiley‐Liss, Inc.
The nile foold and world weather
Authors: Bliss E. W.
Published: July 2010

Correlation coefficients are given with pressure, temperature, rain, ice and wind, and it is shown (a) that the Nile flood takes part in the southern oscillation as a member of the first group, (b) that equatorial temperatures are in inverse relation to the Nile flood, and (c) that the winter North Atlantic circulation varies inversely with the preceding Nile flood. St. Helena pressure has no contemporary relationship with the Nile flood. A formula is derived for prediction on June 1 with a joint coefficient of 0.72.
Diffusion over distances ranging from 3 km. to 86 km
Authors: Richardson L. F. , Proctor Denis
Published: July 2010

This Memoir describes the way in which air is scattered and mixed by the eddies in the wind. In order that the wandering of a piece of air may be observed, the air must have some mark carried with it. Small free balloons have served for this purpose; so has volcano ash. The statistics of the observed scatter may be of interest in connection with factory smoke and town planning. The rate of diffusion has been observed by various authors for air‐masses ranging in size from a few metres to 1,000 kilometres, an comparison of their results shows that Fick's law does not describe atmospheric diffusion.

This research was financially supported by the Government Grant Committee of the Royal Society. The balloon records were obtianed from Major J. M. MacLulich, of Brighton, and from the Leagure of Nations Union.
The variance of upper wind and the accumulation of mass
Authors: Richardson Lewis F. , Proctor Denis , Smith Robert Clifford
Published: July 2010

The variance—that is to say “the mean, for many observations, of the square of the deviation” of the vertical velocity from zero—is about 1/4 metre2 second−2.

The difference between a real horizontal wind and the value obtained for it by observing a balloon through a single theodolite has a variance from its mean of about 1 or 2 metres2 second−2 This variance increases with the speed of the mean‐wind.

The difference between the W‐E wind component at two times at the same place had a variance from its mean which changed with the time‐interval in the remarkable manner shown in Fig. 3. The asymptotic value for indefinitely long time‐intervals is 88 metres2 second−2. The curve starting at no variance for zero time‐interval rises irregularly with a peak at 6 hours, it cuts the asymptote at about 1 or two days, attains a maximum at 11 days, and cuts the asymptote again at 19 days. This relates to the summer of 1918, June 6 to September 28; and the features of the curve might well be different for a different season.

The difference between the winds at the same time and height at two places on the map has a variance from its mean which has been deduced from Durward's statistics, and also independently for some short distances. The results are shown in Fig. 4. Between 10 and 100 kilometres Durward's results show that (variance of difference of component velocity) = k × (distance of stations apart), where k = 5·4×10−3 cm. sec.−2 for the component parallel to the resultant at one member of the pair, and k = 3·6×10−3 cm. sec.−2 for the component at right angles.

Improving the simultaneity of the observations at paired places, by reducing the time‐error from 30 minutes to 5 minutes, quite often strangely increases the variance of the difference of wind‐components.

If there be a square of side l on the map such that 10 km. < l < 100 km., and the wind is accurately known at all points of three sides but only at the centre of the remaining side, then we are uncertain of the fractional rate of change of area of the air which fills the square at one initial instant, the uncertainty being expressed by a “standard deviation” of per second, where k is the constant mentioned above.

Thus, in the stated range, large squares give better results than small ones. This behaviour of the wind is contrasted with the behaviour of most of the functions commonly discussed in books on finite differences. When the method of finite differences is to be applied to the dynamics of wind, a necessary preliminary will be to smooth the observational data1.
Some aspects of surfaces of discontinuity
Authors: Douglas C. K. M.
Published: July 2010

The following are the chief points contained in the various sections of the paper:‐

(1) Some factors tending to produce sharp fronts at the earth's surface are discussed.

(2) Examples of soundings of upper air temperature through rainy fronts are given. It is found that the surface of discontinuity is normally smoothed through a layer about a kilometre thick, inversions being rare, especially in deep depressions. A considerable thickness of nimbus cloud is often formed below the discontinuity, probably owing to turbulence in air made damp by rain. It is thought that some rain belts, with associated fronts resembling “occlusions,” are developed in polar air and are not strictly “occlusions” at all.

(3) Further evidence is given showing that warm sectors are not surface phenomena, but are of fundamental importance in determining the upper air conditions over depressions. It is argued that the fall of pressure in the warm sector in a deepening depression must be due to the spreading over of air from higher latitudes in the upper part of the troposphere and in the stratosphere. The corresponding feature of a developing anticyclone is a spreading over of tropical air at high levels.

(4) Subsidence is discussed in a rough quantitative manner. In a developing anticyclone the downward movement is probably of the order of a kilometre per day at the 3‐kilometre level. The development of inversions with dry air above them (comprising a very large percentage of all inversions in the troposphere above 500 metres), is considered to be due to subsidence combined with turbulence up to a definite limit. Emphasis is laid on the importance of both cloud particles and precipitation in preventing dynamical warming at a fixed level by subsidence.

(5) A list of 16 striking wind discontinuities observed by pilot balloons in the British Isles in the last nine years is given, with some remarks on their relation with fronts and surfaces of subsidence.

(6) Turbulence at sloping surfaces of discontinuity is discussed on the basis of a criterion due to L. F. Richardson.

(7) The over‐running of warm air by cold air is referred to, and it is thought that except near the ground this takes the form of continuous rather than of discontinuous motion. It is shown that a vertical front of any appreciable magnitude must be very much smoothed out.

An appendix is added dealing with the combination of rotary and translatory motions.

The general line of argument is that the more important pressure changes are due mainly to large‐scale horizontal movements at high levels, considered in conjunction with movements at lower levels. When depressions grow deeper the resulting convergence in the lower levels influences the subsequent behaviour of already existing fronts and in certain cases forms new fronts. When anticyclones develop, the subsidence causes inversions to form which are entirely different from frontal surfaces, and in addition the divergence may sharpen up fronts at the boundaries of the anticyclones.
on the relation between temperature and pressure in the troposphere
Authors: Douglas C. K. M.
Published: July 2010

It is shown that the high correlation coefficients between pressure‐and temperature high up in the troposphere are closely related to the constancy of the lapse‐rate of temperature. The correlations between the mean temperature of the column up to 9 km. and the temperatures at 3 and 6 km. are very high. Some factors tending to produce a constant lapse‐rate are discussed. It is previously shown that the observed pressure‐temperature correlations do not necessarily imply a “solid current” or “barotropic” motion, but are consistent with very large changes of wind with height, both in direction and velocity, provided that these are spread through most of the troposphere and are not concentrated at a surface of discontinuity.

Groups of extreme cases show that when the barometer at sea level is very low or very high the troposphere contributes about half the deviation from the mean. Both cyclones and anticyclones can be grouped into systems largely confined to the troposphere, and systems extending to the stratosphere. The argument in favour of an advectional theory is developed. It is shown that the mean pressure at 8 km. over deep cyclones is no lower than over well marked polar currents.
Report on the phenological observations in the british isles from december, 1930, to november, 1931. no. 41
Authors: Clark J. Edmund , Margary Ivan D. , Marshall Richard , Cave C. J. P.
Published: July 2010

1931 was officially described as “wet and dull,” the emphasis is on the latter; yet it was the tenth successive year with excess of rain, the total being that of eleven average years. A new table gives for each of the thirteen districts the number of weeks showing “decided” and “excessive” divergences from the averages for temperature, rainfall and sunshine. Out of the 572 events thus possible for sunshine during the spring and summer months there were only five decidedly bright against 72 dull. December, 1930, and November, 1931 alone were much on the warm side; March and September were cold. There were no records of “excessive” warmth in spring and summer, but 12 of “cold.” Such short cold spells in spring threw the flower records back half a week, and although migrants reached our coasts to date, their progress inland was belated. Fig. 4, with its areas of earliness and lateness in flowering, shows only small and scattered cases of the former— covering but one‐tenth of our islands. Nearly half lay in northwest Ireland, with four days early, whilst Dartmoor fell 20 days behind its natural lateness. Slugs and weeds, as might be expected, caused exceptional trouble. Fig. 6a, showing the average advance of migrant arrivals for 16 years, adds to the value of the associated tables.

Thanks to a second broadcast in March, 1931, the corps of observers slightly exceeded 600. More would be specially welcome in west Ireland and north Scotland. The tables are based on more than 17,000 records.
The apparent colour of lights at night; with an observation of “blue fog”
Authors: Middleton W. E. Knowles , Patterson J.
Published: July 2010

On the basis of the CLE. (1931) colour metric an expression is developed for the colour co‐ordinates and luminosity of a given light source seen at night through an atmosphere of known optical properties. This is applied to an observation on a mercury vapour lamp in a highly selective haze of the type sometimes called “blue fog”.
The dynamics of large hailstones
Authors: Bilham E. G. , Relf E. F.
Published: July 2010

The form of the relation between terminal velocity and diameter is deduced from values of the drag coefficient obtained from observations on spheres towed by aeroplanes. Values of the terminal velocity are calculated for various mean specific gravities and it is concluded that an upper limit, about 1.5 lb., is set to the mass attainable by a spherical hailstone by aerodynamical considerations.
Photometric study o f atmospheric pollution
Authors: Digby W. P.
Published: July 2010

A photometric method of comparing the loss of reflecting value through tarnishing of polished metal plates is described and shows the wide daiiy and seasonal effects of changes in the polluting media in the atmosphere for different metals simultaneously exposed in the same place.

The different rates of tarnishing of the same metal plates exposed during the same week in rural, London and industrial areas are very marked.

Extreme cases in Westminster for polished copper are losses of 38 and 50 per cent in five hours in December fogs, whereas on four successive days in February, 1936, the loss in five hours varied between 5 and 11 per cent. For a summer day in 1935 a 10 per cent loss in 24 hours seems normal.

For short periods of say, one to two days in the winter and a week in the summer, copper is a good indicator. For longer periods “fine” silver is better. Aluminium responds slowly while the useful range of nickel appears t o be between those of copper and of silver.

In two appendices, the loss of reflection value is correlated with independent measurements of sulphur in the atmosphere.

Further lines of research are indicated.
The correlation of the amount of ozone with other characteristics of the atmosphere
Authors: Meetham A. R. , Dobson G. M. B.
Published: July 2010

Day to day variations in the total amount of atmospheric ozone are shown to be more closely correlated with those of potential temperatures in the stratosphere than with those of any other function of temperature and pressure, or with those of any other geophysical phenomenon yet investigated. A method of correlating with a certain variable associated with surface pressure distribution is exploited, and of three upper air phenomena considered the height of the tropopause is found to have the closest correlation with this variable. A speculative explanation of the close connection of the amount of ozone with other characteristics of the atmosphere is offered.
A method of predicting night minimum temperatures
Authors: Boyden C. J.
Published: July 2010

A simple general relationship, which appears to be applicable in any climate, is found connecting monthly mean values of maximum and minimum dry‐bulb temperatures with mean wet‐bulb temperatures. The formula is extended for predicting individual minimum temperatures on nights when there is no appreciable change of air‐mass between the times of maximum and minimum temperature, allowance being made for wind speed, cloudiness and fog formation.
Haboobs and instability in the sudan
Authors: Farquharson J. S.
Published: July 2010

The dust‐storms of the Sudan, called haboobs, are shown to be associated with thunder squalls. Several haboobs are discussed with particular reference to upper winds and upper air temperatures, an indication of the speeds of the vertical currents associated with a haboob being obtained on one occasion by means of a series of pilot balloon observations in close sequence. A value of 108for the coefficient of eddy diffusivity in a haboob is derived. Conditions associated with instability in the Sudan are investigated and it is suggested that they may be referred to a discontinuity between southwest monsoon and northeast trade, the slope of which is given by the expression:the symbols having the usual‐significance. A series of photographs taken with the co‐operation of the R.A.F. illustrates the conditions in some of the haboobs.
The theory of hailstone formation
Authors: Schuma T. E. W.
Published: July 2010

A fairly detailed mathematical analysis is presented of the generally accepted theory that the formation of large hailstones is due to the capture of under‐cooled water drops which lie in their path. It is shown that the principal factors which determine the ultimate size of a hailstone are its average density, the height at which its nucleus is formed, the average upward velocity of the air and the concentration of condensed water in the region of the atmosphere where the temperature is below 0°C. The interrelation between these various factors is shown by means of a number of curves.

It is further demonstrated that the values of water content of the clouds and of upward air velocities, measured or deduced independently, are sufficient to account for the formation of hailstones at least 8 cm. in diameter.

The matter of the disposal of the latent heat of the water which solidifies on the surface of the hailstone is also examined in some detail, and it is shown that this heat is disposed of quite effectively, partly by conduction to the surrounding atmosphere and partly by evaporation from the surface of the hailstone. Only in the case where the surface temperature of the hailstone approaches 0°C. does its incapability to get rid of its surplus heat act as a factor retarding its rate of growth, and consequently its ultimate size.
Modern views on atmospheric electricity
Authors: Whipple F. J. W.
Published: July 2010

The central theme of the address is the circulation of electricity through the atmosphere.

Clouds from which precipitation is falling act as generators of electricity. Recent worli by Sir George Simpson and Mr. F. J. Scrase supports the view that the separation of positive and negative electricity is mainly due to the impact of snow particles in the upper parts of the clouds. The snow particles carry negative electricity downwards and a current of positive electricity flows upwards to the “Heaviside layer” to come down again in distant places where fine weather happens to prevail.
Local temperature variations in the nottingham district
Authors: Tinn Arnold B.
Published: July 2010

The unusual temperature readings at Garforth and Wokingham, and later those of Mr. E. L. Hawke at Rickmansworth, suggested an examination of local records near Nottingham. The author has found that considerable variations occur in the Nottingham district, though the topography offers no unusual features. An area of relatively high land, with irregular spurs, stretches north‐north‐east from Nottingham Castle. The monthly values of three stations for the nine years 1928‐1936, and those of five other stations for other periods, are analysed. It is found that local differences of 10°F. in the minima may occur, and the mean monthly minima may differ by over 4°F. Average differences are tabulated. A detailed daily analysis of four stations is made for the two years April, 1935, to March, 1937. It shows that variations tend to be greatest with winds from north‐west through north to east, and least with south to west winds. Although fine weather, a rising barometer and a low humidity favour large variations, it appears that conditions producing low minima do not always give appreciable differences. Rainy, windy conditions bring the differences to a minimum. Differences of 6°F. in the maxima may occur on certain warm sunny days in summer, and variations of 8°F. in foggy conditions. Topographical features give Attenborough the most “continental” temperatures. The importance of uniformity in the hours of setting the thermometers is demonstrated, and positions are indicated where additional screens might give useful data.
The application of wet‐bulb potential temperature to air mass analysis. IV
Authors: Hewson E. W.
Published: July 2010

This paper describes:‐

The moisture content of subsiding polar continental air over North America, under conditions when there was no likelihood of an increase in the moisture content due to precipitation from overrunning air. Two situations of this type are discussed, and no evidence is found of any appreciable increase above 850 mb.

The degree of homogeneity in polar continental air masses. The vertical distributions of wet‐bulb potential temperature Θ1 as observed nearly simultaneously at adjacent stations within an air mass are discussed in relation to their effect on the accuracy of computations of subsidence.

The vertical velocity of air in the warm sector of a depression. It is shown that in the warm sector considered, the ascent of the air near the surface was nearly twice as rapid as that at about 600 mb. The vertical velocity of the surface air was of the order of 4 cm./sec., and that of the air at about 600 mb. was of the order of 2 cm./sec.

The effect of turbulence in the air near the surface. The changes of temperature and moisture content in the surface layers of a moving air mass are discussed in the light of the theory of turbulence, as developed by Richardson and Taylor.
Evaporation over catchment areas
Authors: Lloyd David
Published: July 2010

Some of the most authentic data of the general rainfall over British drainage areas and the run‐off in annual periods are marshalled. The difference between these observed quantities of water—i.e., the losses in annual periods from all causes—is fundamentally accepted from other research to be principally the effect of evaporation including evapo‐transpiration.

The paper examines the variation in the annual total loss over eight drainage areas by a statistical method. It is postulated that loss is a joint function of meteorological elements and the geological formation penetrated by any rain water; further, that in the present stage the joint functional causation can be simplified to one of separate functions. Thus, it is assumed that the variations in loss can be associated with the rainfall providing the opportunity for evaporation, with the temperature, with the sunshine, and (as following the primary loss in the zone of aeration, influent seepage may provide a flow in the zone of saturation which later may provide a deferred opportunity for evaporation from the capillary fringe and effluent seepage from ground water) with the geological formation. Regressions of loss on the available postulated controls have been inferred. By inductive reasoning, an equation is found approximately representing the observations over the eight areas, by which the annual loss expected on account of various influences can be estimated.
The intensity of ultra‐violet radiation from the sky in Iraq
Authors: Kennedy Walter P. , Wright H. L.
Published: July 2010

Hæmotological investigations in Baghdad suggested that the climate altered the blood of normal persons as compared with Britain, and as part of the analysis of the climatic factors, day‐today measurements were made of the ultra‐violet component of northern sky shine, using Owens's instrument. In this a Chance No. 14 filter is separated from a sheet of photographic paper by a graded series of tubes, giving a scale of 13 arbitrary values from 1 to 204. 'The upper end of the scale is much more open than the lower, and this must be considered a disadvantage in very bright conditions such as the Iraq summer. The instrument is exposed for 24 hours at 45° to the zenith pointing north.

The daily measurements from August, 1936, to August, 1937, are given in graphic form, and also as monthly means. With the latter, various other meteorological data are tabulated to show the trend and range of climatic variation, and to indicate some of the major causes of fluctuation in the ultra‐violet values. The direction of influence of these variables is discussed briefly, but integration of the factors is not attempted. The paper is preliminary; further studies are in progress.
On the occurrence of snow‐cover in Great Britain
Authors: Manley G.
Published: July 2010

Hitherto practically no information has been forthcoming with regard to the frequency with which a snow‐cover may be expected on the uplands and mountains of Great Britain. Variations with altitude are very great; variations from year to year are also very great; few highland stations are available, while their records are often brief and interrupted. Further, the interpretation, analysis and criticism of the existing data with regard to snow‐lying are difficult, and are only to be undertaken after a close survey of the environment and other features of the reporting stations, of which the majority are on low ground.

A relationship has now been derived between the mean temperature of the winter months and the average frequency of occurrence of snow‐lying, which after test appears to be generally applicable to any given place over a period of years. It is necessary, however, to allow for several additional factors, notably quantity of snowfall, which influence the duration if snow‐cover. It appears that, making these allowances, a reasonable estimate can be made of the frequency of snow‐cover a t the majority of places in Great Britain; also, of the extent to which the expectation of snow‐cover varies with small fluctuations in mean winter temperature, over a period.

The deductions, with regard to uplands and mountains, should be of general interest to many beside those concerned with questions of transport.

In the course of the work upwards of ninety observing stations have been investigated, and the tables of frequency of snow‐lying for eighty‐six of these may also be of value until more rigorous analysis can be undertaken.
A note on theories of the electric fields below clouds
Authors: Chalmers J. Alan
Published: July 2010

Attention is drawn to the discrepancy between the electric fields actually existing below thunder clouds, as measured by the alti‐electrograph, and those expected on a theory due to Wilson. An attempt to remove the discrepancy by the consideration of the presence of negative ions as well as the positive ions produced by point discharge decreases, but does not remove it, and there remains an unsolved problem.
Direction‐finding of sources of atmospherics and South African Meteorology
Authors: Schonland B. F. J. , Hodges D. B.
Published: July 2010

An account is given of investigations on the location of sources of atmospherics in South Africa with visually‐operated cathode‐ray direction‐finders, extending over a period of fifteen months and employing stations in Johannesburg, Durban and Bulawayo.

The accuracy with which a thunderstorm source can be located by this method was found to be ±50 km. for storms at distances less than 750 km. At greater distances the accuracy decreases but is usually less than ±100 km. at 1,500 km.

Of the land sources 76 per cent. were identified with thunder‐clouds and 18 per cent. with nimbus cloud.

Sources over the oceans were found t o be closely associated with areas of low pressure, 89 per cent of such lows having associated sources. The progress of the lows could be followed by this method for several days. Their associated sources in the majority of cases lay in the warm sector from NNE. to ESE. of the centre of the low.

The monthly and seasonal distributions of sources over the land agree with the distributions found by Brooks from thunderstorm data, except that over the Indian Ocean the number of atmospherics sources reaches a maximum in the winter.

A discussion is given of the possibilities of the device in meteorology in Southern Africa and of difficulties encountered in the practical day‐by‐day use of the system. A commentary follows by three officers of the Rhodesia Meteorological Service.
Local distribution of thunder rains round Nottingham
Authors: Tinn Arnold B.
Published: July 2010

A belief exists in Nottingham that there is some relation between the paths of thunderstorms and the valley of the River Trent. This investigation was made with a view to testing this speculation and to discovering whether any tendency did exist in the local distribution of thunder rains round Nottingham. Information was obtained from 34 rain gauges for thunder days over a period of ten years, and the data charted and analysed.

It is found that there are areas which appear to be more subject to heavy thunder rains, and also areas having a comparative immunity. There seems to be some basis for the belief that these rains do tend to be heavier near the River Trent, but this tendency is more marked for the stretch of valley between the confluences of the rivers Erewash and Leen with the Trent. Eastwards of the Leen the river valley appears to be less subject to the heaviest falls.
Atmospheric opacity at Valentia
Authors: Wright H. L.
Published: July 2010

To confirm the variation of atmospheric opacity with relative humidity, inferred in a previous paper from theoretical considerations, observations of visibility at Valentia are utilised to deduce values of atmospheric opacity. These values are grouped according to the relative humidity and the direction of the wind. Examination of the results shows beyond doubt that, in air free from smoke, opacity varies with relative humidity in a manner which corresponds very closely with that indicated by the theoretical equations, provided that in these equations suitable values are inserted for the number of nuclei and for a quantity depending on the mass of salt in each nucleus and its hygroscopic properties.
Evaportation‐loss per month from two drainage areas
Authors: Lloyd David
Published: July 2010

Monthly data of the apparent loss by evaporation, etc., of moisture from Vyrnwy and Rivington drainage areas are examined in relation to the rainfall and the temperature.

After discussing the subject matter, the association and the degree of association are determined on the hypothesis that variations in evaporation‐loss can be associated with the variations in rainfall and temperature in a joint functional manner. The regressions have been computed together with the formal evaluation of the significance of the statistics.

The results show that, when the temperature is constant, the evaporation‐loss is proportional to the rainfall; when the rainfall has a given value, the loss increases in relation to the temperature; while the loss is reduced according to the previous rainfall. There is similarity in the relations at Vyrnwy and Rivington.
Theoretical aspects of the size distribution of fog particles
Authors: Schumann T. E. W.
Published: July 2010

Following some very interesting work by Houghton and Radford on the determination of size distribution of drops in fogs and clouds, a theory is here presented to account for the experimental results obtained.

The basis of the theory is that due to Brownian movement, to turbulence, and to the influence of gravity, collisions between the drops take place and thet upon collision coalescence results. There will thus be a gradual increase in the average size of the drops consutling the fog due to these collisions, and the problem with which one is confornted is to detemine what the resultant size distribution of the drops will be.

In a simple case, where it is assumed that the frequency of distribution curve. The result thus obtained shows very satisfactory agreement with the experimental values given by Houghton and Radford.

It has also been found possible to obtain an approximate theoretical value for the rate of growth of the “most preferred” drop sizes, but it would appear that in nature the rate of growth is several times more rapid than the theoretical value.

The theory might prove useful in showing how research should be directed in order to arrive at a full understanding of the mechanism by which fogs and clouds are formed.
A new approach to the study of the seasonal incidence of british rainfall
Authors: Crowe P. R.
Published: July 2010

The rainfall records for the period 1881‐1930 of seventy British stations are analysed by a method of direct comparison of monthly values which does not involve the calculation of means. The tendency towards a regular annual régime of rainfall being rather weak over most of these islands, the object is to try and single out significant facts from the mass of detail which is purely fortuitous in character. The results are expressed in maps and tables.

Taking the country as a whole the periods of most rapid change in precipitation conditions are shown to have been from June to August and from December to February. There is, however, a considerable amount of regional contrast, particularly in the comparison, of August with October values, whilst the distribution of anomalous conditions in September is also of interest.

The analysis is then carried back to the period 1831‐1880 for twelve stations. The general verdict seems to be that rapid rainfall transitions during that period fell between April and June, October and December. The rainy period was thus the same length as in the later half century but occurred earlier in the year. At the same time the September anomaly disappeared.

If the test of significance employed is not seriously at fault—and it would seem to err if anything on the side of severity—we must face the conclusion that the hypothesis of an ultimate normal of rainfall may have to be reconsidered.
Meteorological and soil factors affecting evaporation from fallow soil
Authors: Penman H. L. , Keen B. A.
Published: July 2010

Using the conception of natural periods, for which the difference between rainfall and drainage can be equated to the evaporation, the mean daily rates of evaporation from a block of fallow soil at Rothamsted are examined for 94 periods varying in length from 13 to 45 days. In seeking correlations with single daily meteorological observations two types of treatment are employed. (1) The year is considered in three seasons of four months each—summer, winter and two equinoctial pairs of months—and it is shown that an almost complete description of evaporation can be obtained in terms of rainfall only, the nature of the correlation varying from season to season. (2) A general treatment is attempted in physical terms, considering evaporation as due to diffusion across a non‐turbulent boundary layer whose thickness is determined by wind velocity, the soil surface being assumed to be continuously at 100 per cent R.H. The general agreement between observed and predicted values is very good in winter. The summer data are shown to lie between the theoretical limits imposed by the assumptions of (i) continuous 100 per cent R.H. at the surface, and (ii) a steady retreat of the 100 per cent R.H. layer into the soil, i.e., no upward movement of liquid during the evaporation process. The considerable scatter in the data is attributed partly to the inadequacy of single daily meteorological observations but chiefly to the lack of knowledge of the conditions existing at the soil surface.
Cold and warm fronts in baroclinic waves
Authors: Hoskins B. J. , Heckley W. A. J.
Published: July 2010

Previous studies have shown how simple baroclinic waves may exhibit either a primary cold front or a primary warm front. In this paper it is shown that many of the quite realistic differences between the cold and warm fronts are a consequence of the forward tilt of the temperature wave with height. This forward tilt is proved to be a necessary feature of a growing baroclinic wave. Thus a dynamical distinction between cold and warm fronts is postulated.
Air flow over a two‐dimensional hill: Studies of velocity speed‐up, roughness effects and turbulence
Authors: Britter R. E. , Hunt J. C. R. , Richards K. J.
Published: July 2010

Wind tunnel measurements have been made of the streamwise mean and turbulent velocities over a rough, bell‐shaped, two‐dimensional hill, with height h and maximum slope 0.26, placed in a neutrally stable boundary layer of thickness 10 h and roughness length zo = 0.02 h. Close agreement is found between the mean velocity and predictions obtained from Taylor's (1977) computational model and Jackson and Hunt's (1975) analytical linearized model, for locations at or upwind of the hill top but not in the wake. Examination of the models shows that the shear stresses are only important in an inner region close to the hill surface, so that, as suggested by Jackson and Hunt (1975), the perturbation to the mean flow outside this region is essentially inviscid. the theory shows that over very rough surfaces, such as wooded or urban terrain, the height of this inner region can be of the same order as the height of the roughness elements (so that in our experiments no measurements could be made in this region).

In a second experiment flow over a smooth hill on a rough surface was studied. the additional increase of wind speed over the hill top can be estimated by assuming a linear superposition of the velocity changes produced by the changes in elevation and in surface roughness (in this case rough to smooth). In the lee of a hill, however, the change in roughness significantly alters the flow with flow separation being suppressed and here a linear superposition is not appropriate.

Finally we consider why observed changes in turbulence structure close to the surface differ from those well above the surface. Calculations of these changes based on the simple theoretical arguments of equilibrium shear layers and rapidly distorted turbulent flows agree well with turbulence measurements in wind tunnels and in the field.
The quasi‐geostrophic equations: Approximation, predictability and equilibrium spectra of solutions
Authors: Bennett A. F. , Kloeden P. E.
Published: July 2010

Two well‐posed initial‐boundary value problems for the quasi‐geostrophic equations have been identified. the first is defined in a vertical annular cylinder with specified temperatures on the horizontal bottom and top surfaces. the second is defined in a box with periodic boundary conditions on the sides and with rigid bottom and top surfaces; bottom topography is included. Well‐posedness is established by theorems which determine conditions under which there exist unique solutions depending continuously on the initial and other data. the theorems are stated here, but proved elsewhere.

Completely rigidly contained quasi‐geostrophic motion is in general an ill‐posed problem, due to over‐specification of circulation integrals around edges where vertical and horizontal boundaries meet.

The theorems are used to infer (1) sufficient conditions for the convergence of finite‐element Galerkin approximations of Fix (1975) to exact solutions, (2) the predictability type of the solutions as defined by Lorenz (1969), and (3) that the long‐time high wave‐number spectra of the equations are steeper than the inertial ranges and the statistical equilibrium spectra of Kraichnan (1967). Implications for numerical circulation models are drawn.
On the mountain torque in barotropic planetary flow
Authors: Egger J. , Metz W.
Published: July 2010

An attempt is made to understand the long‐term balance of the total relative angular momentum M of an inviscid barotropic fluid forced by orography. the problem is treated by integrating the barotropic potential vorticity equation with the β‐plane approximation, and on the sphere, using spectral methods. First, a highly truncated system containing only the superrotational flow and one wave component is studied by analytical means. A fairly complete understanding of the behaviour and the climatic mean value of M is achieved. Then, less truncated systems with up to five zonal wave‐numbers are investigated by numerical integrations. It turns out that a climatic mean value can be ascribed to M if the integration is carried out for several weeks or more. It is demonstrated that this long‐term mean value can be estimated reasonably weil on the basis of the study of the highly truncated system. A possible application of these results to more realistic fluid systems is suggested.
On the scattering of sound in a turbulent flow
Authors: Robson R. E. , Potts R.
Published: July 2010

The formula for the cross‐section for scattering of sound in a turbulent flow, upon which SODAR meteorology relies, is derived from a simplified, physically appealing argument.
Observations of condensate profiles over arctic leads with a hot‐film anemometer
Authors: Andreas Edgar L. , Williams Richard M. , Paulson Clayton A.
Published: July 2010

During the AIDJEX Lead Experiment on the Arctic Ocean large‐amplitude, high‐frequency spikes were observed on the voltage signals of hot‐film sensors being used for turbulent velocity measurements near the water surface. Because over leads in winter temperature gradients are very steep and the super‐saturation extreme, condensate droplets can form and grow to measurable size even in the few seconds the air is over the lead. the voltage spikes resulted when these condensate droplets struck the hot‐films. We could, therefore, use the hot‐film information to determine not only turbulence quantities but also condensate concentration profiles and the flux of condensate droplets at the surface of leads. Condensate droplets were roughly 10 μm in diameter, concentrations within 20cm of the surface were usually 20‐80mg kg−1 (50‐220 droplets cm−3), and the condensate flux was of order 3mgm−2s−1.

Non‐dimensional condensate profiles are well modelled by

where c* is a concentration scale and h, an estimator of the internal boundary layer height, is fetch dependent. the condensate flux is related to average quantities through the Nusselt number, Nuc, and the fetch Reynolds number, Rx: NUc

Because c* also depends on the condensate flux, the simplicity of the profile relation and this Nusselt number equation suggest two alternative ways to estimate condensate flux at the surface of leads from the measurement of bulk environmental parameters.
The impact of FGGE data coverage and improved numerical techniques in numerical weather prediction in the Australian region
Authors: Leslie L. M. , Mills G. A. , Gauntlett D. J.
Published: July 2010

This paper describes the results from an extensive series of experiments aimed at enhancing the skill of the Australian Numerical Meteorology Research Centre (ANMRC) limited area analysis/forecast system.

Significant increases in model performance were achieved, in the sense of reducing S1, skill scores and in forecasting precipitation, in three ways: (1) improved data base since the beginning of FGGE; (2) the application of a more realistic lateral boundary specification, particularly nesting within a hemispheric forecast model; and (3) the reduction of truncation errors by either decreasing the grid spacing or (more efficiently) employing higher order difference operators.

The improvement in skill is sufficiently large to suggest that when implemented operationally the quality of routine prediction of synoptic scale patterns over the Australian region will be considerably improved.