bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ecological aspects of meteorology
Authors: Salisbury E. J. 
Published: July 2010

AbstractThe relative importance of extreme and mean climatic conditions in respect to their influence upon the persistence of species. The biological significance of temperature summations. The importance of absolute minima, even when infrequently paralleled, in influencing geographical distribution. Frost severity in relation to the survival of “winter annuals” and of “summer annuals.” Maximum temperatures and their effect upon flower and seed production. The nature of the soil surface and its effect upon air temperatures.The influence of meteorological conditions upon plant life as modified by the biology of the species. The importance of katabatic winds in modifying temperatures affecting plant life.Duration and intensity of sunshine as they effect reproduction; photoperiodism.Precipitation and its role: (1) as a source of raw material; (2) as an erosion agent; (3) in leaching. The significance to plant life of the seasonal incidence and intensity of precipitation.Meteorological factors as influencing soil development and the extent of their modification by the plant covering.Ecological aspects of wind; its direct and indirect effects.The influence of meteorological factors on the conditions of life in relation to the time factor as illustrated by dune soils. Edaphic succession.
Report on the phenological observations in the British Isles from December, 1937, to November, 1938 no. 48
Authors: Gunton H. C. 
Published: July 2010

AbstractDevelopment of organisation. Meetings of the Main Conference and Executive Committee; steps taken. Presentation of records. The weather of 1938 and its effects. Explanation of diagrams. Conclusions; general principles. Evidence with reference to a dominant factor in relation to the responses to meteorological conditions.
The seasonal and geographical distribution of absolute drought in England
Authors: Lewis Lilian F. , Bilham E. G. 
Published: July 2010

AbstractA section of British Rainfall has been devoted to absolute droughts since 1888, but the data have not hitherto been summarized in order to determine which areas in England are most subject to drought and in what season of the year absolute droughts may be expected to occur most frequently. In a preliminary investigation it was found that absolute droughts were comparatively rare and an exhaustive research was therefore not attempted but attention was confined to selected stations with long and reliable records. Complete lists of absolute droughts at six stations during periods of from 80 to 95 years and at three other stations over periods from 43 to 52 years are included in the tables. The data reveal three notable facts:—(1) The large number of absolute droughts experienced in south‐east England and the southern midlands compared with the number in north‐east England, although the average annual rainfall is approximately the same in each case; (2) the greater number of absolute droughts recorded at Liverpool than at Stonyhurst, due to the shelter afforded to Liverpool from the moist south‐west winds by the Welsh mountains and the greater height of Stonyhurst above mean sea level; (3) the larger number of absolute droughts experienced on the south‐east coast compared with the number on the more unsettled south‐west coast. The information was next analysed in order to investigate the seasonal incidence of absolute drought. The method adopted was to start with January 1 and count the number of occasions when that day formed part of an absolute drought at a given station. The process was repeated for January 2, January 3, and so on throughout the year. The results are shown graphically on a single diagram, with the days of the year as abscissæ and the number of occasions of absolute drought as ordinates. Finally the odds to one against a “drought‐day” (a day which has been included in a period of absolute drought) were evaluated for each calendar month at each station.
The distribution of wet‐bulb potential temperature in four selected cyclones
Authors: Firesah A. M. 
Published: July 2010

AbstractThe distribution of wet‐bulb potential temperature has been investigated in four cyclones, each by means of serial sounding balloon ascents made at one station. The results are plotted as though they represented observations along a vertical cross‐section through the moving cyclone. Lines of equal wet‐bulb potential temperature are drawn, and these are found to show a characteristic form of distribution at warm fronts, cold fronts and occlusions. At warm fronts the lines are closely crowded together. At cold fronts they show a nose raised some kilometres above the ground, the wet‐bulb potential temperature decreasing with height in the air below the nose. The air in this region usually shows marked latent instability capable of being realised after only relatively small upward displacement. At occlusions the lines of equal wet‐bulb potential temperature have a pronounced V‐shaped form.
Some factors influencing the development and occlusion of warm sectors
Authors: Douglas C. K. M. 
Published: July 2010

AbstractThe initial formation of a warm sector is attributed mainly to geostrophic motion, associated firstly with external systems and secondly with deformation of the warm air mass. The occlusion process is due to a combination of convergence with a suitable distribution of geostrophic motion. The concentration of convergence ahead of the warm front is attributed mainly to the isallobaric effect and not to curvature.
A dutch radio‐meteorograph
Authors: Insje C. M. A. , van Soest J. L. 
Published: July 2010

AbstractThis paper contains an account of the radio‐meteorograph which has been developed in Holland in order to secure accuracy, lightness and cheapness. Following Moltchanov's principles it sends out letters in the Morse code which can be received on an ordinary shortwave receiving set. One valve is employed. The signaller is driven by a small electric motor and the set is operated by either one or two 4 1/2 volt flashlight batteries according to the height to be reached. The total weight with two batteries is 585 grams. Experience shows that a very large proportion of the radio‐meteorographs are recovered in good condition, fit for further use.
On the determination of sea‐level isotherms with special reference to south africa
Authors: Schumann T. E. W. , le Roux J. J. 
Published: July 2010

AbstractThe first part of this paper contains a discussion of the application of the method of least squares for calculating vertical temperature gradients and thus reducing temperatures as recorded at station level, to sea level.The second part is devoted to a discussion of the results arrived at. Apart from South Africa, the lapse rates for India and the Western and Eastern U.S.A. were also calculated, forty or fifty representative stations being selected in each area. For South Africa the temperature‐influencing factors of altitude, latitude and rainfall are considered simultaneously, whereas for India and the U.S.A. only the factors of altitude and latitude are taken into account.The values both of the lapse rate and of the variation of temperature with latitude are represented graphically, and explanations are offered for their seasonal variations.
Variations in annual, seasonal and monthly rainfall over the British Isles, 1870‐1939
Authors: Glasspoole John 
Published: July 2010

AbstractThe paper includes statistics of the general monthly rainfall over the British Isles, both in inches and as percentages of the average, for the seventy years 1870‐1939. The general trend of the variations is shown by diagrams of ten‐year means for each month, based on the similar statistics for England and Wales, Scotland and Ireland separately. Similar diagrams are given to show the variations for the winter half‐year, summer half‐year and seasonal year separately.
Evaporation‐loss per month over drainage areas, II. Loss over three areas
Authors: Lloyd David 
Published: July 2010

AbstractThe data from three more large drainage areas are examined by the same method as in the former paper on this subject. The results show again that the variations in loss can be largely associated with variations in rainfall and temperature. It is also demonstrated that, with similar climatic conditions, the loss increases as the sub‐surface has increasing permeability.
The frequency‐distribution through the year of abnormally high and low daily mean temperatures at Greenwich observatory
Authors: Hawke E. L. 
Published: July 2010

AbstractThis paper presents the results of an analysis of thermometric records at Greenwich Observatory over the period 1841‐1936 undertaken with the object of ascertaining the number of occasions on which each day of the year gave a mean temperature above and below the smoothed average value to specified extents. Days with positive departures of at least 10°F. and 15°F. are classed as “warm” and “very warm,” and those with corresponding negative departures as “cold” and “very cold,” respectively. Diagrams and tables referring these several categories to the seasons and calendar months, as well as to pentads and individual dates, are given and discussed. It is shown that the average year contains 17·5 “warm” days, 0·7 “very warm” days, 11 “cold” days, and 1·3 “very cold” days; that the winter months December to February provide 43 per cent of the “warm” days, 53 per cent of the “cold days,” and 86 per cent of the “very cold” days; that there is an entire absence of “very cold” days from March 17 to November 15; and that only three “cold” days are on record for August. Instances, 15 in all, of very exceptional heat and cold, represented by daily mean temperatures at least 20°F. above and below the average, are also listed, special reference being made to the single extant case of a positive departure so great as 20°F. (May 22, 1922). Explanations are advanced for anomalies brought to light by the investigation.
The eddy diffusivity and the temperature of the lower layers of the atmosphere
Authors: Cowling T. G. , White A. , Chapman S. 
Published: July 2010

AbstractMethods of calculating the eddy diffusivity κ are discussed. It is shown that methods which assume that κ can be regarded as independent of the height, even through a shallow layer, lead to erroneous results: in consequence the frequent use in the literature of the approximate equation of transfer of heat κθ||=θ is to be deplored. It is also shown that there is a large diurnal variation of κ at any level, and that neglect of this may also lead to incorrect and discordant results. Using the values obtained for κ, it is shown that certain features of the temperature variation cannot be explained by convection alone, and it is suggested that they may possibly be due to radiation.
Model predictions of neutrally stratified planetary boundary layer flow over ridges
Authors: Taylor P. A. 
Published: July 2010

AbstractA numerical model of the local flow above an infinite series of two dimensional ridges is used to investigate the extent to which form drag on the ridges is balanced by reductions in surface shear stress compared to that for a plane surface. With a constant eddy viscosity Mason and Sykes (1979) results an confirmed and there is only a relatively small net increase in the horizontal force on the terrain due to the presence of topography. A larger increase is found when height dependent eddy viscosities are used. the nature of velocity defects produced by individual ridges are examined for the two cases.
On the distribution of mean radiative cooling at the top of a stratocumulus‐capped mixed layer
Authors: Deardorff James W. 
Published: July 2010

AbstractThe fraction, r, of the net in‐cloud radiative flux difference existing within the mean capping inversion of a stratocumulus‐topped mixed layer is calculated, assuming an exponential diminution of radiative flux below local cloud‐top height. Its dependence upon hoλ and Δh/ho is presented, where ho is the depth of the well‐mixed portion of the boundary layer, λ is the radiative extinction length, and Δh is the thickness of the mean capping inversion, or entrainment zone, within the context of ensemble averaging or horizontal averaging. the calculation makes use of laboratory observations on the distribution of mixed‐layer matter within the entrainment zone of a convectively mixed layer. the fraction r is shown to vary widely between its limits of 0 and 1 and under different configurations of stratocumulus mixed layers.For a given net radiative flux at the top of the cloud, it is shown that changes in λ and r have a modest effect upon the buoyancy flux profile and a strong effect upon the entrainment rate. Buoyant production of turbulence within the well‐mixed layer is found to be maximized when r lies in the vicinity of 0.3.
Statistical prediction of continental planetary albedo
Authors: Linder David I. , Stouffer Ronald J. , Cahir John J. , Panofsky Hans A. 
Published: July 2010

AbstractRegression equations have been derived for albedo in the United States, summer and winter, as a function of conventional meteorological variables of the type that might be available from a numerical model. For monthly mean patterns, the variance reduction was from 60% in summer to 84% in winter on test samples. On a day to day basis, the reduction of variance was from 45% in summer to 55% in winter. Still, errors of estimate are smaller in summer than in winter.The principal predictors were the mean relative humidity below 500 mb, and the pole‐ward meridional wind component aloft. In addition, a snow‐cover variable was needed in winter. Dynamic predictors, such as vorticity advection or vertical velocity, had relatively little skill and did not enter the equations consistently. Also, stability parameters played an unimportant part.
Maximum entropy production states in quasi‐geostrophic dynamical models
Authors: Shutts G. J. 
Published: July 2010

AbstractMathematical expressions for the time‐mean production rate of statistical, hydrodynamical entropy are introduced in the context of the two‐level quasi‐geostrophic equations and Gibbsian thermodynamics. These form the basis of an investigation into the hypothesis put forward by Paltridge that the climatic‐mean fields are those which maximize this quantity. the entropy production rate is treated as a functional of the surface wind field (obtained by linear extrapolation) and the temperature field as defined in the two‐level equations of quasi‐geostrophic dynamics. Using the calculus of variations, two coupled second‐order differential equations are obtained for these fields and they are solved analytically and numerically for betaplane and spherical‐polar geometries respectively. A global torque constraint is applied using the method of Lagrange multipliers.The zonal‐mean surface wind equation derived is found to be identical to Green's surface wind equation obtained from his vorticity transfer theory, apart from the redefinition of some empirical constants. an important difference regarding the method of satisfaction of the torque constraint results in realistic surface winds in spherical geometry in contrast to those found by White (1977) using an extension of Green's original work.The extremal flow field of an equivalent barotropic model of a wind‐driven ocean basin circulation is also investigated and is found to resemble a superposition of Fofonoff's non‐linear inertial solution and a wind stress forced circulation.
The response of numerical weather prediction systems to fgge level iib data. Part I: Analyses
Authors: Hollingsworth By A. , Lorenc A. C. , Tracton M. S. , Arpe K. , Cats G. , Uppala S. , Kållberg P. 
Published: July 2010

AbstractWe present an intercomparison of analyses of the main FGGE level IIb dataset with three advanced analysis systems. the aims of the work are to estimate the extent and magnitude of the differences between the analyses; to identify the reasons for the differences; and, finally, to estimate the significance of the differences for forecast skill. We restrict ourselves primarily to a consideration of the extra‐tropical analyses. the subject of tropical analyses merits separate treatment.We discuss objective evaluations of analysis quality, such as fit to observations, statistics of analysis differences, and mean fields. In addition we place substantial emphasis on subjective evaluation of a series of case studies which were selected to illustrate the importance of different aspects of the analysis procedures, such as quality control, data selection, resolution, dynamical balance, and the role of the assimilating forecast model. In some cases the forecast models are used as selective amplifiers of analysis differences to assist in deciding which analysis was more nearly correct in the treatment of particular data. In part II we consider the overall impact of the analysis differences on forecast quality, and the implications for predictability.In general the analysis systems draw reasonably well to the data, although each system has its own characteristics in this regard. the root mean square differences between the analyses are of the expected order of magnitude, although there are clear differences in the closeness of agreement between different pairs of analyses. Systematic differences arising from particular components of the assimilation suites can be identified.The discussion of the case studies highlights those areas where differences of approach to the analysis problem have led to significant differences in the analyses. Some of the case studies suggest strongly that analysis differences in the vicinity of active baroclinic zones are of particular importance. In order to validate these suggestions in one case, we present an experiment where one analysis is transplanted, locally, into another, to show that large differences in the medium‐range forecasts are attributable to localized differences in the analyses.The results presented here, together with the forecast verification results of part II, suggest that in some cases uncertainties in the analysis are a major contributor to the loss of forecast skill in the medium range.
A study of the impact of aircraft wind observations on a large‐scale analysis and numerical weather prediction system
Authors: Barwell B. R. , Lorenc A. C. 
Published: July 2010

AbstractAn observing systems experiment to assess the impact of aircraft observations on analyses and forecasts from a numerical model is described. Parallel runs with and without aircraft observations show significant analysis differences in the upper troposphere over northern hemisphere oceans, the aircraft giving a better representation of jet strengths and less reliance on poorer quality observations. This positive impact extends to the shape and position of upper tropospheric features in forecasts from these analyses though the magnitude of the improvements is somewhat less.These results are in broad agreement with those from a similar experiment carried out at the European Centre for Medium Range Weather Forecasts. Some differences attributable to the response of the different analysis schemes used are discussed in the light of geostrophic adjustment theory and are studied further using model forecasts from perturbed initial conditions. These studies suggest that beneficial effects on forecasts can be achieved by distributing single‐level data throughout several model levels and using wind observations to update the rotational component of the wind field.A simple linearized theoretical model supports these conclusions and is used to investigate the effects of the repeated insertion analysis procedure used in our experiments. This effectively suppresses the generation of high frequency waves but shows undesirable effects in the presence of a large mean advective velocity.
Potential vorticity in the stratosphere derived using data from satellites
Authors: Clough S. A. , Grahame N. S. , O'Neill A. 
Published: July 2010

AbstractMaps of Ertel's potential vorticity, Q, are computed on an isentropic surface in the middle of the stratosphere. They are derived using data from stratospheric sounding units on board NOAA satellites. the reliability of the maps is demonstrated mainly by conservation of Q that is shown in successive analyses, and by the close agreement obtained using independent data from two satellites.The maps are used to follow the movement of material during the course of strong disturbances which occurred in December 1981. They clearly show the breaking of planetary waves in the stratosphere, an inherently nonlinear process. the effect of wave breaking on the structure of the westerly vortex is considered. Any mixing of Q on isentropic surfaces during wave breaking is shown to be far from complete in the examples studied.The behaviour of diagnostics based on zonal averaging, such as the Eliassen‐Palm flux, is accounted for by local changes in the distribution of Q. the implications of our findings for the study of stratospheric dynamics are discussed.
The frontal transition zone and microphysical properties of associated clouds
Authors: Ryan B. F. , King W. D. , Mossop S. C. 
Published: July 2010

AbstractA study of the cloud structure and precipitation in the transition zone of cold fronts over western Victoria shows that the important precipitation parameters, such as cloud top temperature and depth, are determined synoptically. Pre‐frontal clouds experience slow uplift over substantial depths; this results in cold deep clouds with lifetimes of the order of tens of hours. In the post‐frontal clouds the uplift is mesoscale and shallow and causes short‐lived cloud elements.These dynamic and thermodynamic featurea determine the cloud microphysics and largely the associated rainfall. Precipitation in pre‐frontal clouds forms mostly through lightly rimed ice crystals produced at low temperatures; the process can be very efficient in glaciating the cloud but not necessarily efficient in producing ice crystals large enough to survive the fall to the surface. In the post‐frontal systems the ice crystals are produced at much higher temperatures in the presence of higher liquid water contents and the precipitation depends very strongly on cloud depth and duration.
Isotopic study of hail: The δd‐δ18O relationship and the growth history of large hailstones
Authors: Jouzel Jean , Merlivat Liliane , Federer Bruno 
Published: July 2010

AbstractSimultaneous deuterium and oxygen‐18 measurements were performed on three large hailstones. On a δD‐δ18O diagram, the representative points of the samples are generally shifted to the right compared with the curve calculated for the cloud liquid phase, especially for clear layers. This effect is due to evaporation of collected water between times of collection and freezing. A theoretical model is developed for both the wet and dry growth regimes which satisfactorily explains the experimental results.In the framework of the same study, interpretation of radial variations of deuterium content for eleven large hailstones from three storms is presented. the trajectories are reconstructed using the ICM isotopic cloud model which gives more realistic results than the adiabatic model used earlier. Its application shows that the most common growth temperatures are for the layers between ‐15° and ‐20°C and that all the studied graupel embryos originate from around the ‐15°C isotherm. There is good agreement between calculated and estimated updraught speeds and between structural, crystallographic and isotopic features which when combined can serve as a quantitative tool to study both hailstone growth regimes and hailstone trajectories.