bluuebunny/crossref_metadata_2025_split huggingface dataset:
Local winds in the southern alps, new zealand
Authors: Sturman A. P. , Fitzsimons S. J. , Holland L. M. 
Published: February 2007

AbstractA study is made of local wind development in New Zealand alpine valleys. The general characteristics of alpine airflow regimes are examined using both climato logical and case study approaches. Thermo topographic and dynamic effects are the major influences on valley airflow, the relative significance of each varying spatially as well as seasonally and diurnally. Case studies show that clear relationships exist between micro meteorological characteristics within an alpine valley and the phases of local wind development. In particular, boundary layer stability and energy flow characteristics are seen to vary with different phases of local wind development. The examples studied illustrate basic characteristics of local airflow, but particularly the development of nocturnal mountain winds with a transition to daytime up‐valley flow. The airflow shows classic local wind characteristics, regarding depth, speed, and return currents. An intermediate layer frequently occurs between the alpine valley wind regime and the gradient flow above. This layer of generally light winds may be persistently north‐westerly and the result of regional dynamic forcing of the gradient wind. Alternatively, under weak gradient airflow, it may exhibit variability indicating regional thermal forcing.
Temporal and spatial rainfall variability in the mountainous region of the reventazón river basin, costa rica
Authors: Chacón R. E. , Fernandez Walter 
Published: February 2007

AbstractTwo seasonal periods with different rainfall characteristics were identified in the mountainous region of the Reventazón River basin, Costa Rica, a region of about 1770km2 with altitudes in the 50O‐3000km range. These seasonal periods are December‐April, in which orographic rain predominates, and May‐November, in which convective showers predominate.The temporal variability of rainfall in the study area was examined using the coefficient of variation. It was found that the largest values of the coefficient of variation occur at high altitudes and the lowest values at middle altitudes. They are large in the December‐April period and small in the May‐November period.Correlation analysis was used to determine the spatial variability of rainfall in the study area. The results obtained show that the monthly and seasonal values of the correlation coefficient are generally larger than 0.7 over the study area in the December‐April period. In the May‐November period, the values of the correlation coefficient are in general quite small, less than 0‐3 for distances less than 50 km in the case of seasonal totals. In this latter period, a few values of the correlation coefficient larger than 0.7 are observed, but they correspond to areas with correlation radii less than 3 km.
Vertical velocity forced by topography in the southern hemisphere
Authors: Vianello Rubens Leite 
Published: February 2007

AbstractThe vertical component of wind forced by topography in the Southern Hemisphere is calculated using the equation given by Saltzman and Irsch (1972). This equation contains the contribution of Ihe zonal mean. Results show that the vertical velocity forced by topography in the Southern Hemisphere is in genera! comparable to that in the Northern Hemisphere. As in the case of the Northern Hemisphere, the zonal deviations of wind contribute significantly to the vertical velocity.
Urban modification of diurnal temperature cycles in birmingham, U.K.
Authors: Johnson D. B. 
Published: February 2007

AbstractThe urban heat island has traditionally been studied by showing its magnitude at a particular point in time, normally at night, when it reaches its maximum. The following paper adopts the strategy of Oke and Maxwell (1975) using heating and cooling rates to study the heat island. This method has the advantage of showing how the heat island develops and decays throughout the day. As the results reveal the most important changes occur at sunrise and sunset, the relative importance of the generating processes are considered with reference to the radiation budget of the urban surface. Results are reinforced by using urban and rural thermograph data.
Intra‐ and inter‐hemispheric teleconnections using seasonal southern hemisphere sea level pressure
Authors: Harnack Robert P. , Harnack Jeremi 
Published: February 2007

AbstractIn this study spatial and temporal relationships involving Southern Hemisphere (SH) sea level pressure (SLP) were examined using a 25‐year data set assembled for this purpose, with special emphasis on discovering inter‐hemispheric teleconnections in the seasonal SLP field. Principal component and correlation analysis was employed. The most important findings include:

Season‐to‐season autocorrelation of SLP is at least as large in the SH as in the Northern Hemisphere (NH), though the amount of area of significant autocorrelation is not great in either hemisphere (i.e. a total global area of 17‐24 per cent).
Principal component (PC) analysis performed on SH SLP in conjunction with Monte Carlo tests of significance showed that three or four PCs, explaining 40 to 58 per cent of the variance, represent the climatic signal in the data set.
Field significance tests applied to each teleconnection map, produced for each grid point in the SH, implied that there is a strong likelihood of real inter‐hemispheric relationships in NH winter. There was much less certainty in the other seasons. Examination of significant teleconnection maps suggested SH links to the Southern Oscillation, the North Atlantic Oscillation, Siberian High strength, and the ‘West Pacific pattern’ described by Wallace and Gutzler (1981).
Large‐scale features of satellite‐derived outgoing long‐wave radiation in relation to monsoon circulation over the indian region
Authors: Prasad K. D. , Verma R. K. 
Published: February 2007

AbstractThe monthly mean outgoing long‐wave radiation data from June 1974 o May 1981 were analysed for dominant eigenvector patterns. The first three eigenvector patterns explain nearly 93 per cent of the total variance. The first eigenvector pattern exhibits an annual cycle with a pronounced variation in the outgoing long‐wave radiation over the tropical belt between 10 and 20°N. This is largely indicative of strong seasonal shift of the major area of cloudiness associated with the Intertropical Convergence Zone. The second eigenvector pattern shows an out‐of‐phase relationship between north India and the equatorial region, having a pronounced semi‐annual oscillation. The third eigenvector pattern exhibits the characteristic features of the north‐east monsoon over south‐east peninsular India. The first and second harmonics, corresponding to annual and semi‐annual oscillations, exhibit the major characteristic features of the first two eigenvectors, respectively.The interannual variation of the outgoing long‐wave radiation for the summer monsoon period shows a close association with the large‐scale monsoon rainfall over India.It is concluded that the satellite‐derived outgoing long‐wave radiation can be used to monitor more comprehensively the large‐scale monsoon circulation and its year‐to‐year variability in view of its spatial coverage over oceanic areas.
Climatic subdivisions in saudi arabia: An application of principal component analysis
Authors: Al‐Jerash Mohammad A. 
Published: February 2007

AbstractTwo computer programs were executed on the available climatic data of fifty stations dispersed throughout Saudia Arabia. The first was a program for calculating the variables that represent potential evapotranspiration, soil moisture content and actual evapotranspiration. The aim of this step was to broaden the base of analysis whereby the processing of twenty‐four climatic variables becomes possible. The second was a principal component analysis program. The application of this program was carried out in two stages. First, on the twenty‐four climatic variables. This has led to the identification of five climatic components as being the principal factors that control the spatial variations of the climate in Saudi Arabia. Secondly, on the scaled distance matrix that was originally calculated using the station scores of the five components. This resulted in grouping the fifty climatic stations into six categories each of which represents a distinct spatial climatic subdivision of the country.
The extrapolation of recent climatological series with spectral canonical regression
Authors: Guiot Joel 
Published: February 2007

AbstractThis paper describes a simple but efficient method, based on classical techniques, which enables one lo estimate missing data and to extrapolate short instrumental climate series from other instrumental or proxy ones. By mutually exclusive digital filters, the variations of the data are decomposed into a rough spectrum. A canonical analysis is performed on each of these parts, providing relationships for each principal time‐scale. A global equation is then computed by inverse transformation. Generally, the predictands are better fitted by this method than by a standard regression. The improvement is shown for both instrumental and proxy data. The method can easily be applied in many topics where relationships between two groups of variables have to be estimated: agroclimatology, ecology and geophysics in general. It can run on a microcomputer with a BASIC program available from the author.By this method, a reconstruction of June‐July temperature at Marseille (France) is proposed showing a period of weak variability of the temperature during 1400‐1850, that is to say a period of rare warm summers with very cold summers only in the early 16th and late 17th centuries. An extrapolation of the instrumental series at Nice from corresponding series of Marseille and Gap is also developed.
Seasonal relationships between indian summer monsoon rainfall and the southern oscillation
Authors: Parthasarathy B. , Pant G. B. 
Published: February 2007

AbstractAssociation between the all‐India summer monsoon (June to September) rainfall and an index of the Southern Oscillation (SO) is studied in relation to the vagaries of the monsoon rainfall and the seasonal characteristics of the SO. The Southern Oscillation index (SOI) used is the difference of normalized sea surface pressure between Tahiti and Darwin, two stations located in the core regions of the circulation systems associated with the SO. The data length of 46 years from 1935 to 1980 is used in the detailed examination of the nature of association between these parameters.The SOI values of different months and standard seasons show opposite tendencies during deficient and excess years of all‐India monsoon rainfall. The correlation coefficients (CC) between the all‐India monsoon rainfall series and the SOIs of summer monsoon (JJA), autumn (SON) and winter (DJF) minus spring (MAM) seasons are significant at the 1 per cent level. The correlations have been examined by dividing the series into two equal halves of 23 years and different sliding window widths of 10, 20 and 30 years. The least squares fit line is represented by the equation y (all‐India monsoon rainfall) =85.9 ‐ 2.7x (DJF minus MAM, SOI), the variance explained by this line is about 13 per cent. In view of the large spatial variability of the summer monsoon rainfall the correlations are examined for the rainfall series of various meteorological subdivisions of the country. The CC between the monsoon rainfall of the subdivisions north of 16°N and west of 80°E and the SOI series of DJF minus MAM is significant at the 5 per cent level or above.Potentialities of the SOI of DJF minus MAM, an important premonsoon circulation parameter, are examined for the seasonal prediction of Indian summer monsoon rainfall, and the limitations of single parameter prediction models are discussed.
Synoptic and satellite aspects of the southwestern u.s. summer ‘monsoon’
Authors: Carleton A. M. 
Published: February 2007

AbstractSatellite infrared imagery for three years (1980, 1981, 1982) are analysed using a colour enhancement technique to derive a cloud climatology of the southwest United States summer ‘monsoon’. Diurnally‐stratified and weekly statistics are obtained for different cloud levels and used as an index of the monsoon intensity in each year. Strong diurnal variations in cloudiness, related to surface heating, are identified for July and August, as are marked interannual differences. These regional‐scale cloud variations are found to correlate more closely with the 700mb wind direction than with the height of the 700 mb pressure surface when considered for a representative station (Winslow, Arizona). A satellite‐based definition of ‘monsoon’ best considers variations of the total cloud rather than of any individual cloud level(s).Several surface and 700 mb synoptic circulation indices are identified and related statistically to the intraseasonal cloudiness changes. The most significant association is found for the variations in latitude of the Bermuda high pressure ridge that presumably relates to changes in subsidence. However, the sign of this relationship may reverse in years when other circulation systems, notably the North Pacific anticyclone, also influence the desert Southwest. Consideration of the zonal westerly index between 45 and 65°N tends to improve the correlation between the Bermuda ridge and summer monsoon cloudiness over the region. Such cloud‐circulation studies have implications not only for climate dynamics but also for ongoing solar energy research in the American Southwest.
A contribution to the upper‐air climatology of tropical south america
Authors: Chu Pao‐Shin 
Published: February 2007

AbstractAn upper‐air climatology of tropical South America is presented using objectively analysed geopotential height, temperature and wind data from various radiosonde stations for the common period 1970‐1974.In the lower troposphere the South Atlantic high dominates the geopotential height patterns extending deeply into interior Brazil in Southern winter. In the upper troposphere, contour gradients are concentrated around the subtropical region in winter. Temperature analysis shows the steep meridional gradient in winter. In summer, the Peruvian‐Bolivian Altiplano heating effect is manifested in the mid‐tropospheric temperature fields and also in the thickness field.Lower‐tropospheric flow throughout the year is marked by an anticyclonic turning of easterlies over much of eastern Brazil. Easterlies originating from the South Atlantic high penetrate further inland in Southern winter. Upper‐tropospheric flow changes dramatically from mainly westerly in winter to a well‐defined anticyclone over the Altiplano and a trough downstream over northeast Brazil in summer. Thickness and temperature patterns indicate that the upper anticyclone is maintained by a warm‐core system whereas the trough is marked by a relatively cold temperature. Upper tropospheric flows are equivalent barotropic in nature over tropical South America. The map discussion of summer and winter circulation is complemented by cross‐sections of meridional wind component along approximately 60°W.
On the zonally averaged temperature in the southern hemisphere
Authors: Satyamurty P. , Brahmananda Rao V. 
Published: February 2007

AbstractThe observed meridional temperature gradients in the middle and high latitudes of the southern hemisphere are much higher than the critical gradients necessary for the manifestation of baroclinic instability in a two‐level quasi geostrophic model. This is in contrast to the ‘baroclinic adjustment’ observed in the northern hemisphere by Stone (1978).
Energy balance climate modelling: An alternative dynamic parameterization
Authors: Cerveny Randall S. , Balling Robert C. 
Published: February 2007

AbstractThis paper describes a dynamic parameterization for a simple global climate model that is based on the planetary boundary layer equations of horizontal motion. This new parameterization resolves many of the problems associated with other representations of the general circulation in simple climatic models. The model developed in this study accurately simulates the presently observed zonally‐averaged temperature and wind field patterns. Sensitivity tests demonstrate that a model with the new dynamic parameterization meets or exceeds the performance levels of other one‐dimensional energy balance global climate models. By solving many of the problems associated with the available alternative circulation parametcrizations, the new circulation representation based on the equations of motion appears to improve the quality of the popular simple climate models.
On the radiation budget in the alps
Authors: Müller Hans 
Published: February 2007

AbstractThis study reviews the investigations on the radiation budget in the Alps at elevations above 1500 m a.s.l. Regarding outgoing radiation, only that from snow and ice is considered. Physical relationships between radiation and variables such as elevation, month and cloud amount are discussed. The individual components of the radiation budget are analysed first, and then an attempt is made to synthesize radiation balances.Elevation dependencies between 2000 and 3500 m a.s.l. in the canton of Valais (south‐western Switzerland) in summer (June to August) for average cloud conditions (1931‐1960) are as follows: the cloud amount increases from 0.507 to 0.582. The maxima occur in June. Global radiation increases from 22.7 to 23.6 MJm−2d−1. The maxima occur in June. Counter‐radiation decreases from 25.8 to 21.9 MJm−2d−1. The maxima occur in July. For average albedo, the radiation balance of horizontal glacier surfaces decreases from 15.3 to 5.3 MJm−2 d−1, with the maxima occurring in July. For albedo conditions after snowfall, the radiation balance decreases from 2.7 to 1.3 MJm−2dd−1, the maxima occurring in June or July.The study has the following applications, among others: it can (1) contribute to the understanding of the genesis of the climate of the Alps, (2) assist in the development of runoff models for heavily glacierized basins and (3) be helpful in the use of solar energy.
Long‐term trends of surface air temperature in india
Authors: Hingane L. S. , Rupa Kumar K. , Ramana Murty Bh. V. 
Published: February 2007

AbstractSalient features of the long‐term variation of surface air temperature for India as a whole and for different regions of the country have been presented. Temperature data at 73 fairly widespread stations, for the period 1901‐1982. have been used in the study. Seasonal and annual temperature anomaly series have been obtained for the different regions. Such series have also been obtained for latitude‐ and longitude‐wise classifications. The long‐term variation in the temperature has been evaluated by linear trend.The results indicate a slight but definite warming trend in the mean annual Indian temperatures. This warming is found to be mainly contributed by the post‐monsoon and winter seasons. West coast, interior peninsula, north central and north‐east regions of the country have shown pronounced warming in the mean annual temperatures. The post‐1940 cooling reported for the Northern Hemisphere is not conspicuous in the mean annual Indian temperature anomalies.
Anomalous mid‐atmospheric heights and persistent thunderstorm patterns over florida
Authors: Michaels P. J. 
Published: February 2007

AbstractA principal component analysis (PCA) of Florida thunderstorm patterns (1948‐1982) revealed three statistically significant spatial modes of variation from summer‐to‐summer. The most important was in the region of sea breeze convergence, which has been previously hypothesized to be the main initiator of summer thunderstorms over peninsular Florida.A companion analysis of 500 mb height data over the south‐eastern U.S. uncovered only one significant pattern of variation from the mean, when tested against uncorrelated data. We hypothesized, prior to testing, that dynamic considerations would make it negatively correlated with the most important thunderstorm pattern. A subsequent regression analysis allows that hypothesis to continue to be entertained. A canonical analysis verifies this finding.The results suggest that the sea‐breeze‐related thunderstorm patterns are influenced over seasonal and longer time scales by the first 500 mb component. There has been a significant secular change both in the most important thunderstorm pattern and its related 500 mb pattern over the period of this study.
Climatology of the terrestrial seasonal water cycle
Authors: Willmott Cort J. , Rowe Clinton M. , Mintz Yale 
Published: February 2007

AbstractCalculations of the spatial and seasonal variations of the continental fields of snow‐cover, soil moisture and evapotranspiration are presented and interpreted. The calculations were made with a water budget analysis that is based on observed average monthly precipitation and an estimate of potential evapotranspiration derived from observed average monthly surface temperature, using a modified version of the method of Thornthwaite. Monthly average water budget analyses were made for 13,332 stations over the globe and, then spatially interpolated to a regular grid at 1° by 1° latitude‐longitude intervals. From the monthly fields on a 4° by 5° subset of the 1° by 1° grid, the annual mean and standard deviation as well as the first and second annual harmonics were extracted and are displayed on global maps. Of the three fields, soil moisture has the largest space‐time variation; snow‐cover the smallest variation; and evapotranspiration an intermediate level of variation.
Variation of spatial annual precipitation sums in central europe in the period 1881‐1980
Authors: Brázdil R. , Ŝamaj F. , Valoviĉ Ŝ. 
Published: February 2007

AbstractThe analysis of atmospheric precipitation variation in Central Europe in the period 1881‐1980 is based on the series of the so‐called spatial annual precipitation sums for the F.R.G., the G.D.R., Poland, Bohemia, Moravia, Slovakia and Hungary and for the Baur series. The annual precipitation variation in the above period is studied by means of series of 5‐year and 11‐year gliding means. Methods of autocorrelation analysis, spectral analysis (partly according to Blackman and Tukey, partly maximum entropy spectral analysis), coherency analysis and numerical bandpass filtering were used for analysing precipitation periodicities and cycles.In the period studied, the western part of Central Europe (the Baur series, F.R.G., also G.D.R.) shows a generally increasing precipitation trend at below‐mean sums approximately up to 1920, whereas a more or less decreasing tendency is typical of the remaining series. Periods with analogous lengths appear in precipitation series in the whole of Central Europe and at the same time the lengths of significant periods are shortened from 4.4 and 5.0a (a = year) in the western part to 3.3 and 3.6a in the eastern part. At the same time, significant coherence among the studied series most frequently appears for periods of 2.5 and 13.3a. Periods with lengths of 2‐3 years take a more conspicuous part in the total variance of the corresponding series (about 30 per cent), except in the cases of Slovakia and Hungary, where the maximum share is shifted to oscillations with periods of 3‐4 years and for the F.R.G. and the Baur series to the interval of 4‐6 years. The course of the filtered series refers to the length and phase instability of the periodicities found, which complicates the use of the knowledge obtained for long‐term precipitation forecasting.