bluuebunny/crossref_metadata_2025_split huggingface dataset:
The spatial organisation of daily rainfall in eastern New South Wales
Authors: Sumner Graham N. 
Published: February 2007

AbstractProduct‐moment correlation are used to provide an estimate of the degree of association of daily rainfalls between a number of sited in eastern New South Wales. Completely dry days are omitted from the analysis so that the coefficients obtained represent the strength of association between sites for days on which rainfall occurs. Maps showing the strength of links between sites are used to illustrate general trends in the spatial organization of daily rainfall on a monthly basis. Certain very district seasonal changes in rainfall patterns emerge, principally distinguishing the summer (December to February) from the cooler part of the year (April to October) in terms of the nature of association and the separation of discrete rainfall areas. Many of these comprise groups of two or three Bureau of Meteorology forecasting areas. More widespread rainfall associated with lager‐scale atmospheric disturbance occurs in February, and in April and May, but during the April to October period the Divide is seen as a very important climate, as well as topographic, feature. At other times smaller topographic units apparently exert a control over rainfall occurrence. This is particularly true of the Hunter valley which is the center of rainfall development for a wide area in January. Sea breeze front effects are also seen as important enhancers of rainfall in the summer.
Sub‐saharan rainfall update for 1982; continued drought
Authors: Lamb Peter J. 
Published: February 2007

AbstractThe 1982 value of a sub‐Saharan rainfall index previously published for 1941‐1981 is given. This establishes that the drought which commenced in 1968 and persisted very strongly throughout the 1970s and 1980‐1981 continued into 1982. which was the third driest year of the period 1968‐1982, and also appears to have received substantially less rainfall than the drought years of the 1940s. Several meteorological and socioeconomic implications of this situation are discussed. The paper also provides a recomputation of the entire 1941‐1982 index time series that was permitted by the forward extension of the database since the original calculation for 1941‐1974.
Spatial patterns of precipitation in England and Wales and a revised, homogeneous England and Wales precipitation series
Authors: Wigley T. M. L. , Lough J. M. , Jones P. D. 
Published: February 2007

AbstractThe spatial patterns of precipitation variability over the United Kingdom are examined for the period 1861–1970 using principal components analysis. Most of the variance (around 50 per cent) is explained by the first component, which is characterized by uniform variability over the whole region. Higher‐order components isolate differential variability between different regions. The first four components are essentially the same for all months, all seasons and the annual total, highlighting the intra‐annual constancy of inter‐regional variability and pointing to strong geographical and topographical control. A subdivision of the analysis period into two halves produces no change in the component patterns, but changes in the variance explained by the first component imply that summer precipitation has become less spatially variable since 1915. On the basis of the principal components analysis the England and Wales region is divided into five coherent subregions. A regression technique is developed to produce a homogeneous area‐average precipitation series for England and Wales using the longest site precipitation records available and maintaining even spatial coverage. The method used allows changes in the reliability of the area‐average due to changes in the density of station coverage to be quantified. An empirical relationship between the standard error of estimate of area‐averaged precipitation and the number of recording sites is derived. Significant inhomogeneities in the Nicholas and Glasspoole England and Wales precipitation series at 1915 and 1957 are detected and quantified. The Nicholas and Glasspoole series as a whole is found to underestimate precipitation amounts noticeably in the late eighteenth and early nineteenth centuries.
A stochastic model to generate sequences of hourly mean wind speeds for different sites in the United Kingdom
Authors: Smith S. G. 
Published: February 2007

AbstractA stochastic model has been developed to generate sequences of hourly mean wind speeds for different sites in the United Kingdom. A feature of its formulation is that three distinct wind speed regimes have been identified within a time series and each regime fitted separately. Sixteen stations providing data over a 15 year period have been used to develop and test the model. Results are encouraging, more especially for the higher speeds.
Indian rainfall in relation to the sunspot cycle: 1871–1978
Authors: Ananthakrishnan R. , Parthasarathy B. 
Published: February 2007

AbstractThe paper presents the results of a detailed study of the annual rainfall of India in relation to the sunspot cycle for the period 1871 to 1978. Rainfall time series of individual stations as well as of meteorological subdivisions have been examined for the full period (108 years) and for two half periods.The correlation coefficients (CC) of 306 stations for the full period lie between 4–0–29 and −0–14 with a preponderance of positive over negative values in the ratio 4:1. Twenty‐six CC values are significant at the 5 per cent level. The CC values for the two subseries reveal appreciable temporal variations, the correlations being higher for the first half. Lag correlations between the rainfall and sunspot series indicate that the CC values tend to increase when the rainfall is correlated with sunspot numbers 1 to 3 years later and to decrease when correlated with sunspot numbers 1 to 3 years earlier.Examination of the all‐India rainfall series and the sunspot series for the full period shows that excess rainfall years were significantly more during the ascending phase of alternate cycles. Superposed epoch analysis and the Student t test show that the rainfall around the maximum of even cycles characterized by high sunspot activity is significantly higher than the corresponding rainfall in the odd cycles with lesser spot activity. Correlation study with a 15‐year sliding window reveals large temporal variations in the CC values.Although most of the variance in the rainfall time series is due to causes unconnected with the sunspot cycle, the present study suggests the existence of a weak positive association between Indian rainfall and sunspots on the 22‐year time scale, although the causal connection is unknown.
Riverflow reconstruction from precipitation data
Authors: Jones P. D. 
Published: February 2007

AbstractIn the United Kingdom few river catchments have overflow records longer than 35 years. The wealth of precipitation data in the United Kingdom enables long records of riverflow to be produced with a catchment model calibrated over the recent period. For most parts of England and Wales it is shown that monthly sequences of riverflow that account for 90–95 per cent of the variance of the measured riverflow can be produced back to 1860. Reconstructions are made on 10 catchments (size range 400–4500 km2) in both upland and lowland Britain. Reliable reconstructions are possible using as few as 4 rainguage records.The reconstructions provide not only a valuable database for the study of the effect of climatic change on riverflow, but also allow stationarity, homoscedasticy and changes in the frequency of extreme events to be examined. It is shown that on the 10 catchments extreme droughts with a duration of 18 months are three times more likely to have occurred between 1925 and 1979 than between 1870 and 1924. The significance of this and other findings are discussed in the context of water resource analysis. The reconstructed riverflows, apart from their obvious use for water resource analysis, also provide a valuable climatological database for the possible further extension of riverflow using proxy climate indicators such as tree rings.
A Southern Hemisphere sea level pressure data set for use in climatic studies
Authors: Harnack Jeremi , Harnack Robert P. 
Published: February 2007

AbstractA 25‐year (1956–1980) Southern Hemisphere sea level pressure (SLP) data set (G‐SLP) for the region 10°S–50°S was created by manually extracting interpolated grid point data from monthly SLP maps contained in the German publication Die Witterung in Übersee. Comparison of long term means with published means indicated that the major large‐scale circulation features on the original maps were retained through the extraction process. Comparison between a short term subset (1972–1979) of the data set and A‐SLP, derived from a SLP data set produced by the Australian National Meteorological Analysis Centre of the Australian Bureau of Meteorology, substantiated the reasonableness of the extraction process and suggested areas of possible data problems. The 50°S data was determined to be insufficient for statistical studies owing to missing data. Most areas of significant difference between G‐SLP and A‐SLP, as determined by a Student's t test, can probably be accounted for by the fact that A‐SLP includes satellite data not included in G‐SLP. Analysis of the informational content of the G‐SLP data set is presented, the results of which strongly suggest that the derived data set will be useful in large‐scale climatic studies involving interannual variability of Southern Hemisphere SLP.
The relationship of soil temperature to vegetation height
Authors: Green F. H. W. , Harding R. J. , Oliver H. R. 
Published: February 2007

AbstractUsing extensive observations of air and soil temperatures made under a variety of vegetated surfaces (forest, heather and grass) the influence of vegetation characteristics on the mean soil temperature is considered. It is demonstrated that the main influence is the height of the vegetation, with canopy density only a subsidiary factor. Consideration of the energy balance from two catchments in Wales (one forested and one grassland) strongly suggests that it is the aerodynamic resistance (itself related to vegetation height) which is the determining factor.
Graphical and statistical techniques to describe snow‐cover variations in mountain environments
Authors: Risser Vincent , Martin Serge 
Published: February 2007

AbstractThis paper attempts to provide some practical suggestions for graphical and statistical methods used to describe interannual and seasonal variations of the snow‐cover amount. Essentially two techniques are developed: (i) the ‘probability calendar’, which gives for each day of the cold season (December to May) information on the probabilities of observing some given thickness of the snow‐pack, and (ii) ‘probability charts of evolution’, which give probabilities for the evolution during the snow‐melt period of a snow‐pack having a given thickness at a given date. In order to build these charts we develop statistical models of the melting and compaction of snow using standard meteorological data.
Monthly estimates of wind speed and wind run for Australia
Authors: Hutchinson M. F. , Kalma J. D. , Johnson M. E. 
Published: February 2007

AbstractThis paper introduces the first comprehensive wind speed and wind run maps for Australia. Maps for January, April, July and October based on analyses for all twelve months are presented and discussed. They show, in turn, the distributions of mean 9 a.m. and mean 3 p.m. wind speed at a height of 10 m, the distribution of the ratio between mean daily wind speed and the mean of 9 a.m. and 3 p.m. wind speeds and, finally, the distribution of mean daily wind run at a height of 2 m. The wind speed and wind run maps have been produced from Laplacian smoothing spline surfaces fitted to wind speed observations and to wind run observations and estimates at approximately 500 Bureau of Meteorology stations. The ratio maps, which may be used to estimate wind run from 9 a.m. and 3 p.m. wind speeds, have been similarly produced from data at just 73 Bureau of Meteorology anemograph stations but with independent validation at 68 stations which record both wind speed and wind run. The fitted surfaces are functions of latitude, longitude and a suitable transformation of distance inland from the coast. The degree of data smoothing imposed by the surface fitting procedure has been chosen to minimize for each surface the mean square predictive error estimate as measured by generalized cross‐validation.
Seasonally stratified correlations of the 200 mb tropical wind field to the Southern Oscillation
Authors: Selkirk Rennie 
Published: February 2007

AbstractThe response of the 200 mb tropical wind field to the Southern Oscillation and central equatorial Pacific sea surface temperature is examined with correlation and regression analyses on a seasonally stratified basis. Although there are differences in magnitude, all seasons are found to exhibit the following set of responses: during periods of low Southern Oscillation Index and high equatorial sea surface temperature there are easterly anomalies of the equatorial zonal wind and westerly anomalies in the adjacent subtropics. These anomalies are consistent with the circulations in simple models of the Walker circulation in which the longitudinal scale of equatorial heating is increased, resulting in reduced zonal overturning at the equator (weakened Walker circulation) and increased meridional overturning and acceleration of the subtropical westerlies in a region slightly to the west of the anomalous heating centre. The correlation and regression results also show that central Pacific equatorial sea surface temperature is an excellent index of the heating anomalies.Theoretical results have predicted that the importance of remote forcing from the tropics in higher latitudes is dependent upon the strength of the intervening zonal wind field. Season‐to‐season differences are particularly apparent in the northern hemisphere responses of the zonal wind field to the Southern Oscillation: remote responses are relatively strong when the mean zonal winds over the Pacific region and corresponding values of standing wave group velocity are relatively large and vice versa. A similar correspondence is not found south of the equator as the correlation results do not vary as strongly with season. This may be due to greater equatorial trapping of Southern Oscillation anomalies in the same season when subtropical winds are more favourable for meridional coupling.
The statistical effects of incomplete sampling of coherent data series
Authors: Parker D. E. 
Published: February 2007

AbstractAn expression is derived for the equivalent number of independent values obtained by partial sampling of a coherent, i.e. autocorrelated, time‐series or spatial series of data. The expression is a function of both the coherence of the data values and the coherence of the sampling, i.e. the non‐randomness of the distribution of available data. For a data series with high autocorrelation the distribution of the sampling in time or space is more important than for a relatively incoherent data series. Meteorological data are used as illustrative examples. The derived expression can be used in estimating the variance of sample means.
Air temperature variations in Greece. Part 2. Spectral analysis
Authors: Flocas A. A. , Giles B. D. 
Published: February 2007

AbstractPower spectrum analysis is applied to annual and seasonal temperature data at three Greek stations. The results are tabulated and oscillations of 9, 4.8, 4.0, 2.7 and 2.2 years occur in most sets of data. The statistical importance of the results is indicated by 95 per cent, 90 per cent and null continuum levels. The quasi‐biennial oscillation is very clear but seems to be composed of individual cycles of 24, 26 and 32 months.
Estimating solar radiation in A tropical environment using satellite data
Authors: Nunez M. , Hart T. L. , Kalma J. D. 
Published: February 2007

AbstractDaily values of satellite derived reflectivity and daily totals of incoming solar radiation were obtained over a six‐month period for a network of stations in tropical Queensland, Australia.A definite linear relationship was observed between the reflectivity of the earth‐atmosphere system and the atmospheric transmissivity calculated as the portion of extraterrestrial radiation reaching the surface.The scatter in the relationship was largely due to variation in the number of satellite scans available each day and to variations in aerosol absorption.Using the regression model, the transmissivity of solar radiation has been calculated over the entire study region for the months of August 1982 and January 1983. The spatial variability of incoming solar radiation has been discussed. It was found that the spatial pattern is strongly dependent on topography and wind direction.
Regional variations in the annual cycle of rainfall in Ireland as revealed by principal component analysis
Authors: Logue J. J. 
Published: February 2007

AbstractPrincipal component analysis is applied to long‐term average monthly rainfall amounts expressed as percentages of the annual average in order to study variations in the annual cycle of average rainfall in Ireland. It is found that these variations can be described in terms of two principal components (PCI and PC2) which together account for about 80 per cent of the total variance. PCI represents a tendency for rainfall to be high in summer as compared to winter and is a maximum in the midlands and north‐east. PC2 represents a tendency for the first half of the year to be relatively wet and the second relatively dry and is a maximum in the south‐east. Physical explanations for these features of the rainfall climate are suggested.
Climatological premises of soil drought forecasting
Authors: Sadowski M. J. 
Published: February 2007

AbstractArgumentation and premises to formulate soil drought forecasting in Poland in the summer of 1982 are presented in this paper. The forecast was formulated in the spring of 1982 and was based on such premises as the relationship between mean atmospheric pressure for the summer season APL (May‐August) and the atmospheric pressure of the proceeding winter season APZ (January‐March), long‐lasting sea surface temperature (SST) anomalies in the Norwegian Sea and the central part of the northern Atlantic which preceded the occurrence of drought, and the frequency of drought in Poland.It has been stated that a good relationship exists between the atmospheric pressure departure in a summer with soil drought and the same values for the preceding winter season. In the area with values of winter and summer pressure departure higher than 4hPa only summer soil drought occurred in Poland during the twentieth century. Such summer seasons are preceded by long periods with SST anomalies in the M and K/R weather ship areas. As a rule when either of these regions has positive anomalies then the other has negative.Weather conditions in the summer of 1982 have confirmed the correctness of the argument which ended in the formulation of a forecast, as well as the high consistency of forecast weather conditions with those which occurred.
Temporal and spatial characteristics of Arizona dust storms (1965–1980)
Authors: Nickling W. G. , Brazel A. J. 
Published: February 2007

AbstractHourly meteorological data for four first order stations (Phoenix, Tucson, Winslow and Yuma) were used to identify dust storms which occurred in Arizona from 1965 to 1980. Supporting data on diurnal dust storm frequencies for three Air Force bases in southern Arizona were also used in the analysis. In this study, dust storms have been defined as blowing dust events when visibility is reduced to si‐6 km. Data, however, were also collected for all events when visibility was sll‐3 km which is the dust storm definition used by Orgill and Sehmel (1976).In general, Yuma experiences the most dust storms per year followed closely by Phoenix, with Tucson and Winslow having very few events. Dust storms at Phoenix, on average, tend to be more severe than those experienced at the other sites. The most intense and frequent dust storms in Arizona occur during the summer months and are associated with strong downdrafts generated by intense thunderstorm activity. Several less intense dust storms of longer duration also occur at most sites during the late winter and early summer months with peak occurrence in April. These events are usually associated with cyclonic storm activity including cold frontal passages and upper level cut‐off lows which are common throughout the state at this time of year.Phoenix and Tucson are dominated by late, afternoon dust storms (1700–1800 h) especially during the summer months. Start times are much more irregular at Yuma and Winslow but modes are evident al 0900 h and 1200 h respectively.Phoenix and Tucson experience relatively short duration dust storms averaging 66 and 15 minutes, respectively. Although these dust storms are relatively short, they are rather intense, which is indicated by low visibilities associated with these dust storms. In contrast, storms at Yuma and Winslow are typically longer, lasting more than two hours (160 and 202 minutes, respectively).The dust storm frequency patterns based on visibility criteria pose an important question as to whether higher annual sediment fluxes result from many low‐to‐intermediate magnitude events or fewer, higher magnitude events. This question cannot be readily answered at the present time because of the lack of sediment load data during dust storms. Although meteorological conditions may play a major role in dust storm generation, detailed research is required to evaluate the relative importance of antecedent moisture conditions, surface soil and vegetation conditions, and anthropogenic factors.
A global archive of land cover and soils data for use in general circulation climate models
Authors: Wilson M. F. , Henderson‐Sellers A. 
Published: February 2007

AbstractA new global archive of soil type and land cover data derived for use in GCM climate models is described. The data are archived al a resolution of 1° latitude × 1° longitude. The method of construction of the component data sets is given together with ‘reliability estimates’. The soils data form the only published data set designed specifically for use in climate studies. The land cover data are compatible with the soils data, forming a coherent and complete data set and seem to be comparable with other land cover information. Recommendations are made about combining and coarsening the data to the grid of any general circulation climate model. Methods of parameterizing surface radiative and hydrological properties in climate models are proposed.