bluuebunny/crossref_metadata_2025 huggingface dataset:
Genome instability and chromosomal rearrangements in a heterothallic wine yeast
Authors: Miklos Ida , Varga Tamás , Nagy Ágnes , Sipiczki Matthias
Published: February 2007

Wine strains of Saccharomyces cerevisiae are usually homothallic diploids and show chromosome length polymorphism. We describe the analysis of a heterothallic strain heterozygous for the mating types a and α. Surveying cultures of the strain, we found a remarkable degree of heterogeneity in ploidy and in electrophoretic karyotype. The CHEF analysis of tetrads and dyads revealed an enormous variability of band patterns hampering the analysis of chromosome segregation. We propose that the instability of ploidy and chromosome polymorphism might be due to heterothallism that precludes the process ‘genome renewal’ (MORTIMER et al. 1994) by selfdiploidization of spore clones.
Cu2+ efflux and its regulation in Cu‐resistant (Cur) cyanobacterium Nostoc calcicola BRÉB
Authors: Pandey P. K. , Singh S. P. , Bisen P. S.
Published: February 2007

Cu2+‐tolerant/resistant (Cur) strain of the cyanobacterium Nostoc calcicola BRÉB., developed in the laboratory, showed remarkable growth in ambient medium containing 40 μM Cu2+ (5 μM Cu2+ being lethal for wild type strain). It showed 22% less Cu2+ uptake compared to Cus (Cu‐sensitive) cells. Cur cyanobacterial cells were characterized by a time‐dependent Cu2+ efflux in contrast to no cation efflux by Cus cells. Cu2+ efflux pattern in Cur cells consisted of two distinct phases: First rapid efflux (10 min) followed by slower second one at least up to 1 h. Cu2+ efflux depended to a major extent on light generated ATP1), as the dark exposed Cur cells showed 87% reduction in Cu2+ efflux. The lowering in Cu2+ efflux in presence of various metabolic inhibitors/uncouplers like carbonyl cyanide‐m‐chloro phenyl hydrazone (CCCP)1), N,N'‐dicyclohexycarbodiimide (DCCD), azide (NaN3) and p‐chloromercuribenzoate (pCMB) indicated the involvement of ‐SH group, membrane potential and ATP hydrolysis in the regulation of this process. Cu2+ efflux was also initiated in such a medium containing 100‐fold lower Cu2+ concentration (0.4 μM) compared to 40 μM Cu2+ (saturing concentration for metal uptake) and not before. It is suggested that Cu2+ efflux in N. calcicola cells may be the predominant mechanism of Cu2+ resistance/tolerance in this organism and are regulated at different levels by different modifying factors.
The effect of heparin on the activity of Trichosporon cutaneum casein kinase I
Authors: Wojda Iwona , Frajnt Magdalena , Jakubowicz Teresa
Published: February 2007

Casein kinase I from Trichosporon cutaneum ribosome‐free extracts was purified. Its molecular mass was calculated for 33 kDa. It was shown that casein, phosvitin and Trichosporon cutaneum ribosomal protein of 15 kDa were preferable substrates for the enzyme. It was found that heparin can stimulate or inhibit CKI activity depending on the substrate used. Stimulation of casein and inhibition of phosvitin phosphorylation was observed. In addition it was shown that ribosomal proteins of 19 kDa and 38 kDa were phosphorylated by CKI only in the presence of heparin.
Nucleotide sequence of the Staphylococcus aureus transposon, Tn5405, carrying aminoglycosides resistance genes
Authors: Derbise Anne , de Cespedes Gilda , Solh Nevine El
Published: February 2007

Tn5405 is a 12 kb staphylococcal composite transposon delimited by two inverted copies of the insertion sequence IS1182. This transposon carries two aminoglycosides resistance genes, aphA‐3 and aadE, an altered gene similar to sat4 from Campylobacter coli BE/G4, and three open reading frames of unknown functions.
Monthly variability of satellite‐derived cyclonic activity for the southern hemisphere winter
Authors: Carleton Andrew M.
Published: February 2007

A satellite‐derived climatology of cloud vortices for the Southern Hemisphere winter (June to September) indicates that significant within‐season changes occur in the areal frequencies of extratropical depressions. This variability is found to be most strongly associated with the climatic frontal zones, while on a zonally‐averaged basis, the semi‐annual oscillation of the circumpolar vortex appears to dominate the latitudinal changes in cyclonic activity between June and September. Surface‐atmosphere interactions evidently play a key role in the wintertime circulation at middle and high latitudes. Cyclogenesis over the Southern Oceans is observed to be linked closely to the baroclinity associated with the Oceanic Polar Front, while on a regional scale, the presence of a time‐averaged zone of in situ cyclogenesis over sub‐antarctic latitudes of the South Pacific is found to be augmented by the influence of the unique winter season sea ice regime in that sector.
Sea breezes along the Canterbury coast in the vicinity of Christchurch, New Zealand
Authors: Sturman A. P. , Tyson P. D.
Published: February 2007

Observations are presented suggesting the significance of sea breezes in producing distinctive diurnal boundary layer oscillations over Christchurch. Sea breeze effects are shown to be an all‐year phenomenon reaching their maxima in summer. The interaction of onshore wind components with south‐westerly gradient winds (even under cloudy conditions) appears to produce a distinctive all‐seasons diurnal rhythm in the gradient wind. The development of shallow north‐easterlies blowing into an orographically‐induced lee trough, preceding the onset of ground north‐westerlies, is shown to produce a complicated system of onshore airflow when combined with the sea breeze. Under such conditions it is argued that a sea breeze return current may be discerned.

Canterbury sea breezes are an important feature of the local climate and correspond in many respects to classical sea breeze models. Notwithstanding, it is their site‐specific characteristics that render them of particular interest.
Net incoming radiation estimated from hourly global radiation and/or cloud observations
Authors: Nielsen L. B. , Prahm L. P. , Berkowicz R. , Conradsen K.
Published: February 2007

From routine hourly observations reported during 5 years at one site in Denmark, empirical relations for net radiation over green grass are found. These relations give an estimate of the net radiation for the measuring site from the geographical position, local time, representative surface albedo, measured global radiation and/or total cloud cover in oktas. Cloud types are taken into account, if the reported clouds are mainly cirrus forms. This is a result of a classification of the net radiation according to cloud cover and type, i.e. a total of 90 classes. Different relations are found for different cloud covers.

The derived procedure is used on another site in Denmark with another representative surface albedo. From 10 years of data, consistency is found for net radiation measurements at the two sites, allowing extrapolation of the derived net radiation procedure to other sites in Denmark. Data from the Wangara experiment (Clarke, 1971), covering 40 days, showed a similar relation for clear sky conditions, but revealed another general dependency of net radtation upon cloud cover than that found in Denmark. Therefore, relations of the kind found in this study are related to the weather and climate of the measuring site. Comparisons between net radiation estimated from the models and measurements from different sites is r2 ⋍ 0.9.
A principal component and spectral analysis of European rainfall
Authors: Tabony R. C.
Published: February 2007

The main patterns of European rainfall anomalies were obtained from a principal component analysis of 182 homogeneous rainfall series from 1861 to 1970. The most important component corresponded to an anomaly of the same sign and magnitude covering most of the area examined. The principal components were essentially the same for all seasons and limited networks of stations back to 1786 showed that they were stable with lime. Spectral analysis of the patterns revealed cycles in European rainfall at periods of 2.4 years in summer and 2.1 and 5 years in the winter half year. The first of these is the most likely to represent a permanent feature of the atmosphere.
Spatial analysis of secular temperature fluctuations
Authors: Lawson Merlin P. , Balling Robert C. , Peters Albert J. , Rundquist Donald C.
Published: February 2007

The identification of global trends in secular temperature has resulted in various theories explaining temporal climatic fluctuations. Few investigators have attempted to regionalize these trends as derived from climatic statistics. This study attempts to: (1) review methodological problems inherent in the study of climatic fluctuations; (2) suggest a methodology to overcome some of the difficulties; and (3) develop discrete regions of temperature variation. The results presented in this study significantly complement the information derived by depicting large areal units by climatic summary statistics. Nine discrete regions of temperature trend are developed for the United States, and the contiguity of the resulting regions suggests that climatic fluctuations display distinct spatial patterns.
Evidence of an 11‐year periodicity in tree‐ring series from formosa related to the sunspot cycle
Authors: Mori Yukihiro
Published: February 2007

It has been pointed out previously that tree‐ring series from Formosa show an 11‐year periodicity related to the sunspot cycle. However, significance tests of this finding have not been made and therefore the statistical reliability has not been known. Spectra of tree‐ring series from other sites reported before show no evidence that the 11‐year sunspot cycle appears in tree‐ring series. Spectral analyses have been made of published tree‐ring data from Formosa and previous studies have been re‐examined. Tree‐ring series from two different sites in Formosa show an 11‐year spectral peak at the level of confidence higher than 90%. Cross spectral analysis between the tree‐ring series and the Zurich annual sunspot number shows that the 11‐year fluctuations in the tree‐ring series are related to the sunspot cycle with a time lag of 1/4 phase at the 99% confidence level. Using a band‐pass filter technique, it is found that the 11‐year fluctuations in tree‐ring series correspond to almost each cycle of the sunspot number except for periods of low solar activity. Significant 11 ‐year fluctuations in the tree‐ring series appear during most of the periods of an ‘active’ sun as estimated by carbon 14 abundance in tree‐rings.
Empirical orthogonal analysis of 700 mb geopotentials during the summer monsoon over Asia
Authors: Sikka D. R. , Prasad K. D.
Published: February 2007

Mean monthly 700 mb geopotential anomaly fields over the Asiatic region for the four summer monsoon months June to September based on 15 years data (1964 to 1978) have been analysed through an empirical orthogonal functions technique. The analysis shows that the first five dominant functions explain about 80 per cent of the total original variance, thereby affording a method by which 93 per cent of the data reduction is possible in each of the months considered. Correlations have been derived for the first three dominant functions of a month with the corresponding functions of the other months. Similarly, the time amplitudes of the first three functions of a month have been correlated with the corresponding time amplitudes of the other three months. The correlation analyses show that the first function and its associated amplitude for June are significantly correlated with the corresponding functions and amplitudes of the other three months. The time amplitudes of the first and the second functions have been used to determine analogous mean monthly anomaly patterns among different years of the data under study.
The effect of weather conditions on the public demand for meteorological information
Authors: Smith Keith
Published: February 2007

This paper describes how regional Weather Centres in Britain supply meteorological information to the community. With reference to the public enquiries directed to the Glasgow Weather Centre, it is shown how the demand for such information is likely to reflect a mix of socio‐economic and atmospheric factors. Spontaneous daily enquiries recorded over a 2‐year period in Glasgow are analysed through a regression model to demonstrate wide differences in weather sensitivity between demand categories. The most numerous enquiry types are shown to be those most dependent on weather conditions. Finally, it is suggested that any future work should incorporate a measure of behavioural influences in order to provide the best delineation of enquiry demand characteristics.
Climatology of tropical cyclone genesis in the Australian region
Authors: McBride J. L. , Keenan T. D.
Published: February 2007

Statistics of tropical cyclone origin in the Australian region are presented for the period July 1959‐June 1979. Cyclone genesis is found to occur in preferred areas and to have a high incidence of coastline developments, often with the precursor system forming over land. There is an average of 1.3 occurrences per year of ‘regeneration’ whereby a cyclone develops from a pre‐existing cyclone which has lost intensity after crossing on to the continent.

A synoptic analysis of individual developments over five years reveals that 84 per cent of the pre‐cyclone cloud clusters first appear on the gradient level monsoon shear line, whereas 97 per cent are on the shearline at the point of development. Statistical evidence is given for the enhancement of lower and upper level vorticity fields by mid‐latitude systems prior to cyclone genesis, but on a case by case basis the role of these systems is highly variable.

The structure of the pre‐cyclone systems for individual cases and composites shows the upper level warm core and large scale cyclonic surrounding circulation in the middle and lower troposphere, known to exist for similar systems in other parts of the world. At upper levels the systems are surrounded by tangential winds in the anticyclonic sense beyond 6 degrees latitude radius.
Climate and energy balance on the arctic tundra
Authors: Ohmura Atsumu
Published: February 2007

Energy balance measurement on the arctic tundra on the midwest coast of Axel Heiberg Island, N.W.T., Canada, is summarized. The methods and the instruments as well as their difficulties in the arctic field conditions are described. The seasonal characteristics of the energy balance are presented for the dry snow, the melt and the postmelt periods. The diurnal variations of the energy balance for each of these periods are also presented.

The climatic differences for the regions of the tundra, glaciers and the arctic seas become prominent during the three summer months of June, July and August. The energy balance at the present site is compared with that of Barrow, Alaska, revealing a high degree of similarity. The slight differences between them are more net radiation, more sensible and latent heat fluxes, larger Bowen ratio and less soil heat flux at Barrow. These differences are considered to be due to the larger distance of the present station from the coast.

The energy balance on and in the dry snow cover is investigated. The stability of the snow cover is attributed to the high reflectivity as well as to the large absorptivity of its surface with respect to solar radiation. The absorption occurs mainly at the surface of the snow cover rather than its interior. This condition facilitates the efficient removal of the absorbed energy from the surface by the atmosphere.

The energy balance on the tundra is compared with those on the Central Arctic Ocean, the ablation area of the polar glaciers, the accumulation area of the glaciers and the boreal forests. The surfaces of the tundra, ablation area of the glaciers and the Central Arctic Ocean are found to receive similar net radiation, despite the albedo differences. The fundamental difference among these surfaces is the magnitude of the latent heat of melt. This component on the ablation area of the glaciers and the Central Arctic Ocean is four to six times larger than on the tundra, which results in differential heating and evaporation in these regions. This difference is considered to be the basis of the milder climate in the tundra region in the Arctic.

More substantial differences are found between these low altitude arctic surfaces and the accumulation areas of the glaciers and the boreal forests. The differences are due to the large variation in albedo for the former and to the difference in global radiation for the latter. These differences ultimately regulate the regional variations in net radiation, sensible and latent heat fluxes.
Studies of the indian summer monsoon with a coarse‐mesh general circulation model, part 1
Authors: Druyan Leonard M.
Published: February 2007

A coarse‐mesh (8° latitude × 10° longitude), global domain climate model is shown to produce useful simulations of the sea‐level pressure and the precipitation distribution over south Asia during spring and early summer. Although the computations produce excessively fast development of the monsoon trough, the trend of increasing rainfall over the Indian subcontinent finds expression in the simulations. The model precipitation increases seasonally too early over southern India but the pattern by July correctly depicts a maximum south of the Tibetan plateau.

Four pairs of simulations during the model onset month tested the sensitivity of the onset to small arbitary differences in atmospheric stale. The results suggest that the timing of Indian precipitation may not be predictable from consideration of antecedent measurable atmospheric parameters.
Principal component analysis of the lamb catalogue of daily weather types: Part 1, annual frequencies
Authors: Jones P. D. , Kelly P. M.
Published: February 2007

Principal component analysis is applied to annual weather type frequencies for the British Isles. The results objectively define characteristic relationships between the different types, and are used to determine changes in the atmospheric circulation in the region of the British Isles over the period 1861 to 1980. It is shown that, as far as annual frequencies are concerned, only six (of the 27) weather types are needed to define and monitor changes in the atmospheric circulation.

The component amplitudes are correlated with temperature and rainfall data, and physically reasonable relationships are identified. The analysis is extended to the period 1781 to 1785, and similarities are found between the extremes experienced during that period and during the 1970s.
Analysis of the spatial pattern of July temperature departures (1943–1972) over Canada and estimates of the 700 MB midsummer circulation during middle and late holocene
Authors: Diaz Henry F. , Andrews John T.
Published: February 2007

The pattern of July temperature variability over Canada north of ∼50°N for the period 1943–1972 has been analysed by means of principal component analysis. Our objective was to assess the spatial similarities between modern temperature fluctuations at the interannual scale and those derived from paieotempe nature records encompassing a period of the last 6000 14C years.

A comparison of the first four principal components from each data set suggests that contemporary midsummer temperature variations offer a reasonable analogue to Holocene fluctuations on the order of a few centuries. The Keewatin‐Baffin Island‐Ungava Peninsula region appears to be within the area of maximum temperature response.
Drought in the United States: 1895–1981
Authors: Karl Thomas R. , Koscielny Albert J.
Published: February 2007

Statewide averages of temperature and precipitation, from January 1895 to April 1981, were interpolated to a grid and Palmer Drought Severity Indices (PDSI) calculated for each of the grid points. Principal component (PC) analysis was performed on the gridded values of PDSI. By rotating the PC, nine readily identifiable patterns of drought are delineated. Each PC relates to different regions of the country, and is characterized by a distinct annual oscillation of monthly average precipitation. A high degree of confidence is placed in the state gridded data as patterns compare favourably to those derived using smaller averaging areas.

Univariate and multivariate autoregressive spectral estimation procedures together with the traditional spectral estimation techniques were used to investigate the spectra and coherence of the PC scores. No significant cycles were found in the 86‐year (1036 months) data set. Coherence was very low (<0.30) for all frequencies between the various patterns depicted by the PC.

Both the spectra of PC scores and drought duration statistics point to the major difference in droughts across the United States; droughts persist much longer in the interior portions of the country than in areas closer to the coasts. Sensitivity tests on the PDSI indicate that this is not directly attributable to the spatially varying available soil water capacity parameter used in the PDSI calculations. This is not to say that soil moisture evaporation does not indirectly influence drought duration, but merely that the differing lengths of droughts in the United States are real and not an artefact of the mechanics in the PDSI calculations.
Climate reconstruction from tree rings: Part 1, basic methodology and preliminary results for England
Authors: Briffa K. R. , Jones P. D. , Wigley T. M. L. , Pilcher J. R. , Baillie M. G. L.
Published: February 2007

Ring widths of oak trees (Quercus petraea Liebl. and Q. robor L.) from a network of 14 sites (13 in the British Isles and one in France) are used to reconstruct spatially‐averaged temperature and rainfall for England. A multiple linear regression technique is used, in which the regressors are orthogonal principal components of the ring widths. The multiple correlation coefficients are, statistically, highly significant, and the regression models' stability has been confirmed using independent data. These results demonstrate the usefulness of tree‐ring widths for climate reconstruction in temperate, maritime areas.
The spatial and temporal characteristics of northern Hemisphere surface air temperature variations
Authors: Jones P. D. , Kelly P. M.
Published: February 2007

The spatial and temporal characteristics of variations in surface air temperature over the Northern Hemisphere landmasses during the present century are determined. The spatial patterns of change accompanying major warming and cooling episodes are mapped. The spatial representativeness of the Northern Hemisphere average is assessed and implications for proxy climate studies are considered. Finally, the seasonal breakdown of trends and correlations between monthly and annual data for the Arctic and Northern Hemisphere is considered.

It is shown that, although generally similar, significant differences in the spatial patterns of change accompanying warming and cooling in the Northern Hemisphere average have occurred. In particular, the early 20th century warming was more coherent spatially (as well as more rapid and stronger) then either the cooling that followed or the recent warming. Various regions tend to vary consistently with the Northern Hemisphere average but the relationships are not as marked or widespread as some investigators have claimed or assumed.

The annual Northern Hemisphere average is shown to be more strongly correlated with late spring and summer temperatures than with winter temperatures (although in the latter season the variability is greatest). Trends in temperature over the Northern Hemisphere have been strongest in April and May, whereas over the Arctic they have been strongest in January. This seasonal distribution may give an indication of the physical mechanisms underlying these climatic variations.
An example of the climatological processing of the atmospheric landscape component
Authors: Prošek P , Brázdil R.
Published: February 2007

The paper describes the methods and main results of processing the atmospheric component of the landscape on the scale of the local climate in the surroundings of the towns of Rosice and Oslavany over an area of about 280 km2.

The analysis of the local climate is based on the results of measurement of the authors' own network of 13 topoclimatic stations and on processing the material from 5 precipitation measuring stations from the network of the Czech Hydrometeorological Institute.

For characterizing the local climate of the studied territory 9 characteristics of the diurnal regime of air temperature and humidity and the annual regime of precipitation were used, for which correlation and regression relations to the parameters of the relief (height above sea level, angle and. azimuth of slope) of the territory studied were determined. Finding the regression relations enabled the extension of point measurements of meteorological elements to the whole area of the territory studied and by means of statistically determined intervals of extremity of the characteristics employed to fill with them the basic information system‐a hexagonal network covering the territory under investigation. This in turn made it possible to outline partial climatomesochores in the territory of interest.

By the summation of the values of selected characteristics of meteorological elements an overall characteristic of the local climate was determined, the so‐called relative climatic potential.
Independence of rainfalls through the rainy season and the implications for the estimation of rainfall probabilities
Authors: Dennett M. D. , Rodgers J. A. , Stern R. D.
Published: February 2007

A detailed study of more than 50 years of daily rainfall records from three sites in seasonally arid West Africa revealed no dependence between rainfall at different times within the rainy season. Years were grouped on the basis of the date of the start of the rains and rainfall models fitted separately to early, medium and late start groups. Any differences between the groups in subsequent rainfall pattern bordered on statistical significance and were too small to be of practical significance. Thus, the best estimates of the probabilities of rainfall events are obtained by considering all years of the rainfall record. As rainfalls at different times of the season can be assumed to be independent, it is straightforward to calculate conditional distributions, for example, the probability distribution of the length of the rains given the actual starting date. The calculation and value of using conditional distributions are discussed.
Rainfall distribution, variability and probability in plateau state, Nigeria
Authors: Odumodu L. O.
Published: February 2007

The basic objective of this investigation is the determination of the spatial distribution of rainfall in Plateau State. Nigeria. The results show that the greatest amounts of rainfall are obtained in the southern and western parts of the State and on the southern and western margins of the high Plateau in particular. This pattern of rainfall distribution is explained partly by the movements and positions of the ITD (intertropical discontinuity) at various times of the year, and partly by the interplay of the direction of rainbearing south‐westerly winds with the physiographic features in the State.

In general, also, the rainfall amounts are higher on the highland parts of the Stale than on the lowlands. Conversely, rainfall variabilities are higher on the lowlands of the State than on the high Plateau. Furthermore, rainfall variabilities are higher at the beginning and at the cessation of rainfalls than in the middle of the rainy season. Examples of implications of high rainfall variability and low probability of receiving certain given threshold amounts of rainfall at different phenological stages of crop developments, are given. These examples serve to substantiate the need for supplementary irrigation facilities in the Slate.
Monthly extreme air temperatures at Rothamsted
Authors: Challenor P. O. , Carter D. J. T.
Published: February 2007

Monthly minimum and maximum air temperatures recorded at Rothamsted in Hertfordshire, England, from 1901‐1978 are analysed using the generalized extreme value distribution. Temperatures with return periods of 50 and 100 years, with their associated confidence limits, are produced for each month. The very low temperatures recorded in December 1981 and January 1982 are considered in the light of these results. The probability of air frost for each month is evaluated. From the distributions of monthly extremes the distributions of annual minima and maxima are derived. The assumptions implicit in the analysis, independence and stationarity, are examined. It is found that the data can be considered stationary in all cases except for the October minima, which appear to have been increasing over recent years. Correlations between monthly extremes are generally low with little discernible pattern, but confidence limits have not been determined.
Quasi‐periodic meteorological series and second‐order autoregressive processes
Authors: Jolliffe Ian T.
Published: February 2007

Quasi‐periodic behaviour in meteorological or climatological series is a widespread phenomenon; various attempts have been made to explain such behaviour in physical terms, often invoking external influences in the explanations. While it is not disputed that external influences or feedback mechanisms may have a part to play, it is argued in the present note that a substantial part of quasi‐cyclic behaviour can often be explained by a simpler mechanism, namely second‐order dependence of a series on its own past. The plausibility of second‐order dependence is discussed, and the way in which such dependence leads to quasi‐periodic behaviour is described. Data on sunspots. Baltic ice area and a zonal circulation index are used to illustrate these ideas.
Water need in provence, Languedoc‐Roussillon (southern FRANCE)
Authors: Giles B. D.
Published: February 2007

The paper considers the water requirements in the south of France. The historical development of water distribution schemes is described before a consideration of the general precipitation distribution in Provence and Languedoc‐Roussillon. The precipitation and potential evapotranspiration (calculated by the Thornihwaite/Mather bookkeeping method) data for 1931–1960 and for 1971–1980 are discussed and compared. A series of diagrams illustrates the monthly variation of surplus, deficit, use and recharge at seven stations over the latter ten‐year period. Maps showing wide variations in surplus or deficit in 1971, 1976 nad 1980 are presented. Finally, the implications of water provision for agriculture and tourism are considered.
The influence of clouds on climate with A focus on high latitude interactions
Authors: Crane K. G. , Barry R. G.
Published: February 2007

The global cloud distribution is recognized as forming a major component of the Earth's climate through its influence on both the energy and moisture exchanges in the earth‐atmosphere system. This review concentrates on the radiative effects of clouds and examines a number of modelling and empirical studies that have addressed the possible significance of the role of cloud cover in climate change. This question is still not fully resolved. One reason for this is inadequate data and, therefore, some of the cloud climatologies available and the associated problems of data collection and interpretation are discussed. The review focuses specifically on interactions at high latitudes and describes recent studies which suggest that there may be a relationship between sea ice extent and cloud cover. Some possible consequences of this are discussed in the context of a high latitude response to climate change.
The distance factor in the relationships between solar radiation and sunshine
Authors: Baker Donald G. , Skaggs R. H.
Published: February 2007

The effect that distance (d) has upon the correlation coefficient (r) obtained between paired radiation (R) and sunshine (S) stations was determined for the North Central region of the United States. Distances between stations varied from 0 to 608 km.

In the regression of r against d three features of interest were found. First, the slope of the annual r values with distance is essentially linear from about 60 to 550 km and equals about −0.12/100 km. Secondly, from d = 0 to 60 km, the value of r remains constant at about 0–88, creating a ‘zone of indifference’ due to inherent differences between radiation and sunshine recording instruments and the insensitivity of the latter. Thirdly, beyond about 550 km the slope appears to reach a constant value, which varies with season but is about r = 0–30 on an annual basis.

Seasonal and geographical differences in the degree of correlation between r and d are noted and discussed briefly.
On the homogeneity of the annual temperature of central England since 1659
Authors: Probert‐Jones J. R.
Published: February 2007

Two statistical models are developed to represent the annual temperature of central England from 1659 to 1973, and two similar models to represent the annual standard error (continentality). From these models, 95 per cent confidence intervals are obtained for the highest and lowest means over periods of 10, 30 and 50 years in a sequence of 315 years. Within the limits of accuracy of both the data and the models, no mean lies outside the confidence intervals, and it is concluded that in terms of both annual temperature and annual standard error the climate of central England is statistically homogeneous over these 315 years. Nevertheless, the 25 year period 1674–1698 was particularly cold, and may possibly represent the end of the ‘little ice age’ if it existed.
Synoptic consideration of snowfall in Athens
Authors: Prezerakos N. G. , Angouridakis V. E.
Published: February 2007

In this paper an attempt is made to study the synoptic evolution of the barometric systems which cause snowfall in Athens. Some simple statistical characteristics of the snowfall in Athens were found and related to the synoptic evolution.

The study is based on the synoptic observations at the Hellinikon Meteorological Station for the period 1956–1973 and upon the mean charts and their anomalies, of 500 mb height, 500–1000 mb thickness and mean sea level (M.S.L.) pressure.

Specifically, we examine the annual and monthly variations of snow days in Athens and their relation to the synoptic evolution of two synoptic types, A and B.

In type A, the centre of action seems to be a quasi‐stationary wedge of a meridional block which, on the 500 mb charts, is located over the British Isles and NW Europe. This wedge is accompanied by a maximum of positive height anomalies and it steers, on its eastern flank, smaller perturbations which reach Greece accompanied by polar or arctic air.

In type B, the centre of action is located over the north of Scandinavia with the form of an Omega block on the 500 mb charts. On the eastern flank of this system, a maximum of vorticity is created moving south‐south‐westwards, arriving over Greece from the northeast.
The influence of weather variability on evaporation leeward of A medium porous barrier
Authors: Rollin E. M.
Published: February 2007

Black porous disc atmometers were used to measure daily evaporation (E) at a distance of 4H (where H is barrier height) leeward of a medium porous hedge and in the open. The modification of E at the sheltered position was defined, in relative terms, as the percentage of the sheltered E to that in the open (relative E) and in absolute terms as the difference between the open and sheltered E totals. Although relative E was found to vary as a linear function of the relative wind (RW), E differences varied also with the meteorological conditions influencing the ‘evaporative climate’, identified here by the weather parameters: cloud cover, relative humidity and wind speed. For a particular value of relative E, the E differences were greatest on days with no cloud, low humidity and moderate wind speed and least on cloudy, humid days with low wind speed.
Comparison of rainfall time series over South Africa generated from real data and through principal component analysis
Authors: Harrison M. S. J.
Published: February 2007

Time series (scores) of rainfall from cloud bands across South Africa, generated through S‐mode principal component analysis, are compared with equivalent estimated time series developed from satellite imagery and surface data. The cloud bands, which link the tropical and temperate circulations, accounted for the highest explained rainfall variance over the interior of South Africa in the principal component analysis. For most summer months the principal component scores are useful first approximations to the true time series.
Method of study and cartography of the potential Sunny periods in mountainous areas
Authors: Bocquet G.
Published: February 2007

In mountainous areas, the duration of sunny periods is an important but often unknown climatic parameter. The difference in amounts of sunshine between exposed and shade sides of mountains must be treated circumspectly, sometimes corrected, for it is dependent on the action of shadows and thus can sometimes reduce the amount of sunshine at a given spot quite considerably.

By using a computerized calculation comparing the apparent movement of the sun and the positions of the summits surrounding a given point, the duration of sunshine at this given point can be calculated for a chosen period of the year.

This same calculation repeated for frequent points within a same area is transferred to a grid. This grid can be used to draw maps of the potential amount of sunshine for that area at a precise date or between two given dates.

This kind of study can be a valuable aid, not only in research into the environment (the amount of insolation is a determining factor in the melting of snow or ice, the evaporation of lakes, the development of vegetation etc.) but also in the planning of an area (solar energy, exposition of buildings in an urban setting, research into sites for new tourist resorts etc.).
Homogeneity analysis of rainfall series: An application of the use of A realistic rainfall model
Authors: Thompson C. S.
Published: February 2007

One approach in the stochastic modelling of rainfall is to derive a distribution function which has physically meaningful parameters. Such a distribution is derived from a Poisson process of rainfall occurrence with an independent exponentially distributed rainfall amount. The distribution appears to fit monthly precipitation totals extremely well.

This type of model has many potential applications in climatology and hydrology. The homogenizing of long term rainfall sequences is one of these, and a methodology for this process is presented here. A 130 year record, from Auckland, New Zealand with three changes of site, is used to evaluate the procedure described.

The significant advantage in the proposed method is that the homogeneity testing is done within the single rainfall record and the use of comparison stations is not required.
July‐August rainfall in West‐Central Kenya
Authors: Davies T. D. , Vincent C. E. , Beresford A. K. C.
Published: February 2007

The annual rainfall distribution in west‐central Kenya (34°−38°E, 1°N–1°S) exhibits marked spatial variation because of the complicated nature of the local topography. The annual distributions are classified into a number of types on the basis of ‘rainfall seasons’. Over parts of the area of study, precipitation falling in July and August makes an important contribution to the yearly total (up to 33 per cent). The spatial variation of the rainfall in this period, during the so‐called ‘dry season’ over much of Kenya (between the two main ‘monsoon’ rains) is examined in some detail, especially its relationship with altitude. The distribution of the July and August rainfall indicates that it is associated with a westerly airstream overlying the lowest layers of the atmosphere.
A statistical evaluation of the efficiency of the climatic normal as a predictor
Authors: Sabin Thomas E. , Shulman Mark D.
Published: February 2007

Monthly and annual temperature and precipitation data were studied to determine the most efficient normal for predictive purposes using root mean square error. The number of years over which the normal was calculated was varied, and the value where the minimum error occurred was found to differ considerably from month to month, but there existed some conformity between stations within the same month.

A Monte Carlo simulation was developed for the above procedure. The simulation of the station relocation for temperature data at Flemington, New Jersey suggested that the relocation could limit the most efficient length of the climatic normal to a shorter period. The results from a simulation of annual temperature trends at New Brunswick, New Jersey closely agreed with those found with actual data. Thus, the low value found for the most efficient normal is largely due to these trends. Relocations were found to have little effect on the most efficient normal for precipitation data.

A modified procedure, varying the number of iterations, showed that RMSE was also dependent on the period of record selected. With this procedure the most efficient normal was found to be between 35 and 40 years for a station with minor relocations, and longer for a benchmark station. In most cases, however, there was little difference between a 10‐year normal and the most efficient normal.
The goodness of fit of the weibull and rayleigh distributions to the distributions of observed wind speeds in a topographically diverse area
Authors: Tuller Stanton E. , Brett Arthur C.
Published: February 2007

The goodness of fit of the Weibull and Rayleigh distributions to the observed wind speed distribution was investigated at seven coastal weather stations markedly influenced by local topography and possessing relatively long periods of record. Wind speeds will he Rayleigh or Weibull distributed if four conditions specifying the circular normal distribution for wind velocity are met. These conditions were not met at the seven stations because of the influences of local topography and storm systems. In all cases the null hypothesis that there is no difference between the Weibull or Rayleigh distributions and the observed distribution had to be rejected with the large sample sizes employed. The transformation of wind velocity involved in deriving the Weibull distribution helps make the distribution more circular normal and the Weibull distribution gave better fits than the Rayleigh distribution. The fits were generally best al those stations with the most circular normal wind velocity distributions and the lowest percentage of calms.
Review article wind climate studies for wecs siting
Authors: Druyan Leonard M.
Published: February 2007

The many considerations which come into play in the determination of sites for wind energy conversion systems (WECS) are synthesized from a cross‐section of the literature. Prevailing strategies select candidate regions from interpolations of existing wind data and narrow the selection according to local terrain and sometimes vegetative and/or geomorphological indicators. The economic success of a WECS project requires that wind characteristics prove better than certain minima so that planners are obliged to apply scrupulous observational and statistical procedures both in making preliminary estimates of the wind climate and, afterwards, in validating the estimates at the chosen final site(s).
Association between summer temperature and precipitation patterns over the great lakes region and water supplies to the great lakes
Authors: Brinkmann W. A. R.
Published: February 2007

Empirical orthogonal function (EOF) analysis was applied to the combined set of summer temperature precipitation over the Great Lake region, and water supplies to the Great Lakes. The purpose of this analysis to determine the association between these three variables. The results show that the predominant association between temperature and precipitation is a negative one, although a positive association is important central and eastern portions of the region. The water supplies to the lakes are more closely associated (positively) with precipitation than with temperature.

Comparison between the results of the EOF analysis of the combined set of temperature, precipitation, water supplies (TPS) and the results of separate EOF analyses of temperature (T), precipitation ( P ), and supplies (S) shows that although the first loading patterns of T, P and S do appear in the combined loading of TPS, they do not appear together in the same pattern of TPS. This result provides further insight into the of the association between these variables.
The southern oscillation over the indian ocean
Authors: Cadet Daniel L.
Published: February 2007

The Southern Oscillation (SO) signal at the surface level over the Indian Ocean is studied during the period 1954‐1976‐ The data set consists of ship observations analysed on a grid mesh of 2 degrees to determine monthly mean fields of wind, pressure, SST. air temperature and cloud cover. Time series of the parameters over different areas show the evidence of an SO signal over the Indian Ocean. Warm and high pressure episodes occur during El Nino event years. High correlation exists between pressure, SST, air temperature fields and the SO index (SOI) north of 10cS. Significant correlation between SOI and cloudiness and zonal wind is mainly found in the eastern Indian Ocean. Composite analysis of he pressure, SST, cloud cover and zonal component of the wind suggests that minimum cloudiness occurs slightly ahead of maximum pressure whereas weaker westerlies over northern Indian Ocean are associated with higher SST a few months later. Power spectral analysis demonstrate the existence of a major periodicity at 40 months, Fields of percentage of variance in the spectral range between 30 and 50 months show a stronger SO signal in the eastern than in the western part of the Indian Ocean, From bandpass filtering and phase spectral analysis of the time series, the phase relationships between the different parameters are determined. Minimum cloudiness occurs with maximum pressure during a phase of decreasing westerlies which reduce the cooling of the ocean and induces an above normal SST and air temperature. The results also suggest the eastward propagation of zonal wind anomalies over the equatorial Indian Ocean. Warmings over the eastern Indian Ocean are occurring simultaneously with the warmings over the Central Pacific Ocean.
A 500 mb synoptic climatology of pacific north‐west coast winters in relation to climatic variability, 1948–1949 to 1977–1978
Authors: Yarnal Brent
Published: February 2007

Within the context of a 500 mb synoptic climatology, relationships between synoptic types and Pacific north‐west coast climatological regimes are investigated. Distinct fluctuations in thermal and moisture trends are identified for the winters of 1948‐1949 to 1977‐1978. Within any one of these climatological regimes, interannual variability in temperature and precipitation is related to the frequency of occurrence of synoptic types associated with warm and wet conditions, respectively. However, the analysis suggests that mixing of data from differing regimes may contribute to within‐type variation, often identified as a major methodological problem in synoptic climatological research.
Principal component analysis of mediterranean rainfall
Authors: Goossens Ch. R.
Published: February 2007

Principal component analysis has been used to group the European Mediterranean stations into homogeneous regions. The annual rainfall records used were from 90 stations distributed all over the European Mediterranean countries.

Major components were selected by a dominant‐variance selection rule, called rule N. The most important component corresponds to a fairly uniform field, the second marks the climatological distribution of cyclonic disturbances, the third shows a gradient from north‐east to south‐west and the fourth exhibits the existence of two centres of anomalies with a negative ridge and a positive value on each side.

A cluster analysis based on these major eigenvectors shows the existence of five climatic regions. A subjective method, using the zero‐line characterizing the significant eigenvectors, shows similar results.