bluuebunny/crossref_metadata_2025_split huggingface dataset:
El Nino/southern oscillation modification to the structure of the monsoon and tropical cyclone activity in the Australasian region
Authors: Evans Jenni L. , Allan Robert J. 
Published: February 2007

AbstractStreamfunction and velocity potential fields, calculated from monthly averaged station data sets, are composited for ENSO and anti‐ENSO extremes in the Australasian region. Four January and four February data sets are used for each of the composites. Gridded sea‐surface temperature (SST) and highly reflective cloud (HRC) data are composited in a similar manner. These data are used to investigate the effect of the phase of ENSO on the Australasian summer monsoon and tropical cyclone activity in the region.Changes in the structure of the monsoon are found to be consistent with composited tropical cyclogenesis and cyclone track data. These effects extend to the north and west of Australia, in addition to the signal previously identified in the Queensland region. During ENSO phases, the summer monsoon trough is weak and displaced equatorward, vertical wind shear is reduced and warmer SSTs are found to the north‐west of Australia and in the central equatorial Pacific. Tropical cyclone activity is reduced to the north‐east of Australia, but increases to the north and north‐west of the continent. Owing to the associated changes in the steering flow, coastal crossings are enhanced in Western Australia and the Northern Territory, but suppressed in Queensland. In the anti‐ENSO composite, the reverse generally is observed. Features specific to the anti‐ENSO are that far fewer storms occur to the north of Australia and storms off the west coast tend to track off‐shore, persisting further south. This southward persistence also is evident on the east coast, but here the likelihood of coastal crossing is enhanced compared with the ENSO composite.
SOI phase relationships with rainfall in eastern Australia
Authors: Stone Roger , Auliciems Andris 
Published: February 2007

AbstractPhases of the Southern Oscillation Index (SOI) have been identified using cluster analysis. The monthly phases are associated with amounts of rainfall expressed in terms of probability distributions for various locations in eastern Australia. The phase representing rapid rise in SOI indicates above median rainfall during Southern Hemisphere autumn and spring at the locations analysed. The phase representing consistently positive SOI generally corresponds with above median rainfall amounts while the phase representing consistently negative SOI corresponds with below median rainfall amounts. As SOI phases relate to actual rainfall amounts, expressed in terms of probability distributions, the phases have, for instance, direct application to agricultural decision support programmes.
The horizontal and vertical extension of the Persian Gulf pressure trough
Authors: Bitan Arieh , Sa'Aroni Hadas 
Published: February 2007

AbstractThe Persian Gulf Barometric Trough is an extension of the south‐west Asian Monsoon. It starts in the middle of June, stabilizing by the end of the month, remaining dominant during July and August and disappears very quickly in mid‐September. Because of its thermal origin its height is limited to about 1500 m. Above it dominates, during the summer months, the subtropical high‐pressure system with its Azores extension covering the Mediterranean region. The transitional zone between these two pressure systems is an inversion zone, whose lower base sometimes reaches the mountain tops of Israel and even lower. On such occasions the daily maximum temperatures are higher at the stations in the mountains than in the coastal plain.Because of its thermal origin, it was expected that diurnal changes of temperature must affect the horizontal and vertical extension of the Persian Gulf Trough. However, the diurnal fluctuations of the pressure are mainly remarkable at stations at the margin of the trough, while at those stations affected directly by it, the daily fluctuations are minimized by irregular periodic changes in the intensity of the Persian Trough occurring every few days. These changes are due mainly to fluctuations of the upper level high‐pressure system. Changes in the position of the Persian Trough influence greatly the daily weather in the Levant.
General circulation model simulations of winter and summer sea‐level pressures over north America
Authors: McCare Gregory J. , Legates David R. 
Published: February 2007

AbstractTemporal variability of synoptic‐scale circulation is a dominant factor in regional temporal climate variations. In the midlatitudes, temporal variability of synoptic‐scale circulation has been found to be related to temporal variations in regional air temperature and precipitation. General circulation model (GCM) simulations of long‐term changes in synoptic‐scale circulation may be useful in assessing the effects of climate change on regional air temperature and precipitation.Atmospheric pressure is an important component of synoptic‐scale circulation. In this paper, observed sea‐level pressures were used to evaluate winter and summer sea‐level pressures over North America simulated by the Goddard Institute for Space Studies (GISS) and the Geophysical Fluid Dynamics Laboratory (GFDL) general circulation models. The objective of the study is to determine how similar the spatial and temporal distributions of GCM‐simulated daily sea‐level pressures over North America are to observed distributions.Overall, both models are better at reproducing observed within‐season variance of winter and summer sea‐level pressures than they are at simulating the magnitude of mean winter and summer sea‐level pressures. Results indicate that winter sea‐level pressures are better simulated by the GISS model than by the GFDL model. The GFDL model simulates anomalously high winter sea‐level pressures over north‐eastern North America. In summer, the GISS model underestimates sea‐level pressures, whereas the GFDL model overestimates sea‐level pressures over most of North America. Kolmogorov‐Smirnov tests indicate that much of the error in model simulations can be attributed to differences between simulated and observed means. Comparisons of spatial correlation matrices of observed and simulated sea‐level pressures indicate that GCMs simulate spatial variability of sea‐level pressures that is similar to observed. These results suggest that GCMs are able to simulate major components of synoptic‐scale circulation over North America, especially for winter.
An analysis of Australian seasonal rainfall anomalies: 1950–1987. I: Spatial patterns
Authors: Drosdowsky Wasyl 
Published: February 2007

AbstractA detailed analysis of the variability of Australian district rainfall on seasonal time‐scales over the period 1950–1987 is described. This paper, Part I, describes the dominant spatial modes or patterns of variability. The major analysis tool is rotated principal component analysis (RPCA), used in both the S and T modes. Various criteria are examined to determine the number of components to rotate, including conducting trial rotations and comparison of the resulting patterns with the corresponding one‐point correlation maps. The stability of the chosen solutions is examined by repeating the analysis on various subsets of the data.The S‐mode analysis, which groups districts with similar temporal variation, provides a regionalization of the continent into eight coherent and approximately equally sized regions. The results of this analysis closely resemble those obtained from cluster analysis.The T‐mode analysis clusters seasons with similar large‐scale spatial variations (anomaly patterns). The similarity measure used in the T‐mode analysis is the congruence coefficient, rather than the correlation or covariance. The patterns produced by this analysis consist of continental‐scale anomalies, similar in some respects to the unrotated S‐mode patterns, but more amenable to meteorological interpretation. In particular the first pattern, which accounts for approximately 25 per cent of the total variance consists of anomalies of the same sign over the entire continent centred on south‐east Australia.The relationship between the two modes of representation is also explored. Regression equations are developed to express the spatially complex T‐mode patterns in terms of the localized S‐mode patterns, and alternatively, to partition the variance of each of the S‐mode patterns between the T‐mode components. In Part II the temporal variability and the relationship of these patterns to the Southern Oscillation and other large‐scale circulation anomalies are examined.
Luni‐solar 18.6‐ and solar cycle 10–11‐year signals in USA air temperature records
Authors: Currie Robert G. 
Published: February 2007

AbstractSpectrum analysis of 1197 USA air temperature records yields evidence for two peaks with periods 18.8 ± 1.7 and 10.4 ± 0.5 years. Tests by the t‐statistic show that both are significant at confidence levels of 99.9 per cent, and both account for 23 per cent of total variance in the raw data. They are identified as the luni‐solar 18.6‐year Mn and solar cycle Sc 10–11‐year signals in climate, induced by the twelfth largest constituent tide acting on the Earth and a variation of 10 to 11 years in the Sun's luminosity of the order of 0.1 per cent. Amplitude and phase of Mn wavetrains are highly non‐stationary with respect to both time and geography; in particular, abrupt 180° phase changes in wave polarity are often observed. Amplitude and phase of the Sc waves are also highly non‐stationary, with those east of the Rocky Mountains out of phase with waves to the west. These results consolidate and greatly extend and clarify earlier studies of Currie based on far less American data.
Synoptic climatology of atlantic coast North‐Easters
Authors: Davis Robert E. , Demme Gregory , Dolan Robert 
Published: February 2007

AbstractA classification of extratropical storms in the north‐western Atlantic Ocean is developed based upon the storm's origin, track, and intensification. All storms producing at least 1.6‐m deep‐water waves at Cape Hatteras, North Carolina from 1943 to 1984 are included. Eight distinct storm types are identified, and their seasonality, interannual variation, and relationship to a previously devised storm‐intensity scale are discussed. The most dangerous storms are cyclones which originate either over Florida or north of Cuba from October through to April, travel northward, and are blocked by a stagnating anticyclone over New England or the North Atlantic. Coastal storm frequencies declined from the mid‐1960s through to the mid‐1970s and increased through to 1984, but the frequency of potentially damaging storms has increased since 1965.
Decreasing precipitation trend in the Marathon area, Greece
Authors: Amanatidis G. T. , Paliatsos A. G. , Repapis C. C. , Bartzis J. G. 
Published: February 2007

AbstractThe long‐term precipitation series (1926–1990) from a 10 rain gauge station network in the Marathon area, Greece, have been statistically examined for trends. Application of the Mann—Kendall rank statistic test to the annual time series revealed a significant decreasing trend in the precipitation over the area. Similar decreasing trends are observed in neighbouring regions to the Marathon area (Athens basin and Beotia). The differences in precipitation trends during the transitional seasons among the three areas seem to be caused by the urbanization process. The seasonal variations and the periodicities of precipitation in the study areas also are examined. Finally, the spatial distribution of precipitation and the relation of precipitation amounts to the station height in the Marathon area are discussed.
The effect of domain shape on principal components analyses: A reply
Authors: Legates David R. 
Published: February 2007

AbstractIn a previous paper, I reevaluated the domain shape dependence arguments of Buell and concluded that ‘unrotated’ principal components do represent, to a very large degree, the underlying structure represented in the dispersion matrix. Richman's comments are largely based as a defence of component rotation—a subject that was not addressed in my original paper. It is my thesis that much of the alleged uninterpretability of ‘unrotated’ components stems from an attempt to retrieve characteristic scenarios or ‘modes of the variation’ (which PCA does not purport to do) and not from an overdependence on the shape of the domain. This misapplication often results from a confusion of the goals of principal components analysis and common factor analysis as is evidenced in Richman's comments.
Monthly‐mean temperature anomalies in relation to spatial scale in Japan
Authors: Murata Akihiko M. 
Published: February 2007

AbstractUsing monthly‐mean temperature data over Japan, the monthly‐mean temperature anomaly (MMTA) is investigated with special reference to its spatial scale. Relationship between occurrence probability of the MMTA and distance indicates that the occurrence probability is almost constant up to around 800 km and then rapidly decreases in magnitude. However, re‐examination of the relationship reveals that the MMTA has a spatial scale of around 1600 km as a minimum, which corresponds to the macro β or α scale. In addition to this principal investigation, seasonal dependence and temporal changes of the MMTA are also investigated.
Class—A Canadian land surface scheme for GCMS, II. Vegetation model and coupled runs
Authors: Verseghy D. L. , McFarlane N. A. , Lazare M. 
Published: February 2007

AbstractIn the companion to the present paper, the soil model associated with CLASS (Canadian Land Surface Scheme) was outlined. In this paper, the accompanying vegetation model is described. This model includes physically based treatment of energy and moisture fluxes from the canopy as well as radiation and precipitation cascades through it, and incorporates explicit thermal separation of the vegetation from the underlying ground. Seasonal variations of canopy parameters are accounted for. The morphological characteristics of the ‘composite canopy’ associated with each grid square are calculated as weighted averages over the vegetation types present. Each grid square is divided into a maximum of four separate subareas: bare soil, snow‐covered, vegetation‐covered, and snow‐and‐vegetation covered.Test runs were done in coupled mode with the Canadian Climate Centre GCM, to evaluate the performance of CLASS compared with that of the simpler land surface scheme previously used. Two versions of CLASS were run: one with ponded surface water saved between time steps, and one with it discarded. For the seasons of June—July—August and December—January—February, diagnostic calculations showed that the old scheme underestimated the globally averaged land surface screen temperature by as much as 3.0°C, and overestimated the globally averaged precipitation rate over land by up to 1.0 mm day−1. CLASS, on the other hand, produced screen temperature anomalies, varying in sign, of 0.2–0.3°C, and positive precipitation anomalies of 0.6–0.7 mm day−1. The relatively poor performance of the old model was attributed to its neglect of vegetation stomatal resistance, its assumption that the contents of the soil moisture ‘bucket’ had to be completely frozen before the surface temperature could fall below 0°C, and its use of the force‐restore method for soil temperatures, which systematically neglects long‐term thermal forcing from the soil substrate. The assumption made in most GCMs that excess surface water immediately becomes overland runoff is shown to result in substantial overestimates of surface screen temperatures in continental interiors.
Variations of some seasonal rainfall characteristics in Queensland, Australia: 1921–1987
Authors: Lough J. M. 
Published: February 2007

AbstractSummer and winter indices of rainfall total, intensity, and contributions of rain‐days of different intensities were developed from 70 stations in Queensland over the period 1921–1987. In both summer and winter, only a few days of relatively high intensity rainfall contribute most to the seasonal rainfall total. In wetter summers, although the numbers of rain‐days of different magnitude rainfall all increase, it is days with rainfall in excess of 50 mm day−1 that contribute most to the increased seasonal total. Year‐to‐year and longer time‐scale variations in seasonal rainfall totals are matched by similar variations in secondary rainfall characteristics, i.e. wetter years or periods are likely to have more rain‐days and rainfall of greater intensity than drier years or periods. Variations of the secondary rainfall characteristics show similar relationships with the Southern Oscillation as total rainfall. The correlations with the SOI are, with one exception, insignificant for the period, 1921–1950, of ‘weak’ SOI teleconnections. Only the date by which 15 per cent of the summer seasonal rainfall is accumulated (representing pre‐monsoon rainfall) has maintained a significant and stable relationship with the SOI over time. Rainfall in Queensland is more closely linked with the number of tropical cyclones actually making landfall than the total number of cyclones in the region. Even in years when the large‐scale circulation is not conducive to tropical cyclone activity, a single tropical cyclone crossing the coast can lead to substantial rainfall amounts.
The random nature of drought: Mathematical and physical causes
Authors: Gordon A. H. 
Published: February 2007

AbstractAnnual and monthly rainfall records for three regions of the United Kingdom and five locations in Australia have been examined with specific regard to the frequencies of droughts and dry spells. It is shown that plots of cumulative totals of precipitation tend to obey are sine law behaviour and the excursions above and below the × axis fall within the limits of patterns to be expected by chance.Runs of successive values of negative anomalies from the monthly median were counted and their mean and theoretical recurrence times computed. Chi‐square tests suggested that the frequencies of runs were no more nor less than might be expected from chance expectation in the United Kingdom. In Australia the frequencies in the Perth, W. A., Adelaide, S. A., and Hobart, Tasmania records showed similar characteristics to those in the United Kingdom. However in Melbourne and Sydney the frequencies of runs of negative anomalies from the monthly median showed high significance > 1% that they were more frequent than would be expected. This higher than expected frequency of droughts and dry spells is attributed to the ENSO factor. It is suggested that overall the occurrence of precipitation events is a chance mechanism although some regions, notably southeast Australia, northeast Brazil and the Sahel are affected by climatically forced mechanisms such as sea surface temperature anomalies, blocking, over grazing etc. A discussion is offered of the meaning of “naturally” occurring drought in terms of physical interactions described by nonlinear mathematical equations and alternatively in terms of casino probability.
A comparison of Lamb circulation types with an objective classification scheme
Authors: Jones P. D. , Hulme M. , Briffa K. R. 
Published: February 2007

AbstractAn objective scheme, initially developed by Jenkinson and Collison, is used to classify daily circulation types over the British Isles, along the lines of the subjective method devised by Lamb. The scheme uses daily grid‐point mean sea‐level pressure data for the region. The results of the analysis over the period 1881–1989 are compared with ‘true’ Lamb weather types. The frequencies of objectively developed types are highly correlated with traditional Lamb types, especially so for synoptic (cyclonic and anticyclonic) types, although still good for wind directional types. Comparison of the two classification schemes reveals negligible differences between the correlations of the counts of circulation types and regional temperature and rainfall. The major difference between the two classification schemes is that the decline of the westerlies since 1940 is less evident with the objective scheme.
Deterministic signals in European fish catches, wine harvests, and sea‐level, and further experiments
Authors: Currie Robert G. , Wyatt T. , O'Brien Douglas P. 
Published: February 2007

AbstractMaximum entropy spectrum analysis of six fish catch series, seven series giving dates of wine harvest, and forty four height of sea‐level records from Europe yields evidence for two peaks with periods 18–19 and 10–11 years, the same terms recently reported in European tree‐ring chronologies. For each series the two wavetrains are obtained by bandpass filters, summed, superimposed on the trend‐like components of the raw data, and plotted against the raw data. The contribution, on average, of the waves to total variance in the raw data varies from a high of 50 per cent for fish catches to a low of 14 per cent for dates of wine harvest (the mean contribution for height of sea‐level is 18 per cent). The peaks are identified as the 18·6‐year luni‐solar, Mn, and 10–11‐year solar cycle, Sc, signals, which also have been reported recently in other climate variables, such as air temperature, air pressure, in rain‐gauge and tree‐ring data from North and South America, South Africa, Tasmania, and New Zealand; and in sea‐surface temperature as well as in American crop yield and other economic data. Further experiments show that with 110 years, or more, of data the Yule‐Walker method of spectrum analysis has sufficient resolution to resolve both signals. It is also shown that failure to apply a properly designed digital high‐pass filter to climate records prior to spectrum analysis usually leads to failure in detecting the terms.
Spectral band resolution of solar radiation in Athens, Greece
Authors: Jacovides C. P. , Kallos G. B. , Steven M. D. 
Published: February 2007

AbstractA 14‐year (1977–1990) record of global solar radiation measurements performed in Athens, Greece, has been utilized to determine the distribution of radiant energy in the various wavelength bands. The monthly mean values of the irradiation ratios in the spectral intervals, blue (0·380–0·525 μm), green‐orange (0·525–0·630 μm), red (0·630–0·710 μm), and photosynthetically active radiation (PAR) (0·380–0·710 μm) and the global irradiation (0·3–2·8 μm) compare favourably with values reported in the literature for different locations over a wide geographical area.The irradiation ratios exhibit seasonal variations attributable to changes in local air‐mass climatology. It is observed that the proportion of the radiant energy in the various spectral bands relative to the global solar irradiation increases as sky conditions change from ‘clear’ to ‘partly cloudy’. Finally, the observed seasonal dependence of the broad‐band spectral energy distribution is essentially caused by changes in the composition of the air masses (turbidity, airborne pollutants, clouds) in residence at the measurement site in the course of the year.
A preliminary assessment of the spatial and temporal characteristics of human comfort in China
Authors: McGregor Glenn R. 
Published: February 2007

AbstractA simple empirical index of human thermal comfort is applied to the problem of assessing China's human climate resource. Considerable spatial and temporal variation of the human climate resource occurs in China. The human climate resource is discussed in terms of its synoptic‐scale climatic controls and the implications the spatial and temporal variations of the resource holds for the rapidly developing tourist industry in China.