bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heavy rainfalls over East Asia
Authors: Matsumoto Jun 
Published: February 2007

AbstractThe mean annual and monthly frequency distribution of heavy rainfalls for the period 1971–1980 are investigated over the whole of East Asia, including Japan, China, Korea, USSR, and Hong Kong. The highest frequency region (< 10 times per year) is shown to be located along the southern coast of Japan. The second highest region (< 8 times per year) is located along the southern coast of China. The high‐frequency area advances northward over China during the summer monsoon season, in accordance with the northward advance of the ‘Mei‐yü frontal zone’. Maps of the axes of high‐frequency heavy rainfall areas (frequency per 10‐day period) and of maximum‐frequency 10‐day periods at each station, clearly reveal the intra‐seasonal shift of the heavy rainfall area during the summer monsoon season.According to the dominant causes of heavy rainfalls, four regions are identified. The investigated area is also divided into three regions (I‐III) with respect to the annual frequency distribution of heavy rainfalls. Based on these regional divisions, the northern limit of the influence of the ‘Mei‐yü front’ is determined in terms of heavy rainfall occurrence.
Morphology of bistable 180° phase switches in 18.6‐year induced rainfall over the north‐eastern United States of America
Authors: Currie Robert G. , O'Brien Douglas P. 
Published: February 2007

AbstractUsing a novel data presentation technique, bistable 180° phase switches in 18.6‐year induced precipitation over the northeastern United States of America are re‐examined. It is found that bistable switching in 19‐year wavetrains occurred principally at epochs 1898–9, 1917.5, and 1954.7, although some occurred at mid‐epoch 1908–2, and at epochs 1936.1 and 1973.3 (epochs are dates of maximum in the luni‐solar 18.6‐year tide). The 180° phase switch at 1898.9 occurred along the northern Atlantic seaboard, and by epoch 1954.7 this invading ‘cell’ from the east blanketed virtually the entire region. O'Brien and Currie (1988) have provided a construct in mathematical physics which can explain how such sudden readjustments in the standing wave pattern for air pressure occur on subcontinental scales, and such adjustments are found in other climatic parameters such as air temperature and pressure. Results for seven tree‐ring chronologies in the region are also given, and are found to have serious inconsistencies both among themselves and also with respect to instrumental rain‐gauge data.
A five‐year radar climatology of convective precipitation for New Jersey
Authors: Croft Paul J. , Shulman Mark D. 
Published: February 2007

AbstractA radar climatology of convective precipitation for New Jersey during the summer season (May‐September) was developed using manually digitized radar (MDR) data from four local radar sites. Convective precipitation frequencies were determined by tabulating occurrences of echo intensity levels equal to 2 or more for each of 63 grid boxes located in and around New Jersey. Convective precipitation frequencies over a 5‐year period (1978–1982) were plotted by grid box, and isopleths of duration and intensity level were constructed. The distribution of the frequency of occurrence of convective activity was examined for thunderstorm (level 3 or more) occurrence and severe thunderstorm (level 5 or more) occurrence. The highest convective frequencies occurred over south‐eastern Pennsylvania while the greatest frequency of more intense convection occurred over south‐central New Jersey. An analysis of variance (ANOVA) was performed on the data set to determine the relative variability of convective precipitation in the grid. Year‐to‐year and week‐to‐week variability was high whilst intergrid‐box variability was low. Duncan's multiple range test (DMRT) was applied to compare individual years to each other, and individual weeks to each other. When grid boxes were assigned to four climatological regions and DMRT applied, some regions were found to be significantly different from one another. No significant differences were found between grid boxes within each region. There was no interaction between grid regions and years as differences in mean convective activity between regions remained generally constant from year to year. The distribution of convective activity over New Jersey was found to be determined by local climatological factors while the total frequency from year to year was determined by the mean synoptic pattern.
Reconstruction of New Zealand summer temperatures to 1730 ad using dendroclimatic techniques
Authors: Norton D. A. , Briffa K. R. , Salinger M. J. 
Published: February 2007

AbstractThe first statistically calibrated and verified reconstructions of past New Zealand temperatures are presented. The reconstructions of summer (December‐March) temperature are derived from a grid of ten subalpine Nothofagus menziesii (Hook. f.) Oerst. and N. solandri (Hook. f.) Oerst. tree‐ring chronologies using dendroclimatological techniques. A regression model where climate in year i is estimated as a function of tree growth in years i−1, i and i + 1 for each chronology is used. Two reconstruction models are developed (for 1853–1915 AD and 1916–1979 AD) and account for 55 per cent and 66 per cent of the temperature variance respectively. Verification of these models accounts for 34 per cent and 42 per cent of the temperature variance over an independent time period. Analysis of the spectral properties of the reconstructions indicates that relatively short‐period variability (<30 years) is better reconstructed than is longer period variability (>60 years). The reconstructions, extending back to 1730 AD, provide statistically reliable estimates of annual to decadal temperature variations. The relative coolness of the 1780s and late 1840s and warmth of the 1750s appear to be notable features of the reconstruction. The reconstructions indicate a far more complicated sequence of palaeotemperature variations than have previously been inferred for New Zealand.
Ocean‐atmosphere interactions in low‐latitude Australasia
Authors: Allan Robert J. , Pariwono John I. 
Published: February 2007

AbstractAn analysis of ocean‐atmosphere interactions in low‐latitude Australasia is undertaken using simultaneous and lagged cross correlations and with reference to specific El NiñTo/Southern Oscillation (ENSO) and anti‐ENSO episodes during the period 1964–1983. Major emphasis is placed on the relative importance of wind‐stress‐sea‐surface‐temperature (SST) mechanisms and cloudiness‐radiation mechanisms, and the possible influence of SST advection, oceanic mixing, Indonesian throughflow, and low‐frequency forcings on ocean‐atmosphere couplings in the region.The evolution of ENSO events in Australasia is usually marked by a distinct alternation from anti‐ENSO to ENSO conditions. Ocean‐atmosphere dynamics, involving primarily wind and radiative forcings, have been seen to be linked to such developments. However, SST advection and oceanic mixing are also found to play integral roles in forcing and feedback processes. Thus anti‐ENSO (ENSO) events are marked by easterly (westerly) wind‐stress anomalies in the western equatorial Pacific, southerly (northerly) wind‐stress anomalies in eastern Indonesian and eastern Coral Sea regions, +(−)SST anomalies and weak (strong) SST advection in northern Australian waters, positive (negative) cloudiness anomalies over Australasia and high (low) sea‐level anomalies at southern Philippine and northern Australian stations. There are also indications that ENSO‐like conditions can develop in Australasia with no apparent events in the wider Pacific basin. However, there seems to be no conclusive evidence for the influence of oceanic throughflow on ocean‐atmosphere interactions, and thus ENSO or anti‐ENSO phases. Nevertheless, there are indications that Indonesian throughflow is modulated by remote low‐frequency forcings that are also apparent in SST anomalies in northern Australian waters.The potential for precursors of ENSO and anti‐ENSO events in the Australasian region is high. All of the parameters examined in this study show significant lead/lag correlations, with the strongest persistence generally centering on the Southern Hemisphere winter‐spring period.However, further investigation of potential and suggested links with coherent precipitation patterns over the region is still required. Moreover, any future developments in our understanding of ocean–atmosphere interactions in Australasia will need to address the general problem of establishing and maintaining extensive data networks.
The influence of long‐range transport of air pollutants on summer visibility at Dublin
Authors: Leavey Maurice , Sweeney John 
Published: February 2007

AbstractPhotochemical air pollution has recently been identified as a European as well as North American phenomenon. This paper examines periods of visibility reduction at Dublin Airport and suggests that summer hazes are associated with long‐range transport of pollutants from continental and British sources. Back trajectory analyses of air masses during a number of episodes appear to imply that transport beneath a stable, inverted layer may occur in certain meteorological circumstances, particularly involving passage over a cool sea surface. Major donor areas are probably in the Paris Basin, Ruhr, Low Countries, the English Midlands and London area.
A contribution to the study of action centres in the North Atlantic
Authors: Sahsamanoglou H. S. 
Published: February 2007

AbstractThe North Atlantic High appears notably weakened from the beginning of the examined period (1873–1980) until the beginning of this century. From then until 1930, it exhibits an increased central pressure. From the beginning of the period until 1914, the North Atlantic High exhibits a significant trend of intensification and at the same time a trend of displacement to the west. From 1915 until 1963 it exhibits a trend of weakening and a trend of eastward displacement. The North Atlantic Low has not exhibited a significant trend of its central pressure, but it has shown a small trend of displacement to the west. There is generally a negative correlation between the pressures of these two centres of action and a positive correlation between latitudinal position of the centres. The meridional component of the pressure gradient created between the two action centres, appears to have low values during epochs of low frequency of westerlies and high values when the westerlies are more frequent.
The role of radiation geometry in the climate response of Mount Kenya's glaciers, part 3: The latitude effect
Authors: Kruss Phillip D. , Hastenrath Stefan 
Published: February 2007

AbstractTwo earlier papers in this series investigated the role of solar radiation geometry in defining the glacier climate of Mount Kenya from the references of both horizontal and sloping surfaces. The present study examines the effect of latitude through a series of model simulations for clear‐sky conditions. This study answers the question about whether sloping or horizontal surfaces are the most appropriate for climatic heat and mass budget studies of glaciers throughout the region from 0° to 60° latitude, and also investigates, in quantitative terms, the latitude‐forced changes in radiation amount reaching high mountain glaciers owing to geometry effects. While preserving mountain topography, calculations were performed successively for the Equator, 15°, 30°, 45°, and 60°N and S. For the mountain as a whole, values tend to be larger for horizontal than for sloping surfaces, except for the domains poleward of 45° latitude. The altitudinal variation of radiation is, for the true equatorial location of Mount Kenya, characterized by an overall decrease upward, for both horizontal and sloping surfaces, as a consequence of the topographic obstruction increasing from the peripheral towards the central higher portions of the mountain. The altitudinal pattern changes with latitude, such that at 60°N radiation increases towards higher elevation bands, which are better exposed when solar elevation angles are low. Similar to results for the complete mountain, for the extremely steep southward facing Diamond Glacier, radiation drops off from the Equator towards the higher latitudes of the Southern Hemisphere, with values smaller for sloping than for horizontal surfaces. In the Northern Hemisphere, by contrast, the Diamond Glacier surface is most favourably oriented for radiation around 30–45°N. The latitude effect on the mountain climate is moderate within the tropical belt, while substantially different radiation characteristics result with a shift to high latitudes. Overall it is found that the use of a horizontal reference surface is as good an approximation, and typically an even more acceptable one, at higher latitudes than at the Equator. This is not so for only the steepest of glaciers.
Mixed analog/persistence prediction of seasonal mean temperatures for the USA
Authors: Livezey Robert E. , Barnston Anthony G. , Neumeister Brian K. 
Published: February 2007

AbstractThe operational analog prediction system used as input to official USA seasonal temperature category forecasts was modified to produce anomaly forecasts instead of most probable class forecasts. These modified forecasts led to more conservative predictions, but were more reliable for above‐and below‐normal classes. They were subsequently combined with persistence forecasts in a variety of objective ways in the hope of producing forecasts more skilful than either input. Several versions of two basic mixing approaches, bivariate linear regression and persistence plus analog‐predicted change, were tried. All combined schemes were, overall, more skilful than either of the component schemes. Bivariate linear regression slightly outperformed persistence plus analog‐predicted trend. The former was most skilful when use of the regression forecast was limited to cases where the regression coefficient for the analog term was positive and significance tests were passed at least to a minimal extent in a cross‐validated examination of the regression equation.
Convection and rainfall over Mexico and their modulation by the Southern Oscillation
Authors: Cavazos Tereza , Hastenrath Stefan 
Published: February 2007

AbstractThe role of the Southern Oscillation (SO) in the interannual variability of convection and rainfall over Mexico is studied by correlation analysis of long‐term precipitation records, a satellite‐derived set of highly reflective clouds (HRC), upper‐air soundings, surface ship observations, and an SO index defined as high for anomalously high low pressure at Tahiti/Darwin.Highly reflective clouds and rainfall have a similar annual cycle and interannual variability, except in certain regions and seasons with prevalence of stratiform cloudiness. During the boreal winter (November‐April) dry season, the low SO phase (or El NiñMo) is, in much of the country, characterized by increased precipitation associated with the enhanced influence of mid‐latitude westerlies. However, in the Isthmus of Tehuantepec, most exposed to Norte invasions, precipitation is larger in the high SO phase. During the boreal summer (May‐October) rainy season, precipitation is more abundant in the high SO phase, when the northward retraction of the North Atlantic High, weaker trades, and a northward displaced near‐equatorial trough are conducive to enhanced ascending motion over the area.
Analysis of the Kuwait city urban heat island
Authors: Nasrallah Hassan A. , Brazel Anthony J. , Balling Robert C. 
Published: February 2007

AbstractTwenty‐three years of maximum and minimum air temperature data are analysed for selected stations in and near Kuwait City, Kuwait. The results of a series of statistical analyses reveal the general lack of a well‐developed heat island in this rapidly expanding urban area. This finding is in stark contrast to the identification of large heat islands in the growing arid‐land cities of North America. The similarities in the urban‐rural landscape of the Kuwait City environment and its close proximity to a large water body are suggested as explanations for the observed temporal and spatial temperature patterns.
Low‐latitude volcanic eruptions and the El Niñmo/Southern Oscillation: A reply
Authors: Nicholls N. 
Published: February 2007

AbstractThe Handler‐Andsager hypothesis that low‐latitude eruptions are the “only cause” of El NiñMo events is tested by examining El NiñMo events and low‐latitude eruptions case‐by‐case. This examination confirms that low‐latitude eruptions are not the only cause, or probably even a cause of El NiñMo events. The Handler‐Andsager hypothesis can, at best, account for about one quarter of the El NiñMo events of the past fifty years, and none of the strong events. There is conclusive evidence from stratospheric data that at least some El NiñMo events were not caused by low‐latitude eruptions. Some of the eruptions composited by Handler and Andsager occurred after the start of El NiñMo events and could not, therefore, be the cause of these events. The case‐by‐case examination reveals the dangers of uncritical acceptance of composites.
The CFC greenhouse potential of scenarios possible under the montreal protocol
Authors: Bach Wilfrid , Jain Atul K. 
Published: February 2007

AbstractMeasurement campaigns have given concrete evidence of serious ozone destruction both over the Antarctic and the Arctic regions. This has spawned international action for the protection of the ozone layer, such as the Vienna Convention in 1985 and the Montreal Protocol in 1987. Current chlorofluorocarbon (CFC) reduction plans are, however, inadequate. Therefore, a strengthening of the Protocol's provisions is intended for 1990. The urgency of the Protocol's revision gains strength by the fact that the ozone depleting CFCs have also a strong greenhouse potential, thereby contributing significantly to climatic change.In this paper we consider five CFC production and emission scenarios (scenarios A‐E) that are possible under the Protocol's provisions, and two phase‐out scenarios by 2000 and 1996, respectively (scenarios F and G). The possible global mean surface temperature changes are calculated with the parameterized form of a one‐dimensional radiative‐convective model from 1986 to 2050 for the five CFCs (11, 12, 113, 114, and 115) controlled by the Protocol, eight additional CFCs, some of which could be used as possible substitutes, and the main greenhouse gases CO2, CH4, N2O. The key findings are as follows. Without control, in 2050 the equilibrium global mean warming due to the five CFCs could rise sixteen fold above the 1985 vulue. The present Protocol provisions would still permit two to nine times higher equilibrium temperatures than today. A phase‐out by 2000 and 1996 would, over the period of 1986–2050, result in a reduction from the present equilibrium temperature change of 9 and 18 per cent, respectively. In addition, the other CFCs (e.g. CCl4, CH3CCl3, HFC‐22) may add significantly to global warming and thus should also be controlled. The high greenhouse warming potential provides another strong motive for the necessity of a phase‐out of all ozone‐depleting CFCs.
Decadal‐scale changes of the circulation in the tropical atlantic sector associated with Sahel drought
Authors: Hastenrath Stefan 
Published: February 2007

AbstractTrends in the general circulation setting during 1948–1983 accompanying the progressive aggravation of drought in sub‐Saharan Africa are investigated from ship observations over the tropical Atlantic and surface station records in western Africa.Decadal‐scale circulation changes in the Atlantic sector include a pressure rise over the tropical North Atlantic; southward displacement of the near‐equatorial wind confluence and associated maximum cloud belt; acceleration of the north‐east trades and possibly a strengthening of the South Atlantic trades, along with increasing cloudiness in the equatorial zone; increasing cloudiness over the tropical North Atlantic and Central American seas; and cooling of surface waters in a band across the tropical North Atlantic contrasting with warming in the South Atlantic. These changes occurred in all seasons, but were most pronounced at the height of boreal summer.Records at land stations in western Africa show that near the coasts the temperature and pressure trends are consistent with the adjacent ocean areas. In the interior of sub‐Saharan Africa, warming trends prevail in boreal summer, presumably as a direct consequence of reduced inflow of cool maritime monsoon air; the concomitant downward pressure trends at continental stations in sub‐Saharan Africa may reflect the hydrostatic effect of increasing temperature. In contrast to boreal summer, slight cooling trends and pressure rises prevail in the interior during winter.In the course of the past four decades, the near‐equatorial wind confluence over the eastern Atlantic migrated southward by 200 km in July–August and 150 km for the rainy season as a whole. Given the steep meridional precipitation gradients across the Sahel, these circulation shifts are large enough to account for the observed downward trend in Sahel rainfall.
Regionalization and spatial estimation of ethiopian mean annual rainfall
Authors: Eklundh Lars , Pilesjö Petter 
Published: February 2007

AbstractThis study aims at developing methods that will lead to the generation of a reliable mean annual precipitation data base for Ethiopia. Multiple regression models have been formulated that explain the mean annual rainfall as a function of elevation and geographical location. The estimations, based on yearly values from a data set of 63 Ethiopian rainfall stations with records between 1969 and 1985, were developed for the whole country as well as for the already existing Food and Agricultural Organization (FAO) rainfall pattern regions and a new zonation derived by principal component and common factor analyses (PCA/CFA). In the PCA/CFA study, monthly rainfall values between 1968 and 1985 for 43 stations were used. The optimal zonation was derived by testing 36 different combinations resulting in different rainfall pattern regions. The alternatives tested were: correlation and covariance dispersion matrices, PCA and CFA eigentechni‐ques, unrotated and rotated (Varimax and Direct Oblimin) components/factors and number of possible significant components/factors (3, 7, and 11). Principal component analysis of covariance matrix, Varimax rotation and seven extracted components gave by far the best relationship between mean annual rainfall, elevation, and geographical location. Models explaining at least 72 per cent of the variation in rainfall were constructed for regions covering about 98 per cent of the country, which is better than models based on the FAO rainfall pattern regions (69 per cent explained variation for 81 per cent of the country) and a model for the whole country (66·5 per cent explained variation).