bluuebunny/crossref_metadata_2025_split huggingface dataset:
The nature and development of rainstorms in Coastal East Africa
Authors: Sumner G. N. 
Published: February 2007

AbstractUsing data for a 29‐month period from an intense network of extended scale autographic raingauges at Dar es Salaam, various different storm types are identified, which are thought to be representative of the East African coast as a whole. The primary means of identification of storm types were storm morphology, mode of development and movement. Three major storm groups are proposed: (i) linear storms which develop parallel to the coast along sea or land‐breeze fronts, (ii) smaller elliptical outbreaks developing in situ, and (iii) small, moving elliptical ‘air mass’ storms apparently associated with the prevailing trade wind circulation. A fourth but far less numerous group is composed of large, often heavy, amorphous storms whose origins probably lie with larger‐scale tropospheric perturbations, rather than with local causes.
Annual rain‐water over India, its variability and impact on the economy
Authors: Mooley D. A. , Parthasarathy B. , Sontakke N. A. , Munot A. A. 
Published: February 2007

AbstractThe total volume of rain‐water over India has been computed for each of the years during the period 1871‐1978 on the basis of the rainfall data for a fixed network of 306 raingauges. The mean, the standard deviation and the coefficient of variation of the series of annual rain‐water volume are 3143 km3, 300 km3 and 9.5 per cent, respectively. The series is homogeneous and random. The serial correlation is 0.013 which is too low to suggest any relationship between successive terms. Gaussian distribution gives a good fit to the series.The series giving the percentage area of the country with a deficiency of 20 per cent or more, as well as the percentage area with an excess of 20 per cent or more have been obtained. These bring out the variability in the deficiency and excess of rain‐water over the country during the period. The years of well‐marked rain‐water deficiency/excess over India have been identified by utilizing the criterion of 40 per cent or more area under rain‐water deficiency/excess. The occurrence of such years has been found to be random and the number of such years in five‐year periods appears to be distributed in accordance with the Binomial and the Poisson Probability models.The impact of marked deficiency/excess on the All India Index of food grain prices and All India Index of food grain production has been examined. It is found that the impact of well‐marked deficiency can generally be seen clearly but that of well‐marked excess is seen clearly in some cases only. This is understandable. Overall excess in a year may or may not result in floods which have the potentiality to damage crops. The impact of the well‐marked deficiency of 1918 has been maximum.Remedial measures which would make the economy of the country less dependent on the variability of the annual rain‐water have been discussed.
The nature and impact of Hurricane Allen—August 1980
Authors: Oliver J. 
Published: February 2007

AbstractHurricane Allen threatened to be a storm of devastating potential in the Caribbean and on the Gulf coast of Texas or Louisiana. Although it deepened on three occasions to the intensity of a category 5 storm on the Saffir‐Simpson Scale, its track was such that the islands escaped the worst possible effects. By the time it had reached close to the Texas coast the storm had started to fill. Storm surge damage was the major cause of damage, though locally in the Caribbean islands and to some extent in Texas, this was compounded by wind and/or rain effects. The forecasts gave a clear indication of the magnitude of the impending threat and, except in Haiti, the loss of life was fortunately very small. The track, the variations in intensity and the landfall were predicted efficiently and errors in track positions were smaller than the longer period averages for different forecast periods for other tropical cyclones.
Nature and possible causes of droughts on the canadian prairies‐case studies
Authors: Dey B. 
Published: February 2007

AbstractThere has been increasing interest in recent years in the study of droughts because of their economic, social and political impacts on society. Two summer droughts that affected the Canadian Prairies in 1961 and 1967 are examined. Based on a synoptic climatological approach, the investigation reveals that droughts occurred when the weather type WR (mid‐tropospheric ridge dominant) was persistent with a ridge over western Canada. A study of the 1976–1977 winter drought supports this interpretation. In all three cases, a quaststationary mid‐tropospheric ridge over western Canada acted as a block which displaced the jet stream, cyclones and moist air masses to a location north of the Canadian Prairies, while anticyclonic circulation under the high pressure ridge gave atmospheric stability and dry conditions on the Canadian Prairies.
The southern oscillation: Sea surface temperature and wind relationships in a 100‐year data set
Authors: Newell Reginald E. , Selkirk Rennie , Ebisuzaki Wesley 
Published: February 2007

AbstractThe development of sea surface temperature (SST) and surface wind anomalies during the course of the Southern Oscillation is examined with a 100‐year data set covering most of the Pacific Ocean region. Correlation coefficients of SST and winds with Wright's (1975) Southern Oscillation Index (SOI) are presented for lags and leads up to four seasons relative to the Index. The primary SST response is in the eastern and central equatorial ocean, the regions usually associated with the El Nino phenomenon, but there are important SST and wind changes elsewhere in the Pacific. Significant precursors in the SST include warming (cooling) in the northwest subtropical Pacific up to one year preceding positive (negative) SOI and like‐signed anomalies near New Guinea one season later, in addition to the cooling (warming) along the Chilean coast and in the eastern equatorial region beginning 3 seasons before positive (negative) SOI. (Positive SOI corresponds to pressures higher than average over the south‐east Pacific and lower than average over the western equatorial Pacific.) The major wind response is an area of easterly (westerly) anomalies in the central and western equatorial ocean beginning (in the latter portion) north of the equator 2 seasons before positive (negative) SOI. There is evidence for increased (decreased) westerlies in the southern mid‐latitudes as well as easterly and southerly (westerly and northerly) anomalies in the southeast subtropics 1‐3 seasons before positive (negative) SOI. For both SST and surface winds, little seasonal dependence of the correlation results is found for the equatorial anomalies, but in the Indonesian‐New Guinea region positive correlations are found in the latter portion of the year; mid‐latitude SST anomalies in both hemispheres are restricted to June to August.The mechanisms that determine the response of the SST and winds to the SOI are examined and compared with the factors that control the seasonal cycle in selected regions. Subtropical precursors to positive SOI are consistent with enhanced subsidence, higher anticyclonic vorticity and stronger oceanic gyres. Advection seems to account for the spreading of the SST anomalies westward along the equator. SST anomalies in the Indonesian region may be due to solar radiation changes accompanying cloud cover variations.
Spatial and temporal aspects of the surface wind regime on the canterbury plains, New Zealand
Authors: McKendry Ian G. 
Published: February 2007

AbstractSeasonal and diurnal patterns produced by the interaction of synoptic scale winds and two thermo‐topographic systems, the land/sea breeze and mountain/plain winds, are investigated in a spatial context. Together with gradient winds and the shallow ‘lee trough’ north‐easterlies these local winds create a wind regime composed of several distinctive regional element, the boundaries of which are transitional in nature and dependent on time day and year and the strength of synoptic influences. The sea breeze maximum frequency by day in summer in coastal areas whereas katabatic flows are most frequent by night, in winter adjacent to the Alps. Banks Peninsula strongly influences the wind regime by funnelling north‐easterly airflow onto the plains and possibly creating a zone of sea breeze convergence extending inland. South of Banks Peninsula the interaction of onshore wind components with north‐easterly synoptic winds appears responsible for the diurnal rhythm in the synoptic wind, a phenomenon already observed north of Banks Peninsula in relation to south‐westerly gradient winds.Practical and theoretical implications of the regional study are discussed.
Secular variations of surface temperature and precipitation patterns over the great lakes region
Authors: Brinkmann W. A. R. 
Published: February 2007

AbstractSpatial patterns of surface temperature and precipitation variability over the Great Lakes region and their changes during the past 78 years are examined using eigenvector analysis. The results show that the region is homogeneous in terms of temperature variations. The most important regional temperature trends have been very similar to the trends in the average annual temperature for the Northern Hemisphere. In the case of precipitation, however, an important boundary divides the region into a north‐western and south‐eastern portion. Positive precipitation anomalies occurred over the south‐east during the early part of this century and again after about 1960. The north‐western portion, on the other hand, experienced wet conditions during most of the intervening years.
Estimation of the daily global solar irradiation at Corvallis, Oregon (U.S.A.) from the hours of bright sunshine, the daily temperature range and relative humidity
Authors: Rao C. R. Nagaraja , Bradley William A. 
Published: February 2007

AbstractSimple empirical relationships based on the hours of bright sunshine, the daily temperature range and relative humidity have been developed to estimate the daily global solar irradiation at Corvallis, Oregon (U.S.A.). It is observed that the greater part of the variability in the daily solar radiation income at the surface is explained by changes in the available solar energy at the top of the atmosphere in the course of the year. The relationship based on the hours of bright sunshine yields estimates of the daily global solar irradiation which compare favorably with the measured values (coefficient of determination >0‐90).
The impact of wind circulation on the incidence and nature of rainstorms over Dar es Salaam, Tanzania
Authors: Sumner Graham N. 
Published: February 2007

AbstractUsing storm rainfall data from a dense network of autographic raingauges at Dar es Salaam, Tanzania, storm characteristics (morphology, alignment and time of occurrence) are related to prevailing gradient wind. There is a pronounced seasonal variation in the time of day at which storms generally occur, related to seasonal changes in the larger‐scale wind regime between the north‐easterly and south‐easterly trade winds. Many storms occur at times when there is a convergence between locally‐generated land‐ or sea‐breezes and the gradient wind, and their origin along these lines of convergence is further demonstrated by occurrence of both elliptical and linear morphology storms aligned along the coast. The trend of the coast is shown to control the alignment of storms, particularly by day, whereas by night gradient wind is more important. At this time, storms tend to form along the direction of the gradient wind. The most active storms form in the middle of the day, are linear in nature, aligned parallel to the coast, and occur when the gradient wind is either offshore or blows along the coast from the south‐south‐east.
Climatological contingency analysis and seasonal forecast skill in the United States
Authors: Lawson Merlin P. , Dewey Kenneth F. , Heim Richard 
Published: February 2007

AbstractTercile contingency tables were computed using 75 years (1895–1969) of state‐weighted monthly temperature and precipitation data. The data were grouped into 3‐month seasons and ranked for each state into three equally probable terciles. By comparing each season with the antecedent season, the magnitude of interseasonal persistence (or reversal) which exceeded chance was measured and mapped for the United States.The patterns of interseasonal tendencies are quite varied and demonstrate that there are geographical regions with substantial persistence of climatic anomalies between seasons. There were also regions which reverse tendencies (for example, a wet spring tending to follow a dry winter). The average excess tendency over chance for all contingencies is approximately 9 per cent. Seasonal forecasts were then generated (for an independent data period of 1970–1978) using only these contingency relationships. Standard skill scores were calculated and it was determined that these climatological interseasonal tendencies could not alone produce seasonal forecasts exceeding chance.
What if increases in atmospheric CO2 have an inverse greenhouse effect? I. Energy balance considerations related to surface albedo
Authors: Idso S. B. 
Published: February 2007

AbstractAn analysis of northern, low and southern latitude temperature trends of the past century, along with available atmospheric CO2 concentration and industrial carbon production data, suggests that the true climatic effect of increasing the CO2 content of the atmosphere may be to cool the Earth and not warm it, contrary to most past analyses of this phenomenon. A physical mechanism is thus proposed to explain how CO2 may act as an inverse greenhouse gas in Earth's atmosphere. However, a negative feedback mechanism related to a lowering of the planet's mean surface albedo, due to the migration of more mesic‐adapted vegetation onto arid and semi‐arid lands as a result of the increased water use efficiency which most plants experience under high levels of atmospheric CO2, acts to counter this inverse greenhouse effect. Quantitative estimates of the magnitudes of both phenomena are made, and it is shown that they are probably compensatory. This finding suggests that we will not suffer any great climatic catastrophe but will instead reap great agricultural benefits from the rapid increase in atmospheric CO2 which we are currently experiencing and which is projected to continue for perhaps another century or two into the future.
Riverflow reconstruction from tree rings in southern Britain
Authors: Jones P. D. , Briffa K. R. , Pilcher J. R. 
Published: February 2007

AbstractRing widths of oak trees (Quercus petraea Liebl. and Quercus robur L.) from a network of seven sites in southern Britain and northern France are used to reconstruct riverflow for three river catchments in southern Britain. These dendrohydrological reconstructions, made using a principal components regression technique, are the first such reconstructions in Europe. The results are statistically significant, and the stability of the regression models is verified using independent data. The reconstructions are more reliable for low flow events; a finding which is potentially useful for water resource planning. The reconstructions indicate a possible increase in the frequency of extreme low flows over the period 1755–1859, compared to 1860–1979, which although not of conclusive statistical significance, warrants further investigation.
On the climate of dome C, antarctica, in relation to its geographical setting
Authors: Wendler G. , Kodama Y. 
Published: February 2007

AbstractAutomatic weather stations have been successfully deployed in the hostile climate of Antarctica, where temperatures can drop below −80°C and wind speeds are up to 100m.p.h. These stations use satellites for transmission of their data (Argos System). Three years of data had been collected at Dome C (3280m), East Antarctica, before breakdown of the equipment occurred in January 1983. These data were analysed and compared with data from other stations in Antarctica. Results show that the temperature at Dome C can drop very low (−84.6°C), a new absolute world minimum is not expected to be found, however. The annual course of the temperature displays the typical ‘coreless’ winter phenomenon, with no systematic temperature changes for 4 to 5 months, and mean temperatures of about −60°C during this time. This fits well into the picture found at other high altitude inland stations of Antarctica. The wind speeds observed at Dome C were the lightest, not only of all interior stations in Antarctica, but of all antarctic stations, including coastal and near‐coastal ones. This illustrates the well‐known dependence of the katabatic winds on slope angles and topography. Despite steep and deep surface inversions, katabatic winds generated at higher elevations on the continental slopes do not appear to override Dome C, but flow around it. By contrast, the winds observed in the coastal regions of Adelie Land, some 1000 km away from Dome C, belong to the strongest found anywhere on the earth. Another indication that Dome C is free from any gravity flow can be found in the fact that the winds display a diurnal maximum during the summer months around noon or early afternoon, at a time when the inversion strength is at a minimum. For gravity flow, one would expect a minimum in wind speed at that time, as observed in the coastal region.
The Southern Oscillation and its relation to the monsoon rainfall
Authors: Bhalme H. N. , Jadhav S. K. 
Published: February 2007

AbstractThe interannual fluctuations in the Southern Oscillation indices (Wright, 1975) and their relations to the Indian monsoon (June‐September) rainfall have been examined for the period of 106 years from 1875 to 1980. The monsoon rainfall is significantly (99.9 per cent level) correlated with the Southern Oscillation indices for the seasons: MJJ (0.59), ASO (0.67), NDJ (0.53), and FMA of the following year (0.38). The fluctuations in the Southern Oscillation index for the ASO season appear strongly related to the nearly simultaneous monsoon rainfall of India. This implies that the large positive (negative) value of the Southern Oscillation index, signifying strengthening (weakening) of the Walker circulation coincides with large excess (deficient) monsoon rainfall over India. The coherence spectrum reveals that the Southern Oscillation index and the monsoon rainfall are highly correlated in the period range of about 2–2.5 years and 4–6 years. The first of these periods corresponds with the Quasi‐Biennial Oscillation and the latter agrees with the features of the Southern Oscillation, suggesting a strong link between Indian monsoon rainfall and these two phenomena. The striking feature of the composites of the Southern Oscillation index averaged for all the drought years and for all the flood years is the simultaneous occurrence of low (high) Southern Oscillation index and droughts (floods) in India. However, this association has limited use in long‐range prediction. A preliminary study suggests that a nearly simultaneous occurrence of major climatic anomalies of the tropics, such as droughts in India and El Niño off the coast of Peru, are linked to the Southern Oscillation, indicating some kind of time dependent zonal east‐west circulation, i.e. Walker circulation.
A generalized classification of South African summer rain‐bearing synoptic systems
Authors: Harrison M. S. J. 
Published: February 2007

AbstractS‐mode principal component analysis has been applied to standardized monthly South African rainfall fields and the synoptic systems represented on the higher eigenvectors identified by matching the spatial distribution of rainfall on each component with that of the various weather systems as revealed by satellite imagery. Summer systems identified include cloud bands connecting the tropical and temperate circulations, tropical and subtropical cyclones, coastal depressions, cyclones on the continental west coast and troughs associated with cold fronts on the east coast. The new classification is contrasted with earlier equivalent schemes. The uses of the results in terms of the search for geophysical controls on the development of each of the identified systems are discussed.
The atmospheric modulation of extended wet and dry spells over South Africa, 1958–1978
Authors: Tyson P. D. 
Published: February 2007

AbstractDifferences in annual geopotential heights at the 850 and 500 mb levels between 16 pairs of stations have been submitted to principal component analysis to identify the most important statistically uncorrelated pressure patterns accounting for the variance of the annual pressure field over South Africa and adjacent oceans. By correlating component scores for the period 1958/9 to 1977/8 with annual rainfall an attempt has been made to determine the regional rainfall responses to variations in different circulation types. Regional variations in annual rainfall are shown to be significantly linked to variations in both low latitude forcing, associated with tropical easterly airflow and cyclonic wave perturbations therein, and mid‐latitude forcing, associated with a variety of both cyclonic and anti‐cyclonic perturbations in the westerlies. It has been shown that it is primarily variations in the atmospheric field of motion at the 500 mb level that are responsible for year‐to‐year differences in annual rainfall totals.
Blocking signatures in the northern hemisphere: Frequency distribution and interpretation
Authors: Knox John L. , Hay John E. 
Published: February 2007

AbstractIn a companion paper (Knox and Hay, 1983) the authors developed objective identification criteria, adaptable to machine processing methods, by relating the blocking anticyclone to its associated positive anomaly of 5‐day mean 500 mb height. Anomalies meeting the criteria were called ‘blocking signatures’. Moreover, by using an empirically derived pentad displacement threshold, it was possible to identify ‘blocking signature sequences’ corresponding to the life history of blocking episodes.In this paper we present and interpret the spatial and temporal distribution of blocking signatures during the 33 year period 1946 to 1978 inclusive. The frequency of occurrence is presented by area, and by longitude for each season and for the year. The results are, in general, in agreement with published studies for the oceans, but they also reveal a high frequency of blocking signatures over the North‐eastern Canadian Archipelago. This particular result, ‘the Baffin Island paradox’, is further investigated and rationalized.The interannual variation of blocking signature frequency over the Northern Hemisphere showed substantial fluctuations, particularly with regard to the more persistent episodes. However, because of the small size of the sample (33 years) relative to the time scale of the fluctuations (order of one decade) it was not possible to draw statistical conclusions.
Urban and rural humidity distributions: Relationships to surface materials and land use
Authors: Henry James A. , Dicks Steven E. , Marotz Glen A. 
Published: February 2007

AbstractMost weather elements are modified by urban areas. Humidity is among the least studied of the modified elements. Quantitative associations of urban and rural humidity variations with surface materials and land use in Lawrence, Kansas, a relatively small eastern Great Plains city are examined. Results are based on 45 dew point temperature distributions obtained in summer and autumn. Man‐made surface materials are consistently negatively correlated with humidity, whereas most natural surfaces are positively related. Residential and educational‐institutional land uses and undeveloped land are related positively to morning and afternoon humidity values; fewer significant relationships exist between evening humidity distributions and land use.