bluuebunny/crossref_metadata_2025_split huggingface dataset:
The distribution of rainfall intensity in Israel, its regional and seasonal variations and its climatological evaluation
Authors: Sharon D. , Kutiel H. 
Published: February 2007

AbstractA large body of data has been used to study the distribution of instantaneous rainfall intensity in Israel and its variations in space and in time. Time resolution is ±3 minutes. Besides the direct uses that the numerical results may have for practical purposes, the results have been used here to characterize rainfall in a climatologically more meaningful way. This includes reference to the atmospheric processes and surface‐conditioned effects that influence rainfall formation, and the identification of regional and seasonal variations in these processes. Thus, it has been shown that contrary to prevalent views, orographic rainfall in Israel is characterized by low intensity, apparently resulting from a continuous advection of moist air through a zone of gradual topographically forced uplifting.In the presentation of results, emphasis has been put also on the significance of results from the point of view of rain‐conditioned processes occurring on the earth surface, such as in hydrology, geomorphology, etc. In this context, the water yield from high intensity rainfall has been shown to reflect a high degree of concentration, both areally (through convergence in the atmosphere and run‐off processes on the ground surface) and in time (in warm seasons and in certain parts of the day). These features, as well as the relative frequency of high‐intensity rains itself, has been shown to be more pronounced in the arid Negev than in the more humid parts of the country. This explains at least in part the increased uncertainty characterizing rainfall in the arid zone.
Forecasting of monsoon performance over India
Authors: Bhalme H. N. , Jadhav S. K. , Mooley D. A. , Murty Bh. V. Ramana 
Published: February 2007

AbstractThe technique of screening‐regression analysis is applied to forecasting the monsoon performance (percentage rainfall departure) over India from the immediately preceding May's meteorological variables. The resulting prediction equation with five variables performed well, with a few exceptions, on independent data. The forecasting scheme shows some promise of providing a useful forecast of monsoon rainfall departures over India before the beginning of the season.
The response of a global food model to possible climate changes: A sensitivity analysis
Authors: Liverman Diana M. 
Published: February 2007

AbstractThis paper describes some ways in which global simulation models of relationships between envrionment, economics and population, might be used to examine the impacts of climate change on the world food system. The paper presents an analysis of the response of the International Futures Simulation model to changes in crop yields as a surrogate for climate. This sensitivity analysis provides a range of scenarios of how global and regional food systems might respond to a variety of climate changes. It also demonstrates how these models can respond in an unrealistic or unstable way to certain types of variation. The analysis provides some insight into the complex responses of actual food systems to changes in food production.
Daily totals of solar UVB radiation estimated from routine meteorological measurements
Authors: Webb A. R. , Steven M. D. 
Published: February 2007

AbstractDaily totals of solar ultraviolet‐B (300–316 nm) and fullband (300–3000 nm) radiation were measured over 18 months at Sutton Bonington in the English Midlands. A relation was established between the little‐measured but biologically active UVB waveband and the routinely recorded full solar radiation. A linear relation between the ratio of energy in the two wavebands and the cosine of the zenith angle at noon enables the UVB irradiation to be estimated from the full waveband. Information about ozone amounts, either daily values or monthly means, allows the estimates to be improved.
The nature of rainfall variability in Africa South of the Equator
Authors: Nicholson Sharon E. 
Published: February 2007

AbstractThe spatial patterns of rainfall variability over southern and equatorial Africa are examined using a regionally averaged data set comprising approximately 700 station records. Seasonal persistence of anomalies is also considered. Typical rainfall departure patterns, or anomaly types, are derived using a linear correlation method to assess the similarity of annual departure maps for the years 1901 to 1973. Six basic types describe most of the variability in the area 0 to 35°S. These indicate a remarkable spatial coherence of anomalies, but with a strong tendency for opposition between the equatorial and subtropical latitudes. The results are given an interpretation in terms of circulation features and synoptic situations affecting southern Africa.
Change of rainfall distribution and circulation patterns over Southern Africa in summer
Authors: Taljaard J. J. 
Published: February 2007

AbstractThe change of mean monthly rainfall, expressed as a percentage of mean annual rainfall, is described for the region south of 17°S during the course of summer. The areas with most rapidly increasing rainfall during monthly intervals are found to follow an almost circular path, starting out along the east coast and the adjacent interior in September and then being successively displaced to Zimbabwe, northern Botswana and northern South West Africa/Namibia, central and southern South West Africa/Namibia and ending in the central Cape Province in March. Several features of the atmospheric circulation and humidity are suggested and described as being partly responsible for the changing rainfall distribution.
Analysis of persistence in daily monsoon rainfall over India
Authors: Singh S. V. , Kripalani R. H. 
Published: February 2007

AbstractIn earlier studies the authors have established that monsoon rainfall up to the time scale of at least 5 days is dependent on its past value. In this study we examine the dependence in daily rainfall for 12 stations spread all over India, and in daily rainfall of 10 meteorological regions during the summer monsoon; (i) by analysing the rainfall as a stochastic point process by fitting Markov chains of orders 1 to 4 to the station data and (ii) by fitting autoregressive and autoregressive moving average models to the spatially averaged data. The significant conclusion is that the Markov chain of order 3 fits the runs of wet and dry spells better than chains of lower order, and that the autoregressive model of order 1 fits the spatially averaged rainfall amounts satisfactorily as compared to the higher order autoregressive or ARMA models.Examination of rainfall intensities during spells of various lengths has revealed that the rain intensity is greater during spells of 2 or 3 days than on isolated days. The rain intensity is greater on the days lying in the middle of a wet spell than on isolated days or on the first and the last days of a longer wet spell.
Characteristics and frequency of reversals in mean sea level pressure in the north Atlantic sector and their relationship to long‐term temperature trends
Authors: Moses T. , Kiladis G. N. , Diaz H. F. , Barry R. G. 
Published: February 2007

AbstractReversals in the usual monthly mean sea level pressure (SLP) gradient over the North Atlantic during winter—an extreme mode of the North Atlantic Oscillation—are documented back to 1867. Such events are typically associated with well‐below‐normal temperatures in north‐west Europe and above‐normal precipitation amounts in the western Mediterranean area. Also noted during these events is the tendency for above‐normal temperatures in western Greenland and below‐normal temperatures in the eastern United States.Temporal changes in the frequency of SLP reversals relate well to trends in the strength of the zonal wind and the frequency of blocking in the north‐east Atlantic area. Part of the fluctuations in temperature in western Europe during the last century can be explained by these changes in circulation. Nevertheless, major trends in winter temperature over this period, particularly the early 20th century rise in temperature, remain when adjustments are made to account for the effects of circulation changes during reversal winters. This suggests that mechanisms other than changes in the frequency of circulation regimes also play an important role in determining hemispheric temperature trends on these time scales.
Good king wenceslas: Alternative strategies for the U.K. department of health and social security(DHSS)
Authors: Giles Brian D. , Kings John 
Published: February 2007

AbstractThe U.K. Department of Health and Social Security (DHSS) is required to make, to those eligible, a single payment for additional fuel costs during a period of exceptionally severe weather. Previous methods of assessing exceptionally severe weather, criticized on a number of grounds by Social Security Commissioners, resulted in parliamentary debate and frequent press attention. Work on exceptionally severe weather in winter in Birmingham is presented here for the period since November 1959. Three measures of cold—mean daily temperature, degree days and windchill—are assessed for their usefulness in identifying exceptionally severe weather as a single day occurrence and/or as runs of days, during the winter months from November to March. Recommendations are made that thresholds based on probability of occurrence be used and that windchill is the best of the three measures which could be used in future winters. It is concluded that although climatologists can provide the necessary data, probability levels and parameters, it must be Parliament and the DHSS who must define ‘period’ and ‘exceptionally severe’. In either case the final decision can only be a political one.
Low‐latitude volcanic Eruptions and their effects on Sri Lankan rainfall during the north‐east monsoon
Authors: Mukherjee B. K. , Indira K. , Dani K. K. 
Published: February 2007

AbstractRecent studies have pointed out the modification of climate by aerosols released in the stratosphere by strong volcanic eruptions. The rainfall at 15 meteorological stations in Sri Lanka and the low latitude (20° N to 20° S) volcanoes, having volcanic explosivity index (VEI) 4 or more, for a period of 112 years (1869–1980), are investigated to examine the effects of the eruptions on the rainfall activity over Sri Lanka during the north‐east monsoon season (November and December). The present study has suggested deficient rainfall in 14 out of 15 Sri Lankan stations during both the first and the first two successive north‐east monsoon seasons, which followed 53 to 80 per cent of volcanic eruption years. Also 53 to 100 per cent of the stations received deficient rainfall during both the first and the first two successive north‐east monsoon seasons following 12 out of 20 volcanic eruption years. Occurrence of deficient rainfall to the north of the inter tropical convergence zone (ITCZ) over Sri Lanka after the eruptions of the low‐latitude volcanoes could be attributed to the southward shift of the ITCZ due to depletion of the solar radiation caused by the aerosols released in the stratosphere by the strong volcanic eruptions.
A multivariate classification and regionalization of west African climates
Authors: Anyadike R. N. C. 
Published: February 2007

AbstractCluster analysis is used to group into regions over West Africa, a climatic data set which had been previously reduced to four factors. The regions thus derived are more firmly climate based than is the case with previous classifications. Various degrees of generality are also achieved by the methods, ranging from five regions at the primary level to twenty regions for more detailed work. Overall, a ten‐region climatic cluster is found to be optimal for most purposes.
England and Wales precipitation: A discussion of recent changes in ariability and an update to 1985
Authors: Wigley T. M. L. , Jones P. D. 
Published: February 2007

AbstractRecent changes in precipitation variability are examined for five regions of England and Wales. The only statistically significant changes that have occurred over the past 10 years have been an increase in the frequency of extreme dry summers and wet springs. The importance of large‐scale climate forcing factors, such as pressure gradients and weather types, in controlling precipitation variations is examined using simple correlation analyses. The homogenized England and Wales precipitation series is updated to 1985.
Investigation of the sensitivity of the land‐surface parameterization of the NCAR Community Climate Model in regions of tundra vegetation
Authors: Wilson M. F. , Henderson‐Sellers A. , Dickinson R. E. , Kennedy P. J. 
Published: February 2007

AbstractA series of sensitivity experiments has been conducted using a version of the NCAR Community Climate Model (CCM) and a complementary zero‐dimensional land‐surface model in order to invesligate the sensitivity of the models to surface process parameterizations in northern high latitudes. The study was motivated by anomalously high surface temperatures at these latitudes in a control simulation with the CCM. The effects of perturbing the maximum vegetation cover, distribution of the roots within the active soil layer, the depth of the active soil layer, soil albedo, and of maintaining a fully saturated upper and active soil layer were explored. Little response occurred in either model when the depth of the soil or the root distribution was altered. Increasing the percentage of ground covered by vegetation increased the canopy air temperature but generally reduced soil temperatures in the zero‐dimensional model. However, in the CCM integration the surface air temperature increased over most of the region for this change. This response seems to be due to the high level of precipitation during the three‐dimensional integration and is similar to one of the zero‐dimensional computations in which a large rainfall event was prescribed on the second day of the 10 day integration. Maintaining the moisture contents of both soil layers at their capacity caused a decrease in soil temperatures at most locations in the CCM and in the zero‐dimensional model once the soil in the control began to dry out. Increasing the soil albedo also produced soil and surface air cooling in both models. All the integrations underlined the considerable sensitivity of the land‐surface parameterization scheme to the instantaneous and preceding soil moisture conditions. Reduction in surface temperatures achieved was significantly less than the original discrepancy between CCM temperatures and observations. Part of the discrepancy could be caused by unrepresentative observational data and a model bias toward high levels of net surface radiation. In addition, preliminary calculations suggest that explicit inclusion of permafrost may be necessary before a fully satisfactory representation of the tundra land‐surface climate can be achieved. This conclusion may be important for CO2‐induced climate‐change studies.
Some features of the south‐west monsoon rainfall of Cochin and Minicoy
Authors: Ananthakrishnan R. , Kajan C. K. 
Published: February 2007

AbstractSeveral characteristics of (he south‐west monsoon rainfall of the low latitude stations of Cochin (coastal) and Minicoy (island) have been studied using the hyetograms of these stations for the ten year period 1973–1982. Both stations exhibit diurnal variations of rainfall with maximum activity in the post‐midnight hours and minimum in the afternoon hours. The amplitude of the diurnal variation increases for rain events of increasing intensities. The integrated duration of the seasonal rainfall is about 250 h at Cochin and 110 h al Minicoy. Half the total rain from heavy falls is received in a fifth of the total duration; half the total duration accounts for only a fifth of the total rain from light falls.The association between cumulative percentage rainfall (x) and cumulative percentage rain duration (y) is found to be of the form x = ay exp (byc) where a, b and c are empirical constants. The average rain intensity varies from about I mm/h to 25 mm/h along this rainfall curve. An equation of the same form also gives a satisfactory representation of the variation of cumulative percentages of rain amount/rain‐duration/rain hours with rain events of increasing amounts.
On bistable phasing of 18‐6‐year induced drought and flood in the Nile records since AD 650
Authors: Currie Robert Guinn 
Published: February 2007

AbstractA maximum entropy analysis of winter and summer flood records of the Nile from ad 622 to 1490 shows evidence for periodic lunar nodal 18′6‐year(as well as weaker 10–11 year cyclic) induced drought/flood in regions of Africa drained by this river. This supports the results of Hameed (1984) who analyzed the same records using the Fourier transform method, and of Hameed and Currie (1985) who studied the summer flood records of the modern period (ad 1690–1962) using the maximum entropy method. The nodal term exhibits bistable phasing with respect to dates or epochs of maximum in the nodal tide, a phenomenon previously found in drought/flood proxy data in South America (Currie, 1983), in India (Currie, 1984a), in North America (Currie, 1984c), in China (Currie and Fairbndge, 1985), and in precipitation data for the northeastern United States (Currie, 1987c). Evidence for the 10–11 year solar cycle term in the Nile records is also discussed. Tyson (1980,1981) found terms near 19‐ and 11‐years in South African rainfall data, with the former exhibiting a bistable switch in phase at the beginning of our century, which is in agreement with results of Hameed and Currie (1985) for the modern Nile record.
Some features of the growing season precipitation fluctuations in the Interior Plains of North America
Authors: Oladipo E. Olukayode 
Published: February 2007

AbstractLong‐term growing season precipitation series for the period 1931–1978 at 407 stations in the Interior Plains of North America and for a decreasing number of stations with records dating back to 1875 were subjected to various statistical analyses in order to understand their inter‐annual and long‐term variability. Only a few stations showed any sign of inhomogeneity, there being no evidence of any significant trend in the precipitation series. The higher degree of spatial variability of seasonal precipitation series over the southern Plains indicated a higher frequency of occurrence of thunderstorms in the sub‐region compared with the northern Plains and the Canadian Prairies.The test for normality by Fisher's statistic and the Geary coefficient indicated that about 20 per cent of the precipitation series were not normally distributed. For meaningful statistical analysis, there is always the need to convert the frequency distribution of rainfall series from non‐normal to normal. Using only the square root transformation method, most of the non‐normal cases were transformed to normal.Subperiods analysis as tested by Cramer's test indicated that, although the 1941–1970 normal was wetter than the preceding non‐overlapping 30‐year normal period, there had been no significant secular change in the growing season precipitation in the Interior Plains, at least since 1911. Analysis of the precipitation anomalies decade by decade from the 1941–1970 averages indicated that the 1940s and 1960s were generally wet, while other decades, especially the 1930s and 1950s were particularly dry. The 30‐year period 1941–1970 was probably the most anomalously wet period in the nearly 104‐year time sequence considered. On the whole, the results of the statistical analyses indicated no significant changes in some of the secular features of growing season precipitation totals in the Interior Plains.
The effect of urbanization on some characteristics of relative humidity in Ibadan
Authors: Adebayo Yinka R. 
Published: February 2007

AbstractExamined in this work was the effect of urbanization on some aspects of the diurnal, seasonal and spatial patterns of relative humidity in Ibadan. Two approaches were adopted in the analyses. Firstly, a rural‐site station was used as a control, while its 20‐year (1961–1980) data were compared with those of the two urban‐located stations. Secondly, isoline maps of the spatial patterns were produced‐ In doing this, occasional, diurnal recordings were carried out at strategic locations over a period of 1 year.The analyses show that relative humidity was lower within the city than in the rural area. The mean difference varied from 2 to 3 per cent at 0900 h to about 10 per cent at 1500 h. There was a seasonal trend in this difference. While there was virtually no difference by 0900 hand a difference of just about 5 per cent existed at 1500 hat the peak of the wet season, the situation at the height of the dry season was different. By then, whereas the relative humidity was about 3–6 per cent lower in the urban area at 0900 h, the difference was about 12–17 per cent at 1500 h. The isoline maps also reflect the diurnal and seasonal patterns, and the attenuation of relative humidity with increase in the intensity of urbanization. The analyses do not confirm there was any significant decrease in relative humidity, over time, as a result of the impact of the city‐growth.
South African rainfall, the Southern Oscillation and a Southern Hemisphere semi‐annual cycle
Authors: Lindesay J. A. 
Published: February 2007

AbstractSignificant differences in rainfall over central South Africa are known to occur between opposite extremes in the phase of the Southern Oscillation, but details of both temporal and spatial aspects of the modulation of South African rainfall with the phase changes of the Oscillation remain to be described. Zero‐lag correlations between the Tahiti—Darwin Southern Oscillation Index and monthly and 3‐month seasonal rainfall over South Africa suggest that the rainfall—Southern Oscillation Index association is best defined in the late summer season January—March and in a north‐west to south‐east aligned zone across the central summer rainfall region of South Africa. Rainfall in this zone is directly related to the Southern Oscillation Index, increasing during high phase summers. An apparent semi‐annual cycle in the rainfall—Southern Oscillation Index correlations over central South Africa is in phase with the November and February turning points of a semi‐annual cycle in atmospheric circulation parameters over southern Africa. A plausible circulation mechanism is suggested to account for some of the spatial and temporal characteristics of the association between the Southern Oscillation and South African rainfall.
Changing rainfall patterns in Western Sudan
Authors: Eldredge Elizabeth , Khalil Suhair El Sayeed , Nicholds Nigel , Abdalla Atif Ali , Rydjeski Denis 
Published: February 2007

AbstractRainfall series to 1986 have been examined for North Darfur and North Kordofan. Annual and monthly series are presented and analysed. Relatively dry conditions have persisted in this region since 1966 due mainly to a decline in rainfall during July, August and September, the critical months for the annual agricultural cycle. Changes in daily rainfall magnitude and frequency are examined for these four rainy season months. It is recommended that agricultural planning and government policies be based on recent meteorological patterns.