bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the northward advance of the Itcz and the onset of the southwest monsoon rains over the southeast Bay of Bengal
Authors: Ananthakrishnan R. , Pathan J. M. , Aralikatti S. S. 
Published: February 2007

AbstractThe pentad rainfall data of six stations in the Andaman‐Nicobar group of islands for the period 1953‐1978 have been analysed to study the northward advance of the ITCZ and the onset of the summer monsoon rainfall over the southeast Bay of Bengal. It is found that at the island stations south of 10°N the summer monsoon rains set in on the average towards the end of April which is a month in advance of the onset of the monsoon over the south Kerala coast of peninsular India. At the island stations to the north of 10°N the onset occurs about the first week of May. These dates are ahead of those shown in the existing diagrams giving the average onset dates of the summer monsoon over the southeast Bay of Bengal. Examination of the frequency and latitude of formation of cyclonic disturbances in the Bay of Bengal and the progressive seasonal variations of the tropospheric winds over the aerological station of Port Blair during April‐May lend support to the earlier onset dates.
Canyon geometry and the nocturnal urban heat island: Comparison of scale model and field observations
Authors: Oke T. R. 
Published: February 2007

AbstractA simple hardware scale model is used to simulate nocturnal cooling rates for rural and urban environments under calm and cloudless conditions. Comparison with field observations gathered under similar conditions shows the model capable of reproducing many of the features of the temporal development of urban heat islands and the long‐wave radiative exchange in urban canyons. The model is used to investigate the roles played by rural/urban differences in geometry and thermal admittance. The results of the experiments show that canyon geometry in the central portion of a city (as measured by the sky view factor) is a relevant variable in producing nocturnal urban heat islands due to its role in regulating long‐wave radiative heat loss. It is also demonstrated that this measure is central to the relationship between city size and heat island intensity. The importance of canyon geometry as a feature of urban design is discussed. Thermal admittance differences can also produce realistic heat island features but their magnitude requires quantification in the field.
On the stability of temperature eigenvector patterns
Authors: Gray B. M. 
Published: February 2007

AbstractEigenvector spatial patterns for European temperatures have been investigated for seven periods between 1761 and 1969. When the number of observations greatly exceeds the number of stations used in the analysis, the main patterns of anomaly are seen to be stable in time, appearing in the same position in the eigenvalue ranking order in each period. Patterns which are time‐invariant are concluded to have physical significance.
Synoptic controls over katabatic layer characteristics above a melting glacier
Authors: Stenntng Alison J. , Banfield Colin E. , Young Gordon J. 
Published: February 2007

AbstractThe objective was to demonstrate the degree of control exercised by synoptic‐scale meteorological conditions upon the development and characteristics of a katabatic layer above a melting glacier. Field measurements were undertaken at a point on the snout of a temperate‐alpine type valley glacier in Alberta during part of the 1979 ablation season. At this site vertical wind velocity profiles were recorded within a 7 m layer above the glacier surface, together with vertical air temperature difference over 1‐4 m and wind direction at 2 m. An hourly sampling period was chosen to facilitate investigation of the variation of near‐ice wind and temperature conditions under varying large‐scale synoptic weather patterns.Five synoptic types were identified for the study period using a subjective classification. The greatest number of significant differences between pairs of types occurred for 700 mbar temperature and relative humidity, 500 mbar temperature, and local cloud‐cover and barometric pressure at the glacier site. Representative estimates of the glacier katabatic force and synoptic pressure‐gradient force indicated the former exceeded the latter by about 12:1 under strongly developed warm anticyclones and by about 3:1 during cool cyclonic situations.Consequently under anticyclonic conditions a well developed katabatic layer was often observed with a wind velocity maximum below 5 m, whereas weaker katabatic layer development characterized cyclonic conditions. During anticyclonic influence increased deviation of ambient (700 mbar) winds from the down‐glacier direction produced significantly stronger katabatic layer inversion strength but had little impact on katabatic wind velocity or direction. Under cyclonic control across‐slope ambient winds were associated with weaker katabatic wind velocity and inversion strength, together with deflection of surface wind direction. An inverse relationship between katabatic layer wind velocity and inversion strength was significant for two synoptic types.
Monitoring a changing climatic series
Authors: Craddock J. M. 
Published: February 2007

AbstractFormulae are developed for finding statistics to describe the latest state of a climatic time series without assuming that the character of the series will remain unchanged with time. The choice of formulae is discussed, and reasons given for the parameter settings which make the operations specific. Applications of the technique are illustrated by the extracts from analyses of British records covering most of the years 1821 to 1980, six being of rainfall and two of temperature.
Response of the antarctic ice sheet to a climatic warming: A model study
Authors: Oerlemans J. 
Published: February 2007

AbstractIt is generally believed that the increasing CO2 content of the atmosphere will lead to a substantial climatic warming in the polar regions. In this study the effect of consequent changes in the ice accumulation rate over the Antarctic Ice Sheet is investigated by means of a numerical ice flow model. In the model runs, temperature increases linearly with time during 100 years, and is kept constant afterwards.The results indicate that a climatic warming will probably lead to a sea‐level lowering of some tens of centimetres in the next centuries. This is because for Antarctic conditions the increase in snow accumulation exceeds the increase in melting. This estimate does not take into account the effects of possible surging of parts of the Antarctic Ice Sheet and the response of the Greenland Ice Sheet (which may be quite different).
Snow cover conditions in the northern Hemisphere during the winter of 1981
Authors: Foster J. L. , Rango And A. 
Published: February 2007

AbstractDuring the winter of 1981 the mean snow covered area in the Northern Hemisphere was less than any other year in the 15‐year record (1966‐1981) except 1970. For North America, the mean snow cover area was the lowest on record, and for Eurasia the mean snow cover area was the second lowest since records began in 1966. It has been observed that the average winter snow cover in both North America and Eurasia for both 1980 and 1981 decreased from that of the previous year, the first time this has been observed in the 15‐year period of record. Assessment of any long term climatic trends must wait extension of the snow cover data base.
Snow and ice balance in britain at the present time, and during the last glacial maximum and late glacial periods
Authors: Lockwood J. G. 
Published: February 2007

AbstractSimple parameterizations are used to estimate monthly mean ablation of snow and ice, and also the distribution of monthly mean precipitation in Britain. Together these enable estimates to be made of snow storage at various levels and the gradients of days with snow cover with elevation. Small semi‐permanent snow patches below the regional snow line are included in the discussion. The theoretical estimates fit the actual observations very closely. A similar approach is then used to estimate snow balances for the British Devensian ice sheets. Probable snow accumulation/elevation relationships are produced for 24,000 yr BP. Estimates suggest that the British ice sheet was just in balance at the lime of its maximum advance around 18,000 yr BP. The growth and decay of British ice sheets are considered and two stable states are suggested for ice‐age climates, one without an ice‐sheei and the other with a massive ice‐sheet.
Multiple interpolation in climatological spectra
Authors: Gray B. M. 
Published: February 2007

AbstractThe variable length record method of spectral analysis is considered as a composite of perturbations of a simple harmonic analysis. By smoothing over near neighbours, the composite spectrum can be made to approach the true spectrum. Since the method is computationally expensive, a less costly technique of multiple interpolation is considered and shown to produce equivalent results. This method is suitable for examining the low frequency end of cli ma to logical spectra.
Comparison of normal and below normal July precipitation patterns in central Iowa
Authors: White Gary R. , Vaughan Harry C. 
Published: February 2007

AbstractPrevious discussions of wet, dry and normal years in Iowa have been related primarily to the departure of rainfall from a climatological average. Rainfall during the month of July is examined because of its importance on the local cash crop, maize. The first section of the paper deals with the variability of areal precipitation patterns within the central Iowa climatological network (1000 km2/gauge) for the years 1930‐1978. Results of this study seemed to indicate that examination of a fine‐grid rain gauge network (1‐64 km2/gauge) was needed. Weather radar data also were used to provide a better data base to study the size and variability of July precipitation areas. In the second section, July 1976 (dry) and July 1977 (normal) were chosen to provide a comparision of precipitation patterns between a dry and normal precipitation year. The results show that, during a dry year (40 per cent below normal), there are nearly the same number of days with rain occurring as in a normal year. The most important factor in the comparison of the two years is that the size and number of individual precipitation echoes are both about 40 per cent less during 1976 than in 1977.
Studies of the Indian summer monsoon with a coarse‐mesh general circulation model, part II
Authors: Druyan Leonard M. 
Published: February 2007

AbstractA previous paper (Part I) discussed the performance of a coarse‐mesh general circulation model in studies of the Indian summer monsoon. Part II herein describes impacts on the simulated monsoon climate due to prescribed changes in the lower boundary conditions: lowering and flattening of the Himalayan Mountains and cold and warm sea‐surface temperature (SST) anomalies in the Arabian Sea. Results indicate that it is the Himalayas that are responsible for the observed north‐westerly flow aloft over northern India before onset and the delay in precipitation onset there until late June or July. SST anomalies, which are held constant throughout four‐month simulations, affect local precipitation computations via changes in stability and cause impacts of the opposite sign immediately downwind. Neither of the two anomalies tested resulted in statistically significant precipitation impacts over India.
The effect of altitude on the daily range of temperature
Authors: Linacre Edward 
Published: February 2007

AbstractAlthough it has been claimed that the daily range of screen temperature increases with altitude on a mountain, this appears not to be true generally. Data from sixteen sources indicate a confusion of evidence, though there appears to be some evidence of an increase of daily temperature range with height from 0‐200 m, and of a decrease between 750 m and 3400 m. The low‐altitude increase is attributed to the sea's moderating influence at the coast. The higher altitude decrease may be due to stronger winds or to more cloud. The evidence for a decrease may be confounded in some places by either peculiarities of locale or the increased daily fluctuation of radiation at highest altitudes.
Cave climate: Assessment of airflow and ventilation
Authors: De Freitas C. R. , Littlbjohn R. N. , Clarkson T. S. , Kristament I. S. 
Published: February 2007

AbstractStudy of cave climates is a neglected aspect of microclimatology. An understanding of the processes that control cave climate is required in the study of cave flora and fauna, thermodynamic conditions for karst processes underground, hydrogeologic features of speleothems as well as human use of caves for recreational and commercial purposes. An understanding of cave airflow is of central importance as the climate of a cave is a function of air exchange with the outside environment. The study site is the Glowworm Cave of New Zealand and is of particular interest because of its heavy visitor use and the presence of climate sensitive cave fauna on which the value of the cave as a tourist attraction depends.The study examines airflow using conventional methods together with experimental procedures using SF6 and CCl2F2 tracer gases. The results show that the rate and direction of airflow are a direct response to a thermally induced disequilibrium in air density between the cave and outside air. Both diurnal and seasonal patterns in the direction of airflow were identified. Reversal of airflow occurs when the cave to outside air density gradient is zero rather than when thermal conditions of the cave and external air are the same. Major and minor airflow routes through the cave were identified. The results of the gas tracer experiments allowed estimation of rates of air change in different parts of the cave and confirm the marked difference in ventilation that occurs within the cave. Information of this type is important because of the relationship between natural ventilation and CO2 buildup. There is also the effect of ventilation on differences in climate within the cave as the thermal and moisture effects of outside air will not be as pronounced in parts of the cave where air change is limited.
A probability analysis of precipitation surplus or deficit
Authors: Takhar H. S. , Cook D. J. 
Published: February 2007

AbstractThe surplus or deficit of precipitation is of fundamental importance in hydrology. An analysis is presented which provides for the prediction of surplus or deficit conditions as far as six months ahead. Data from Yorkshire, together with thirteen years data from a station in Nottinghamshire, are used statistically to analyse problems in water supply, irrigation and drainage. This analysis is based upon a technique developed by Stol in which differences between evaporation and precipitation are analysed over different periods of time.
Extreme distributions of Australian annual rainfall in relation to sea surface temperature
Authors: Streten N. A. 
Published: February 2007

AbstractSea surface temperature (SST) measurements from 1950 to 1969 are analysed for an extensive region of the Southern Hemisphere for six years of very high and very low areal extent of above normal Australian continental rainfall. Years of extensive drought are found to be associated with a predominantly low SST persisting throughout the year over the eastern Indian Ocean and the south west Pacific in the Australasian region particularly at low latitudes; very wet years over the continent are associated with a persistently warm SST extending from the equator to mid latitudes in the same region. Although the extreme years tend to be related to extremes of a Southern Oscillation index this is not always the case. Examination of SST over the eastern Pacific for the same years indicates some evidence that its thermal anomalies are in general opposite to those in the Australasian region though this is not so in all cases. Eastern South Pacific SST data sequences for years preceding and following individual extreme rainfall years over Australia show rapid and differing changes so that their forecasting potential is very limited.
The value of climate information: A decision‐analytic approach
Authors: Winkler Robert L. , Murphy Allan H. , Katz Richard W. 
Published: February 2007

AbstractA decision‐analytic approach to the problem of assessing the value of climate information is presented and an application of this methodology to a decision‐making problem involving the use of climate information is described. First, decision analysis is discussed briefly with emphasis on its informational aspects. Then a decision‐making situation is considered in which a farmer must decide which of two crops to plant in the face of uncertainty as to whether growing season precipitation will be above or below average. It is assumed that information concerning growing season precipitation is embodied in a climate forecast provided by a meteorologist and that this information constitutes the basis for the farmer's decision. Several probabilistic models for the climate forecasts are considered, including symmetric and asymmetric discrete distributions and a normal model. These models can provide reasonable descriptions of currently available climate forecasts. The analysis reveals that relatively uncertain climate information may be of value in some decision‐making situations, although the value of climate forecasts with skill levels commensurate with existing seasonal forecasts does not approach the value of perfect forecasts. Nevertheless, in the situations considered, once a minimum level of skill is achieved, further improvements in the forecasts result in steadily increasing benefits. Finally, it is indicated that decision analysis is also applicable to more complex situations in which climate information may play an important role.
Teleconnections and the siege of time
Authors: Ramaoe C. S. 
Published: February 2007

AbstractThe recent surge of interest in climate has resurrected correlation coefficients as tools for identifying ‘significant’ atmospheric teleconnections. Unfortunately, large coefficients may diminish and even change sign with time, suggesting absence of real physical relationships.Some statistical evidence supports the view that higher than normal sea surface temperatures in the central and eastern Pacific ‘cause’ less than normal rainfall in the Indian summer monsoon. However, a study of individual Augusts uncovers major exceptions and at the same time fails to confirm that Indian summer rainfall influences central and eastern Pacific rainfall or that the Southern Oscillation Index can be consistently related to conditions in either region.Around 1963‐1964 the apparent relationship between the Southern Oscillation Index and Indian rainfall reversed. At about the same time other global climatic relationships changed, raising the possibility of identifying and describing a major global climatic singularity separating two distinct statistical populations.
Fluctuations in the surface temperature and surface salinity of the north‐east Atlantic at frequencies of one cycle per year and below
Authors: Taylor A. H. 
Published: February 2007

AbstractTime‐series of monthly sea surface temperature and salinity data (1951‐1974) from stations in the N.E. Atlantic were investigated by calculating cross‐spectra using the method of maximum entropy analysis. This new technique has not previously been applied to climatological problems. The temperature and salinity data were also compared with surface heat‐flux and evaporation time‐series and wind observations. The main features of the seasonal cycle are apparent in the results, in particular, the close synchronism of the temperature cycle across the region. In addition, the results show that: variations in the seasonal flux of low salinity water led to short period anomalous salinity values, salinity and temperature anomalies tended to drift with the surface currents, and salinity and temperature changes at the lowest frequencies were caused by displacements of water masses which do not seem to have been forced locally. Fluctuations in heat‐flux and evaporation contributed to variations on a timescale of about three years and it is shown that these gave rise to additional spectral peaks by interacting with the seasonal cycle.
Solar and net radiation in Peninsular Malaysia
Authors: Hu Hing Chong , Lim Joo Tick 
Published: February 2007

AbstractLinear regression equations relating the global solar radiation and sunshine duration are derived for a total of 14 stations in Peninsular Malaysia. Mean monthly global solar radiation values for other stations which have only sunshine data are estimated using these regression equations. The intensities of global solar radiation during different times of the day and under different meteorological conditions are discussed. Maps of mean monthly global solar radiation are presented and discussed. It is found that the distribution pattern of global solar radiation follows somewhat with that of rainfall pattern.Net radiation was estimated using empirical equations developed by Chang (1970), Davies (1967). Selirio et al. (1971) and Penman (cited by Chang, 1970). Comparison of the estimated net radiation with the limited net radiation record available shows that the Davies' formula gives the best estimates. Hence Davies' formula is used for the estimation of net radiation. Maps of estimated net radiation are similarly prepared and discussed.
The estimation of missing climatological data
Authors: Tabony R. C. 
Published: February 2007

AbstractVarious methods of estimating montly means and extremes of climatological data are examined. Any generalized method is likely to be based on a correlation matrix, but the incompleteness of the data introduces problems with this approach. These are illustrated by program BMDPAM of the BMDP suite, which produces estimates inferior to those using traditional methods based on single station comparisons. Principal component analysis is considered likely to be the best statistical technique for estimating missing values among highly correlated data. The high quality correlation matrix required as input can be obtained by using a simple estimating procedure to produce a preliminary set of complete data. A simple technique devised for estimating climatological data in the U.K. was found to give results similar to those obtained from an eigenvector scheme used for quality control purposes. The accuracy of the technique is such that it is suggested that satisfactory averages could be estimated for stations with only 10 years of data, and possibly less.
A statistical method for quality control of routine temperature observations in developing countries
Authors: Stigter C. J. , Hyera T. M. , Mjungu Y. B. 
Published: February 2007

AbstractA simple statistical method is outlined to evaluate and improve routine temperature observations from meteorological stations in developing countries. This quality control achieves two things. It identifies anomalous data before storage or use. It also reveals whether thermograph, minimum thermometer, maximum thermometer and dry bulb thermometer have to be checked and/or how their data must be improved to be internally consistent. In addition this statistical approach assesses differences between averaging methods. It can be concluded that with this cost‐efficient method, temperature data accuracy obtained will be adequate for agricultural purposes and other climatological applications.