bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chinooks in Southern Alberta: Some distinguishing nocturnal features
Authors: Nkemdirim Lawrence C. 
Published: February 2007

AbstractVarious attempts to define chinooks from commonly observed surface weather phenomena have met with limited success. It is now apparent that many of the features normally considered unique to chinooks in southern Alberta are shared with other weather types. A new study found that there were statistically significant differences between both the means and variances of weather variables measured in chinooks and non‐chinooks in only one of eight variables considered. The means differed significantly in three parameters whereas the variances differed in four. But the significance attained by the difference in variance was always higher than attained in the mean, indicating that discrimination between the two weather types was more strongly expressed in the range of conditions experienced than in the mean condition. Collectively the variables were able to separate chinooks from non‐chinooks in all but one of the events studied.
Synoptic‐dynamic character of ‘bursts’ and ‘breaks’ in the South‐West U.S. summer precipitation singularity
Authors: Carleton Andrew M. 
Published: February 2007

AbstractMarked intraseasonal variations in the intensity of the south‐west U.S. summer precipitation singularity (the ‘Monsoon’) are identified for the years 1980–1982 from a previously developed satellite cloud climatology. These ‘bursts’ and ‘breaks’ are examined synoptically by compositing sea level pressure and 500 mb height data. Both types of events are controlled by the upper‐level flow. This typically involves, for bursts, the intrusion into subtropical latitudes of a trough in the westerlies with attendant cold air advection. In conjunction with intense surface heating, this produces widespread atmospheric destabilization over the South‐west. Monsoon breaks are characterized by enhanced ridging of the Bermuda and North Pacific subtropical anticyclones with associated subsidence over southern Arizona/California. Between‐year differences in these composite patterns are identified, and it is suggested that wetter summers may be characterized by larger within‐season variations in 500 mb heights and isobaric curvature compared with drier summers. Several 500 mb synoptic types associated with burst events are determined subjectively, and composite patterns are derived. These indicate that bursts occasionally occur with anticyclonic conditions aloft, but the latitude of the ridge seems critical in determining the extent of moist air penetration from the south.Twice‐daily aerological soundings at five stations in the South‐west and northern Mexico are also used to determine the thermodynamic characteristics of bursts and breaks and the dominant source of monsoon moisture. Monsoon bursts in Arizona are evidently a combination of moisture from the Gulf of Mexico, transported on a light south‐easterly flow, and more rapid lower‐level ‘surges’ originating in the Gulf of California. Moisture from the latter source is transported rapidly into the Great Basin on a low‐level wind‐speed maximum of marked directional constancy. This study has implications for longer‐term summer rainfall‐synoptic circulation variations in the American South‐west.
A Technique for estimating regional surface albedos using geostationary satellite data
Authors: Nunez M. , Skirving W. J. , Viney N. R. 
Published: February 2007

AbstractData from the Japanese geostationary meteorological satellite are used to map surface albedo in Tasmania, Australia. Satellite data are corrected for atmospheric depletion and the narrow spectral window of the satellite sensor. The effect of non‐Lambertian reflection is discussed.A composite albedo map is presented based on eight mostly cloudless images taken at 10.00 and 13.00 local time in a period spanning the end of January to the beginning of February, 1985. The map features a distinct east west gradient in the albedo, with lowest values measured in the rain‐forest environment of the western highlands. Highest values are observed among areas of cleared farmland in the eastern midlands.
Subjectivity in A computer‐assisted synoptic climatology I: Classification results
Authors: Yarnal Brent , White Dale A. 
Published: February 2007

AbstractNumerous computer‐assisted synoptic climatological classifications were performed to determine the validity of a commonly used ‘objective’ typing scheme. In this study, the correlation‐based Kirchhofer technique was used to classify a large population of daily mean sea level pressure grids. Unlike previous methodological studies, metric parameters were held constant while the form of the data used in the classifications was varied. It is demonstrated that sample size, number of grid points and the particular random sample used will affect the classification results, thereby confirming previous work that has suggested that such typing schemes are extremely subjective. It is recommended that users of correlation‐based techniques obtain a number of relatively large random samples of size n ≥ 1000 and perform several classification runs in order to reach an ‘optimum’ solution.
A note on the effect of urbanization on temperature in Ibadan
Authors: Adebayo Yinka R. 
Published: February 2007

AbstractThe effects of urbanization on the temperature characteristics of a tropical city are examined. Twenty‐year records of maximum, minimum and mean temperatures were extracted from four established meteorological stations in the Ibadan area. Three stations are within the urban region and the remaining one, which serves as the control station, is situated in a rural environment, outside the city. Analysis shows that the urban heat island effect of the city is clearly reflected in the magnitudes of night‐time minimum and mean temperatures, whereas the day‐time maximum temperature is slightly lower, in the city. There is no clear evidence of any change in the urban temperature excess over time. The heat island effects of the city are more noticeable towards the end of the dry season and in the early part of the rainy season. The mean heat island, as reflected by the night‐time minimum temperature, is about 1.0 K during the dry season, and 0.5 K during the rainy season.
The CO2 temperature response. A comparison of the results from general circulation models with statistical assessments
Authors: Schönwiese Christian‐D , Malcher Jürgen 
Published: February 2007

AbstractGeneral circulation models (GCMs), which simulate the climate response to a doubling of the atmospheric carbon dioxide (CO2) concentration show a considerable variety of results even in respect to the globally averaged air temperature response near the ground. There is a need to verify the GCM results against an observational climatic data basis where noi only the global average but also the regional patterns and seasonal variations in the response are important. The statistical assessments described here are based on an annual time series 1851–1984 of the mean northern hemisphere surface air temperature and on corresponding monthly gridded data 1881–1980. The noise is reduced using a Gaussian 10 year low‐pass filter. Natural forcing is taken into account in terms of volcanic and solar forcing parameters. The sensitivity of the CO2‐induced temperature signal obtained from the statistical regression model is tested using different CO2 time series and both a linear and a logarithmic CO2‐temperature relationship. The statistical CO2 doubling simulations give results that are similar to most of the GCM experiments with respect to the zonal mean and seasonal response but not always with respect to the regional changes. Finally, the regional CO2 induced signals are statistically compared with those due to volcanic forcing.
An analysis of the rainfall regimes on the coastal region of Guyana
Authors: Shaw Anthony B. 
Published: February 2007

AbstractRainfall on the Guyana coastal region is produced by mesoscale synoptic systems occurring throughout the year and by large‐scale systems associated with the seasonal movement of the ITCZ. Consequently, the rainfall is highly variable in time and space. This variability has often adversely affected crop production.Daily rainfall data are examined for a selected sample of stations in order to establish the onset dates of effective and persistent rainfall within the two major rainfall seasons. Onset dates show significant inter‐station and yearly variations for the winter (short wet) season while they vary only moderately for the summer (long wet) season.Correlation analysis has also been used to examine the spatial coherence of the rainfall. Seasonal differences have been found. Winter rains tend to be more localized and appears to be produced by a larger number of small‐scale systems. Summer rains appear to be more spatially coherent owing to the influence of energetic large‐scale systems associated with the ITCZ.
Climate patterns derived from chinese proxy precipitation records: An evaluation of the station networks and statistical techniques
Authors: Ronberg Baruch , Wang Wei‐Chyung 
Published: February 2007

AbstractThe 510‐year, 120‐stalion proxy precipitation records published by the State Meteorological Administration of the People's Republic of China were used to study the large‐scale climate patterns, including the climate regions and interregional relationships. In this paper, we present a study of the sensitivity of the climate patterns of recent years (1950–1979) to choice of stations and statistical techniques. First, the original highly inhomogeneous 120‐station network is reduced to a quasi‐uniform network comprising 93 stations. Next, based on the reduced network, two new networks arc derived‐a47‐station network with the same spatial domain and a 29‐station network with half the domain. The climate patterns for these station networks are compared by use of two different statistical procedures, principal component analysis/cluster analysis and factor analysis with orthogonal and oblique rotations. It is found that the climate patterns remain similar when the density and domain of the 120‐station network are systematically reduced. It is also found that similar climate patterns are obtained using either of the chosen statistical techniques, although factor analysis appears to be more sensitive to changes in the network than principal component/cluster analysis. Examination of measurement data also reveals large‐scale climate patterns similar to those derived from the proxy data. Finally, the climate patterns are shown to be consistent with geophysical factors.
Subjectivity in a computer‐assisted synoptic climatology II: Relationships to surface climate
Authors: Yarnal Brent , White Dale A. , Leathers Daniel J. 
Published: February 2007

AbstractEarlier work has demonstrated that the results of a correlation‐based (Kirchhofer) synoptic classification are dependent on the way that the internal parameters and data are used. In this study, varying classifications are compared to the climate at one location. The results show that associations between temperature and the synoptic patterns are usually physically interpretable and somewhat stable, whereas precipitation‐synoptic type relationships are more difficult to explain and highly variable. We conclude that varying classifications do not produce equivalent synoptic climatologies. Furthermore, we know of no apparent objective or subjective means for determining a ‘best’ classification. Based on these findings, we discourage the use of correlation‐based techniques in all but the most controlled situations.
Alternative strategies for the UK department of health and social security (DHSS): Some comments
Authors: Moores W. H. 
Published: February 2007

AbstractGiles and Kings (1987) suggest the use of windchill as an alternative indication of coldness for use in the UK Department of Health and Social Security's exceptionally cold weather payments scheme. It is argued here that the use of windchill confers no obvious benefit and would result in added problems.
Comments on ‘power spectra and coherence of drought in the interior plains by E. O. Oladipo’
Authors: Currie Robert Guinn 
Published: February 2007

AbstractOladipo failed to detect any long‐period signals in precipitation records from North America, in particular those from the states of Arkansas, Illinois and Iowa. In this paper evidence is presented for signals near 19 years and 10 to 11 years in 64 records from these three states. A series of errors led to Oladipo's failure to detect the terms, and these are discussed.
An approach to the variability of urban surface energy budgets under stratified synoptic weather types
Authors: Todhunter Paul E. 
Published: February 2007

AbstractA simulation‐based method for examining the response of urban canyon energy budgets to stratified synoptic weather types is outlined and briefly illustrated. The approach contains three steps: (1) an objective grouping procedure consisting of a principal components analysis of sixteen climatic variables followed by a cluster analysis of the resulting component scores is applied to the Boston, Massachusetts Typical Meteorological Year data set to group each day into a limited number of synoptic weather types; (2) a characteristic day is identified for each weather type based upon a minimized sum‐of‐squares criterion; (3) the URBAN3 numerical model is used to simulate the surface energy budget of a standard urban canyon for each of the synoptic weather types.Results illustrate the response of urban canyon surface energetic patterns to stratified synoptic weather types. The objective grouping procedure utilized should be applicable to a wide variety of computer modelling applications involving complete daily climatic data sets.
Recent decadal climate variations in the tropical Pacific
Authors: Cooper Neill S. , Whysall Kim D. B. , Bigg Grant R. 
Published: February 2007

AbstractThe existence of two major variations in the climate of the tropical Pacific during the period 1920–1983 is demonstrated. During 1937–1946 an anomaly of much longer duration than, but of somewhat similar character to, an El Niño event occurred. It contained within it several swings of the Southern Oscillation Index previously thought to be separate events, but which we hypothesize to be part of a longer coherent disruption to the tropical Pacific ocean‐atmosphere system. This anomaly is described using ship observations of winds and sea‐surface temperature, island sea‐level pressure records and length‐of‐day measurements. In all records examined the anomaly was persistent, and as strong as the recent 1982/1983 El Niño, though of far different character. Evidence for a long‐term change in the atmospheric circulation over the tropical Pacific in the 30 years since 1950 is also presented. A combination of the trade winds gradually strengthening by 1 ms−1 over this time and changes in subtropical pressure of up to 1 mb leads to a hypothesized change in the circulation.
Macro‐regional definition and characteristics of Indian summer monsoon rainfall, 1871–1985
Authors: Gregory S. 
Published: February 2007

AbstractA case is made for regional‐scale Indian summer monsoon rainfall data and analysis, intermediate between the widely used all‐India and meteorological subdivision data sets. Macro‐regional units are constructed from the data provided by Parthasarathy et al., 10 being defined using principal components analysis and a classification algorithm. The temporal changes of summer monsoon rainfall over the period 1871–1985 are analysed and described for each of these regions, and the marked diversity of fluctuations between the regions is emphasized by a variety of methods. The degree of relationship is considered for each region between drier and wetter conditions and (i) El Niño and non‐El Niño years, and (ii) SST anomalies in the eastern tropical Pacific. Clear regional differences are apparent, but even statistically highly significant relationships are not large in any absolute sense. The need for explanatory analyses at the regional scale, in addition to those at the more common all‐India scale, is stressed.
Statistical distribution of daily rainfall and its association with the coefficient of variation of rainfall series
Authors: Ananthakrishnan R. , Soman M. K. 
Published: February 2007

AbstractThe paper deals with the statistical analysis of the daily rainfall series (monthly, seasonal, and annual) of 15 Indian stations representing a wide variety of rainfall regimes, utilizing the data for the period 1901–1980. The study focuses attention on the normalized rainfall curve (NRC) depicting the association between cumulated percentage rain amount (x) and cumulated percentage number of rain days (y) of the rainfall series. It is shown that the NRC is uniquely determined by the coefficient of variation (CV) of the rainfall series. There is no universal NRC that can represent all rainfall regimes.The equation x = y exp[ — b(100 — y)c], where b and c are two empirical constants, gives a good analytical representation of the NRCs over a wide range of CV values of the rainfall series. This analytical equation is able to account for the occurrence of high rainfall intensities towards the upper extremity of the NRC for rainfall series with high values of CV. The rain intensity corresponding to any point on the NRC is inversely proportional to the slope of the tangent at that point. The point where the slope is 45° corresponds to the mean rain amount per rain day (r) of the rainfall series. It is shown that days with rain amount greater than r (considered as days of significant rainfall) constitute about 30 per cent of the rain days and contribute 75–80 per cent of the total rain amount, with some local and seasonal variations.
Relationships between the Southern Oscillation and the rainfall of Sri Lanka
Authors: Suppiah Ramasamy 
Published: February 2007

AbstractThe Southern Oscillation (SO) signals in the monthly and seasonal rainfall of Sri Lanka are studied by using statistical analyses. Correlation coefficients (CCs) between the rainfall of the first intermonsoon season (March‐April) and the seasonal Southern Oscillation Index (SOI) of August‐September‐October (ASO) and November‐December‐January (NDJ) are positive and significant. In particular, March rainfall in region A is significantly correlated with the subsequent SOI of ASO and NDJ. The CC between the rainfall of the southwest monsoon season (May‐September) and the SOI is also positive. Cumulative rainfall of the peak monsoon months (July and August) reveals a strong and positive correlation with the seasonal SOI.The CC between the rainfall of the second intermonsoon season (October‐November) and the SOI is negative and significant. The rainfall of this season is also significantly correlated with the SOI (Tahiti‐Darwin) of May‐June‐July (MJJ). The SOI of MJJ serves as a particularly useful predictor for this seasonal rainfall. The CC between the rainfall of the northeast monsoon season (December‐February) and the SOI is also negative but weak.Large signals appear in wind anomalies over Sri Lanka prior to El Niño/Southern Oscillation (ENSO) events. Upper level easterlies (westerlies) and weak (strong) low‐level easterlies are dominant in March before the La Niña (El Niño) years. These wind anomalies persist until the ENSO events reach maturity.Based on the results of correlation analysis and wind anomalies, schematic models of the zonal circulation along the Equator between 60°E and 140°W are presented for La Niña and El Niño phases for northern hemispheric summer and winter seasons.
Mean seasonal and spatial variability in gauge‐corrected, global precipitation
Authors: Legates David R. , Willmott Cort J. 
Published: February 2007

AbstractUsing traditional land‐based gauge measurements and shipboard estimates, a global climatology of mean monthly precipitation has been developed. Data were obtained from ten existing sources, screened for coding errors, and redundant station records were removed. The edited data base contains 24,635 spatially independent terrestrial station records and 2223 oceanic grid‐point records. A procedure for correcting gauge‐induced biases is presented and used to remove systematic errors caused by wind, wetting on the interior walls of the gauge, and evaporation from the gauge. These ‘corrected’ monthly precipitation observations were then interpolated to a 0·5° of latitude by 0·5° of longitude grid using a spherically based interpolation procedure. Bias‐corrected spatial distributions of the annual mean and intraannual variance are presented along with a harmonic decomposition of the intra‐annual variance.
A search for accelerations in records of European mean sea level
Authors: Woodworth P. L. 
Published: February 2007

AbstractLong records from European tide gauges have been inspected for evidence of modifications in the rate of change, or ‘accelerations’, of mean sea level (MSL). In general, no evidence was found for MSL accelerations significantly different from zero over the period 1870 to the present, although non‐zero accelerations were observed at individual stations. Changes in surface air pressure may have been responsible for an overall slightly negative acceleration observed in northern Europe. In order to extend the study to time‐scales longer than a century, data from the oldest European MSL records at Brest, Sheerness, Amsterdam and Stockholm starting in 1807, 1834, 1700 and 1774, respectively, were also investigated with the result that a positive acceleration of order 0·4 (mm year−1) per century appears to be typical of European Atlantic coast and Baltic MSL over the last few centuries. Although of interest as an indicator of past climate change, this small low‐frequency MSL acceleration is an order of magnitude less than that anticipated over the next few decades as a result of greenhouse warming. A conceptual study of possible future Newlyn (UK) tide gauge data has shown that the MSL acceleration anticipated from the global warming should be apparent in the records by the early part of the next century.
North pacific circulation anomalies, El Niñto and anomalous warmth over the North American continent in 1986–1988: Possible causes of the 1988 North American drought
Authors: Weber Gerd‐Rainer 
Published: February 2007

AbstractThe relationships between 300/1000 mbar thickness anomalies over the North Pacific Ocean and thickness anomalies over the adjacent North American continent are investigated on the basis of monthly anomalies for the 34‐month period January 1986 to October 1988. It is found that in 21 out of the 34 months a pattern exists that links negative anomalies over the North Pacific Ocean to positive anomalies over the North American continent. Using teleconnection analysis, it can be shown, that in spring a strong relationship exists between positive anomalies over the western half of the North American continent in mid‐latitudes and negative thickness anomalies over the North Pacific Ocean in mid‐latitudes as well as between positive anomalies over the North Pacific Ocean in tropical and subtropical latitudes. Statistically, the strongest relationships emerged between the thickness gradient departures 20°–30°N over the east‐central Pacific Ocean and positive anomalies over North America. The abnormal warmth over the North American continent in the springs of 1986, 1987, and 1988 may be explained in terms of an intensified circulation across the Pacific Ocean, which resulted in large positive thickness anomalies downstream over the North American continent. The intensification of those anomalies in the spring of 1988 is discussed as a contributing factor to the initiation of the 1988 North American drought.