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Height Data (height + data)
Selected AbstractsFloodplain friction parameterization in two-dimensional river flood models using vegetation heights derived from airborne scanning laser altimetryHYDROLOGICAL PROCESSES, Issue 9 2003David C. Mason Abstract Two-dimensional (2-D) hydraulic models are currently at the forefront of research into river flood inundation prediction. Airborne scanning laser altimetry is an important new data source that can provide such models with spatially distributed floodplain topography together with vegetation heights for parameterization of model friction. The paper investigates how vegetation height data can be used to realize the currently unexploited potential of 2-D flood models to specify a friction factor at each node of the finite element model mesh. The only vegetation attribute required in the estimation of floodplain node friction factors is vegetation height. Different sets of flow resistance equations are used to model channel sediment, short vegetation, and tall and intermediate vegetation. The scheme was tested in a modelling study of a flood event that occurred on the River Severn, UK, in October 1998. A synthetic aperture radar image acquired during the flood provided an observed flood extent against which to validate the predicted extent. The modelled flood extent using variable friction was found to agree with the observed extent almost everywhere within the model domain. The variable-friction model has the considerable advantage that it makes unnecessary the unphysical fitting of floodplain and channel friction factors required in the traditional approach to model calibration. Copyright © 2003 John Wiley & Sons, Ltd. [source] Influences of the Indian Ocean dipole on the Asian summer monsoon in the following yearINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 14 2008Yuan Yuan Abstract By exploring the spatiotemporal features of the Indian Ocean Dipole (IOD) both on the sea surface and in the subsurface ocean, the present article reveals that the subsurface dipole mode, with larger amplitude than the surface one, is likely to prolong the dipole signal for a long time. Using the wind and geopotential height data from NCEP/NCAR, this article further investigates IOD impacts on the Asian summer monsoon activities in the following year. A normal (late) South China Sea summer monsoon onset is associated with the previous positive (negative) IOD. In the summer after an IOD year, a positive (negative) IOD tends to induce a stronger (weaker) 100-hPa South Asian High, with a more (less) eastward-extending high ridge, and also an enhanced (a weakened) 500-hPa western Pacific subtropical high, with a westward-advancing (an eastward-retreating) high ridge. Influenced by the anomalous 850-hPa Asian monsoon circulations and the longitudinal position of the 500-hPa subtropical high ridge, summer rainfall in China also exhibits different patterns corresponding to different phases of the IOD in the previous year. Copyright © 2008 Royal Meteorological Society [source] Seedling Growth of Agronomic Crops in Crude Oil Contaminated SoilJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2006I. Issoufi Abstract Phytoremediation of hydrocarbon-contaminated soil shows promise as a low-cost alternative to most remediation methods. This study evaluated seedling growth of six crop species in crude oil contaminated soils. The experiments were conducted in a greenhouse. Weathered crude oil was added to an Ipava silt loam soil at the rate of 0 (control), 10, 50 and 100 g of crude oil kg,1 of soil, which was then placed into pots. Irrigation was used to maintain soil moisture at approximately field capacity. Five seeds of Zea mays, Meticago sativa, Lolium perenne, Triticum aestivum, Glycine max or Vicia villosa were sown per pot. The experimental design was completely randomized with five replications per treatment. Germination and seedling height data were recorded on day 7, 14, 21 and 28. Plants were harvested on day 28, separated into shoots and roots and dried to measure biomass. Analysis of variance was used to determine treatment significance. Significant treatment mean values were separated using Tukey's Honestly Significant Difference Test. Based upon percent emergence and plant biomass production in contaminated soil, Z. mays and G. max seedlings show the greatest potential to enhance remediation. [source] Global patterns in plant heightJOURNAL OF ECOLOGY, Issue 5 2009Angela T. Moles Summary 1. ,Plant height is a central part of plant ecological strategy. It is strongly correlated with life span, seed mass and time to maturity, and is a major determinant of a species' ability to compete for light. Plant height is also related to critical ecosystem variables such as animal diversity and carbon storage capacity. However, remarkably little is known about global patterns in plant height. Here, we use maximum height data for 7084 plant Species × Site combinations to provide the first global, cross-species quantification of the latitudinal gradient in plant height. 2. ,The mean maximum height of species growing within 15° of the equator (7.8 m) was 29 times greater than the height of species between 60° and 75° N (27 cm), and 31 times greater than the height of species between 45° and 60° S (25 cm). There was no evidence that the latitudinal gradient in plant height was different in the northern hemisphere than in the southern hemisphere (P = 0.29). A 2.4-fold drop in plant height at the edge of the tropics (P = 0.006) supports the idea that there might be a switch in plant strategy between temperate and tropical zones. 3. ,We investigated 22 environmental variables to determine which factors underlie the latitudinal gradient in plant height. We found that species with a wide range of height strategies were present in cold, dry, low productivity systems, but there was a noticeable lack of very short species in wetter, warmer, more productive sites. Variables that capture information about growing conditions during the harsh times of the year were relatively poor predictors of height. The best model for global patterns in plant height included only one term: precipitation in the wettest month (R2 = 0.256). 4. ,Synthesis. We found a remarkably steep relationship between latitude and height, indicating a major difference in plant strategy between high and low latitude systems. We also provide new, surprising information about the correlations between plant height and environmental variables. [source] Long-term canopy dynamics in a large area of temperate old-growth beech (Fagus crenata) forest: analysis by aerial photographs and digital elevation modelsJOURNAL OF ECOLOGY, Issue 6 2004YUKO HENBO Summary 1Long-term canopy dynamics in a large area of temperate old-growth beech forest in the Daisen Forest Reserve, south-western Japan (11.56 ha studied over 43 years), were investigated using digital elevation models (DEMs) of the canopy surface, constructed from aerial photographs taken in the growing season (i.e. with foliage) in 1958, 1978, 1992 and 2001. A ground surface DEM at the same resolution (a 2.5 × 2.5 m grid) was constructed using aerial photographs taken when foliage was absent (winter 2002). Canopy height data were obtained by calculating differences in elevation between the canopy and the ground surface, and a canopy height profile was constructed. 2Topographic data for a 4-ha plot, located within the 11.56-ha area, were obtained via a ground survey and used to validate the ground surface DEM derived from aerial photographs. 3Canopy height class distributions changed significantly over the 43 years. The total number of gaps, defined as areas where canopy height was , 15 m, decreased but total gap area increased over time. Total gap area in 2001 was twice that of 1958. The density of gaps decreased as gap size increased. 4Gap formation rates increased from 0.47% year,1 (1958,78) to 1.30% year,1 (1992,2001), with a mean of 0.77% year,1, and substantially exceeded closure rates, which fluctuated from 0.28% year,1 (1958,78) to 0.54% year,1 (1978,92), with a mean of 0.39% year,1. Gaps generally expanded and became connected to each other. 5Temporal variation in gap formation and closure might be correlated with the frequency and severity of typhoon disturbances but, if the observed trends continue, this old-growth beech stand may become an open stand. The long-term dynamics of this forest type appear to be far from equilibrium. [source] The prevalence of overweight and obesity among Danish school childrenOBESITY REVIEWS, Issue 7 2010S. Krue Summary In 14 Danish municipalities physicians have gathered weight and height data from 7541 9th grade students (86.7% of all students in 9th grade participating). Overall 25.2% of the population were overweight (body mass index > 90th percentile). Boys were more frequently overweight than girls (29.3% vs. 21.1%) (P < 0.05). 14.1% of the boys and 8.2% of the girls were obese (body mass index > 97th percentile). Categorizing the participating municipalities by socioeconomic status students in municipalities with low status had a significantly higher prevalence of overweight than students in municipalities with high status. Overweight and obesity among Danish school children is a major concern and there are significant social differences in the prevalence of overweight. [source] Correlation between the dioptric power, astigmatism and surface shape of the anterior and posterior corneal surfacesOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 3 2009David Mas Abstract A knowledge of the shape of the cornea is of major importance for the planning and monitoring of surgery, and for the correct diagnosis of corneal diseases. Many authors have studied the geometry of the second corneal surface in the central region and it has been stated that there is a high correlation between the central radii of curvature and asphericities of the two corneal surfaces. In this work we extend this study to a larger, central, 6 mm diameter of the cornea. Surface height data, obtained with an Oculus Pentacam from 42 eyes of 21 subjects, were analysed to yield surface power vectors. Corneal heights of both surfaces were also decomposed into low-order Zernike polynomials and the correlations between each of the power vectors and low-order Zernike coefficients for the two surfaces were studied. There was not only a strong correlation between spherical powers and Zernike defocus coefficients, but also between the astigmatic components. The correspondence between the astigmatism in both surfaces found here can be of the utmost importance in planning optical surgery, since perfect spherical ablation of the first surface does not assure total correction of corneal astigmatism. [source] A critical comparison of stratosphere,troposphere coupling indicesTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 644 2009Mark P. Baldwin Abstract Assessing stratosphere,troposphere coupling in observational data or model output requires a multi-level index with high time resolution. Ideally, such an index would (1) represent spatial patterns in the troposphere that are most strongly coupled with stratospheric variability and (2) be robust and computationally feasible in both observations and standard model output. Several of the indices used to diagnose extratropical stratosphere,troposphere coupling are based on the Northern and Southern Hemisphere annular modes. The annular mode indices are commonly defined as the leading empirical orthogonal functions (EOFs) of monthly-mean, hemispheric geopotential height. In the lowermost troposphere, the structure of the annular modes is defined as the leading EOF of the near-surface geopotential height field, and these patterns correspond well to the patterns of variability induced by stratospheric circulation changes. At pressure levels above the surface, the structure of the annular modes is typically found by either calculating the local EOF or regressing geopotential height data onto the leading principal component time series of near-surface geopotential height. Here we make a critical comparison of the existing methodologies used to diagnose stratosphere,troposphere coupling, including EOF-based indices as well as measures based on zonal-mean wind at a fixed latitude and geopotential height over the polar cap. We argue in favour of an alternative methodology based on EOFs of daily zonally-averaged geopotential. We find that (1) the daily evolution of stratosphere,troposphere coupling events is seen most clearly with this methodology, and (2) the methodology is robust and requires few subjective choices, making it readily applicable to climate model output available only in zonal-mean form. Copyright © 2009 Royal Meteorological Society [source] Environmental and entomological factors determining Ross River virus activity in the River Murray Valley of South AustraliaAUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 3 2009Craig R. Williams Abstract Objectives: 1) To determine whether environmental and mosquito abundance variables could be used to explain fluctuations in the activity of Ross River (RR) virus, in the River Murray Valley of South Australia (SA). 2) To develop models at the local government spatial scale to understand local variability in RR activity factors. Method: Notification data of RR virus positive serology, mosquito surveillance, meteorological and river height data were analysed for the period 1999 to 2006. Stepwise multiple regression was used to determine significant environmental factors and to create descriptive models. Results: The three models developed for different regions of the Valley explained significant amounts of variation in notification rates (R2 0.77 , 0.98). Regional variation in the models was observed, with differences in significant mosquito species evident. Rainfall was a significant predictor of RR virus activity in two of the models, while the height of the River Murray was significant in the third. An overall model for the entire SA section of the Valley contained only time-lagged mosquito abundance variables (R2 0.52). Conclusion: Although rainfall, river height and mosquito abundance are significant factors in determining RR virus activity, there are regional differences in this relationship. Implications: The regional variability of RR virus activity drivers has been defined, and has implications for the forecasting of future activity in this part of SA. The models provided here can provide the foundation for an effective RR virus early warning system, but only if criteria for action, lines of responsibility and the resources required have been determined. [source] Weight and Welfare of Australians, 1890,1940AUSTRALIAN ECONOMIC HISTORY REVIEW, Issue 2 2001Greg Whitwell Views differ on whether living standards in Australia improved between 1890 and 1940. The pessimists, relying principally on product and incomes measures, argue that living standards stagnated; the optimists, using augmented measures of well-being, argue that living standards may have improved. This paper contributes to this debate between the pessimists and optimists by using alternative measures of living standards, namely the height and body mass index (BMI) of male Australian army recruits of World Wars I and II. The nature and usefulness of these measures is examined. The major findings are that the height data indicate an unequivocal improvement in living standards in the period under consideration. The BMI data tend to support a similar conclusion, but the results are ambiguous and there are difficulties in using them alone to determine exactly what happened to living standards. [source] Longitudinal growth and height velocity of Japanese children with Down's syndromeACTA PAEDIATRICA, Issue 9 2003J Kimura Aim: To determine the natural growth pattern of Japanese children with Down's syndrome. Methods: Longitudinal height data of 85 patients (43 males, 42 females) from birth to final height were analyzed. Based on these data, semi-longitudinal standard growth curves and height velocity curves for Down's syndrome were drawn. Results: The means ± SD of final height of males and females with Down's syndrome were 153.2 ± 5.6 and 141.9 ± 4.2 cm, respectively. They were ,3.0 SD and ,2.8 SD for Japanese standards. Mean peak height velocities were 8.9 and 7.5 cm y,1, and the ages at peak height velocity were 11.6 and 10.2 y for males and females, respectively. Conclusion: The mean height of patients with Down's syndrome was around ,2 SD for normal children before puberty. Their pubertal growth spurt starts about 1 y earlier and their peak height velocity was about 1.3,1.4 cm shorter than for normal children. [source] New reference for the age at childhood onset of growth and secular trend in the timing of puberty in SwedishACTA PAEDIATRICA, Issue 6 2000YX Liu The objectives of the present work were to present a new reference for the age at childhood onset of growth and to investigate the secular trend in the timing of puberty in a community-based normal population in Sweden. A total of 2432 children with longitudinal length/height data from birth to adulthood were used to determine the two measures by visual inspection of the measured attained length/height and the change in growth velocity displayed on a computer-generated infancy-childhood-puberty (ICP) based growth chart. The series represents a sample of normal full-term children born around 1974 in Göteborg, Sweden. We found about 10% of children were delayed (>12 mo of age) in the childhood onset of growth based on the previous reported normal range, i.e. 14% in boys and 8% in girls. Distribution of the age at childhood onset of growth was skewed. The medians were 10 and 9 mo for boys and girls, respectively. After natural logarithmic transformation, the mean and standard deviation (SD) were 2.29 (anti-log 9.9 mo) and 0.226 for boys, 2.23 (anti-log 9.3 mo) and 0.220 for girls, respectively. The 95% normal ranges were 6.3-15.4 and 6.0-14.3 for boys and girls, respectively. The distribution of the timing of PHV was close to the normal distribution. The mean values were 13.5 y for boys and 11.6 y for girls with 1 y SD for both sexes. Conclusion: A downward secular trend in the onset of puberty was clearly shown in the population. The age at childhood onset of growth did not correlate with the timing of puberty (r=,0.01 and 0.05, p > 0.7 and 0.1 in boys and girls, respectively). Normal ranges of the age at childhood onset of growth are in need of revise, as this study indicates. The new reference presented here could be a reliable indicator in further studies. [source] | |||||||||||||