Hui Shuk Ying. / Thesis submitted in: October 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 135-149). / Abstracts in English and Chinese. / ACKNOWLEDGEMENTS --- p.ii / ABSTRACT --- p.iii / 中文摘要 --- p.v / TABLE OF CONTENTS --- p.vi / LIST OF TABLES --- p.viii / LIST OF FIGURES --- p.ix / LIST OF SYMBOLS --- p.xii / Chapter CHAPTER I --- INTRODUCTION --- p.1 / Chapter 1.1. --- Background --- p.1 / Chapter 1.2. --- Situation in Hong Kong --- p.4 / Chapter 1.3. --- Physical setting of Hong Kong --- p.7 / Chapter 1.4. --- Climate of Hong Kong --- p.9 / Chapter 1.5. --- Objectives of the study --- p.12 / Chapter 1.6. --- Significance of the study --- p.12 / Chapter 1.7. --- Organization of the thesis --- p.13 / Chapter CHAPTER II --- LITERATURE REVIEW --- p.14 / Chapter 2.1. --- Introduction --- p.14 / Chapter 2.2. --- Nature of Urban Heat Island (UHI) --- p.15 / Chapter 2.3. --- Characterization of UHI --- p.16 / Chapter 2.3.1. --- Diurnal variation --- p.17 / Chapter 2.3.2. --- Seasonal variation --- p.19 / Chapter 2.3.3. --- Spatial distribution of UHI --- p.20 / Chapter 2.4. --- Effects of weather factors on UHI intensity --- p.22 / Chapter 2.5. --- Relationship between urban factors and UHI intensity --- p.27 / Chapter CHAPTER III --- WEATHER DATA AND METHODOLOGY --- p.34 / Chapter 3.1. --- Surface meteorological observation --- p.34 / Chapter 3.1.1. --- Meteorological stations --- p.35 / Chapter 3.1.2. --- Methods of observation --- p.40 / Chapter 3.2. --- Acquisition and processing of data --- p.42 / Chapter 3.3. --- Detection of urban heat island in Hong Kong --- p.46 / Chapter 3.4. --- "Characterization of UHI intensity, frequency and temporal patterns" --- p.48 / Chapter 3.5. --- Evaluation of relationship between UHI intensity and weather conditions --- p.49 / Chapter 3.6. --- Evaluation of correlation between UHI intensity and city growth --- p.51 / Chapter CHAPTER IV --- RESULTS AND DISCUSSION --- p.52 / Chapter 4.1. --- Temperature evolution in Hong Kong --- p.52 / Chapter 4.1.1. --- Urban center --- p.52 / Chapter 4.1.2. --- New town --- p.57 / Chapter 4.1.3. --- Rural areas --- p.64 / Chapter 4.1.4. --- Discussion of the temperature changes in Hong Kong --- p.68 / Chapter 4.2. --- Urban heat island in Hong Kong --- p.75 / Chapter 4.2.1. --- Basic characteristics of UHI --- p.75 / Chapter 4.2.2. --- Annual patterns of UHI --- p.83 / Chapter 4.2.3. --- Seasonal patterns of UHI --- p.87 / Chapter 4.2.4. --- Discussion of the UHI phenomenon --- p.96 / Chapter 4.3. --- Weather effect on UHI intensity --- p.102 / Chapter 4.3.1. --- UHI phenomena and weather conditions --- p.103 / Chapter 4.3.2. --- Relationship between UHI intensity and meteorological elements --- p.106 / Chapter 4.3.3. --- Discussion of weather effects on UHI intensity --- p.115 / Chapter 4.4. --- Correlation of urban indicators and UHI intensity --- p.121 / Chapter CHAPTER V --- CONCLUSIONS AND RECOMMENDATIONS --- p.128 / Chapter 5.1. --- Summary of findings --- p.128 / Chapter 5.2. --- Limitation of the research --- p.133 / Chapter 5.3. --- Prospects of the study --- p.134 / REFERENCES --- p.135

No description available.

A comprehensive analysis of midlatitude intraseasonal variability in extended integrations of General Circulation Models (GCMs) developed at the National Aeronautics and Space Administration Goddard Space Flight Center is conducted in the first part of this thesis. The model statistics, three-dimensional structure, and dynamical characteristics of storm tracks and large-scale weather regimes are diagnosed and directly compared to parallel observational analyses. Results indicate that several aspects of simulated intraseasonal phenomenon are linked to errors in the zonally asymmetric circulation. During the boreal winter, anomalously large meridional temperature gradients and enhanced zonal winds in the simulations are linked to suppressions in baroclinic wave activity in the models. As a result lower-frequency modes in the GCMs are more strongly driven by baroclinic dynamics. Nonetheless, the GCMs successfully reproduce the North Pacific midwinter suppression phenomenon. In an effort to provide insight into the North Pacific midwinter suppression, the second part of this work stratifies the boreal cool season into three stages, where the early and late (middle) stages approximately correspond to the seasonal maxima (minimum) in synoptic eddy activity that occurs over the North Pacific. Analyses using this unique approach reveal that during the midwinter suppression period, cyclonic perturbations entering the North Pacific storm track core from Asia are already deficient in magnitude compared to early and late winter stages. In both observations and model simulations, the North Pacific midwinter suppression feature is discovered to have a clear organized extension upstream into Siberia. Thus, the final portion of this thesis examines the causes for the midwinter suppression of upper tropospheric Rossby wave packets propagating across Asia prior to entering the North Pacific storm track. The study unveils an increased sensitivity of synoptic-scale wave packets with a large-scale, upper-tropospheric flow pattern over Siberia during midwinter. This interaction with the large-scale pattern over Siberia results in a general dampening of synoptic eddy amplitudes over Asia, which is proposed to be the contributing factor to the North Pacific midwinter suppression phenomenon.

In this cumulative dissertation, different features and methods are presented to assess and process multi-sensor derived radar data for climatological analysis. The overall objectives were to appraise the limitations of an hourly radar-based quantitative precipitation estimate (QPE) product and to develop and apply reasonable approaches to process these data. Hence the spatial and temporal limitations of radar-derived precipitation rates are discussed in the context of climatological applications, and two types of climatologies are obtained, first a climatology of daily precipitation fields and second a long term precipitation climatology. These relate to questions concerning the methodologies rather than climatological significance or assessment of precipitation and its role in the water balance. Current radar data availability limits such a hydro-climatic analysis. The thesis consists of three peer-reviewed publications. All investigations in this thesis are based on the RADOLAN rw-product of the German Weather Service (DWD) for an extended study region including the Free State of Saxony, Germany, for the period from April 2004 to November 2011. The first publication is dedicated to the classification of daily precipitation fields by unsupervised neural networks. In the presented work, the quality of the radar-derived precipitation rates is analysed by a temporal comparison between recording and non-recording gauges and the corresponding pixels of the RADOLAN rw-product on hourly and daily bases. The analysis shows that a temporal aggregation of the original product should be limited to a temporal scale up to 24 h because of the processing algorithms and the reappearance of previously suppressed errors. Nevertheless, an unsupervised neural network was successfully used for the classification of daily patterns. The derived daily precipitation classes and corresponding precipitation patterns could be assigned to properties of the associated weather patterns and seasonal dependencies. Hence, it could be shown that the classified patterns not only occurred by chance but by statistically proven properties of the atmosphere and of the season. The second publication is primarily concerned with two tasks: first, the pixel-wise fitting of mixture distributions on the bases of the obtained patterns from the first publication, and second, the analysis of spatial consistency of the radar-derived precipitation data set. The fitted parametric distribution functions were analysed in terms of Akaike\'s information criterion and the Kolmogorov-Smirnov test. These benchmarks showed, that the performances are best for mixture distributions derived by an initial classification by an unsupervised neural network and cluster analysis, and by gamma distributions. These results underline the significance of the derived precipitation classes obtained in the first publication. Furthermore, the Kolmogorov-Smirnov test indicates that independent of the distribution function, the radar-derived daily precipitation rates under the assumption of the deployed parametric distribution function has the best or most natural order of precipitation rates at spatial scales from 2 to 4 km for daily precipitation fields. Thus, it is recommended to use the original radar product at these scales rather than at 1 km resolution for daily precipitation sums. In the last publication, the focus shifts from daily to long-term precipitation climatology. The work introduces a rapid and simple approach for processing radar-derived precipitation rates for long-term climatologies. The method could successfully be applied to the radar-derived precipitation rates by excluding or correcting the errors that reappear due to temporal aggregation. Despite the fact that the approach is empirical, the introduced parameters could almost be objectively derived by means of simulation and optimisation. This could be achieved by utilising the reasonable relationship between elevation and precipitation rates for longer periods. Finally, the obtained results are compared to two independently derived precipitation data sets. The comparison shows good agreement of the precipitation fields and illustrates a reasonable application of the introduced procedure. The presented results support the application of the approach for precipitation aggregates of, at least, annual or longer periods. However the derivation of climatologies led to satisfactory results at the respective temporal scales, though the influence of radar-specific errors can only be minimized to a certain degree. Further studies have to prove if an application independent processing of radar-derived precipitation rates leads to higher qualities and validities of the derived data in time and space.

Submitted by Miriam Rodrigues Silvestre null (miriam@fct.unesp.br) on 2016-04-12T19:42:55Z No. of bitstreams: 1 Tese_MRS.pdf: 22047618 bytes, checksum: 7c7834a117ebe81c7554b7808f8593b5 (MD5) / Approved for entry into archive by Ana Paula Grisoto (grisotoana@reitoria.unesp.br) on 2016-04-15T12:40:50Z (GMT) No. of bitstreams: 1 silvestre_mr_dr_prud_par.pdf: 1762323 bytes, checksum: 590891333b2addf8f715166f578950f5 (MD5) / Made available in DSpace on 2016-04-15T12:40:50Z (GMT). No. of bitstreams: 1 silvestre_mr_dr_prud_par.pdf: 1762323 bytes, checksum: 590891333b2addf8f715166f578950f5 (MD5) Previous issue date: 2016-03-08 / Essa tese aborda o uso da Estatística na Climatologia Geográfica, através da identificação das técnicas mais usuais e possíveis falhas em sua aplicação em análises geográficas do clima, bem como sugestões de alternativas para as diversas situações e necessidades, de acordo com as possibilidades. As fontes de informações utilizadas foram trabalhos apresentados no Simpósio Brasileiro de Climatologia Geográfica (SBCG) e artigos publicados na Revista Brasileira de Climatologia (RBClima). Entre os objetivos para os quais se aplicam técnicas estatísticas foram apresentadas técnicas para: preenchimento de falhas, análise exploratória de dados, escolha de anos padrão, análise de tendências em séries com modelos de regressão, testes para análise de tendência, rupturas e consistência de séries, correlação entre duas séries, modelos estatísticos para relacionar uma variável dependente com duas ou mais variáveis independentes, interpolação de dados no espaço, definição de regiões homogêneas, classificação climática e vulnerabilidade socioambiental. Concluiu-se que ainda há algumas aplicações incorretas das técnicas estatísticas e foram realizadas sugestões de outras técnicas que poderiam ser utilizadas. Espera-se que essa tese possa contribuir para a aplicação da Estatística e facilitar a interação entre o geógrafo e o estatístico no desenvolvimento de pesquisas na área de Climatologia Geográfica, bem como na Geografia do Clima. / This thesis discussed the use of Statistics in the Geographical Climatology, by identifying the most common technics and possible failures in its application in geographical climate analyzes and suggests alternatives to the different situations and needs, according to the possibilities. The sources of information used were papers presented at the Brazilian Symposium of Geographical Climatology (SBCG) and articles published in the Brazilian Journal of Climatology (RBClima). Among the objectives for which they apply statistical techniques, were discussed techniques for: gap filling, exploratory data analysis, pattern year choice, trend analysis in series with regression models, tests for trend analysis, ruptures and consistency of series, correlation between two series, statistical models to relate a dependent variable with two or more independent variables, data interpolation in space, definition of homogeneous regions, climatic classification and socio-environmental vulnerability. It was concluded that there is still some incorrect application of statistical techniques and were suggested that other techniques could be used. It is hoped that this thesis can contribute to the application of Statistics and facilitate interaction between the geographer and statistician in the development of research in the field of Geographical Climatology and Climate in Geography.

As possíveis alterações climáticas, em diferentes escalas espaciais e temporais, alicerçam diversas pesquisas em climatologia a fim de compreender a dinâmica climatológica, bem como os atributos climáticos em tal processo. As chuvas, nesse sentido, representam a complexidade no entendimento da dinâmica atmosférica, uma vez que essas apresentam sua gênese apoiadas em diferentes processos atmosféricos. Com isso, o presente estudo compreende o comportamento das chuvas na região de São Carlos a partir da concentração, distribuição e variabilidade dessas nas estações climatológicas do CRHEA/USP, INMET/UFSCar e EMBRAPA sendo essas as adotadas de acordo com a proposta de Monteiro (1973) e a partir da série histórica de 1993 a 2014. No presente trabalho, foi realizado a revisão bibliográfica acerca da temática de gênese das chuvas para o Brasil e para o Estado de São Paulo, além da determinação do cálculo dos índices de PRCPTOT (precipitação total nos dias úmidos), CDD (dias consecutivos secos), CWD (dias consecutivos úmidos), SDII (índice simples de intensidade), RX 1 dia (máximo acumulado em um único dia), RX 5 dias (máximo acumulado em cinco dias) e Rnn (número de dias acima de 20, 35, 46 e 60 mm de chuvas) pelo software R com script RClimdex 1.1. Os dados calculados apresentaram grande flutuação ao longo da série histórica 1993-2014 para todos os índices adotados, o que configura a presença de anos abaixo e acima da média para cada índice, bem como questiona o apontamento de tendências significativas quanto a existência de mudanças climáticas locais e regionais. / The possible climate change, in different spatial and temporal scales, consolidates several climatology researches in order to comprehend the climatologic dynamics, as well as climate attributes in such process. Rain, in this meaning, represents the complexity on the atmospheric dynamic understanding, once it presents its genesis based on different atmospheric processes. With that, the following study comprehends the rain behavior in the region of São Carlos according to its concentration, distribution and variability in the climatological stations from CRHEA/USP, INMET/UFSCar and EMBRAPA, being these adopted according to propose of Monteiro (1973) and from the historical series from 1993 to 2014. In this study, the bibliographic revision was performed concerning the rain genesis for Brazil and for the state of São Paulo theme, apart from the determination of the PRCPTOT (total precipitation on wet days), CDD (consecutive dry days), CWD (consecutive wet days), SDII (simple intensity index), RX 1 day (maximum accumulated in one single day), RX 5 days (maximum accumulated in five days) and Rnn (number of day above 20, 35, 46 and 60 mm of rain) index calculus through the software R with the script Rclimdex 1.1. The calculated data present a great floating along the historical series 1993-2014 for all the admitted index, which sets the presence of years below and above the average for each index, as well as it questions the notation of significant trends as to the existence of local and regional climate changes.

O presente trabalho destina-se a investigação do conceito de tipos de tempo, largamente utilizado na Climatologia Dinâmica, porém sua definição e aplicação ainda constituem obstáculos significativos para a Climatologia. Nesse contexto, a proposta colocada tem como finalidade estudar o conceito de tipos de tempo a partir de uma história das idéias, buscando suas origens e diferentes concepções teóricas e operacionais relacionadas. Destaca-se a preocupação com a delimitação das escalas espaciais e temporais do referido conceito e suas integrações, visando uma compreensão mais adequada deste conceito / This thesis aims to research the concept of \"weather types\", widely used in Dynamic Climatology, however their definition and implementation are still significant obstacles to Climatology.In this context, the proposed project aims to study the concept of \"weather types\" from a history of ideas, seeking their origins and different theoretical concepts and operational related. There is the concern with the delimitation of the spatial and temporal scales of this concept and its integration, aiming at a more adequate understanding of the concept

In this cumulative dissertation, different features and methods are presented to assess and process multi-sensor derived radar data for climatological analysis. The overall objectives were to appraise the limitations of an hourly radar-based quantitative precipitation estimate (QPE) product and to develop and apply reasonable approaches to process these data. Hence the spatial and temporal limitations of radar-derived precipitation rates are discussed in the context of climatological applications, and two types of climatologies are obtained, first a climatology of daily precipitation fields and second a long term precipitation climatology. These relate to questions concerning the methodologies rather than climatological significance or assessment of precipitation and its role in the water balance. Current radar data availability limits such a hydro-climatic analysis. The thesis consists of three peer-reviewed publications. All investigations in this thesis are based on the RADOLAN rw-product of the German Weather Service (DWD) for an extended study region including the Free State of Saxony, Germany, for the period from April 2004 to November 2011. The first publication is dedicated to the classification of daily precipitation fields by unsupervised neural networks. In the presented work, the quality of the radar-derived precipitation rates is analysed by a temporal comparison between recording and non-recording gauges and the corresponding pixels of the RADOLAN rw-product on hourly and daily bases. The analysis shows that a temporal aggregation of the original product should be limited to a temporal scale up to 24 h because of the processing algorithms and the reappearance of previously suppressed errors. Nevertheless, an unsupervised neural network was successfully used for the classification of daily patterns. The derived daily precipitation classes and corresponding precipitation patterns could be assigned to properties of the associated weather patterns and seasonal dependencies. Hence, it could be shown that the classified patterns not only occurred by chance but by statistically proven properties of the atmosphere and of the season. The second publication is primarily concerned with two tasks: first, the pixel-wise fitting of mixture distributions on the bases of the obtained patterns from the first publication, and second, the analysis of spatial consistency of the radar-derived precipitation data set. The fitted parametric distribution functions were analysed in terms of Akaike\'s information criterion and the Kolmogorov-Smirnov test. These benchmarks showed, that the performances are best for mixture distributions derived by an initial classification by an unsupervised neural network and cluster analysis, and by gamma distributions. These results underline the significance of the derived precipitation classes obtained in the first publication. Furthermore, the Kolmogorov-Smirnov test indicates that independent of the distribution function, the radar-derived daily precipitation rates under the assumption of the deployed parametric distribution function has the best or most natural order of precipitation rates at spatial scales from 2 to 4 km for daily precipitation fields. Thus, it is recommended to use the original radar product at these scales rather than at 1 km resolution for daily precipitation sums. In the last publication, the focus shifts from daily to long-term precipitation climatology. The work introduces a rapid and simple approach for processing radar-derived precipitation rates for long-term climatologies. The method could successfully be applied to the radar-derived precipitation rates by excluding or correcting the errors that reappear due to temporal aggregation. Despite the fact that the approach is empirical, the introduced parameters could almost be objectively derived by means of simulation and optimisation. This could be achieved by utilising the reasonable relationship between elevation and precipitation rates for longer periods. Finally, the obtained results are compared to two independently derived precipitation data sets. The comparison shows good agreement of the precipitation fields and illustrates a reasonable application of the introduced procedure. The presented results support the application of the approach for precipitation aggregates of, at least, annual or longer periods. However the derivation of climatologies led to satisfactory results at the respective temporal scales, though the influence of radar-specific errors can only be minimized to a certain degree. Further studies have to prove if an application independent processing of radar-derived precipitation rates leads to higher qualities and validities of the derived data in time and space.

No description available.

Atmospheric dispersion models are being increasingly used by local authorities in the United Kingdom as part of their urban air quality management programmes. Output from dispersion models now forms a vital part of any environmental impact assessment, road improvement or traffic management scheme or environmental health study. This study is centred primarily on Northampton, a county town in Southern England and is concerned with the limitations of meteorological data available to local authorities. The first part of the study investigates the variation in certain key meteorological parameters both within Northampton and between synoptic stations up to 70 kilometres away. The second part examines modelling outcomes using different sets of meteorological data and evaluates the performance of an urban dispersion model in relation to monitored air quality data. Special emphasis is placed on the use of cloud cover as a meteorological input variable. A small case study of monitoring and modelling work carried out in the London Borough of Richmond is also presented