Tesis sobre el tema "ARLD model"

Magister Commercii - MCom
This study investigates the effect of public debt on economic growth in South Africa since 1961-2017. Public debt stock is disaggregated into external debt and domestic debt in order to determine the effect of each on economic growth independently. The study employed the ARDL bound test to estimate the long and short run relationship among several macroeconomic variables - real economic growth, domestic debt, external debt, budget deficit, inflation rate and investment. An error correction model was used to analyses the short-run disequilibrium. The results show that there is a short and long run equilibrium relationship between foreign debt, domestic debt, budget deficit, inflation rate and economic growth. The empirical results indicate that external debt negatively affects the real GDP growth in South Africa, both in the short and long-run. Several policy implications emerged from the empirical results. To keep public debt more manageable, South Africa should improve its debt management. Furthermore, the country can make use of debt to equity swaps by privatizing underperforming parastatals. This would make them competitive and efficient.

Utilisé très souvent de façon métaphorique pour désigner les franges méridionales du Sahara, le Sahel du fait de sa position géographique est une région vulnérable au changement climatique. L’agriculture est fortement pluviale et largement dépendante des conditions climatiques. La prise en compte du changement climatique est indispensable dans la réalisation de la sécurité alimentaire au Sahel. En alliant travaux empiriques et théoriques, cette thèse se propose de contribuer à une meilleure compréhension de l’incidence du changement climatique sur la sécurité alimentaire au Sahel au niveau microéconomique et macroéconomique. Le premier chapitre examine au niveau macroéconomique, la situation de la sécurité alimentaire au Sahel, après avoir analysé son dynamisme démographique. Les résultats de ce chapitre montrent que le Sahel n’a pas encore entamé sa transition démographique. Le taux de croissance démographique est élevé par rapport à la moyenne de l’Afrique subsaharienne. La sous-alimentation est en baisse mais reste prégnante dans cette région. Réduire la sous-alimentation passe nécessairement par la production agricole, qui est tributaire des aléas climatiques. Le deuxième chapitre s’intéresse donc aux effets du changement climatique sur les rendements de certaines cultures (mil, sorgho et maïs) au Sahel. Les résultats indiquent que le changement climatique a un impact globalement négatif sur les rendements agricoles au Sahel. Cette analyse au niveau macroéconomique est ensuite complétée par deux chapitres qui, à un niveau microéconomique, se focalisent sur le comportement des agriculteurs au Sahel. Le troisième chapitre cherche ainsi à analyser l’impact des chocs climatiques mesurés par la perception des agriculteurs sur l’inefficience des parcelles agricoles. Il ressort de cette étude que les chocs climatiques augmentent l’inefficience des parcelles agricoles. A travers la baisse des rendements et l’inefficience des parcelles, le changement climatique peut affecter la pauvreté et la vulnérabilité alimentaire des ménages agricoles burkinabés. A cet effet, le quatrième chapitre identifie les déterminants individuels et contextuels de la pauvreté et la vulnérabilité alimentaire des ménages agricoles burkinabés. Les résultats relèvent qu’en plus des caractéristiques individuelles du ménage agricole comme sa taille ou le niveau d’éducation du chef du ménage, le contexte climatique de résidence permet d’expliquer sa pauvreté et vulnérabilité alimentaire
Often used metaphorically to refer to the southern fringes of the Sahara, the Sahel's geographical position makes it a region vulnerable to climate change. Agriculture is highly rain-fed and largely dependent on climatic conditions. If food security is to be achieved in the Sahel, climate change must be taken into account. By combining empirical and theoretical work, this thesis aims to contribute to a better understanding of the impact of climate change on food security in the Sahel at the microeconomic and macroeconomic levels. The first chapter examines the food security situation in the Sahel at the macroeconomic level, after analysing its demographic dynamism. The results of this chapter show that the Sahel has not yet begun its demographic transition. The demographic growth rate is high compared with the average for sub-Saharan Africa. Undernourishment is on the decline, but remains prevalent in the region. Reducing undernourishment necessarily involves agricultural production, which is dependent on the vagaries of the climate. The second chapter therefore looks at the effects of climate change on the yields of certain crops (millet, sorghum and maize) in the Sahel. The results indicate that climate change is having an overall negative impact on agricultural yields in the Sahel. This analysis at the macroeconomic level is then supplemented by two chapters which, at the microeconomic level, focus on the behaviour of farmers in the Sahel. The third chapter seeks to analyse the impact of climatic shocks, as measured by farmers' perceptions, on the inefficiency of agricultural plots. This study shows that climatic shocks increase the inefficiency of agricultural plots. Through lower yields and plot inefficiency, climate change may affect the poverty and food vulnerability of Burkinabé farming households. To this end, the fourth chapter identifies the individual and contextual determinants of poverty and food vulnerability among farming households in Burkina Faso. The results show that, in addition to the individual characteristics of farm households, such as their size or the level of education of the head of household, the climatic context in which they live helps to explain their poverty and food vulnerability

Mestrado em Economia
Throughout history, countries from all over the world have devoted a considerable amount of resources to produce security. This evidence has motivated a growing number of studies that examine the determinants of the demand for military expenditure. Albeit the difficulty to develop a general theoretical framework and the inexistence of a standard empirical approach to model the demand for military expenditure, it is an important issue to understand which factors may influence the military expenditure demand function of a country. The aim of this dissertation is to find out the main variables affecting the Portuguese military expenditure taking into account a comprehensive set of economic, strategic and political determinants. For this goal, a military expenditures demand model is constructed for the period 1960–2010 employing the Autoregressive Distributed Lag (ARDL) bound testing cointegration approach. The results suggest that the Portuguese defence spending is determined by the country´s economic performance, allies‟ defence speeding and security considerations. As far as the domestic political environment is concerned, the dominant ideology of the party in power seems to be insignificant, while the transition to a democratic regime is considered a relevant determinant with a negative effect on the military expenditure.
Ao longo da história, países de todo o mundo têm empenhado uma quantidade considerável de recursos para produzir segurança. Esta constatação tem motivado um número crescente de estudos sobre as possíveis variáveis explicativas da despesa militar. Apesar da dificuldade em estabelecer um quadro teórico de referência e da inexistência de uma abordagem empírica padronizada para determinar a procura de despesa militar, revela-se importante compreender quais as variáveis que influenciam a despesa militar de um país. O objetivo deste trabalho é aferir quais as principais fatores que poderão determinar a despesa militar de Portugal, tendo em conta um amplo conjunto de variáveis de natureza económica, estratégica e política. A prossecução deste objetivo assenta na construção de uma equação de procura para a despesa militar portuguesa, para o período compreendido entre 1960 e 2010, através de um modelo uniequacional ARDL. Os resultados obtidos sugerem que a despesa militar em Portugal é determinada pelo desempenho económico, pelo gasto militar de países aliados e por considerações relativas à perceção das condições de segurança. No que respeita à influência do ambiente político, a ideologia dominante do partido em funções no Governo surge como não significante, ao passo que a transição para um regime democrático é considerada uma variável relevante, com um efeito negativo sobre as despesas militares.

Sedimentation has become a significant environmental threat in South Africa as it intensifies water management problems in the water-scarce semi-arid regions of the country. As South Africa already allocates 98% of available water, the loss of storage capacity in reservoirs and degraded water quality has meant that a reliable water supply is compromised. The overall aim of this thesis was to develop a catchment scale model that represents the sediment dynamics of semi-arid regions of South Africa as a simple and practically applicable tool for water resource managers. Development of a conceptual framework for the model relied on an understanding of both the sediment dynamics of South African catchments and applicable modelling techniques. Scale was an issue in both cases as most of our understanding of the physical processes of runoff generation and sediment transport has been derived from plot scale studies. By identifying defining properties of semi-arid catchments it was possible to consider how temporal and spatial properties at higher levels emerged from properties at lower levels. These properties were effectively represented by using the Pitman rainfall-runoff model disaggregated to a daily timescale, the Modified Universal Soil Loss Equation (MUSLE) model incorporating probability function theory and through the representation of sediment storages across a semi-distributed catchment. The model was tested on two small and one large study catchment in the Karoo, South Africa, with limited observed data. Limitations to the model were found to be the large parameter data set and the dominance of structural constraints with an increase in catchment size. The next steps in model development will require a reduction of the parameter data set and an inclusion of an in-stream component for sub-catchments at a larger spatial scale. The model is applicable in areas such as South Africa where water resource managers need a simple model at the catchment scale in order to make decisions. This type of model provides a simple representation of the stochastic nature of erosion and sediment delivery over large spatial and temporal scales.

A Disaggregation model was tested for arid land stream flow generating. The test was performed on data from Black River, near Fort Apache, Arizona. The model was tested in terms of preserving the relevant historical statistics on both monthly and daily levels, the monthly time series were disaggregated to a random observation of their daily components and the daily components were then reaggregated to yield monthly values. A computer model (DSGN) was developed to perform the model implementation. The model was written and executed on the Macintosh plus personal computer Data from two months were studied; the October data represented the low flow season, while the April data represented the high flow season. Twenty five years of data for each month was used. The generated data for the two months was compared with the historical data.

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric and Planetary Sciences, 1985.
Microfiche copy available in Archives and Science.
Bibliography: leaves 163-167.
by Michel M. Verstraete.
Sc.D.

A simple model of surface and sub-surface soil temperature was developed at the watershed scale (-100 km²) in a semi-arid rangeland environment. The model consisted of a linear combination of air temperature and net radiation and assumed: (1) topography controls the spatial distribution of net radiation, (2) near-surface air temperature and incoming solar radiation are relatively homogeneous at the watershed scale and are available from ground stations and (3) soil moisture dominates transient soil thermal property variability. Multiplicative constants were defined to account for clear sky diffuse radiation, soil thermal inertia, an initially fixed ratio between soil heat flux and net radiation and exponential attenuation of solar radiation through a partial canopy. The surface temperature can optionally be adjusted for temperature and emissivity differences between mixed bare soil and vegetation canopies. Model development stressed physical simplicity and commonly available spatial and temporal data sets. Slowly varying surface characteristics, such as albedo, vegetation density and topography were derived from a series of Landsat TM images and a 7.5" USGS digital elevation model at a spatial resolution of 30 m. Diurnally variable atmospheric parameters were derived from a pair of ground meteorological stations using 30-60 min averages. One site was used to drive the model, the other served as a control to estimate model error. Data collected as part of the Monsoon '90 and WG '92 field experiments over the ARS Walnut Gulch Experimental Watershed in SE Arizona were used to validate and test the model. Point, transect and spatially distributed values of modeled surface temperature were compared with synchronous ground, aircraft and satellite thermal measurements. There was little difference between ground and aircraft measurements of surface reflectance and temperature which makes aircraft transects the preferred method to "ground truth" satellite observations. Mid-morning modeled surface temperatures were within 2° C of observed values at all but satellite scales, where atmospheric water vapor corrections complicate the determination of accurate temperatures. The utility of satellite thermal measurements and models to study various ground phenomena (e.g. soil thermal inertia and surface energy balance) were investigated. Soil moisture anomalies were detectable, but were more likely associated with average near-surface soil moisture levels than individual storm footprints.

Intrinsic ecological fragility of drylands and increasing anthropic pressures, which often relate to the unsustainable management of groundwater resources, are leading factors in desertification processes. Natural processes alone could not be enough to regenerate those fragile environments from degradation, and it is necessary the corrective interference of local and international communities. In this perspective, the WADIS-MAR Project (www.wadismar.eu) has been funded by the European Community in the frame of the SWIM Programme (www.swim-sm.eu) and started implementation. The aim of the Project was to enable local communities to manage groundwater resources through the application of sustainable agricultural practices and the implementation of water harvesting techniques and MAR systems. The Biskra and Batna region (Algeria) and the Jeffara of Medenine (Tunisia) are the two intervention areas selected in the frame of the Project because characterised by overexploitation of groundwater resources and are highly exposed to desertification processes. The main objective of the present research was the development of a methodology for the hydrogeological characterisation of the Biskra and Batna region finalised to the study of sustainable systems for the management of groundwater resources that could be reply in similar context. The first phase of the research has focused on the collection of literature data, freely released satellite datasets, and field measures carried out by local partners. Collected data were verified, organised within a geodatabase, preprocessed and then imported into a geo-modeler software for the realisation of two 3-D hydrogeological models. The regional scale model extends over the South-western slope of the Aures mountains. 14 and 6 geological cross sections at 1:200.000 and 1:50.000 scale respectively, were realised perpendicular to the main geological structures and integrated with hydrogeological information to obtain the hydrogeological conceptual model of the Biskra and Batna region. From its analysis emerged that: 1) interference between two main fold systems generates dome and basins geometries constituting large storage areas; 2) groundwater recharge can occur in the Aures mountains where the hydrogeological units crop out; 3) a complex faults system influences the groundwater circulation allowing the communication among various aquifers and acting as preferred pathway for groundwater rises towards the surface. The local scale model was developed to define the geometries of the Infèro-Flux phreatic aquifer, near the city of Biskra. 19 geological cross sections were realised at 1:10.000 scale and perpendicular to the groundwater flow direction by integrating geological information into a geomorphological interpretation of the river system. Results show that the aquifer morphology is characterised by an asymmetric geometry of the confining bed and maximum deposit depth of 50 metres. The volume of the alluvium was also estimated and corresponds to 83 Mm3. The conceptual model of the Inféro-Flux aquifer was developed by integrating the hydrogeological and hydrological data into the local scale 3-D model and used to develop a groundwater flow numerical model to estimate the hydraulic conductivity parameter and to obtain quantitative information about the system dynamics. A first hydrogeological dataset was used for the automated calibration of the Kx parameter through the PEST. Resulting values range between 0.00019 and 0.00869 m/s and are coherent with braided stream deposits. A second hydrogeological dataset was used to validate the calibration results. Groundwater budget was compared to the hydrological balance. Results suggest that infiltration alone is not sufficient to allow the simulated inflow from the northern head boundary. Therefore, it is reasonable to consider a further source of alimentation for the Inféro-Flux aquifer. Low residual values confirm the consistency of the numerical model

A stochastic, compartmental Model for Adaptive Livestock Management (MALM) was developed for cow-calf enterprise for Rolling Plains of Texas from an existing model, Simple Ecological Sustainability Simulator (SESS). The model simulates forage and animal production. It runs on a monthly time step. Two stocking strategies, flexible and fixed, were evaluated at seven stocking levels for effects on forage and animal production, range condition, and net ranch income. Evaluation data were obtained from published and unpublished data from Texas A&M Agricultural Experimental Station at Vernon for Throckmorton. The model adequately simulated forage and animal production. Light fixed stocking rates and flexible stocking strategies resulted in cows of median body condition score (BCS) 5, compared to low BCS of 4 under moderate fixed stocking rate, and BCS of 3 under heavy fixed stocking. BCS declined from autumn to early spring and peaked in summer. Cows under light fixed stocking rates and under flexible stocking were heavier (460 kg) compared to those under heavy fixed stocking (439 kg). Replacement rates were lower under light stocking (22 %), compared to flexible (37 %) and heavy stocking (56 %). Calf crops were all above the reported 90 % expected for bred heifers because of the replacement policy. Flexible stocking strategy resulted in higher net income ($19.62 ha-1), compared to fixed light ($5.93 ha-1) or fixed heavy ($-17.35 ha-1) stocking strategies. Coefficient of variation (CV) in net income was highest under heavy stocking (90%) compared to light stocking (60%) and flexible stocking (50%). Maximum net income was obtained between 0.05 AUM·ha-1 and 0.13 AUM·ha-1 when fixed stocking strategy was used but when flexible stocking strategy was used maximum net income was obtained between 0.1 AUM·ha-1 and 0.17 AUM·ha-1. Range condition rapidly declined under fixed heavy stocking, increased under fixed and light flexible stocking, and remained constant under moderate flexible stocking. Heavy fixed stocking decreased range condition rapidly over a 20-year period. MALM was an effective tool to demonstrate effects of different management strategies. The model can function as a strategic or a tactical decision aid. It is concluded that there is potential for this model to assist managers in improving the sustainability of agriculture.

Initial soil surveys are incomplete for large tracts of public land in the western USA. Digital soil mapping offers a quantitative approach as an alternative to traditional soil mapping. I sought to predict soil classes across an arid to semiarid watershed of western Utah by applying random forests (RF) and using environmental covariates derived from Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and digital elevation models (DEM). Random forests are similar to classification and regression trees (CART). However, RF is doubly random. Many (e.g., 500) weak trees are grown (trained) independently because each tree is trained with a new randomly selected bootstrap sample, and a random subset of variables is used to split each node. To train and validate the RF trees, 561 soil descriptions were made in the field. An additional 111 points were added by case-based reasoning using aerial photo interpretation. As RF makes classification decisions from the mode of many independently grown trees, model uncertainty can be derived. The overall out of the bag (OOB) error was lower without weighting of classes; weighting increased the overall OOB error and the resulting output did not reflect soil-landscape relationships observed in the field. The final RF model had an OOB error of 55.2% and predicted soils on landforms consistent with soil-landscape relationships. The OOB error for individual classes typically decreased with increasing class size. In addition to the final classification, I determined the second and third most likely classification, model confidence, and the hypothetical extent of individual classes. Pixels that had high possibility of belonging to multiple soil classes were aggregated using a minimum confidence value based on limiting soil features, which is an effective and objective method of determining membership in soil map unit associations and complexes mapped at the 1:24,000 scale. Variables derived from both DEM and Landsat 7 ETM+ sources were important for predicting soil classes based on Gini and standard measures of variable importance and OOB errors from groves grown with exclusively DEM- or Landsat-derived data. Random forests was a powerful predictor of soil classes and produced outputs that facilitated further understanding of soil-landscape relationships.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
A atual preocupaÃÃo com as mudanÃas climÃticas globais, decorrentes do aumento nas concentraÃÃes de gases de efeito estufa na atmosfera, em especial o CO2, tem despertado a atenÃÃo da comunidade cientÃfica para o ciclo biogeoquÃmico do carbono. Assi, objetivou-se com este trabalho realizar um estudo teÃrico e experimental da dinÃmica da matÃria orgÃnica do solo, como forma de compreender se as alteraÃÃes nas caracterÃsticas fÃsicas, quÃmicas e biolÃgicas do solo influenciam no sequestro e/ou emissÃo de CO2 atmosfÃrico. O estudo foi realizado na Floresta Nacional do Araripe (FLONA- Araripe) e na Unidade de Manejo Florestal (UMF) da Fazenda Pau DâÃrco e Bonfim. Foram selecionados na UMF cinco talhÃes e na Reserva Ambiental e FLONA-Araripe uma Ãrea de aproximadamente 200 m2. Em cada Ãrea foram selecionados cinco pontos aleatÃrios. Foram realizadas 6 coletas durante o perÃodo de 2012, 2013 e 2014 sendo 2 em cada ano nas profundidades de 0-10, 10-20 e 0-20 cm para a realizaÃÃo das analises: fÃsicas, quÃmicas, mineralÃgicas e microbiolÃgicas. Utilizou-se anÃlise de variÃncia, com 6 repetiÃÃes e 7 tratamento. As mÃdias das diferentes profundidades do solo foram comparadas pelo teste de Tukey ao nÃvel de significÃncia 5% aplicou-se a tÃcnica da anÃlise fatorial pelo mÃtodo das componentes principais. Para o estudo teÃrico, utilizou-se o submodelo da dinÃmica da matÃria orgÃnica do solo (MOS) disponibilizado no Aplicativo Century (versÃo 4.0). AcurÃcia das simulaÃÃes foi verificado pelo coeficiente de correlaÃÃo entre dados simulados e observados, calculados pela ferramenta de anÃlise de dados do Microsolft Excel. As Ãreas apresentaram predominÃncias do mineral caulinita e Ãxidos de ferro e alumÃnio nas Ãreas de estudo favorecendo a proteÃÃo do material orgÃnico. Na FLONA-Araripe foram encontrados os maiores teores de COT, ClÃbil, estoque de C, CMIC, C-MOL e, os menores valores da RBS e qCO2, o contrÃrio ocorreu da UMF. AnÃlise de componente principal elucidou que dos oito atributos obtidos na anÃlise de comunalidades sÃo necessÃrios apenas cinco para a compreensÃo da dinÃmica da MOS, resultando em 2 atributos: COT, ClÃbil e o IMC e o NT e CMIC. Na calibraÃÃo, o PRDX adequado foi (140 e 11 g C m-2) respectivamente, para as Ãreas da FLONA-Araripe e UMF. Os ajustes realizados nas constantes de decaimento de carbono em ambas as Ãreas (K) FLONA-Araripe DEC4 (0,00402) DEC5 (0,22500) e DEC3.2 (6,5000) geraram os seguintes erros (0,04;3,7; 2,3%) respectivamente. Os fatores de correÃÃo A*, foram (0,89) para carbono ativo (CA) e carbono passivo (CP) e (1,12) para carbono lento (CL). As variÃveis de entrada temperatura mÃxima e mÃnima foram mais sensÃveis. A validaÃÃo das simulaÃÃes no aplicativo na UMF elucidou que o DEC4 nÃo ocorre reduÃÃo de C nos dois primeiros meses e estÃvel aos 4 anos. DEC5 as reduÃÃes de C nos primeiros meses de manejo e recuperaÃÃo aos 7anos e o DEC 3.2 reduÃÃes de C nos primeiros meses de manejo e estÃvel 5 anos. Neste sentido, a utilizaÃÃo do aplicativo com ajustes necessÃrios nas constantes de decaimento (DEC4, DEC5 e DEC3.2) responde satisfatoriamente ao acumulado de carbono no solo em funÃÃo da qualidade e quantidade da MOS elucidando que a dinÃmica da MOS influencia no sequestro de CO2.
The current concern about global climate change resulting from the increase in greenhouse gas concentrations in the atmosphere, especially CO2, has aroused the attention of the scientific community to the biogeochemical cycling of carbon. This study performed a theoretical and experimental analysis of the dynamics of soil organic matter in an area subjected to clear cutting of native vegetation to understand the influence of changes in physical, chemical and biological soil properties on sequestration and/or emission of atmospheric CO2. The study was conducted at the Araripe National Forest and at the Unit of Forest Management of the Farm Pau dâArco and Bonfim. In the area of sustainable management, there were selected 5 out of 22 plots existing and an area of about 200 m2 in the Environmental Reserve and FLONA- Araripe. In each area, we selected five random sites, at the layers 0-10, and 10-20 and 0-20 cm from 2012 2013 and 2014 amounting to 6 collections. The following analyses were performed: physical, chemical, mineralogical and microbiological. Climate data used in the Application Century, referring to the monthly rainfall, were obtained at the weather station of FLONA- Araripe. It was applied analysis of variance, with 6 replications and 7 treatments at the layers: 0-10, 10-20 and 0-20 cm. Mean values of the different layers were compared by Tukeyâs test at 5% probability, in the software Statistical Analysis Systems, using the factorial analysis by the main components method. For the theoretical study, we used the sub-model of the dynamics of soil organic matter available at Century 4.0. The accuracy of the simulations was verified by the correlation coefficient between simulated and observed data, calculated by Microsoft Excel data analysis tool. The areas showed predominance of mineral kaolinite and iron and aluminum oxides, thus favoring the protection of organic material. At FLONA- Araripe, we found the largest contents of TCO, Clabile, C storage, CMIC, C-MOL and lower RBS and qCO2, the opposite occurred for UMF. Principal component analysis evidenced that from 8 attributes obtained from the commonality analysis only 5 are required to understand the dynamics of MOS, resulting in two factors: TCO, Clabile and IMC and the NT and CMIC. In the calibration, the appropriate PRDX was (140 and 11 g C m-2) respectively for FLONA and UMF. The fits of the carbon decay constants in both areas (K) FLONA- Araripe DEC4 (0.00402) DEC5 (0.22500) and DEC3.2 (6.5000) produced the following errors (0.04, 3.7, 2.3%). The correction factors A* were (0.89) for carbon ative (CA) and carbon passive (CP) and (1.12) for carbon leve (CL). The input variables maximum and minimum temperatures were the most sensitive. The validation of the application in UMF elucidated that the DEC4 there was no reduction in C in the first two months, being stable at four years. DEC5 reductions in C in the first months of management and recovery 7 years and the DEC 3.2 reductions C in the first months of management and stable 5 years. In this sense, the use of the application with necessary fits in decay constants (DEC4, DEC5 and DEC3.2) responds satisfactorily to the carbon accumulated in the soil according to the quality and quantity elucidating the dynamics of SOM influences the CO2 sequestration.

Meadows are critical in arid and semi-arid Argentinean Patagonia because of their importance for regional biodiversity. Despite this, little information on the spatial distribution of meadows is available and no analysis of the potential effect of climate change on meadows has been performed, which hampers conservation planning. In this study, I modeled the spatial distribution of meadows and investigated how climate change may affect the current distribution of meadows in arid and semiarid Patagonia by 2050. In addition, I investigated conservation status and areas of desertification vulnerability of those areas predicted to contain meadows. I used high-resolution imagery available in Google Earth software to visually estimate presence and absence of meadows. To model current and future distribution of meadows I used these observations and different socio-environmental predictor variables. I implemented generalized linear, additive, boosting, and random forest models, as the basis for a mean ensemble technique. I predicted future distribution of meadows using four different general circulation models and the A2 SERES scenario. The final ensemble model was an accurate representation of the current distribution of meadows in Patagonia and indicates they are severely under-represented within protected areas. I determined that overall meadow abundance is going to decrease by 2050 given the changes in climate. However, there were two contrasting trends: severe reduction of meadows in northwest Patagonia and Tierra del Fuego Island, and an expansion of suitable areas for meadows in the south and a small section in the northwest. This first regional map of meadow distribution across Argentinean Patagonia and information on meadows vulnerability to climate change represent key information for planning actions to conserve this critical habitat.

This research is aimed at developing the method for efficiently using the water in irrigation schemes in semi-arid regions. These irrigation schemes are often short of water to irrigate entire culturable command area (CCA) with maximum water requirement of different crops and are characterised with different weather patterns, soils and the possibility to grow several crops. The CCA of these schemes is also large with several users or units, each having different characteristics. The previous research in this field was mostly either on optimum allocation of the resources considering the irrigation scheme as a whole or on evaluating the performance of the irrigation scheme for certain irrigation schedules for different units in the scheme. However in such schemes optimum allocation of resources (land and water) to different crops and their distribution over different units is important (optimum allocation plan, OAP). In the present study, the method and a computer model are developed to prepare OAPs for these irrigation schemes under rotational water supply, by incorporating the concepts of deficit irrigation and productivity and equity in the optimisation process. The previous research stressed the importance of equity observed in different ways but seldom adopted in optimum allocation of resources. Therefore this method includes the preparation of OAPs while observing equity in allocation of land and water resources and distribution of crop production and net benefits. The developed model, Area and Water Allocation Model (A WAM), consists of four phases each one for generating irrigation strategies, preparing irrigation programme for each irrigation strategy, screening irrigation programmes and allocating resources optimally to different crops in different units. The A W AM estimates the irrigation water requirement, crop yield and net benefits by simulating the various process in the irrigation scheme, produces the OAPs at preseason planning with different scenarios of productivity and equity and management options, develops the steady OAP by considering the temporal variability in the weather and modifies the allocation plan optimally during the intraseasonal operation of the irrigation scheme. A W AM operates in seven different modes to achieve this. These are simulation, calibration, generation, optimisation, planning, operation and evaluation. The A W AM was applied to Nazare Medium Irrigation Project (medium lmgation scheme) in semi-arid region of Maharashtra State, India to evaluate the existing practice of irrigation (fixed depth irrigation), full depth irrigation and deficit irrigation for obtaining the OAPs. The practice of deficit irrigation was found to be beneficial over the existing approach and full depth irrigation. The OAPs at preseason planning are obtained for several alternatives and compared. The OAPs were obtained for different equity criteria. The productivity and equity were found to be inversely related. The method is proposed to obtain the stable OAP with A WAM by considering several years' data. The present research contributes towards efficient utilisation of water in the irrigation scheme by incorporating the deficit irrigation and productivity and equity in obtaining OAPs, developing the methods to obtain the steady OAP and modifying the allocation plan optimally during the intraseasonal operation of the irrigation scheme.

Small livestock is an important resource for rural human populations in dry climates. How strongly will climate change affect the capacity of the rangeland? We used hierarchical modelling to scale quantitatively the growth of shrubs and annual plants, the main food of sheep and goats, to the landscape extent in the eastern Mediterranean region. Without grazing, productivity increased in a sigmoid way with mean annual precipitation. Grazing reduced productivity more strongly the drier the landscape. At a point just under the stocking capacity of the vegetation, productivity declined precipitously with more intense grazing due to a lack of seed production of annuals. We repeated simulations with precipitation patterns projected by two contrasting IPCC scenarios. Compared to results based on historic patterns, productivity and stocking capacity did not differ in most cases. Thus, grazing intensity remains the stronger impact on landscape productivity in this dry region even in the future.
Kleinvieh ist eine wichtige Lebensgrundlage für die Landbevölkerung in trockenen Regionen. Wie stark wird sich der Klimawandel auf die Tragfähigkeit der Weideflächen auswirken? Wir benutzten hierarchische Modellierung, um das Wachstum von Sträuchern und einjährigen Kräutern, das wichtigste Futter für Ziegen und Schafe, quantitativ auf die Fläche von Landschaften in der östlichen Mittelmeerregion zu dimensionieren. Die Produktivität ohne Beweidung stieg sigmoidal mit dem mittleren Jahresniederschlag. Je trockener die Landschaft, desto stärker verminderte Beweidung die Produktion. An einem Punkt knapp unter der Tragfähigkeit der Vegetation, sank die Produktion stark mit zunehmender Beweidung, weil die Samenproduktion der Kräuter zu gering war. Wir wiederholten die Simulationen mit Niederschlagsverteilungsmustern gemäß zweier gegensätzlicher IPCC-Szenarien. Zukünftige Produktivität und Tragfähigkeit unterschieden sich in den meisten Fällen nicht von Ergebnissen auf Grund von historischer Niederschlagsverteilung. Allerdings war die zukünftige Produktivität in trockenen Habitaten der semiariden und trocken-mediterranen Regionen niedriger. Somit hat auch in Zukunft die Besatzdichte die größere Auswirkung auf die Produktivität dieser trockenen Landschaft als das Klima. "This abstract is provided by the authors, and is for convenience of the users only. The author certifies that the translation faithfully represents the official version in the language of the journal, which is the published Abstract of record and is the only Abstract to be used for reference and citation."

Arid and semi-arid basins in the Western United States (US) have been significantly impacted by human alterations to the water cycle and are among the most susceptible to water stress from urbanization and climate change. The climate of the Western US is projected to change in response to rising greenhouse gas concentrations. Combined with land use/land cover (LULC) change, it can influence both surface and groundwater resources, both of which are a significant source of water in the US. Responding to this challenge requires an improved understanding of how we are vulnerable and the development of strategies for managing future risk. In this dissertation, I explored how hydrology of semi-arid regions responds to LULC and climate change and how hydrologic projections are influenced by the choice and calibration of models. The three main questions I addressed with this dissertation are: 1. Is it important to calibrate models for forecasting absolute/relative changes in streamflow from LULC and climate changes? 2. Do LSMs make reasonable estimates of groundwater recharge in the western US? 3. How might recharge change under projected climate change in the western US? Results from this study suggested that it is important to calibrate the model spatially to analyze the effect of LULC change but not as important for analyzing the relative change in streamflow due to climate change. Our results also highlighted that LSMs have the potential to capture the spatial and temporal patterns as well as seasonality of recharge at large scales. Therefore, LSMs (specifically VIC and Noah) can be used as a tool for estimating current and future recharge in data limited regions. Average annual recharge is projected to increase in about 62% of the region and decrease in about 38% of the western US in future and varies significantly based on location (-50% - +94 for near future and -90% to >100% for far future). Recharge is expected to decrease significantly (-13%) in the South region in the far future. The Northern Rockies region is expected to get more recharge in both in the near (+5.1%) and far (+9.0%) future. Overall, this study suggested that land use/land cover (LULC) change and climate change significantly impacts hydrology in semi-arid regions. Model choice and model calibrations also influence the hydrological predictions. Hydrological projections from models have associated uncertainty, but still provide valuable information for water managers with long term water management planning.

Treated wastewater (effluent) has been used as a water source for aquifer recharge and sustaining perennial surface water flow. Artificial recharge basins allow effluent to seep into the ground relieving stressed aquifers. However, these basins frequently become clogged due to physical, chemical, and biological processes. Effluent is also used to replace baseflow for dry streambeds. However, little is known about the effect of effluent on stream-aquifer interactions. Effluent from the Nogales International Waste Water Treatment Plant sustains perennial flow in the Upper Santa Cruz River, Arizona. A series of monthly field campaigns were undertaken to understand the impact of effluent on the streambed at 16 different sites along a 30 km river reach. The field campaigns had two foci: physical transformations in the streambed and water source identification using chemical composition. Historic data sets including USGS stream gauging records, NIWTP outfall data, ADWR well transducer data and USGS well chemistry data were also analyzed to provide a larger context for the work. Results indicate that localized clogging forms in the Upper Santa Cruz River. The clogging layers perch the stream and shallow streambed causing a desaturation below the streambed. A clogging cycle is established in the context of a semi-arid hydrologic cycle: formation during dry and hot pre-monsoon months, and removal by a set of large flood flows (10+ m3/sec) during the monsoon season. However, if the intensity of flooding during the semi-arid hydrologic cycle is lessened, the dependent riparian area can experience a die off.

This paper presents an adaptation of the classical model of Streeter-Phelps modeling of Dissolved Oxygen (DO) and Biochemical Oxygen Demand (BOD) in the basin of the Upper Jaguaribe (25,000 km2), State of Ceara, Brazil. The adaptation of the model consisted of the numerical solution of differential equations Streeter-Phelps, considering the effect of incremental flows and sewage releases over the sections, as well as the variability of the sections of rivers and tributaries. For model calibration, including the adjustment of reaeration coefficients (K2) and removal of BOD (Kd), we used the data of the Plan of Management of Waters of the Rio Jaguaribe Basin. Calibration results showed that this simplified model represented well the balance between DO and BOD in a large semi-arid basin, with a good fit for both parameters. For OD, the average deviation was 8.44% and 6.04% by the end and beginning of the rainy season, respectively. As for BOD, the deviations were 18.51% and 30.43% for the two seasons, respectively. In both periods, the OD remained within the standards for Class 2 of Resolution CONAMA 357/2005 throughout the stretch and the BOD breached this limit on a short stretch near the city of Taua. With the already calibrated model were simulated three scenarios: a large full, using as reference flow Q10 of a historical series of Jaguaribe; drought, using the Q50 of the series; and implementation of a WWTP with 80% removal of BOD in all seats. The simulations showed consistent results and that serve as a basis for management of water resources of the study area.
Este trabalho apresenta uma adaptaÃÃo do modelo clÃssico de Streeter-Phelps para modelagem de OxigÃnio Dissolvido (OD) e Demanda BioquÃmica de OxigÃnio (DBO) na bacia do Alto Jaguaribe (Ãrea de 25.000 km2), Estado do CearÃ, Brasil. A adaptaÃÃo do modelo consistiu na resoluÃÃo numÃrica das equaÃÃes diferenciais de Streeter-Phelps, considerando o efeito de vazÃes incrementais e lanÃamentos de esgoto ao longo dos trechos, assim como a variabilidade das seÃÃes dos rios e tributÃrios. Para calibraÃÃo do modelo, incluindo o ajuste dos coeficientes de reaeraÃÃo (K2) e remoÃÃo de DBO (Kd), foram utilizados os dados do Plano de Gerenciamento das Ãguas da Bacia do Rio Jaguaribe. Os resultados da calibraÃÃo mostraram que esse modelo simplificado representou bem o balanÃo entre OD e DBO em uma grande bacia semiÃrida, apresentando um bom ajuste para os dois parÃmetros. Para OD, o desvio mÃdio foi de 8,44% e 6,04% para o fim e inÃcio da estaÃÃo chuvosa, respectivamente. Jà para DBO, os desvios foram de 18,51% e 30,43% para as duas estaÃÃes, respectivamente. Nos dois perÃodos, o OD manteve-se dentro dos padrÃes para Classe 2 da resoluÃÃo CONAMA 357/2005 em todo o trecho e a DBO infringiu este limite em um pequeno trecho prÃximo à cidade de TauÃ. Com o modelo jà calibrado, foram simulados trÃs cenÃrios: uma grande cheia, utilizando como vazÃo de referÃncia o Q10 de uma sÃrie histÃrica do Jaguaribe; estiagem, utilizando o Q50 da sÃrie histÃrica; e, implantaÃÃo de uma ETE com remoÃÃo de 80% de DBO em todas as sedes. As simulaÃÃes apresentaram resultados coerentes e que servem como base para o gerenciamento dos recursos hÃdricos da bacia estudada.

The main purpose of this work is to extend an existing model of growing cattle and grass production in a semi-arid rangeland.The existing model which is basically Dye's (1983) model in differential equation form handles: i) the growth and performance of cattle measured in terms of weight, ii) the initiation of grass growth in early rainy season and its utilisation by the cattle . This model is being extended to simulate woody plants in addition to the grass and to simulate browsing by goats. The densities of vegetation and the stocking rates of both types of animals are being considered. Our model (SAVANNAS) will predict animal productivity in relation to rainfall and density of woody plants (or vegetation condition). A rainfall data file is being used to generate rain which divides into infiltration and run-off. Athough generally dry, semi-arid regions are agriculturally productive, more especially in terms of animal products. An understanding of the climatic conditions by the farmers is all what it takes. It is unfortunate that in these regions, rainfall, being the main driving force behind animal productivity, is unreliable in that it varies both within and over the years. It is in this regard, therefore, that models be built to simulate semi-arid environments. Such models, when run for several (semi-arid) representative rainfall years could be used by farmers. For instance, a model like SAVANNAS will be run for three rainfall years namely 1980/81, 1981/82 and 1982/83, which, respectively represent: very high, about average and very low rainfall (by semi-arid standards). SAVANNAS simulates processes that operate on widely different time scales. The growth and consumption of herbage and leaves and twigs of woody plants are modelled on a daily basis, while the numbers and ages of woody plants are updated every 120 days. The year is divided into four seasons, with the rainy season beginning in September and initiating herbage re-growth. SAVANNAS simulates herbage biomass, which means it allows the re-establishment of the previous year's grass plants . It divides woody plants into age cohorts with the first cohort being seedlings mainly, and the last cohort being adult trees which are usually out of the browsing range of herbivores. It is a model that has a focus on the effects of vegetation (woody plants and grass) on each other and the effects of the animals on vegetation and viceversa. Without overlooking their effects on vegetation production, fires are not considered in SAVANNAS. This is because in communal lands heavy grazing does not allow the accumulation of sufficient dry herbage for fuel.

With a growing world population, estimated to 9.6 billion in 2050, the world food demand is estimated to increase with 45-50 %. One way to meet the demand is to increase the areal yield from the agricultural sector, where rain-fed agriculture has the highest potential. 95 % of the agriculture in Sub-Saharan Africa is rain-fed and the same region is predicted to holds the largest share of poor people in 2015. Since 40-70 % of the rural households highly depend of on-farm sources, investments to increase the agriculture productivity target both the poverty alleviation in the region as well as the world’s food security. By a tripartite methodology, this study analyzed the use of small-scale rain water harvesting (RWH) ponds for supplemental irrigation (SI) of cereals to reduce the inter-annual variability and to increase the areal yield in semi-arid areas in Ethiopia. A physically based simulation model (CoupModel) considering the plant-soil-atmosphere system was used to study how a C4-plant responded to different irrigation scenarios with 30 years climate data (1980-2009) from six regions in Ethiopia. Moreover, two years field data with maize yield from Triple Green project’s experimental fields in Ethiopia was used to analyze the correlation between SI and yield. Finally, ten farmers that used RWH ponds for SI of cereals within Triple Green project were interviewed to find out their perception of the RWH and SI. The model results showed that irrigation almost eliminated the inter-annual variability and increased the areal yield for all the climates. SI was most efficiently used in areas with more than 900 mm precipitation/year were the two annual rain periods could be bridged to create a prolonged growth season (>180 days). The mean annual irrigation water demand was estimated to 224 mm distributed over 7 irrigation events. The field results showed a moderate but significant 10 % increase of the areal yield with SI. None of the farmers wanted to use the RWH for SI of cereals, instead they wanted to use it to water their livestock, grow cash crop seedlings and fruit trees. If the future world food demand is to be targeted, the study suggests societal investments to build infrastructure to collect, store and distribute water for irrigation.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, June 2011.
"June 2011." Cataloged from PDF version of thesis.
Includes bibliographical references (p. 108-109).
This thesis investigates possible conversions of an increasingly unviable type of irrigated agricultural landscape, seen under the influences of three simultaneous processes: urban growth, change of cropping practice and return to the desert. Three new prototypical models are designed and tested: an urban-rural oasis, an adapted rural settlement and an inhabited desert park. An analysis of historical hydrological alteration and agrarian/urban settlement processes in the Colorado River Lower Basin focuses on a region in a pivotal situation: Central Arizona and its agricultural irrigation districts. Here, the three models are tested on a hypothetical site of one square mile and simultaneously investigated in an abstract matrix of regionally applicable principles. In an increasing order, the urbanrural oasis, the adapted rural settlement, and the inhabited desert park reduce water needs by rainwater harvesting/-storage and greywater re-use. They are resilient towards droughts by allowing farmers to temporarily fallow agricultural elements, or, in the case of the desert park, by hosting partially seasonal uses and importing drinking water as necessary. The urban-rural oasis relies on a localized form of agriculture that allows selling all produce directly on site, mainly to its inhabitants, with a large recreational emphasis. The adapted rural settlement targets the emerging new food markets in the urban region with high-value crops, and diversifies production to include native agroforestry for energy production and woodcraft. The desert park contains a low input-output dryland agriculture and sporadic recreational desert harvesters. All three models rely on phased forms of settlement growth, increased income opportunities on site by the (re-)combination of land uses and the creation of microclimates by a strategic arrangement of vegetated land cover in proximity to settlement. Residential options span from medium- to low-density detached courtyard types; different sizes of garden homes, haciendas and farm communities to desert villas, and even RV campgrounds; with the urban-rural oasis having the largest range of choices among the options. Each model may attract broad concentrations and ranges of regional lifestyle groups between urban/suburban, agrarian and nature-oriented communities, of a permanent or an ephemeral nature. A single overarching condition is the realistic acknowledgment of both the obvious challenges and plentiful qualities of the desert. Various cultures could unfold together with the idea of saving water. There seems to be an enormous potential in converting the agricultural landscape into a more resilient and diversified one, along pathways proposed by the three models. Moreover, attempts to free up volumes of water on large sites would be one of the fundamental necessary steps to more permanently embrace both human and natural life in an arid and unique environment like the Lower Colorado River Basin.
by Timo Matti Wirth.
S.M.

The semiarid regions of Ethiopia are exposed to anthropogenic and natural calamities. In this study, we assessed the relationship between Tropical Applications of Meteorology using Satellite data (TAMSAT) and MODIS Normalized Difference Vegetation Index (NDVI) data for the period 2000 to 2014 on decadal and annual basis using multivariate distributed lag (DL) models. Decadal growing season (June to September) values for kaftahumera were calculated from MODIS NDVI data. The growing season NDVI values are highly correlated with the precipitations during the whole study period. A lag of up to 30 days observed in most parts of our study region in which the rainfall has effects on vegetation growth after 40 days. The lag-time effects vary with the distribution of land use types and seasons. A lower correlation was observed in the woodland regions where significant deforestation occurred due to expansion of croplands. The loss in vegetation contributed to the low biomass production attributable to extended loss in vegetation cover.

A prevailing problem in applied hydrology is the estimation of runoff from ungaged small watersheds and drainge basins. In this study, arid and semiarid regions were Grouped according to their climatic, geomorphologic, and soil characteristics, disregarding their geographic position. Eighty watersheds were used in this study from three countries: U.S., Brazil, and Australia. Twenty-two climatic, geomorphologic and soil variables were used for the delineation of homogeneous Groups in the cluster analysis, and two major Groups were defined. The results suggest that homogeneous Groups can be delimited independently of their geographic position. Cluster analysis and Andrews' plot were used for regionalization of the watersheds. The variables used for development of the models for each Group were selected by stepwise multiple regression analysis. The Andrews' plot further examination reinforce the statement that hydrologically similar watersheds are independent of their geographic position. In a preliminary study 60 watersheds were used to determine the most important variables. For Group I, the stepwise multiple regression analysis reduced the available 21 independent variables to three variables: rainfall, soil permeability index, and temperature. For Group II, only two variables were statistically significant (rainfall and watershed form factor). Once the most significant variables were selected, 20 additional watersheds with data were also included in the final study. Upon evaluation of the regression statistics, Group II responded better than Group I. The equations were: UNFORMATTED EQUATION FOLLOWS: Group I "Dry" Q = -68.476 + 0.0784 P + 4.131Temp -3.950Slpr n = 29 R² = 70% SE = 11.16 mm/yr Group II "Wet" Q = 1.29*10⁻¹¹* P⁴·⁴¹* Rf⁻⁰·⁰⁹³ n = 37 R² = 79% SE = 30.52 mm/yr UNFORMATTED EQUATION ENDS Computed annual runoff values for Group II showed a good agreement with observed values, suggesting that the developed equation is good for prediction of the annual runoff water yield. In contrast, predicted values for the Group I showed poor agreement with the observed values, suggesting that the model should be treated with caution.

Soil-Vegetation-Atmosphere-Transfer Schemes (SVATS) are used in global climate studies to simulate and help understand the complex interactions between the climate and the biosphere. There currently exists a multitude of SVATS of varying complexity differing in terms of the modeled physics and the manner and sophistication with which the processes are represented. This analysis uses systems-based multi-criteria techniques to investigate the performance and sensitivity of various SVATS and their parameters. Results indicate that, once complexity reaches a certain level, incorporating more physics does not necessarily result in improved simulations or reduced errors and that several parameters in the models are insensitive regardless of the input data (i.e., vegetation type). To better understand SVATS performance in semi-arid regions, and to evaluate the various impacts of data on the parameter estimation problem, an intensive calibration and validation study is undertaken. Findings show that calibrated parameters result in improved performance over default, proxy site parameters result in similar performance for many time periods, and there is a need to include wet periods with elevated latent heat to capture the variability of climatic conditions such as the monsoon and El Nino winters. Last, a preliminarily investigation of the performance of the BATS2 model is undertaken to evaluate the capabilities to simulate carbon (along with energy and water) fluxes in semi-arid regions. Results show poor performance for carbon flux simulations and that improvements are needed to better represent C4 vegetation for semi-acid regions. Future research will be directed toward integrated modeling (carbon, energy, and water) in semi-arid regions.

Current climate change trends are affecting the magnitude and recurrence of extreme weather events. In particular, several semi-arid regions around the planet are confronting more intense and prolonged lack of precipitation, slowly transforming these regions into deserts. In this thesis we present a stochastic (meso-scale) model for vegetation-precipitation interactions for semi-arid landscapes. Extensive simulations with the model suggest that persistence in current trends of precipitation decline in semi-arid landscapes may expedite desertification processes by up to several decades.

Mestrado em Matemática Financeira
O presente trabalho avalia a relação existente entre o sector financeiro e o crescimento económico em Moçambique no período [1993-2013]. O estudo é feito com base em uma série temporal, cujos os dados são anuais. É utilizada a taxa real de crescimento do PIB per capita (PIB1), como proxy para o crescimento económico, e para o desenvolvimento financeiro foram utilizadas duas variáveis: o crédito ao sector privado como percentagem do PIB (CPS_PIB), e a massa monetária como percentagem do PIB (M3_PIB). A análise de cointegração para a estimação da relação de longo prazo, foi feita através da abordagem Bounds testing com o modelo Autoregressive Distributed Lag (ARDL). Os resultados indicam que o sector financeiro não tem um impacto direto no crescimento económico de Moçambique.
This study evaluates the relationship between the financial sector and economic growth in Mozambique in the [1993-2013] period. The study is based on a time series, whose data are annual. It used the actual rate of growth of GDP per capita, as a proxy for economic growth, and credit to the private sector as a percentage of GDP, the broady money as a percentage of GDP, both as a proxy for financial development. The cointegration analysis to estimate the long-term relationship, was made by Bounds testing approach with the Autoregressive Distributed Lag model (ARDL). The results indicate that the financial sector does not have a direct impact on economic growth of Mozambique.

This thesis contains three main parts. In the first part, we adapt a model developed for the US economy to the unique Chinese economic and institutional context. The uniqueness is mainly from two perspectives: the dual-channel housing financing system in China and the existence of the shadow banking sector (which differs from the shadow banking in developed economies) in China’s housing market. It would be difficult to obtain a clear picture of the Chinese housing market and macroeconomy without a thorough understanding of these two characteristics. This is due to the crucial role played by shadow banking and other informal finance institutions within the context of China in both the development and purchase of housing, in supporting productive economic activities in general, and that the housing market is in turn intricately connected to the health of the Chinese economy, being a key ‘barometer’. The second part of the research is the quantification of the determinants of the scale of shadow banking in China. The quantification is crucial since policy makers need to be aware of how sensitive shadow banking is to various factors. We develop a theoretical framework to explain the evolution of the scale of shadow banking in China. As part of this research, we investigate whether the real interest rate of household saving deposits, the required reserve ratio and bank loans to business and household are the main factors in explaining the evolution of China’s shadow banking. In the third part of research, we employ a credit risk and macroeconomic stress test to investigate the vulnerability of the commercial banks in China. Our originality here is the integration of both the role of shadow banking and housing market related loans in the commercial banks’ stress test scenarios at the macro level. Since a systematic analysis regarding the effect of changes in the macroeconomy and housing market on the credit risk of commercial banks in China is scarce, we use bank stress tests to analyse the credit risk in terms of the non-performing loans ratio of commercial banks in China; this is in response to changes in the macroeconomic factors and housing market. We address the role of the variation of the scale of shadow banking in China in terms of its contribution to the credit risk because of its uncertainty and close link with the commercial banks. Stress tests often focus on a single bank or financial institution yet we apply the same principles to examine the financial system as a whole in China, which would allow us to quantify the systemic risk in the entire Chinese financial system; and which variables, especially shadow banking contribute to the risks and by how much. This thesis contributes to the understanding of how China’s dual-channel housing finance system and shadow banking affect the evolution of house prices; and also, the main driving factors of the scale of China’s shadow banking and whether the housing market related loans and shadow banking pose risks to commercial banks. Possible research questions raised by the main findings of this thesis will enrich the debate on China’s housing market, shadow banking and regular banks, especially at a time when China is reforming its economic structure.

The eddy covariance technique for measuring the exchange of mass and energy between the land surface and atmosphere yields data records with substantial gaps, reported to be as long as 30 to 40% of a time series annually (at a half-hourly time step). The application of these data sets in modeling studies as well as on varying time scales and under non-ideal conditions, requires some interpolation method to infer values for the missing data. This study will consider a neural network regression model for a flux record from a semi-arid riparian site and examine the model's responsiveness to variability in the data available for training. The neural network sensitivity to flux data used for training is evaluated. Model response worsened under reduced training data availability and was dependent on the characteristics of the data.

The object of the research project was to propose and develop innovative theoretical methods for evaluating mass and energy exchange processes within one of the most relevant crop of the agricultural Sicilian context. The study was conceived as a long monitoring program of micrometeorological features of the study orange orchard at different spatial scales (plant, orchard, farm). Different micrometeorological methods, mainly based on Surface Renewal theory, were studied and tested, in order to provide reliable and low cost estimates of sensible heat fluxes within the plant-atmosphere system. Micrometeorological techniques were integrated with in situ measurements of transpiration by up-scaled sap flow techniques, physiological plant features and microclimatic characteristics of the study area. Derived actual crop evapotranspiration fluxes, by means of the resolution of the energy balance equation opportunely corrected for closure, and crop coefficient values were analyzed. All these efforts may contribute to address irrigation water scheduling towards water saving measures.

The influence of climate and antecedent moisture conditions on hydrological and biogeochemical fluxes was studied and contrasted in three nested, high-elevation, snowmelt-dominated catchments in the Sierra Nevada, California and one basin-floor, semi-arid catchment in southeastern Arizona. Investigations were completed within a different two-year period at each site, with the second year being climatically different (typically drier) than the first. Spring snowmelt, widespread winter frontal precipitation, and episodic summer rains induce surface water flow in these catchments, though the timing and magnitude of nutrient redistribution among soil and stream compartments varies in each. Surface water flow from spring snowmelt in high-elevation catchments travels through the subsurface or across the surface as direct runoff A more typical process producing surface water flow in semi-arid catchments is flooding during episodic or widespread rainfall. Hydrograph separations at Emerald Lake, Topaz Lake and Marble Fork catchments in Sequoia National Park, California, revealed that the majority of snowmelt flowed through soil before entering the stream in both average and highsnow years. The Emerald Lake watershed had a higher fraction of old water in its outflow in the average accumulation year because of the previous year's high accumulation and longer melt season. A mixing model analysis performed of the upper San Pedro River, Arizona, for wet and dry years showed that summer flood hydrographs were composed mainly of precipitation and surface runoff in both years, though a higher soil-water input occurred in the wetter year and in early season floods in the dry year. Stream and soil water nitrate concentrations were higher during floods in the dry year. Early season floods in the dry year exhibited more variability in stream water nitrate and sulfate, whereas late season flood concentrations reflected a well-mixed system and therefore less variation of these species during flood hydrographs. These data showed that periods of below average precipitation preceding major runoff periods result both in less soil water and solute export during summer floods in basin-floor catchments and less direct snowmelt in high-elevation catchments. Hydrologic and solute export in each catchment, despite their differing geographical locations, responds in similar ways to climate variability.

The electricity sector around the world is significantly changing towards the adoption of cleaner energy sources and its implementation through distributed generation technologies. The need to expand rural electrification to reduce energy poverty and the trends in decentralizing power generation are becoming major drivers of change. In Mexico, there are very few comprehensive studies on energy use and its impact on rural livelihoods. Energy studies in the development literature tend to analyze livelihoods that do not have access to modern energy services, and do not take into account that many rural communities, although connected to the grid, still may be considered energy poor. This research presents findings of current livelihood conditions of three rural communities in the Mexican state of Chihuahua, in the context of livelihood diversification and energy poverty. This paper also presents a feasibility study for the development of a community energy model that will fulfill energy and vegetable intake requirements for each community analyzed. Results show that these communities can potentially improve their livelihood conditions through the implementation of what this research calls a Community Integrated Sustainable Energy (CISE) model by reducing energy poverty and food insecurity. By adopting a CISE model, communities will become healthier by becoming supporters of energy conservation and energy efficiency strategies. The adoption of this community energy model will also encourage climate change mitigation by increasing resilience to vulnerable communities through enhancing food and energy security. The aim of this research is to inform stakeholders (including policy makers, urban planners, and community members themselves) of the current status of Chihuahua's communities and to start a dialogue in Mexico about engaging in a community-led, clean energy project that would generate electricity for those communities while preserving rural livelihoods.

An organization’s internal processes of identity management is argued to influence its communication, which in turn influence the perceived reputation of the organization. The aim of this study is to investigate how the organizational identity is reflected upon and perceived integrated in employees’ daily work. This is done through applying the internal factors of a theoretical model, comprising of identity, culture and image, at an empirical setting. Literature on organizational identity in relation to organizational culture and organizational image is reviewed followed by conducting 12 semi structured interviews with managers from the marketing and human resource departments at Arla Foods in Sweden. The findings suggest that although employees reflect on the identity, there is a gap between reflection and action, meaning that the identity is not necessarily integrated in practice in the daily work due to different understandings of the organizational culture. In relation to the model, it is suggested that culture may not be so clearly connected to identity, whereas image and identity are very closely related. Also, the context in which the employees conduct their work is shown through the empirical setting, to be important for how employees reflect upon the identity.

This thesis investigates the relationship between Tobin’s Q and regional housing investment in Sweden for the time period of 1998-2012. The relationship is tested through estimation of two models for time-series analysis, a vector error correction model (VECM) and an autoregressive distributed lag (ARDL) model. Depending on which model that is used, I find some evidence of positive correlation between Tobin’s Q and regional housing investment in the long run while the short run dynamics of investment does not seem to be explained by Tobin’s Q. By transforming the regional data into a panel data set and running a fixed effects model, I examine the gain in explanatory power of Tobin’s Q from using disaggregated data rather than aggregated. My findings suggest that using disaggregated data improves the explanatory power of Tobin’s Q on investment. However, the Granger Causality test indicates two-way causality between Tobin’s Q and investment, causing endogeneity problem in the estimated equations.

Many arid region Wadi catchments are facing increasing water scarcity due to the unsustainable human practises such as the over expansion of irrigated agriculture and over exploitation of their groundwater aquifers. The “Soil and Water Assessment Tool” (SWAT) model, which is a comprehensive conceptual, semi-distributed watershed scale model, was selected after a review of the hydrological processes occurring in arid region catchments to simulate the hydrological processes of the Wadi Ham catchment in northeast United Arab Emirates. A sensitivity analysis conducted for SWAT for the total runoff, maximum runoff and days of runoff showed that a DEM resolution of no more than 100 m should be used for proper representation of such mountainous arid catchments. The appropriate size of defined sub-basins was found to be about 18 km 2 . The sensitivity analysis also demonstrated that the most sensitive parameters that affect the ephemeral streamflow are mainly related to the soil and channel properties of the catchment soil depth, soil available water capacity, soil bulk density, soil clay percentage, soil curve number, baseflow recession constant and channel effective hydraulic conductivity. SWAT simulated the ephemeral streamflow in Wadi Ham acceptably. For the calibration period of 1981 and 1982, the performance statistics for DRMS, PBIAS, NSE and PEM were 1.10 m 3 /s, 27.12%, 0.78 and 0.80 respectively. During the validation period between 1983 and 1988, the DRMS, PBIAS, NSE and PEM were 0.93 m 3 /s, -27.30%, 0.57 and 0.70 respectively. SWAT showed very plausible behaviour for reservoir sedimentation, plant growth, irrigation abstraction and groundwater recharge via the transmission losses mechanism. However, SWAT was not able to adequately simulate the recharge from the bottom of the recharge dam reservoir due to an inappropriate maximum effective hydraulic conductivity defined by the model. Two management scenarios were simulated. The first scenario related to the construction of an additional dam upstream and its effect on sedimentation rate in the main reservoir. The second scenario found that the recharge volumes could be enhanced through the construction of a discharge inlet point into the main stream channel for the treated wastewater from the principal town upstream of the catchment. The successful simulation of Wadi Ham represents the first use of SWAT in a truly arid climate. This research has therefore established the feasibility of using SWAT as a tool for integrated catchment modelling in arid region data- poor Wadi catchments and to support improved water resources management in this water stressed environment.

Semi-arid areas are, due to their climatic setting, characterized by small water resources. An increasing water demand as a consequence of population growth and economic development as well as a decreasing water availability in the course of possible climate change may aggravate water scarcity in future, which often exists already for present-day conditions in these areas. Understanding the mechanisms and feedbacks of complex natural and human systems, together with the quantitative assessment of future changes in volume, timing and quality of water resources are a prerequisite for the development of sustainable measures of water management to enhance the adaptive capacity of these regions. For this task, dynamic integrated models, containing a hydrological model as one component, are indispensable tools.
The main objective of this study is to develop a hydrological model for the quantification of water availability in view of environmental change over a large geographic domain of semi-arid environments.
The study area is the Federal State of Ceará (150 000 km2) in the semi-arid north-east of Brazil. Mean annual precipitation in this area is 850 mm, falling in a rainy season with duration of about five months. Being mainly characterized by crystalline bedrock and shallow soils, surface water provides the largest part of the water supply. The area has recurrently been affected by droughts which caused serious economic losses and social impacts like migration from the rural regions.
The hydrological model Wasa (Model of Water Availability in Semi-Arid Environments) developed in this study is a deterministic, spatially distributed model being composed of conceptual, process-based approaches. Water availability (river discharge, storage volumes in reservoirs, soil moisture) is determined with daily resolution. Sub-basins, grid cells or administrative units (municipalities) can be chosen as spatial target units. The administrative units enable the coupling of Wasa in the framework of an integrated model which contains modules that do not work on the basis of natural spatial units.
The target units mentioned above are disaggregated in Wasa into smaller modelling units within a new multi-scale, hierarchical approach. The landscape units defined in this scheme capture in particular the effect of structured variability of terrain, soil and vegetation characteristics along toposequences on soil moisture and runoff generation. Lateral hydrological processes at the hillslope scale, as reinfiltration of surface runoff, being of particular importance in semi-arid environments, can thus be represented also within the large-scale model in a simplified form. Depending on the resolution of available data, small-scale variability is not represented explicitly with geographic reference in Wasa, but by the distribution of sub-scale units and by statistical transition frequencies for lateral fluxes between these units.
Further model components of Wasa which respect specific features of semi-arid hydrology are:
(1) A two-layer model for evapotranspiration comprises energy transfer at the soil surface (including soil evaporation), which is of importance in view of the mainly sparse vegetation cover. Additionally, vegetation parameters are differentiated in space and time in dependence on the occurrence of the rainy season.
(2) The infiltration module represents in particular infiltration-excess surface runoff as the dominant runoff component.
(3) For the aggregate description of the water balance of reservoirs that cannot be represented explicitly in the model, a storage approach respecting different reservoirs size classes and their interaction via the river network is applied.
(4) A model for the quantification of water withdrawal by water use in different sectors is coupled to Wasa.
(5) A cascade model for the temporal disaggregation of precipitation time series, adapted to the specific characteristics of tropical convective rainfall, is applied for the generating rainfall time series of higher temporal resolution.
All model parameters of Wasa can be derived from physiographic information of the study area. Thus, model calibration is primarily not required.
Model applications of Wasa for historical time series generally results in a good model performance when comparing the simulation results of river discharge and reservoir storage volumes with observed data for river basins of various sizes. The mean water balance as well as the high interannual and intra-annual variability is reasonably represented by the model. Limitations of the modelling concept are most markedly seen for sub-basins with a runoff component from deep groundwater bodies of which the dynamics cannot be satisfactorily represented without calibration.
Further results of model applications are:
(1) Lateral processes of redistribution of runoff and soil moisture at the hillslope scale, in particular reinfiltration of surface runoff, lead to markedly smaller discharge volumes at the basin scale than the simple sum of runoff of the individual sub-areas. Thus, these processes are to be captured also in large-scale models. The different relevance of these processes for different conditions is demonstrated by a larger percentage decrease of discharge volumes in dry as compared to wet years.
(2) Precipitation characteristics have a major impact on the hydrological response of semi-arid environments. In particular, underestimated rainfall intensities in the rainfall input due to the rough temporal resolution of the model and due to interpolation effects and, consequently, underestimated runoff volumes have to be compensated in the model. A scaling factor in the infiltration module or the use of disaggregated hourly rainfall data show good results in this respect.
The simulation results of Wasa are characterized by large uncertainties. These are, on the one hand, due to uncertainties of the model structure to adequately represent the relevant hydrological processes. On the other hand, they are due to uncertainties of input data and parameters particularly in view of the low data availability. Of major importance is:
(1) The uncertainty of rainfall data with regard to their spatial and temporal pattern has, due to the strong non-linear hydrological response, a large impact on the simulation results.
(2) The uncertainty of soil parameters is in general of larger importance on model uncertainty than uncertainty of vegetation or topographic parameters.
(3) The effect of uncertainty of individual model components or parameters is usually different for years with rainfall volumes being above or below the average, because individual hydrological processes are of different relevance in both cases. Thus, the uncertainty of individual model components or parameters is of different importance for the uncertainty of scenario simulations with increasing or decreasing precipitation trends.
(4) The most important factor of uncertainty for scenarios of water availability in the study area is the uncertainty in the results of global climate models on which the regional climate scenarios are based. Both a marked increase or a decrease in precipitation can be assumed for the given data.
Results of model simulations for climate scenarios until the year 2050 show that a possible future change in precipitation volumes causes a larger percentage change in runoff volumes by a factor of two to three. In the case of a decreasing precipitation trend, the efficiency of new reservoirs for securing water availability tends to decrease in the study area because of the interaction of the large number of reservoirs in retaining the overall decreasing runoff volumes.
Semiaride Gebiete sind auf Grund der klimatischen Bedingungen durch geringe Wasserressourcen gekennzeichnet. Ein zukünftig steigender Wasserbedarf in Folge von Bevölkerungswachstum und ökonomischer Entwicklung sowie eine geringere Wasserverfügbarkeit durch mögliche Klimaänderungen können dort zu einer Verschärfung der vielfach schon heute auftretenden Wasserknappheit führen. Das Verständnis der Mechanismen und Wechselwirkungen des komplexen Systems von Mensch und Umwelt sowie die quantitative Bestimmung zukünftiger Veränderungen in der Menge, der zeitlichen Verteilung und der Qualität von Wasserressourcen sind eine grundlegende Voraussetzung für die Entwicklung von nachhaltigen Maßnahmen des Wassermanagements mit dem Ziel einer höheren Anpassungsfähigkeit dieser Regionen gegenüber künftigen Änderungen. Hierzu sind dynamische integrierte Modelle unerlässlich, die als eine Komponente ein hydrologisches Modell beinhalten.
Vorrangiges Ziel dieser Arbeit ist daher die Erstellung eines hydrologischen Modells zur großräumigen Bestimmung der Wasserverfügbarkeit unter sich ändernden Umweltbedingungen in semiariden Gebieten.
Als Untersuchungsraum dient der im semiariden tropischen Nordosten Brasiliens gelegene Bundestaat Ceará (150 000 km2). Die mittleren Jahresniederschläge in diesem Gebiet liegen bei 850 mm innerhalb einer etwa fünfmonatigen Regenzeit. Mit vorwiegend kristallinem Grundgebirge und geringmächtigen Böden stellt Oberflächenwasser den größten Teil der Wasserversorgung bereit. Die Region war wiederholt von Dürren betroffen, die zu schweren ökonomischen Schäden und sozialen Folgen wie Migration aus den ländlichen Gebieten geführt haben.
Das hier entwickelte hydrologische Modell Wasa (Model of Water Availability in Semi-Arid Environments) ist ein deterministisches, flächendifferenziertes Modell, das aus konzeptionellen, prozess-basierten Ansätzen aufgebaut ist. Die Wasserverfügbarkeit (Abfluss im Gewässernetz, Speicherung in Stauseen, Bodenfeuchte) wird mit täglicher Auflösung bestimmt. Als räumliche Zieleinheiten können Teileinzugsgebiete, Rasterzellen oder administrative Einheiten (Gemeinden) gewählt werden. Letztere ermöglichen die Kopplung des Modells im Rahmen der integrierten Modellierung mit Modulen, die nicht auf der Basis natürlicher Raumeinheiten arbeiten.
Im Rahmen eines neuen skalenübergreifenden, hierarchischen Ansatzes werden in Wasa die genannten Zieleinheiten in kleinere räumliche Modellierungseinheiten unterteilt. Die ausgewiesenen Landschaftseinheiten erfassen insbesondere die strukturierte Variabilität von Gelände-, Boden- und Vegetationseigenschaften entlang von Toposequenzen in ihrem Einfluss auf Bodenfeuchte und Abflussbildung. Laterale hydrologische Prozesse auf kleiner Skala, wie die für semiaride Bedingungen bedeutsame Wiederversickerung von Oberflächenabfluss, können somit auch in der erforderlichen großskaligen Modellanwendung vereinfacht wiedergegeben werden. In Abhängigkeit von der Auflösung der verfügbaren Daten wird in Wasa die kleinskalige Variabilität nicht räumlich explizit sondern über die Verteilung von Flächenanteilen subskaliger Einheiten und über statistische Übergangshäufigkeiten für laterale Flüsse zwischen den Einheiten berücksichtigt.
Weitere Modellkomponenten von Wasa, die spezifische Bedingungen semiarider Gebiete berücksichtigen, sind:
(1) Ein Zwei-Schichten-Modell zur Bestimmung der Evapotranspiration berücksichtigt auch den Energieumsatz an der Bodenoberfläche (inklusive Bodenverdunstung), der in Anbetracht der meist lichten Vegetationsbedeckung von Bedeutung ist. Die Vegetationsparameter werden zudem flächen- und zeitdifferenziert in Abhängigkeit vom Auftreten der Regenzeit modifiziert.
(2) Das Infiltrationsmodul bildet insbesondere Oberflächenabfluss durch Infiltrationsüberschuss als dominierender Abflusskomponente ab.
(3) Zur aggregierten Beschreibung der Wasserbilanz von im Modell nicht einzeln erfassbaren Stauseen wird ein Speichermodell unter Berücksichtigung verschiedener Größenklassen und ihrer Interaktion über das Gewässernetz eingesetzt.
(4) Ein Modell zur Bestimmung der Entnahme durch Wassernutzung in verschiedenen Sektoren ist an Wasa gekoppelt.
(5) Ein Kaskadenmodell zur zeitlichen Disaggregierung von Niederschlagszeitreihen, das in dieser Arbeit speziell für tropische konvektive Niederschlagseigenschaften angepasst wird, wird zur Erzeugung höher aufgelöster Niederschlagsdaten verwendet.
Alle Modellparameter von Wasa können von physiographischen Gebietsinformationen abgeleitet werden, sodass eine Modellkalibrierung primär nicht erforderlich ist.
Die Modellanwendung von Wasa für historische Zeitreihen ergibt im Allgemeinen eine gute Übereinstimmung der Simulationsergebnisse für Abfluss und Stauseespeichervolumen mit Beobachtungsdaten in unterschiedlich großen Einzugsgebieten. Die mittlere Wasserbilanz sowie die hohe monatliche und jährliche Variabilität wird vom Modell angemessen wiedergegeben. Die Grenzen der Anwendbarkeit des Modell-konzepts zeigen sich am deutlichsten in Teilgebieten mit Abflusskomponenten aus tieferen Grundwasserleitern, deren Dynamik ohne Kalibrierung nicht zufriedenstellend abgebildet werden kann.
Die Modellanwendungen zeigen weiterhin:
(1) Laterale Prozesse der Umverteilung von Bodenfeuchte und Abfluss auf der Hangskala, vor allem die Wiederversickerung von Oberflächenabfluss, führen auf der Skala von Einzugsgebieten zu deutlich kleineren Abflussvolumen als die einfache Summe der Abflüsse der Teilflächen. Diese Prozesse sollten daher auch in großskaligen Modellen abgebildet werden. Die unterschiedliche Ausprägung dieser Prozesse für unterschiedliche Bedingungen zeigt sich an Hand einer prozentual größeren Verringerung der Abflussvolumen in trockenen im Vergleich zu feuchten Jahren.
(2) Die Niederschlagseigenschaften haben einen sehr großen Einfluss auf die hydrologische Reaktion in semiariden Gebieten. Insbesondere die durch die grobe zeitliche Auflösung des Modells und durch Interpolationseffekte unterschätzten Niederschlagsintensitäten in den Eingangsdaten und die daraus folgende Unterschätzung von Abflussvolumen müssen im Modell kompensiert werden. Ein Skalierungsfaktor in der Infiltrationsroutine oder die Verwendung disaggregierter stündlicher Niederschlagsdaten zeigen hier gute Ergebnisse.
Die Simulationsergebnisse mit Wasa sind insgesamt durch große Unsicherheiten gekennzeichnet. Diese sind einerseits in Unsicherheiten der Modellstruktur zur adäquaten Beschreibung der relevanten hydrologischen Prozesse begründet, andererseits in Daten- und Parametersunsicherheiten in Anbetracht der geringen Datenverfügbarkeit. Von besonderer Bedeutung ist:
(1) Die Unsicherheit der Niederschlagsdaten in ihrem räumlichen Muster und ihrer zeitlichen Struktur hat wegen der stark nicht-linearen hydrologischen Reaktion einen großen Einfluss auf die Simulationsergebnisse.
(2) Die Unsicherheit von Bodenparametern hat im Vergleich zu Vegetationsparametern und topographischen Parametern im Allgemeinen einen größeren Einfluss auf die Modellunsicherheit.
(3) Der Effekt der Unsicherheit einzelner Modellkomponenten und -parameter ist für Jahre mit unter- oder überdurchschnittlichen Niederschlagsvolumen zumeist unterschiedlich, da einzelne hydrologische Prozesse dann jeweils unterschiedlich relevant sind. Die Unsicherheit einzelner Modellkomponenten- und parameter hat somit eine unterschiedliche Bedeutung für die Unsicherheit von Szenarienrechnungen mit steigenden oder fallenden Niederschlagstrends.
(4) Der bedeutendste Unsicherheitsfaktor für Szenarien der Wasserverfügbarkeit für die Untersuchungsregion ist die Unsicherheit der den regionalen Klimaszenarien zu Grunde liegenden Ergebnisse globaler Klimamodelle. Eine deutliche Zunahme oder Abnahme der Niederschläge bis 2050 kann gemäß den hier vorliegenden Daten für das Untersuchungsgebiet gleichermaßen angenommen werden.
Modellsimulationen für Klimaszenarien bis zum Jahr 2050 ergeben, dass eine mögliche zukünftige Veränderung der Niederschlagsmengen zu einer prozentual zwei- bis dreifach größeren Veränderung der Abflussvolumen führt. Im Falle eines Trends von abnehmenden Niederschlagsmengen besteht in der Untersuchungsregion die Tendenz, dass auf Grund der gegenseitigen Beeinflussung der großen Zahl von Stauseen beim Rückhalt der tendenziell abnehmenden Abflussvolumen die Effizienz von neugebauten Stauseen zur Sicherung der Wasserverfügbarkeit zunehmend geringer wird.

This research is aimed at developing a model for estimating peak discharge rates and design flood hydrographs for the Machchan catchment in the semi-arid region of Gujarat, India. For many such catchments flow data are not available or are insufficient to extrapolate for determination of design flows. For such situations some direct approaches are required to give information on peak discharge rates and hydrographs. Several methods have been developed by researchers for the design of peak river flow in ungauged catchments but these different methods are complementary to each other. The Cascaded Reservoir Model developed in this research combines some of these methods namely, SCS method, time–area histogram method and Muskingum flood routing method formulated the model.

Age-related cognitive decline (ARCD) is a pattern of deterioration in cognitive functions that gradually impairs the ability to think, reason, concentrate and remember. It has been identified as a major health threat for older adults because of the potential deleterious effects on independence, social engagement and quality of life. The trend in the experimental literature suggests that cardiovascular exercise training may have the capacity to counter ARCD. However, the efficacy of single modality interventions is inconclusive and there is currently a move towards investigating the effects of combination exercise interventions. The assumption is that optimisation of the intervention stimulus, in this way, might induce more pronounced cognitive outcomes than the modest levels of enhancement elicited by cardiovascular training alone. There are theoretical indications that these effects may be more likely to be achieved by the inclusion of motor skills training; as this modality involves complexity and novelty that requires sustained mental effort or cognitive load. The suggestion is that sustained mental effort is likely to both induce (positive) brain changes and stimulate higher-order cognitive processes (executive functions). In theory, the inclusion of these design elements may benefit executive function (higher order cognitive processes most susceptible to ARCD) and induce positive neuroplasticity (the life-long neuronal capacity of the brain to preserve or optimise function, in response to experiential stimuli).
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Rehabilitation Sciences
Griffith Health
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La thèse explore l’utilisation de modèles hydrologiques globaux pour estimer la disponibilité en eau agricole dans le contexte des Andes chiliennes semi-arides. Dans cette région, l’approvisionnement en eau des cultures irriguées de fonds de vallée durant l’été dépend de précipitations se produisant sous forme de neige à haute altitude lors de quelques évènements hivernaux. L’influence des phénomènes ENSO et PDO induit par ailleurs une forte variabilité climatique à l’échelle inter-annuelle, marquée par l’occurrence d’années extrêmement sèches ou humides. La région connaît aussi depuis les années 1980 une progression importante de la viticulture irriguée. Afin de prendre en compte les variations saisonnières et inter-annuelles de la disponibilité et de la consommation en eau d’irrigation, une chaîne de modélisation intégrée a été développée et différentes méthodes de quantification/réduction des incertitudes de simulation ont été mises en œuvre. Les écoulements naturels ont été simulés avec un modèle hydrologique global de type empirique/conceptuel prenant en compte les processus d’accumulation et d’ablation de la neige. En parallèle, les besoins en eau d’irrigation ont été estimés à l’échelle du bassin à partir de modèles phénologiques orientés processus et d’une approche simple du bilan hydrique du sol. Dans l’ensemble, une approche holistique et parcimonieuse a été privilégiée afin de maintenir un niveau d’abstraction mathématique et de représentation des processus équivalent à celui des modèles de bassin couramment utilisés. Afin d’améliorer l’utilité et la fiabilité des simulations obtenues en contexte de changement ou de forte variabilité climatique, l’effet des températures extrêmes sur le développement des cultures et l’impact des pertes en eau par sublimation à haute altitude ont fait l’objet d’une attention particulière. Ce cadre de modélisation conceptuel a été testé pour un bassin typique des Andes semi-arides (1512 km2, 820–5500 m a.s.l.) sur une période de 20 ans incluant une large gamme de conditions climatiques et des pratiques agricoles non-stationnaires (évolution des variétés de vigne, des surfaces et modes d’irrigation, etc). L’évaluation des modèles a été réalisée dans un cadre bayésien en faisant l’hypothèse d’erreurs auto-corrélées, hétéroscédastiques et non-gaussiennes. Différents critères et sources de données ont par ailleurs été mobilisés afin de vérifier l’efficacité et la cohérence interne de la chaîne de modélisation ainsi que la fiabilité statistique et la finesse des intervalles de confiance obtenus. De manière alternative, une caractérisation des erreurs de structure et de l’ambiguïté propre au choix du modèle hydrologique a été réalisée de manière non-probabiliste à partir d’une plate-forme de modélisation modulaire. Dans l’ensemble, la prise en compte explicite de la consommation en eau des cultures a mis en valeur certaines interactions entre paramètres hydrologiques et permis d’améliorer la fiabilité des simulations hydrologiques en année sèche. Finalement, une étude de sensibilité à différents seuils d’augmentation de la température et de la concentration en CO2 a été effectuée afin d’évaluer l’impact potentiel des changements climatiques sur le comportement de l’hydrosystème et la capacité à satisfaire la demande en eau d’irrigation dans le futur
This thesis investigates the use of lumped catchment models to assess water availability for irrigation in the upland areas of northern-central Chile (30°S). Here, most of the annual water supply falls as snow in the high Cordillera during a few winter storms. Seasonal snowpacks serve as natural reservoirs, accumulating water during the winter and sustaining streams and aquifers during the summer, when irrigation demand in the cultivated valleys is at its peak. At the inter-annual timescale, the influence of ENSO and PDO phenomena result in the occurrence of extremely wet and dry years. Also, irrigated areas and grape growing have achieved a dramatic increase since the early 1980s. To evaluate the usefulness of explicitly accounting for changes in irrigation water-use in lumped catchment models, an integrated modeling framework was developed and different ways of quantifying/reducing model uncertainty were explored. Natural streamflow was simulated using an empirical hydrological model and a snowmelt routine. In parallel, seasonal and inter-annual variations in irrigation requirements were estimated using several process-based phenological models and a simple soil-water balance approach. Overall, this resulted in a low-dimensional, holistic approach based on the same level of mathematical abstraction and process representation as in most commonly-used catchment models. To improve model reliability and usefulness under varying or changing climate conditions, particular attention was paid to the effects of extreme temperatures on crop phenology and the contribution of sublimation losses to water balance at high elevations. This conceptual framework was tested in a typical semi-arid Andean catchment (1512 km2, 820–5500 m a.s.l.) over a 20–year simulation period encompassing a wide range of climate and water-use conditions (changes in grape varieties, irrigated areas, irrigation techniques). Model evaluation was performed from a Bayesian perspective assuming auto-correlated, heteroscedastic and non-gaussian residuals. Different criteria and data sources were used to verify model assumptions in terms of efficiency, internal consistency, statistical reliability and sharpness of the predictive uncertainty bands. Alternatively, a multiple-hypothesis and multi-criteria modeling framework was also developed to quantify the importance of model non-uniqueness and structural inadequacy from a non-probabilistic perspective. On the whole, incorporating the effects of irrigation water-use led to new interactions between the hydrological parameters of the modeling framework and improved reliability of streamflow predictions during low-flow periods. Finally, a sensitivity analysis to changes in climate conditions was conducted to evaluate the potential impacts of increasing temperatures and atmospheric CO2 on the hydrological behavior of the catchment and the capacity to meet future water demands