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Livelihood dependency and management on semiarid oak forests : the case of southern Zagros, Iran /Salehi, Alireza, January 2009 (has links) (PDF)
Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2009. / Härtill 4 uppsatser.
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Evapotranspiração e coeficientes de cultura da melancieira irrigada por gotejamento em Alvorada do Gurguéia-PIFerreira, José Orlando Piauilino [UNESP] 16 April 2010 (has links) (PDF)
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ferreira_jop_dr_jabo.pdf: 1268842 bytes, checksum: 715de8aae3de8bec81a7a441b78ef9c9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este experimento foi conduzido em Alvorada do Gurguéia, situada no vale do rio Gurguéia, estado do Piauí, localizado na latitude de 8º 26’ S, longitude 43º 47’ W e altitude de 251 m. Os objetivos deste estudo foram determinar a evapotranspiração (ETc) e os coeficientes de cultura (Kc) da melancieira irrigada por gotejamento. A evapotranspiração de referência (ETo) foi determinada diariamente por dez modelos de estimativa, com parte dos elementos climáticos obtidos em uma estação agrometeorológica automática localizada no centro da área experimental. Os modelos foram: Penman-Monteith-FAO56 (PMFAO56), Penman-Monteith-ASCE (PMASCE), Hargreaves-Samani (HS), Priestley-Taylor (PT), Camargo (CAM), Thornthwaite original (THW), Thornthwaite com correção para a temperatura efetiva calculada como uma função da temperatura média e da amplitude diária e valores de K=0,69 (THW2(0,69)) e K=0,72 (THW3(0,72)) e Thornthwaite com a mesma temperatura efetiva corrigida para o fotoperíodo e valores de K=0,69 (THW2(0,69)) e K=0,72 (THW2(0,72)). A ETc foi medida a partir de três lisímetros de pesagem localizados no centro da área experimental. O desempenho dos métodos foi avaliado utilizando regressão linear simples e diferentes índices: raiz quadrada do erro médio quadrático (RMES), erro percentual absoluto médio (MAPE), índice de concordância (d) e o teste de Scott-Knott, usando como padrão EToPMFAO56. O modelo PMASCE foi semelhante ao PMFAO56, com RMES = 0,05 mm dia-1, MAPE = 0,74%, d = 1,0 e R2 = 0,99. Apenas os modelos, THW2(0,69) e THW3(0,72), não apresentaram médias gerais significativamente diferentes de PMFAO56. Os valores médios de Kc obtidos com o PMFAO56 foram 0,44; 1,58 e 1,28 para os estádios inicial, intermediário e final, respectivamente. Valores estes, assim como os de todos os demais métodos de estimativa de ET0 testados, foram superiores aos obtidos... / This experiment was carried out at the Gurguéia river valley, state of Piauí, Brazil, located at 8º 26’ S latitude, 43º 47’ W longitude an altitude of 251 m. The objectives of this study were to determine the evapotranspiration (ETc) and crop coefficients (Kc) of watermelon by drip irrigated. Reference evapotranspiration (ETo) was daily determined by ten models of the estimation, with part climatics variable obtained an automatic agrometeorological station located in the center of the experimental area. The models were: Penman-Monteith-FAO56 (PMFAO56), Penman- Monteith-ASCE (PMASCE), Hargreaves-Samani (HS), Priestley-Taylor (PT), Camargo (CAM), original Thornthwaite (THW), Thornthwaite with correction for effective temperature computed as a function of the average temperature and of the daily amplitude and values of K=0,69 (THW2(0,69)) and K=0,72 (THW3(0,72)) and Thornthwaite with the same effective temperature corrected for the photoperiod and value of K=0,69 (THW2(0,69)) and K=0,72 (THW3(0,72)). ETc was measured from three weighing lysimeters located in the center of the experimental area. Methods performance was evaluated by using single linear regression and different indices, root mean square error (RMES), mean absolute percentage error (MAPE), index of agreement (d) and Scott-Knott test, using how standard PMFAO56. The model PMASCE was resembling to PMFAO56, with RMES = 0,05 mm dia-1, MAPE = 0,74%, d = 1,0 and R² = 0,99. Only the models, THW2(0,69) e THW3(0,72), not presents generals average significant difference of the PMFAO56. The Kc values obtained were 0,44, 1,58 and 1,28 for the initial, intermediate and final stages, respectively. This values, thus as of the every methods of estimation of the ETo tested, was upper to obtained for watermelon in the Bulletin 56 of irrigation and drainage of the FAO, principally for the intermediate and final stages... (Complete abstract click electronic access below)
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Evapotranspiração e coeficientes de cultura da melancieira irrigada por gotejamento em Alvorada do Gurguéia-PI /Ferreira, José Orlando Piauilino. January 2010 (has links)
Resumo: Este experimento foi conduzido em Alvorada do Gurguéia, situada no vale do rio Gurguéia, estado do Piauí, localizado na latitude de 8º 26' S, longitude 43º 47' W e altitude de 251 m. Os objetivos deste estudo foram determinar a evapotranspiração (ETc) e os coeficientes de cultura (Kc) da melancieira irrigada por gotejamento. A evapotranspiração de referência (ETo) foi determinada diariamente por dez modelos de estimativa, com parte dos elementos climáticos obtidos em uma estação agrometeorológica automática localizada no centro da área experimental. Os modelos foram: Penman-Monteith-FAO56 (PMFAO56), Penman-Monteith-ASCE (PMASCE), Hargreaves-Samani (HS), Priestley-Taylor (PT), Camargo (CAM), Thornthwaite original (THW), Thornthwaite com correção para a temperatura efetiva calculada como uma função da temperatura média e da amplitude diária e valores de K=0,69 (THW2(0,69)) e K=0,72 (THW3(0,72)) e Thornthwaite com a mesma temperatura efetiva corrigida para o fotoperíodo e valores de K=0,69 (THW2(0,69)) e K=0,72 (THW2(0,72)). A ETc foi medida a partir de três lisímetros de pesagem localizados no centro da área experimental. O desempenho dos métodos foi avaliado utilizando regressão linear simples e diferentes índices: raiz quadrada do erro médio quadrático (RMES), erro percentual absoluto médio (MAPE), índice de concordância (d) e o teste de Scott-Knott, usando como padrão EToPMFAO56. O modelo PMASCE foi semelhante ao PMFAO56, com RMES = 0,05 mm dia-1, MAPE = 0,74%, d = 1,0 e R2 = 0,99. Apenas os modelos, THW2(0,69) e THW3(0,72), não apresentaram médias gerais significativamente diferentes de PMFAO56. Os valores médios de Kc obtidos com o PMFAO56 foram 0,44; 1,58 e 1,28 para os estádios inicial, intermediário e final, respectivamente. Valores estes, assim como os de todos os demais métodos de estimativa de ET0 testados, foram superiores aos obtidos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This experiment was carried out at the Gurguéia river valley, state of Piauí, Brazil, located at 8º 26' S latitude, 43º 47' W longitude an altitude of 251 m. The objectives of this study were to determine the evapotranspiration (ETc) and crop coefficients (Kc) of watermelon by drip irrigated. Reference evapotranspiration (ETo) was daily determined by ten models of the estimation, with part climatics variable obtained an automatic agrometeorological station located in the center of the experimental area. The models were: Penman-Monteith-FAO56 (PMFAO56), Penman- Monteith-ASCE (PMASCE), Hargreaves-Samani (HS), Priestley-Taylor (PT), Camargo (CAM), original Thornthwaite (THW), Thornthwaite with correction for effective temperature computed as a function of the average temperature and of the daily amplitude and values of K=0,69 (THW2(0,69)) and K=0,72 (THW3(0,72)) and Thornthwaite with the same effective temperature corrected for the photoperiod and value of K=0,69 (THW2(0,69)) and K=0,72 (THW3(0,72)). ETc was measured from three weighing lysimeters located in the center of the experimental area. Methods performance was evaluated by using single linear regression and different indices, root mean square error (RMES), mean absolute percentage error (MAPE), index of agreement (d) and Scott-Knott test, using how standard PMFAO56. The model PMASCE was resembling to PMFAO56, with RMES = 0,05 mm dia-1, MAPE = 0,74%, d = 1,0 and R² = 0,99. Only the models, THW2(0,69) e THW3(0,72), not presents generals average significant difference of the PMFAO56. The Kc values obtained were 0,44, 1,58 and 1,28 for the initial, intermediate and final stages, respectively. This values, thus as of the every methods of estimation of the ETo tested, was upper to obtained for watermelon in the Bulletin 56 of irrigation and drainage of the FAO, principally for the intermediate and final stages... (Complete abstract click electronic access below) / Orientador: Luiz Carlos Pavani / Coorientador: Edson Alves Bastos / Banca: Aderson Soares de Andrade Junior / Banca: Regina Célia de Matos Pires / Banca: Jose Renato Zanini / Banca: Mario Benincasa / Doutor
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GestÃo de recursos hÃdricos em regiÃes semiÃridas com alta variabilidade de deflÃvios superficiais: anÃlise comparativa entre o Cearà no Nordeste do Brasil e o Leste da AustrÃlia / Management of Water Resources in Semi-arid Regions with High Variability of Superficial Runoffs: Comparative Analysis between Cearà in Northeast Brazil and the Eastern AustraliaBeatriz Costa Canamary 03 April 2013 (has links)
nÃo hà / As peculiaridades de cada paÃs levam à utilizaÃÃo de mecanismos variados de
alocaÃÃo de recursos hÃdricos, nÃo havendo uma regra geral para a resoluÃÃo do
problema de escassez de Ãgua. O conhecimento dos modelos experimentados
internacionalmente, com a identificaÃÃo de suas respectivas vantagens e
desvantagens, sÃo de grande utilidade.
O objetivo principal da gestÃo dos recursos hÃdricos à satisfazer a demanda,
considerando as possibilidades e limitaÃÃes da oferta de Ãgua. Entretanto, para isso,
à necessÃrio o conhecimento de todos os aspectos hidrolÃgicos, climatolÃgicos e
fÃsicos da regiÃo para realizar um planejamento adequado de oferta hÃdrica, alÃm do
conhecimento da populaÃÃo e dos mÃltiplos interesses, para um bom
dimensionamento da demanda.
Entretanto, quando o sistema hÃdrico à alimentado por influxos espacial e
temporalmente variÃveis, que à o que ocorre em regiÃes semiÃridas, a escolha de
um modelo eficaz de gestÃo dos recursos hÃdricos torna-se ainda mais complexa,
devido Ãs incertezas presentes na avaliaÃÃo dos futuros nÃveis de Ãgua. Nestes
casos, as incertezas tÃm um importante papel na gestÃo dos recursos hÃdricos.
Em busca de um estudo mais profundo da gestÃo dos recursos hÃdricos nessas
regiÃes de alta variabilidade climÃtica, foram tomados como anÃlise os modelos
aplicados no Nordeste Brasileiro e na AustrÃlia. O presente trabalho apresenta a
semelhanÃa nas caracterÃsticas do clima dessas regiÃes, a semelhanÃa nos
problemas enfrentados por cada uma delas e, finalmente, traÃa um paralelo, atravÃs
da anÃlise e comparaÃÃo dos diferentes mÃtodos de gestÃo dos recursos hÃdricos
disponÃveis. / The peculiarities of each country lead to the use of various mechanisms of water
allocation. There is no general rule for solving the problem of water scarcity.
Understanding the models experienced internationally, identifying their respective
advantages and disadvantages are very useful.
The main objective of water management is to attend the demand, considering the
possibilities and limitations of water supply. However, for this, it is necessary to know
all hydrological, climatological and physical aspects of the region to conduct a proper
planning of water supply, beyond the knowledge of the population and the multiple
interests, to a good demand sizing.
However, when the water system is supplied by spatial and temporal variability of
inflows, as in semiarid regions, the choice of an effective model for water
management becomes more complex, due to the uncertainties presented in
evaluating future water levels. In these cases, uncertainties have an important role in
water resources management.
In the matter of a deep study of water resources management in these regions of
high climate variability, models applied in Northeast Brazil and Australia were used
as analysis. This paper presents the similarity of climate aspects, the similar
problems faced by each region, and finally draws a parallel comparing different
methods of available water management.
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Comparison of parsimonious dynamic vegetation modelling approaches for semiarid climatesPasquato, Marta 05 December 2013 (has links)
A large portion of Earth¿s terrestrial surface is subject to arid climatic water stress. As in these regions the hydrological cycle and the vegetation dynamics are tightly interconnected, a coupled modeling of these two systems is needed to fully reproduce the ecosystems¿ behavior over time and to predict possible future responses to climate change.
In this thesis, the performance of three parsimonious dynamic vegetation models, suitable for inclusion in an operational ecohydrological model, are tested in a semi-arid Aleppo pine forest area in the south-east of Spain. The first model considered, HORAS (Quevedo & Francés, 2008), simulates growth as a function of plant transpiration (T), evaluating environmental restraints through the transpiration-reference evapotranspiration ratio. The state variable related to vegetation is R, relative foliar biomass, which is equivalent to FAO crop coefficient (Allen et al., 1998), but not fixed in time. The HORAS model was then abandoned because of its unsatisfactory results, probably due to a poor simulation of evaporation and transpiration processes. As for the other two models, WUE-model and LUE-model, the state variable is the leaf biomass (Bl, kg dry mass m-2 vegetation cover). Both models simulate gross primary production (GPP), in the first case as a function of transpiration and water use efficiency (WUE), in the second case as a function of absorbed photosynthetically active radiation (APAR) and light use efficiency (LUE). Net primary production (NPP) is then calculated taking into account respiration. The modelling is focused particularly on simulating foliar biomass, which is obtained from NPP through an allocation equation based on the maximum leaf area index (LAI) sustainable by the system, and considering turnover.
An analysis of the information offered by MODIS EVI, NDVI, and LAI products was also performed, in order to investigate vegetation dynamics in the study site and to select the best indices to be used as observational verification for models. MODIS EVI is reported in literature (Huete et al., 2002) to be highly correlated with leaf biomass. In accordance with the phenological cycle timing described for the Aleppo pine in similar climates (Muñoz et al., 2003), the EVI showed maximum values in spring and minimum values in winter. Similar results were found applying the aforementioned WUE- and LUE- models to the study area. Contrasting simulated LAI with the EVI series, the correlation coefficients rWUE = 0.45 and rLUE = 0.57 were found for the WUE-model and LUE-model respectively. Concerning NDVI, its own definition links this index to the ¿greenness¿ of the target, so that it appears highly linked to chlorophyll content and vegetation condition, but only indirectly related to LAI. Photosynthetic pigment concentrations are reported to be sensitive to water stress in Aleppo pine (Baquedano and Castillo, 2006) so, to compare the models¿ results with NDVI, the simulated LAI was corrected by plant water-stress. The resulting correlation coefficients were rWUE = 0.62 and rLUE = 0.59. Lastly, MODIS LAI and ET were found to be unreliable in the study area because very low compared to field data and to values reported in literature (e.g. Molina & del Campo, 2012) for the same species in similar climatic conditions. The performance of both WUE- and LUE- models in this semi-arid region is found to be reasonable. However, the LUE-model presents the advantages of a better performance, the possibility to be used in a wider range of climates and to have been extensively tested in literature. / Pasquato, M. (2013). Comparison of parsimonious dynamic vegetation modelling approaches for semiarid climates [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34326 / TESIS
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