Thesis (MSc)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Submitted by Maria Medeiros (maria.dilva1@ufcg.edu.br) on 2018-06-14T15:05:54Z No. of bitstreams: 1 ANDRÉ AIRES DE FARIAS - TESE (PPGRN) 2016.pdf: 5737610 bytes, checksum: 24b094da2cef8f2db3a8552a03764f80 (MD5) / Made available in DSpace on 2018-06-14T15:05:54Z (GMT). No. of bitstreams: 1 ANDRÉ AIRES DE FARIAS - TESE (PPGRN) 2016.pdf: 5737610 bytes, checksum: 24b094da2cef8f2db3a8552a03764f80 (MD5) Previous issue date: 2016-02-26 / Capes / Objetivou-se identificar e analisar os períodos de secas na sub-bacia hidrográfica do Rio Taperoá (SBHRT) e os impactos sociais, econômicos e ambientais e ações de convivência com a seca de 2012-2014 no município de Taperoá - PB. Dados pluviométricos, série 19632014, foram utilizados para analisar o regime de precipitação da sub-bacia; e a severidade dos anos secos, por meio do Índice padronizado de precipitação. A identificação dos impactos foi realizada utilizando-se o método de listagem descritiva check-list, questionários, dados bibliográficos e documentais. Para analisar as variáveis socioeconômicas e as ações de convivência foram utilizados os mesmos materiais dos impactos, exceto o check-list. O período chuvoso dos municípios da sub-bacia ocorre de janeiro a maio, precipitações menores do que a média nesses meses causaram graves impactos. Verificou-se que a maioria das secas que ocorreram na SBHRT se enquadram na categoria moderada, seguido por severa e extrema. A SBHRT foi atingida por secas severas e extremas durante todas as décadas analisadas, no entanto, o maior número delas ocorreu nas décadas de 1980, 1990, 2000 e 2010. A seca mais grave foi a de 1998-2000, seguido pela de 1979-1985. A seca de 20122014 não foi a mais grave porque a precipitação foi acima da ocorrida no período de 19982000 e 1979-1985, houve também maior investimento em ações de convivência com as secas e programas sociais implantados pelos governos. Os impactos sociais, econômicos e ambientais da seca de 2012-2014 no município de Taperoá-PB foram: problemas de saúde relativos à baixa disponibilidade hídrica, desigualdade na distribuição de recursos durante a seca, desgaste mental, reduções na alimentação da população, conflitos entre usuários de água, aumento da pobreza, migrações populacionais, redução da pecuária e da produção de culturas, aumento do desemprego, elevação dos custos para transportar água, indisponibilidade de alimentos para animais, perturbação dos ciclos de reprodução, redução de recreação e turismo, prejuízos à flora, à fauna e às espécies piscícolas, e redução da qualidade da água. Os impactos continuaram porque faltou recursos financeiros para implantar programas e as políticas públicas de convivência não foram efetivas, só aparecendo com maior intensidade quando a região estava prejudicada pela seca. Para redução dos impactos é necessário aumentar o número de cisternas, principalmente a calçadão. É necessário também perfurar poços e construir açudes, além de fazer manutenção nos que estejam com capacidade reduzida ou desativados, construir barragens subterrâneas e tanques naturais, terminar e colocar em funcionamento a Transposição do Rio São Francisco, incentivar a gestão dos recursos hídricos, criar programas que visem o fortalecimento da agricultura familiar, incentivando a fenação, silagem, meliponicultura, apicultura, criação de animais e plantas adaptados à região, dentre muitos outros. / This study aimed to identify and analyze the periods of droughts in sub-basin hydrographic of the Taperoá River (SBHTR) and the social, economic and environmental impacts and living actions with drought from 2012-2014 in the municipality of Taperoá - PB. Rainfall data, serie 1963-2014, were used to analyze the sub-basin rainfall regime; and the severity of the dry years, through the Standardized Precipitation Index. The identification of social, economic and environmental impacts was performed using the method of descriptive listing check-list, questionnaires, bibliographic and documentary data. To analyze the socioeconomic variables and of actions of living together were used same materials of the impacts, except the checklist. The rainy period in the municipalities of the sub-basin occurs from january to may, precipitations lower than average in these months caused severe impacts. It was found that most of droughts in SBHRT occurred into the category moderate, following by severe and extreme. The SBHRT was hit by severe and extreme dried for all analyzed decades, however, as many of them occurred in the decades of 1980, 1990, 2000 and 2010. The most severe drought was the from 1998-2000, followed by 1979-1985. The drought of 2012-2014 was not the more serious because the precipitation was above occurred in 1998-2000 and 1979-1985 period, there was also greater investment in coexistence actions with droughts and social programs implemented by governments. The social, economic and environmental impacts of the drought of 2012-2014 in the municipality of Taperoá-PB were: health problems of low flow, unequal distribution of resources during the drought, mental strain, reductions in food supply, conflicts water users, increasing poverty, population migration, reduction of livestock and crop production, rising unemployment, higher costs for transporting water, unavailability of feed, disruption of reproductive cycles, reduction of recreation and tourism, losses in flora, fauna and fish species, and reduced water quality. The impacts continued because they lack financial resources to implement programs and public coexistence policies were not effective, only appearing with greater intensity when the region was hampered by drought. To reduce the impacts is to increase the number of cisterns, especially the boardwalk. You also need to drill wells and build dams, in addition to maintenance on that are with reduced or deactivated capacity, building underground dams and natural ponds, finished and put into operation the Transposition of the São Francisco River, encourage the management of water resources, create programs aimed at strengthening family farming, encouraging haymaking, silage, beekeeping, meliponiculture, husbandry of animals and plants adapted to the region, among many others.

MENVSC (Geography) / Department of Geography and Geo-Information Science / Climate change has brought about a number of global environmental challenges and the worst, climatic disasters such as floods and droughts. In Zimbabwe, particularly in the semi-arid Chivi District, droughts have become more frequent. At the household level, there are a multiplicity of vulnerability and coping mechanisms to this scourge, which have gender dimensions. This study analysed the vulnerability of the Chivi South community to drought and its adaptation with specific consideration to the gender dynamics. The specific objectives for this dissertation were to establish the characteristics and extent of drought occurrences in Chivi District in the last 30 years, assess Chivi South‟s vulnerability to drought, evaluate levels of gender vulnerability to drought, and analyse gendered adaptation to drought. Subsequently, a strategy for drought adaptation in the rural areas of Zimbabwe was drawn. The research was based on the mixed methods approach, as it employed both qualitative and quantitative approaches. Data collection methods included a review of official documents, key informant interviews with community leaders, Non-Governmental Organisations and government officials working in the area, household questionnaires and focus group discussions. The Standardized Precipitation Index was used to determine drought severity. Data was analysed using the SPSS 22.0 software. Capabilities such as Chi-square and cross tabulation were used to effectively analyse data. The Household Vulnerability Index was employed to infer vulnerability and adaptation of the community to drought. Research findings were illustrated using charts, graphs, tables and photographs. The study established the occurrence of droughts in Chivi, with a high prevalence of low magnitude droughts. A decrease in crop food production closely related to drought patterns was noted. Drought vulnerability cuts across the whole gender spectrum, with a sizable number of female headed households being severely exposed. However females adapt better to the effects of drought than males. A holistic approach which seeks to integrate both men and women in decision-making and to improve the community‟s adaptation to drought and other disasters was proposed

Drought is a recurrent extreme climate event with tremendous hazard for every specter of natural environment and human lives. Drought analysis usually involves characterizing drought severity, duration and intensity. Similar to most of the hydrological problems, such characteristic variables are usually not independent. Copula, as a model of multivariate distribution, widely used in finance, actuarial analysis, has won increasingly popularity in hydrological study. Here, the study has two major focuses: (1) fit drought characteristics from Streamflow Drought Index (SDI) or Standardized Runoff Index (SRI) to appropriate copulas, then using fitted copulas to estimate conditional drought severity distribution and joint return periods for both historical time period 1920-2009 and future time period 2020-2090. SDI is calculated based on long term observed streamflow while SRI is based on simulated future runoff. Parameters estimation of marginal distribution and copulas are provided, with goodness fit measures as well; (2) investigate the effects of climate change on the frequency and severity of droughts. In order to quantify the impact, three drought indices have been proposed for this study to characterize the drought duration, severity and intensity changes under the climate change in Upper Klamath River Basin. Since drought can be defined as different types, such as meteorological drought, agricultural drought, hydrological drought and social economical drought, this study chooses Standardized Precipitation Index (SPI), Palmer Drought Severity Index (PDSI) and Surface Water Supply Index (SWSI) to estimate the meteorological, agricultural and hydrological drought, respectively. Climate change effects come from three sources: the inherent reason, the human activity and the GCMs uncertainties. Therefore, the results show the long term drought condition by calculating yearly drought indices, and compared in three ways: First, compare drought characteristics of future time periods with base period; second, show the uncertainties of three greenhouse gas emission scenarios; third, present the uncertainties of six General Circulation Models (GCMs).

Call number: LD2668 .T4 1956 S34 / Master of Science

This thesis seeks to investigate the changes in the characteristics of 20th and 21st century meteorological droughts in the UK to address the following lines of inquiry: 1) How credible are rainfall-based indices in representing hydrological droughts, 2) How coherent are droughts?, 3) Can alternative method of analysis provide new (or additional) information on the uncertainties in climate models?, and 4) Will future drought characteristics change?. Key results, respectively, are summarized as follows: • The drought severity index (DSI), can be considered a good proxy for assessing hydrological droughts as can be seen in its ability to capture the major hydrological events. The main caveat of the DSI is that there is often an underestimation of drought intensity and duration, • Drought covariance is higher for the (i) wet season, (ii) moderate and (iii) shorter duration droughts, • Evaluating climate models using drought statistics produces contrasting results compared with that using the model's precipitation fields. Drought statistics show biases which are largely negative, more intense, and have a greater spatial coverage. • The projected ensemble-mean change is generally greater (and more widespread) for (i) moderate droughts and (ii) wet season compared with extreme droughts and the dry season, respectively with increases in drought intensity, drought covariance index, frequency of drought months and frequency of drought events for a given duration shown for England.

A Dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. November 2016, Johannesburg. / Drought stress is one of the major limitations to crop production worldwide and has been predicted to become more severe in the future due to global climate change. Research has often been focused on genetic engineering to improve the tolerance of plants to abiotic and biotic stresses. Plant growth-promoting rhizobacteria (PGPR) are an alternative mechanism to improve the tolerance of plants to many stresses and is crucial for developing and third world countries. In this study, Helianthus annuus was inoculated with Pseudomonas koreensis and subjected to drought stress. The germination and growth characteristics, leaf water content, leaf electrolyte leakage and leaf area, substrate water content, phenolic compounds and proline concentration, root bacterial counts, as well as recovery and regrowth, were compared between uninoculated and inoculated plants. In addition, the phosphatase activity, siderophore and indole-3-acetic acid (IAA) production, as well as growth at -0.73 MPa was compared between P. koreensis and P. fluorescens. It was found that inoculated plants were significantly taller plants and had a larger leaf area; and had significantly higher phenolic and proline concentration and a higher colonised root surface under drought stress. However, inoculation negatively affected germination and chlorophyll fluorescence. These plants also had a lower substrate water content under drought stress. P. koreensis outperformed P. fluorescens in all parameters studied, except for growth under osmotic stress. It can be concluded that P. koreensis generally improves the drought stress tolerance of H. annuus, however, further investigations are needed to determine the reasons for some of the negative effects. / LG2017

The Mediterranean region has experienced persistent drying since the middle of the 20th Century and global climate models project further drying in the future as a consequence of increasing greenhouse gases. The Mediterranean region is also known to oscillate between decades of relatively wet and dry conditions due to the strong influence of multidecadal North Atlantic Oscillation (NAO). It is therefore of great importance to understand the relationship between forced long-term drying resulting from human influences and those due to natural variability. To this end, we used observations, reanalyses and comprehensive global climate models in this thesis research. The roles of anthropogenic climate change and internal climate variability in causing the Mediterranean region's late 20th Century extended winter drying trend were examined using 20th Century observations as well as 19 coupled climate models from the CMIP3. The drying was strongly influenced by the robust positive trend in the NAO from the 1960s to the 1990s. Model simulations and observations were used to assess the probable relative roles of radiative forcing and internal variability in explaining the circulation trend that drove much of the precipitation change. It was concluded that the radiatively forced trends were a small fraction of the total observed trends. Instead it was argued that the robust trends in the observed NAO and Mediterranean rainfall during this period were largely due to multidecadal internal variability with a small contribution from the external forcing. Differences between the observed and NAO associated precipitation trends are consistent with those expected as a response to radiative forcing. The radiatively forced trends in circulation and precipitation are expected to strengthen in the current century and these results highlight the importance of their contribution to future precipitation changes in the region. The Mediterranean precipitation climatology and trend were further examined by comparing the newest generation of global climate models (CMIP5) used in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, to the previous generation (CMIP3) and to observations over the latter half of the 20th Century for both the summer and winter half years. The observed drying trend since 1950 was predominantly due to winter drying, with very little contribution from the summer. However, in the CMIP5 multimodel mean, the precipitation trend since 1950 is evenly divided throughout the seasonal cycle. This may indicate that in observation, multidecadal internal variability, particularly that associated with the NAO, dominates the wintertime trend. An estimate of the observed externally forced trend showed that winter drying dominated in observations but the spatial patterns were grossly similar to the multimodel mean trend. The similarity was particularly robust in the eastern Mediterranean region, indicating a radiatively forced component being stronger there. These results also revealed modest improvement for the CMIP5 multimodel ensemble in representation of the observed six-month winter and summer climatology. We further explored the detailed mechanisms leading to the NAO-associated precipitation change, such as the role of the change in mean circulation versus that of the storm tracks in the regional moisture budget, which had not been investigated previously. We employed a moisture budget analysis using 15 CMIP5 models and the ERA-Interim Reanalysis to investigate the relationship between the NAO and the various moisture budget terms for the six-month winter and summer. Compared with the ERA-Interim, the models performed well in their simulation of the relationship between the naturally varying NAO and the large-scale moisture budget. Our results indicated that the shift in the midlatitude transient eddies induced modest moisture convergence, rather than divergence, over the Mediterranean under a positive NAO. The reduction in precipitation in this region during a positive NAO was dominated by the mean moisture divergence, which opposed the transient contribution. There were significant differences between the patterns of NAO-induced moisture budget anomaly and changes due to external radiative forcing. Under radiative forcing there was enhanced evaporation over the Mediterranean Sea, Italy and eastern Europe and drying by the shift in the wintertime storms over nearly all of Europe and the Mediterranean. Under a positive phase of the NAO, on the other hand, there was modest reduction in evaporation and wetting by the storms over the Mediterranean, and drying over northern Europe. The dependence of the Mediterranean moisture budget on the NAO was similarly explored in the summer half of the year and in this season the models exhibited more disagreement with observations, but otherwise showed the similar results as winter. The stronger anthropogenic induced drying signal over the eastern Mediterranean provided a basis to examine the possible cause and impact of the recent severe and persistent drought in Syria that occurred directly prior to the uprising of 2011. The drought devastated Syrian agriculture, resulting in food shortages, widespread unemployment, the collapse of rural social structure and a mass migration of agricultural refugees to Syria's urban areas. Anger at the government's failure to ameliorate conditions was one spark for the uprising that evolved into civil war. We found that though droughts occur periodically in Syria due to natural causes it is likely that the recent drought was more extreme due to the century long drying trend caused by increased radiative forcing. It was estimated that the anthropogenic trend made a drought of such severity several times more likely. Droughts as persistent as the recent one are projected to be commonplace in a future warmer world.

Includes bibliographical references. / Cover title. "February 2003." 4/8/03: Also available via Internet.

This thesis seeks to explore and examine the application and use of indigenous knowledge systems (IKS) in the management of drought through a case study of Msinga village communities in the northern parts of KwaZulu-Natal Province, paying specific attention to droughts that have been recorded and that prevail in the area. Government's policy aimed at mitigating and the effect of drought on communities and its effectiveness is examined as well. The question is whether government policy measures supplement rural communities' drought management strategies. The findings demonstrated that droughts are endemic in the study area and that drought-management strategies are as intrinsic to local livelihood systems as are seasonal-adjustment strategies. The findings also indicated that communities in Msinga have knowledge of drought management. However, this knowledge contributes very little to the management of drought. The findings also demonstrated that there is poor capacity in government to deal with disasters and this has serious repercussions for poor rural communities in Msinga. Disaster management requires disaster reduction, planning, and capacity to reduce the losses borne by impoverished households. This process will be more effective if there is efficient mobilization of resources, rapid responses, and a long-term strategy to prevent drought and reduce the risks of vulnerable groups, rather than transferring risks. The new legislation, the Disaster Management Act of 2002, should ensure that any form of financial and bureaucratic bottlenecks are eliminated so that assistance reaches people more quickly and is based on developing a long-term programme targeting the reduction of risks from the drought prevailing in Msinga. It is also important that NGOs in the area are empowered and involved in disaster management and are able to play their full role. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2010.