A Numerical Modeling Study of the Coupled Variability of Lake Victoria in Eastern Africa and the Regional Climate

A Numerical Modeling Study of the Coupled Variability of Lake Victoria in Eastern Africa and the Regional Climate
Author:
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Total Pages:
Release: 2001
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ISBN:

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The objective of this investigation was to investigate and study the coupled atmosphere-lake climate system over the Lake Victoria basin, and determine the corresponding physical mechanisms that are involved. The primary research vehicle for the investigation is a fully coupled model of the regional climate of Eastern Africa and Lake Victoria which has been developed and applied in this study. The atmospheric component of the model is the NCAR Regional Climate Model (RegCM2). The lake component of the model is based on the Princeton Ocean Model (POM) configured for Lake Victoria by replacing the open boundaries in the standard version of the model with a closed coastline and adopting the bythemetry of Lake Victoria. The horizontal resolution is 20 km for both the atmosphere and lake model components. The results show that the bythemetry and geometry of the lake play a fundamental role in determining the climatology of Lake Victoria. There exists Kelvin-like waves in the thermocline trapped along the coast and they propagate clockwise around Lake Victoria with periodicity of about 30 days. The oscillations entirely disappear in the case of the isothermal conditions. The 3-dimensional model produces a surface temperature pattern indicative of horizontal lake water mixing associated with the horizontal spiral pattern that is not present in the 1-dimensional model. Preliminary comparison of the coupled RegCM2-POM model simulation results with the observations indicates that the model produces more realistic lake surface temperatures (LST) and rainfall over and around the lake than the standard version of RegCM2 in which a simple one dimensional thermal diffusion lake model is used. Over Eastern Africa, the regional climate variability is significantly influenced by the circulation over the Lake Victoria basin. Moisture advection contribution is important but secondary to evaporation in explaining the heavy rainfall over the lake. The interaction between the lake-land bre.

Modeling the Variability of the Climate System Over Lake Victoria Basin

Modeling the Variability of the Climate System Over Lake Victoria Basin
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Release: 2004
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ISBN:

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The physical mechanisms associated with the diurnal to inter-annual variability of Lake Victoria Basin and regional climate are examined based on a three-tier modeling approach. First, diagnosis of eastern and the Horn of Africa climate variability, in which the Lake basin climate is intimately embedded, is performed based on two GCM ensemble simulations. The goal was to identify some of the systematic errors inherent in the GCMs before downscaling their output using regional climate model. The second part evaluates the downscaling ability of RegCM3 over eastern Africa based on multi-year ensemble simulations of the short rains season. Finally, the physical mechanisms associated with Lake Victoria Basin climate variability are investigated using a fully coupled RegCM3-3D lake modeling system. Overall, the RegCM3 simulated monthly and seasonal rainfall climatology during the short rains season are consistent with the observed in both the simulations forced by GCM output and NCEP reanalysis over specific homogeneous climate sub-regions. However, over central Kenya highlands the model simulates drier than normal conditions throughout the season. The simulated latitude-time (north-south) rainfall evolution over East Africa is quite consistent with the observed during the entire season. This is also in tandem with the expected ITCZ-driven southward migration of regions of rainfall maxima as the season progresses. A particularly distinct feature is the persistent wet conditions simulated over the equatorial belt, between 1oS and 2oN, throughout the season. The wet conditions are apparently associated with local convection induced by topography and Lake Victoria, since there is substantial reduction in the simulated rainfall amount in the 'no-lake' simulations. In the fully coupled RegCM3-POM simulations, it is evident that topography along the eastern border of Lake Victoria, large-scale moisture transported via the prevailing easterly trades and changes in the physical c.

The East African Great Lakes: Limnology, Palaeolimnology and Biodiversity

The East African Great Lakes: Limnology, Palaeolimnology and Biodiversity
Author: Eric O. Odada
Publisher: Springer Science & Business Media
Total Pages: 578
Release: 2006-03-09
Genre: Science
ISBN: 0306482010

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The Second International Symposium on the East African Lakes was held from 10-15 January 2000 at Club Makokola on the southern shore of Lake Malawi. The symposium was organized by the International Decade for the East African Lakes (IDEAL), a research consortium of African, European and North American scientists interested in promoting the investigations of African Great Lakes as archives of environmental and climatic dynamics. Over one hundred African, European and North American scientists with special expertise in the tropical lakes participated in the symposium which featured compelling presentations on the limnology, climatology, palaeoclimatology and biodiversity of the East African Lakes. It is their papers that comprise this book. The large lakes of East Africa are important natural resources that are heavily utilized by their bordering countries for transportation, water supply, fisheries, waste disposal, recreation and tourism. The lakes are unique in many ways: they are sensitive to climatic change and their circulation dynamics, water-column chemistry and biological complexity differ significantly from large lakes at higher latitudes; they have long, continuous, high resolution records of past climatic change; and they have rich and diverse populations of endemic organisms. These unique properties and the significance of the palaeolimnological records demand and attract research interest from around the world.

Climatic Change and Global Warming of Inland Waters

Climatic Change and Global Warming of Inland Waters
Author: Charles R. Goldman
Publisher: John Wiley & Sons
Total Pages: 481
Release: 2012-11-20
Genre: Science
ISBN: 1118470613

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Effects of global warming on the physical, chemical, ecological structure and function and biodiversity of freshwater ecosystems are not well understood and there are many opinions on how to adapt aquatic environments to global warming in order to minimize the negative effects of climate change. Climatic Change and Global Warming of Inland Waters presents a synthesis of the latest research on a whole range of inland water habitats – lakes, running water, wetlands – and offers novel and timely suggestions for future research, monitoring and adaptation strategies. A global approach, offered in this book, encompasses systems from the arctic to the Antarctic, including warm-water systems in the tropics and subtropics and presents a unique and useful source for all those looking for contemporary case studies and presentation of the latest research findings and discussion of mitigation and adaptation throughout the world. Edited by three of the leading limnologists in the field this book represents the latest developments with a focus not only on the impact of climate change on freshwater ecosystems but also offers a framework and suggestions for future management strategies and how these can be implemented in the future. Limnologists, Climate change biologists, fresh water ecologists, palaeoclimatologists and students taking relevant courses within the earth and environmental sciences will find this book invaluable. The book will also be of interest to planners, catchment managers and engineers looking for solutions to broader environmental problems but who need to consider freshwater ecology.

Lake Victoria Monitored from Space

Lake Victoria Monitored from Space
Author: Joseph Awange
Publisher: Springer Nature
Total Pages: 321
Release: 2020-12-17
Genre: Science
ISBN: 3030605515

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This book employs a suite of remotely sensed products and advanced technologies to provide the first comprehensive space-based sensing of Lake Victoria, the world’s second largest freshwater lake that supports a livelihood of more than 42 million people, modulates regional climate, but faces myriads of challenges. Proper understanding of the lake and changes in its physical dynamics (e.g., water level, shorelines and areal dynamics) resulting from the impacts of climate variation and climate change as well as anthropogenic (e.g., hydropower and irrigation) is important for its management as well as for strategic development before, during and after climate extremes (e.g., floods and droughts) in order to inform policy formulations, planning and mitigation measures. Owing to its sheer size, and lack of research resources commitment by regional governments that hamper its observations, however, it is a daunting task to undertake studies on Lake Victoria relying solely on in-situ “boots on the ground” measurements, which are sparse, missing in most cases, inconsistent or restricted by governmental red tapes. To unlock the potentials of Lake Victoria, this book argues for the removal of obsolete Nile treaties signed between Britain, Egypt and Sudan in the 1920s and 1950s, which prohibits its utilization by the upstream countries. The book is useful to those in water resources management and policy formulations, hydrologists, environmentalists, engineers and researchers. In a unique cross-disciplinary approach, the Book articulates the various climatic impacts and explanations from natural and anthropogenic origins, which affected Lake Victoria and its vicinity, including the drastic increase and depletion of water level in the Lake and dams, floods and droughts, water quality/security, crop health, food security, and economic implications. With no exception as in his many publications, Joseph L. Awange used data analysis methodologies including filtering, adjustment theory, and robust statistics, to quantify the hydrologic and other parameters, and their estimated uncertainties. The Book is recommended for readers from a diverse disciplines, including physical and social sciences, policy, law, engineering, and disaster management. Professor C.K. Shum, Ohio State University.

The Hydrology of the Nile

The Hydrology of the Nile
Author: John V. Sutcliffe
Publisher:
Total Pages: 206
Release: 1999
Genre: Climatology
ISBN:

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Its scope can be seen from the list of contents overleaf.

Monthly Weather Review

Monthly Weather Review
Author:
Publisher:
Total Pages: 1526
Release: 2006
Genre: Electronic journals
ISBN:

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