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Document Type:Latin Dissertation
Language of Document:English
Record Number:53623
Doc. No:TL23577
Call number:‭3367055‬
Main Entry:Alex B. Owusu
Title & Author:Detecting and quantifying the extent of desertification and its impact in the semi-arid Sub-Saharan Africa: A case study of the Upper East Region, GhanaAlex B. Owusu
College:George Mason University
Date:2009
Degree:Ph.D.
student score:2009
Page No:303
Abstract:The semi-arid Sub-Saharan region of Africa is in a state of permanent instability at a variety of spatio-temporal momentum. Efforts at sustaining and managing this fragile but all-important ecosystem and its processes require collecting, storing and analyzing multispatial and temporal data that are accurate and continuously updated in terms of changes (degradation), types and magnitude of change. Remote sensing techniques based on multispectral satellite-acquired data (AVHRR, Landsat TM and ETM+) have demonstrated an immense potential as a means to detect, quantify, monitor and map these changes. However, much of what satellite sensors can detect and capture, especially in the form of vegetation index (NDVI), do not tell the entire story about land degradation. This research used multispectral remote sensing data from three sensors (AVHRR, Landsat TM, and ETM+ and IKONOS) to detect and quantify the spatio-temporal land degradation (desertification) to validate the local observation and perception of desertification. The study also analyzes data on crop production in search of evidence proving or disproving degradation in the semi-arid sahel-sudan savannah transitional vegetation zone of the UER, Ghana. Multispectral satellite-acquired NDVI, from AVHRR, Landsat TM & ETM+, show that vegetation greenness is on the ascendancy, although there are pockets (localized degradation) signs of severe land degradation; field evidence suggests that the increasing NDVI is caused by vegetation succession where locally adapted horsetail grasses have been displaced by environmentally efficient, short-lived, quick maturing and dense grasses due to excessive burning, rapid population growth and inappropriate development policies. Local people's perceptions, supported by crop production data, suggest extensive land degradation. Other evidence includes food insecurity, diseases, rainfall variability and land extensification to marginal lands. Convergence of evidence suggests that desertification has advanced in the area more than previously thought and that more focused, community-based effort would be needed to combat desertification and restore the ecosystem's integrity.
Subject:Health and environmental sciences; Social sciences; Earth sciences; Upper East Region; Desertification; Climate change; Land degradation; Ghana; NDVI; Sahel Africa; Geography; Environmental science; Remote sensing; 0799:Remote sensing; 0768:Environmental science; 0366:Geography
Added Entry:S. L. C. Beach, Guido
Added Entry:George Mason University