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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/399

Title: Classification of time series of NDVI for Assessment of land cover change in Ghana using Noaa/A VHRR data.
Authors: Nyamekye, Clement
Issue Date: 18-Jul-2010
Abstract: Land cover information constitutes key environmental information for many scientific, resource management and policy purposes, as well as for a range of human activities. Hence it has become a major focus for the International Geosphere-Biosphere Program (IGBP) and the International Human Dimensions Program (IHDP) at global and regional levels. Land cover information is currently scarce for Ghana. The country is currently undergoing rapid and wide-range changes in vegetation due to climate change, the practice of slash-and-burn or shifting cultivation. The stud y of these conversions necessitates the use of remote sensing because it provides data at synoptic scales and facilitates the discerning of large- scale ecosystem patterns. Although remote sensing technology has been used for mapping in Ghana for sometime now, there has been no attempt to use either unsupervised or supervised classification methods for NOAA/AVHRR images for the whole of Ghana. Therefore a qualitative approach to the use of historical series of low resolution NDVI data to produce land cover maps of Ghana and also to evaluate the relative change in land cover from 1982 to 2002 has been developed. The study was carried out through the principal component analysis and classification of long term average NDVI values. The interpretation of the resulting classes was based on the comparison between NDVI average temporal profiles of different classes and NDVI reference profiles for selected sites where detailed information about vegetation characteristics are available. The results show the potential of the proposed approach for studies at regional or national level where lack of climate data hinder the utilization of quantitative methods to determine the land cover change within the periods (1982-1992, 1992-2002 and 1982-2002). Again the results of the study shows that the dominant land coverchange process was conversion of natural vegetation to savannah and shrub thicket, which occurred at an annual rate of 4% and 6.5% respectively. Most of the land cover change process occurred in the first period (1982-1992). The overall annual rate of change in land cover (1982-1992) was highest for Savannah (3.8%) and lowest for water (1.03%). The results suggest that, year phenological behavior, as revealed by the NDVI data, can be used to map general patterns in the spatial distribution of Ghana‟s main vegetation formation.
Description: A these submitted to the Department of Geomantic Engineering, Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements for the degree of Master of Science on April, 2010.
URI: http://hdl.handle.net/123456789/399
Appears in Collections:College of Engineering

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