Browsing by Author "Nyamekye, Clement"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- ItemClassification of time series of NDVI for Assessment of land cover change in Ghana using Noaa/A VHRR data.(April, 2010.) Nyamekye, ClementLand 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.
- ItemSoil and water conservation in Burkina Faso, West Africa(Sustainability, 2018-09) Nyamekye, Clement; Thiel, Michael; Schönbrodt-Stitt, Sarah; Zoungrana, Benewinde J.-B.; Amekudzi, Leonard K.Inadequate land management and agricultural activities have largely resulted in land degradation in Burkina Faso. The nationwide governmental and institutional driven implementation and adoption of soil and water conservation measures (SWCM) since the early 1960s, however, is expected to successively slow down the degradation process and to increase the agricultural output. Even though relevant measures have been taken, only a few studies have been conducted to quantify their effect, for instance, on soil erosion and environmental restoration. In addition, a comprehensive summary of initiatives, implementation strategies, and eventually region-specific requirements for adopting different SWCM is missing. The present study therefore aims to review the different SWCM in Burkina Faso and implementation programs, as well as to provide information on their effects on environmental restoration and agricultural productivity. This was achieved by considering over 143 studies focusing on Burkina Faso’s experience and research progress in areas of SWCM and soil erosion. SWCM in Burkina Faso have largely resulted in an increase in agricultural productivity and improvement in food security. Finally, this study aims at supporting the country’s informed decision-making for extending already existing SWCM and for deriving further implementation strategies.