Kwasi Appeaning Addo is a senior lecturer in the Department of Marine and Fisheries Sciences, University of Ghana. He is a technical advisor to the West African Coast Observation Mission involving 11 countries. His research interests include nearshore coastal dynamics and erosion studies; application of drones in shoreline morphological monitoring; application of video systems in short-term shoreline change studies; climate change impact assessment in Delta Regions; coastal vulnerability and risk Assessment to sea level rise. Address: Department of Marine and Fisheries Sciences, University of Ghana, P. O. Box Lg 99, Legon. Ghana
Remote sensing in earth systems sciences, Jan 21, 2022
Input and dissipation source terms contribute significantly to the projection of ocean wave prope... more Input and dissipation source terms contribute significantly to the projection of ocean wave properties in numerical wave models. They form an integral part of the wave energy balance equation. This study investigates the appropriate input-dissipation source terms (Sin-ds) that best estimate the significant wave heights and wave directions in the entire West Africa region (latitudes 10° S–30° N; longitudes 35° W–15° E) and two sub-divisions (north-western or Canary Current sub-region: latitudes 10° N–25° N; longitudes 30° W–10° W, and south-eastern or Gulf of Guinea sub-region: latitudes 2° S–8° N; longitudes 10° W–10° E) using the WAVEWATCH III® (WW3) numerical ocean wave model version 5.16. Five Sin-ds (WAM Cycle 3, ST1; WAM Cycle 4 and variants, ST3; Tolman & Chalikov (1996), ST2; Ardhuin et al. (2010), ST4; and Zieger et al. (2015) ST6) and two additional variants (ST2STAB and ST4STAB) implemented in the WW3 model were investigated and outputs compared with field measured data from four stations in the region. For simulations of the sub-grids, ST2STAB best estimates significant wave heights for both the combined stations of the south-eastern grid and the north-western grid, whereas ST6 and ST2STAB best estimate wave directions for the respective sub-grids. For simulations of the entire West Africa grid, the Sin-ds that best estimate the significant wave heights are ST3, ST2STAB, ST2STAB and ST4/ST4STAB, while ST6, ST4/ST4STAB, ST2STAB and ST1 best estimate wave directions for the four respective stations. A combination of all the stations for the entire West Africa region revealed that ST2STAB best estimates significant wave heights indicated by lowest Hanna & Heinold (1985). American Petroleum Institute.) performance index (HH) and normalized bias index (NBI) values of 0.34 and −23.09% respectively. Wave directions on the other hand are best estimated by ST6 with the least NBI value and mean bias of −1.23% and −1.68±21.48°, respectively, for the entire region. ST2STAB and ST6 are thus identified to be suitable for wave height and wave direction modelling respectively for the entire West Africa region. A major conclusion of this study is that different Sin-ds best estimates the wave heights and directions in the West Africa region. However, ST2STAB would be the appropriate source terms to be used in projecting both wave height and direction since very little differences exist among the various source terms in projecting wave directions.
ABSTRACT Relative sea-level rise will affect vulnerable coastal communities globally. Quantifying... more ABSTRACT Relative sea-level rise will affect vulnerable coastal communities globally. Quantifying this effect on the coastal environment and infrastructure provides critical information that enables coastal managers to develop sustainable mitigation and adaptation measures. Modeling applications have enabled the past, present, and future trends in shoreline morphology to be investigated in detail. Predictive numerical models depend largely on the reliability of the input data. This article reports on using the Soft Cliff and Platform Erosion (SCAPE) numerical model to simulate future shoreline evolution trend in the central Accra coast in Ghana. The model input parameters include historic shoreline recession rates, wave data, tidal data, bathymetry, beach volume, beach topography, historic relative sea-level rise rates, and the shoreline orientation. The data fed the SCAPE numerical model which simulated the emergence of soft rock shore profiles over timescale of decades to centuries, to project future positions of the central Accra shoreline for the next 100 years under different scenarios of climate change. Simulated future shoreline positions overlaid on a 2005 orthophoto map of Accra enabled vulnerable areas and infrastructure at risk to be identified. It emerged that a highly populated community in central Accra will be inundated by 2065, while the Rivera beach resort will be eroded from 2035. A natural fish landing site in Osu (suburb in Accra) will be lost from 2045. The study has demonstrated that considerable ecological, economic, social, and national losses should be expected within the next century. Shoreline change management options should be explored to help mitigate the expected impact of the sea-level rise. Keywords climate change, coastal erosion, coastal management, Ghana’s Accra coast, sea-level rise, shoreline modeling
A thesis submitted to the Department of Materials Engineering, Kwame Nkrumah University of Scienc... more A thesis submitted to the Department of Materials Engineering, Kwame Nkrumah University of Science and Technology, Kumasi,In partial fulfillment of the requirements for the degree of Master of Science in Environmental Resources Management, November-2013
Remote sensing in earth systems sciences, Jan 21, 2022
Input and dissipation source terms contribute significantly to the projection of ocean wave prope... more Input and dissipation source terms contribute significantly to the projection of ocean wave properties in numerical wave models. They form an integral part of the wave energy balance equation. This study investigates the appropriate input-dissipation source terms (Sin-ds) that best estimate the significant wave heights and wave directions in the entire West Africa region (latitudes 10° S–30° N; longitudes 35° W–15° E) and two sub-divisions (north-western or Canary Current sub-region: latitudes 10° N–25° N; longitudes 30° W–10° W, and south-eastern or Gulf of Guinea sub-region: latitudes 2° S–8° N; longitudes 10° W–10° E) using the WAVEWATCH III® (WW3) numerical ocean wave model version 5.16. Five Sin-ds (WAM Cycle 3, ST1; WAM Cycle 4 and variants, ST3; Tolman & Chalikov (1996), ST2; Ardhuin et al. (2010), ST4; and Zieger et al. (2015) ST6) and two additional variants (ST2STAB and ST4STAB) implemented in the WW3 model were investigated and outputs compared with field measured data from four stations in the region. For simulations of the sub-grids, ST2STAB best estimates significant wave heights for both the combined stations of the south-eastern grid and the north-western grid, whereas ST6 and ST2STAB best estimate wave directions for the respective sub-grids. For simulations of the entire West Africa grid, the Sin-ds that best estimate the significant wave heights are ST3, ST2STAB, ST2STAB and ST4/ST4STAB, while ST6, ST4/ST4STAB, ST2STAB and ST1 best estimate wave directions for the four respective stations. A combination of all the stations for the entire West Africa region revealed that ST2STAB best estimates significant wave heights indicated by lowest Hanna & Heinold (1985). American Petroleum Institute.) performance index (HH) and normalized bias index (NBI) values of 0.34 and −23.09% respectively. Wave directions on the other hand are best estimated by ST6 with the least NBI value and mean bias of −1.23% and −1.68±21.48°, respectively, for the entire region. ST2STAB and ST6 are thus identified to be suitable for wave height and wave direction modelling respectively for the entire West Africa region. A major conclusion of this study is that different Sin-ds best estimates the wave heights and directions in the West Africa region. However, ST2STAB would be the appropriate source terms to be used in projecting both wave height and direction since very little differences exist among the various source terms in projecting wave directions.
ABSTRACT Relative sea-level rise will affect vulnerable coastal communities globally. Quantifying... more ABSTRACT Relative sea-level rise will affect vulnerable coastal communities globally. Quantifying this effect on the coastal environment and infrastructure provides critical information that enables coastal managers to develop sustainable mitigation and adaptation measures. Modeling applications have enabled the past, present, and future trends in shoreline morphology to be investigated in detail. Predictive numerical models depend largely on the reliability of the input data. This article reports on using the Soft Cliff and Platform Erosion (SCAPE) numerical model to simulate future shoreline evolution trend in the central Accra coast in Ghana. The model input parameters include historic shoreline recession rates, wave data, tidal data, bathymetry, beach volume, beach topography, historic relative sea-level rise rates, and the shoreline orientation. The data fed the SCAPE numerical model which simulated the emergence of soft rock shore profiles over timescale of decades to centuries, to project future positions of the central Accra shoreline for the next 100 years under different scenarios of climate change. Simulated future shoreline positions overlaid on a 2005 orthophoto map of Accra enabled vulnerable areas and infrastructure at risk to be identified. It emerged that a highly populated community in central Accra will be inundated by 2065, while the Rivera beach resort will be eroded from 2035. A natural fish landing site in Osu (suburb in Accra) will be lost from 2045. The study has demonstrated that considerable ecological, economic, social, and national losses should be expected within the next century. Shoreline change management options should be explored to help mitigate the expected impact of the sea-level rise. Keywords climate change, coastal erosion, coastal management, Ghana’s Accra coast, sea-level rise, shoreline modeling
A thesis submitted to the Department of Materials Engineering, Kwame Nkrumah University of Scienc... more A thesis submitted to the Department of Materials Engineering, Kwame Nkrumah University of Science and Technology, Kumasi,In partial fulfillment of the requirements for the degree of Master of Science in Environmental Resources Management, November-2013
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