Edmund I . Yamba | Kwame Nkrumah University of Science and Technology, Kumasi Ghana (original) (raw)

Papers by Edmund I . Yamba

Research paper thumbnail of Climate drivers of malaria transmission seasonality and their relative importance in Sub‐Saharan Africa

Research paper thumbnail of The dynamics of dry and wet monsoon MCS formation over West Africa: Case assessment of February 13, 2018 and June 18, 2018

Quarterly Journal of the Royal Meteorological Society

Research paper thumbnail of Climate drivers of malaria seasonality and their relative importance in Sub-Saharan Africa

Research paper thumbnail of Reviewing the Past, Present, and Future Risks of Pathogens in Ghana and What This Means for Rethinking Infectious Disease Surveillance for Sub-Saharan Africa

Journal of Tropical Medicine, Jul 14, 2022

The current epidemiological transition makes us wonder how the parallel of infectious diseases (I... more The current epidemiological transition makes us wonder how the parallel of infectious diseases (IDs) might be at the end of each passing year. Yet, the surveillance of these IDs continues to focus on high-profile diseases of public health importance without keeping track of the broad spectrum of the IDs we face. Here, we presented the prevalence of the broad spectrum of IDs in Ghana. Data from the annual reports on Gold Coast now Ghana, Global Infectious Diseases and Epidemiology Network (GIDEON), and the District Health Information Management System II (DHIMS2) databases were examined for records of ID prevalence in Ghana. Using the IDs from these databases, the paper assessed the epidemiological transition, pathogen-host interactions, spatiotemporal distribution, transmission routes, and their potential areas of impact in Ghana. e topmost ID recorded in health facilities in Ghana transitioned from yaws in the 1890s to malaria in the 1950s through 2020. We then presented the hosts of a pathogen and the pathogens of a host, the administrative districts where a pathogen was found, and the pathogens found in each district of Ghana. e highest modes of transmission routes were through direct contact for bacteria and airborne or droplet-borne for viral pathogens. From GIDEON, 226 IDs were identified as endemic or potentially endemic in Ghana, with 42% cited in peer-reviewed articles from 2000 to 2020. From the extent of risk of endemic or potentially endemic IDs, Ghana faces a high risk of ID burden that we should be mindful of their changing patterns and should keep track of the state of each of them.

Research paper thumbnail of Revisiting The Agro-Climatic Zones Of Ghana: A Re-Classification In Conformity With Climate Change And Variability

Research paper thumbnail of The Leeds Africa Climate Hackathon – experiences of running a hackathon and highlights of results

Research paper thumbnail of Article Variabilities in Rainfall Onset, Cessation and Length of Rainy Season for the Various Agro-Ecological Zones of Ghana

This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge... more This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge data from the Ghana Meteorological Agency (GMet) over the period of 1970-2012. The onset and cessation dates were determined from cumulative curves using the number of rainy days and rainfall amount. In addition, the inter-annual variability of the onset and cessation dates for each climatic zone was assessed using wavelet analysis. A clear distinction between the rainfall characteristics and the length of the rainy season in the various climatic zones is discussed. The forest and coastal zones in the south had their rainfall onset from the second and third dekads of March. The onset dates of the transition zone were from the second dekad of March to the third dekad of April. Late onset, which starts from the second dekad of April to the first dekad of May, was associated with the savannah zone. The rainfall cessation dates in the forest zone were in the third dekad of October to the first dekad of November, and the length of the rainy season was within 225-240 days. The cessation dates of the coastal zone were within the second and third dekad of October, and the length of rainy season was within 210-220 days. Furthermore, the transition zone had cessation dates in the second to third dekad of October, and the length of the rainy season was within 170-225 days. Lastly, the savannah zone had cessation dates within the third dekad of September to the first dekad of October, and the length of rainy season was within 140-180 days. The bias in the rainfall onset, cessation and length of the rainy season was less than 10 days across the entire country, and the root mean square error (RMSE) was in the range of 5-25 days. These findings demonstrate that the onset derived from the cumulative rainfall amount and the rainy days are in consistent agreement. The wavelet power spectrum and its significant peaks showed evidence of variability in the rainfall onset and cessation dates across the country. The coastal and forest zones showed 2-8-and 2-4-year band variability in the onsets and cessations, whereas the onset and cessation variability of the transition and savannah zones were within 2-4 and 4-8 years. This result has adverse effects on rain-fed agricultural practices, disease control, water resource management, socioeconomic activities and food security in Ghana.

Research paper thumbnail of Assessment of urban heat island warming in the greater accra region

Scientific African, 2020

The Greater Accra region is the most urbanized region in Ghana. Over the last decade, the region ... more The Greater Accra region is the most urbanized region in Ghana. Over the last decade, the region has undergone rapid population shift and urban sprawl. This has modified the natural environment of the area and led to the formation and warming of Urban Heat Island (UHI). Previous studies have not established enough evidence on the existence of UHI phenomenon in the region. For this reason, this study examined the existence, magnitude, and spatial extent of UHI warming as well as its effect on temperature extremes in the region. The study used Landsat satellite imagery captured in 1991, 2002 and 2017, and in-situ daily minimum and maximum temperature data spanning the period 1980 to 2017. The satellite images were processed and analyzed using an integrated Geographic Information System (GIS) and remote sensing technique while extreme temperature indices were assessed with the ClimPACT2 software. The study found that UHI existed in the region with an increasing spatial coverage and a magnitude of about 4.07 • C, 5.79 • C, and 4.86 • C in 1991, 2002, and 2017 respectively. The built-up and bare land areas experienced the strongest effect of UHI warming. In addition, enhanced UHI warming effect caused an increase in the frequency and intensity of warm temperature extremes in the region. A faster increase in night time temperatures than day time resulted in a decrease in diurnal temperature range of the region. Considering the high rate of warming amidst rapid urban expansion, more warming is expected in the region. This is expected to exacerbate climate extreme events and weather-related health issues. It is also expected to increase energy consumption, air pollution and human discomfort.

Research paper thumbnail of Modelled and observed mean and seasonal relationships between climate, population density and malaria indicators in Cameroon

Malaria Journal, 2019

Background A major health burden in Cameroon is malaria, a disease that is sensitive to climate, ... more Background A major health burden in Cameroon is malaria, a disease that is sensitive to climate, environment and socio-economic conditions, but whose precise relationship with these drivers is still uncertain. An improved understanding of the relationship between the disease and its drivers, and the ability to represent these relationships in dynamic disease models, would allow such models to contribute to health mitigation and adaptation planning. This work collects surveys of malaria parasite ratio and entomological inoculation rate and examines their relationship with temperature, rainfall, population density in Cameroon and uses this analysis to evaluate a climate sensitive mathematical model of malaria transmission. Methods Co-located, climate and population data is compared to the results of 103 surveys of parasite ratio (PR) covering 18,011 people in Cameroon. A limited set of campaigns which collected year-long field-surveys of the entomological inoculation rate (EIR) are ex...

Research paper thumbnail of Variabilities in Rainfall Onset, Cessation and Length of Rainy Season for the Various Agro-Ecological Zones of Ghana

Climate, 2015

This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge... more This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge data from the Ghana Meteorological Agency (GMet) over the period of 1970-2012. The onset and cessation dates were determined from cumulative curves using the number of rainy days and rainfall amount. In addition, the inter-annual variability of the onset and cessation dates for each climatic zone was assessed using wavelet analysis. A clear distinction between the rainfall characteristics and the length of the rainy season in the various climatic zones is discussed. The forest and coastal zones in the south had their rainfall onset from the second and third dekads of March. The onset dates of the transition zone were from the second dekad of March to the third dekad of April. Late onset, which starts from the second dekad of April to the first dekad of May, was associated with the savannah zone. The rainfall cessation dates in the forest zone were in the third dekad of October to the first dekad of November, and the length of the rainy season was within 225-240 days. The cessation dates of the coastal zone were within the second and third dekad of October, and the length of rainy season was within 210-220 days. Furthermore, the transition zone had cessation dates in the second to third dekad of October, and the length of the rainy season was within 170-225 days. Lastly, the savannah zone had cessation dates within the third dekad of September to the first dekad of October, and the length of rainy season was within 140-180 days. The bias in the rainfall onset, cessation and length of the rainy season was less than 10 days across the entire country, and the root mean square error (RMSE) was in the range of 5-25 days. These findings demonstrate that the onset derived from the cumulative rainfall amount and the rainy days are in consistent agreement. The wavelet power spectrum and its significant peaks showed evidence of variability in the rainfall onset and cessation dates across the country. The coastal and forest zones showed 2-8-and 2-4-year band variability in the onsets and cessations, whereas the onset and cessation variability of the transition and savannah zones were within 2-4 and 4-8 years. This result has adverse effects on rain-fed agricultural practices, disease control, water resource management, socioeconomic activities and food security in Ghana.

Research paper thumbnail of Monthly Entomological Inoculation Rate Data for Studying the Seasonality of Malaria Transmission in Africa

Data

A comprehensive literature review was conducted to create a new database of 197 field surveys of ... more A comprehensive literature review was conducted to create a new database of 197 field surveys of monthly malaria Entomological Inoculation Rates (EIR), a metric of malaria transmission intensity. All field studies provide data at a monthly temporal resolution and have a duration of at least one year in order to study the seasonality of the disease. For inclusion, data collection methodologies adhered to a specific standard and the location and timing of the measurements were documented. Auxiliary information on the population and hydrological setting were also included. The database includes measurements that cover West and Central Africa and the period from 1945 to 2011, and hence facilitates analysis of interannual transmission variability over broad regions.

Research paper thumbnail of Article Variabilities in Rainfall Onset, Cessation and Length of Rainy Season for the Various Agro-Ecological Zones of Ghana

This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge... more This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge data from the Ghana Meteorological Agency (GMet) over the period of 1970-2012. The onset and cessation dates were determined from cumulative curves using the number of rainy days and rainfall amount. In addition, the inter-annual variability of the onset and cessation dates for each climatic zone was assessed using wavelet analysis. A clear distinction between the rainfall characteristics and the length of the rainy season in the various climatic zones is discussed. The forest and coastal zones in the south had their rainfall onset from the second and third dekads of March. The onset dates of the transition zone were from the second dekad of March to the third dekad of April. Late onset, which starts from the second dekad of April to the first dekad of May, was associated with the savannah zone. The rainfall cessation dates in the forest zone were in the third dekad of October to the first dekad of November, and the length of the rainy season was within 225-240 days. The cessation dates of the coastal zone were within the second and third dekad of October, and the length of rainy season was within 210-220 days. Furthermore, the transition zone had cessation dates in the second to third dekad of October, and the length of the rainy season was within 170-225 days. Lastly, the savannah zone had cessation dates within the third dekad of September to the first dekad of October, and the length of rainy season was within 140-180 days. The bias in the rainfall onset, cessation and length of the rainy season was less than 10 days across the entire country, and the root mean square error (RMSE) was in the range of 5-25 days. These findings demonstrate that the onset derived from the cumulative rainfall amount and the rainy days are in consistent agreement. The wavelet power spectrum and its significant peaks showed evidence of variability in the rainfall onset and cessation dates across the country. The coastal and forest zones showed 2-8-and 2-4-year band variability in the onsets and cessations, whereas the onset and cessation variability of the transition and savannah zones were within 2-4 and 4-8 years. This result has adverse effects on rain-fed agricultural practices, disease control, water resource management, socioeconomic activities and food security in Ghana.

Research paper thumbnail of Monthly entomological inoculation rates for studying malaria transmission seasonality in Africa

A comprehensive literature review is conducted to create a new database of malaria Entomological ... more A comprehensive literature review is conducted to create a new database of malaria Entomological Inoculation Rates (EIR), a metric of malaria transmission intensity. All field studies include data at a monthly temporal resolution and a duration of at least one year in order to be able to study seasonality variability in transmission. Care is taken to ensure the data collection methodologies adhere to a specific standard and that the location and timing of the measurements are well documented. Auxiliary information on the population and hydrological setting are included. The database includes measurements that cover Sub-Saharan Africa spanning from 1968 to 2013, thus also facilitating analysis of interannual transmission variability over broad regions.

Research paper thumbnail of Estimation of the return periods of maxima rainfall and floods at the Pra River Catchment, Ghana, West Africa using the Gumbel extreme value theory

Heliyon, 2021

The Pra river catchment in Ghana is adversely affected by perennial flooding from high-intensity ... more The Pra river catchment in Ghana is adversely affected by perennial flooding from high-intensity rainfall events. To aid in flood management at the catchment, the Gumbel extreme value distribution has been used to estimate the return periods of maxima rainfall, flood, and consecutive dry and wet days (CDD and CWD) for a period of 5 to 100 years. The results revealed an expected increase in maxima rainfall, CDD and CWD. Maxima rainfall favours the south of the catchment while the CDD decreases northward. Furthermore, an increase in the magnitude of CWD observed at the centre of the catchment had a maximum of approximately 30 days for the 100 year return period, while lower flood volumes had a higher recurrence of 50% to 100% for 1 to 2 year return periods. The inclusion of a projected increase in anthropogenic activities and climate factors at the catchment will slightly affect the magnitude of these variables for the various return periods. Nonetheless, the findings in this study wi...

Research paper thumbnail of Improvement and validation of dynamical malaria models in Africa

Overcoming the serious public health burden of malaria in Africa especially the sub-Saharan Afric... more Overcoming the serious public health burden of malaria in Africa especially the sub-Saharan Africa requires a detailed understanding of malaria epidemiology in the region. To contribute to this effect, this work embarked on several research steps. The first part of this study investigated the impact of climatic and environmental factors on seasonal malaria transmission in Africa. Monthly Entomological Inoculation Rate (EIRm) data initially gathered from different malaria locations across the region via a literature review was utilized for this purpose. The results revealed that rainfall was the primary climatic determinant of malaria seasonality at markedly seasonal rainfall areas such as Sahel and Eritrea. But its impact at bimodal rainfall distributed and more humid zones was more complex. Temperature was not a limiting factor of malaria seasonality in Africa except for East Africa where it can delay the impact of rainfall. The seasonal peaking characteristics of malaria were most...

Research paper thumbnail of Mechanisms of Rainfall Biases in two CORDEX-CORE Regional Climate Models at rainfall peaks over Central Equatorial Africa

Journal of Climate

Two regional climate models (RCMs) participating in the CORDEX-Coordinated Output for Regional Ev... more Two regional climate models (RCMs) participating in the CORDEX-Coordinated Output for Regional Evaluations (CORDEX-CORE) project feature a dipole-type rainfall bias during March-May (MAM) and September-November (SON) over Central Equatorial Africa (CEA), consisting in positive bias in West Central Equatorial Africa (WCEA) and negative bias in East Central Equatorial Africa (ECEA). One is the REgional MOdel version 2015 (REMO2015), and the other is the fourth version of the Regional Climate Model (RegCM4-v7). RCMs are nested in three Earth System Models (ESMs) from the Coupled Model Intercomparison Project phase 5 (CMIP5), and in the reanalysis ERA-Interim, at ~25 Km spacing-grid resolution. This study highlights misrepresented underlying physical processes associated with these rainfall biases through a process-based evaluation. Both RCMs produce a weaker Congo basin cell, associated with a weaker land-ocean zonal surface pressure gradient. Consequently, less water vapour enters the...

Research paper thumbnail of Low‐Level Cloud Development and Diurnal Cycle in Southern West Africa During the DACCIWA Field Campaign: Case Study of Kumasi Supersite, Ghana

Journal of Geophysical Research: Atmospheres

Research paper thumbnail of Endemicity of COVID-19 to Sub-Saharan Africa: A Review of the Past, Present and Future Risk

Research paper thumbnail of Monthly Entomological Inoculation Rate Data for Studying the Seasonality of Malaria Transmission in Africa

Data, 2020

A comprehensive literature review was conducted to create a new database of 197 field surveys of ... more A comprehensive literature review was conducted to create a new database of 197 field surveys of monthly malaria Entomological Inoculation Rates (EIR), a metric of malaria transmission intensity. All field studies provide data at a monthly temporal resolution and have a duration of at least one year in order to study the seasonality of the disease. For inclusion, data collection methodologies adhered to a specific standard and the location and timing of the measurements were documented. Auxiliary information on the population and hydrological setting were also included. The database includes measurements that cover West and Central Africa and the period from 1945 to 2011, and hence facilitates analysis of interannual transmission variability over broad regions.

Research paper thumbnail of Assessment of urban heat island warming in the greater accra region

The Greater Accra region is the most urbanized region in Ghana. Over the last decade, the region ... more The Greater Accra region is the most urbanized region in Ghana. Over the last decade, the region has undergone rapid population shift and urban sprawl. This has modified the natural environment of the area and led to the formation and warming of Urban Heat Island (UHI). Previous studies have not established enough evidence on the existence of UHI phenomenon in the region. For this reason, this study examined the existence, magnitude , and spatial extent of UHI warming as well as its effect on temperature extremes in the region. The study used Landsat satellite imagery captured in 1991, 2002 and 2017, and in-situ daily minimum and maximum temperature data spanning the period 1980 to 2017. The satellite images were processed and analyzed using an integrated Geographic Information System (GIS) and remote sensing technique while extreme temperature indices were assessed with the ClimPACT2 software. The study found that UHI existed in the region with an increasing spatial coverage and a magnitude of about 4.07 • C, 5.79 • C, and 4.86 • C in 1991, 2002, and 2017 respectively. The built-up and bare land areas experienced the strongest effect of UHI warming. In addition, enhanced UHI warming effect caused an increase in the frequency and intensity of warm temperature extremes in the region. A faster increase in night time temperatures than day time resulted in a decrease in diurnal temperature range of the region. Considering the high rate of warming amidst rapid urban expansion, more warming is expected in the region. This is expected to exacerbate climate extreme events and weather-related health issues. It is also expected to increase energy consumption, air pollution and human discomfort.

Research paper thumbnail of Climate drivers of malaria transmission seasonality and their relative importance in Sub‐Saharan Africa

Research paper thumbnail of The dynamics of dry and wet monsoon MCS formation over West Africa: Case assessment of February 13, 2018 and June 18, 2018

Quarterly Journal of the Royal Meteorological Society

Research paper thumbnail of Climate drivers of malaria seasonality and their relative importance in Sub-Saharan Africa

Research paper thumbnail of Reviewing the Past, Present, and Future Risks of Pathogens in Ghana and What This Means for Rethinking Infectious Disease Surveillance for Sub-Saharan Africa

Journal of Tropical Medicine, Jul 14, 2022

The current epidemiological transition makes us wonder how the parallel of infectious diseases (I... more The current epidemiological transition makes us wonder how the parallel of infectious diseases (IDs) might be at the end of each passing year. Yet, the surveillance of these IDs continues to focus on high-profile diseases of public health importance without keeping track of the broad spectrum of the IDs we face. Here, we presented the prevalence of the broad spectrum of IDs in Ghana. Data from the annual reports on Gold Coast now Ghana, Global Infectious Diseases and Epidemiology Network (GIDEON), and the District Health Information Management System II (DHIMS2) databases were examined for records of ID prevalence in Ghana. Using the IDs from these databases, the paper assessed the epidemiological transition, pathogen-host interactions, spatiotemporal distribution, transmission routes, and their potential areas of impact in Ghana. e topmost ID recorded in health facilities in Ghana transitioned from yaws in the 1890s to malaria in the 1950s through 2020. We then presented the hosts of a pathogen and the pathogens of a host, the administrative districts where a pathogen was found, and the pathogens found in each district of Ghana. e highest modes of transmission routes were through direct contact for bacteria and airborne or droplet-borne for viral pathogens. From GIDEON, 226 IDs were identified as endemic or potentially endemic in Ghana, with 42% cited in peer-reviewed articles from 2000 to 2020. From the extent of risk of endemic or potentially endemic IDs, Ghana faces a high risk of ID burden that we should be mindful of their changing patterns and should keep track of the state of each of them.

Research paper thumbnail of Revisiting The Agro-Climatic Zones Of Ghana: A Re-Classification In Conformity With Climate Change And Variability

Research paper thumbnail of The Leeds Africa Climate Hackathon – experiences of running a hackathon and highlights of results

Research paper thumbnail of Article Variabilities in Rainfall Onset, Cessation and Length of Rainy Season for the Various Agro-Ecological Zones of Ghana

This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge... more This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge data from the Ghana Meteorological Agency (GMet) over the period of 1970-2012. The onset and cessation dates were determined from cumulative curves using the number of rainy days and rainfall amount. In addition, the inter-annual variability of the onset and cessation dates for each climatic zone was assessed using wavelet analysis. A clear distinction between the rainfall characteristics and the length of the rainy season in the various climatic zones is discussed. The forest and coastal zones in the south had their rainfall onset from the second and third dekads of March. The onset dates of the transition zone were from the second dekad of March to the third dekad of April. Late onset, which starts from the second dekad of April to the first dekad of May, was associated with the savannah zone. The rainfall cessation dates in the forest zone were in the third dekad of October to the first dekad of November, and the length of the rainy season was within 225-240 days. The cessation dates of the coastal zone were within the second and third dekad of October, and the length of rainy season was within 210-220 days. Furthermore, the transition zone had cessation dates in the second to third dekad of October, and the length of the rainy season was within 170-225 days. Lastly, the savannah zone had cessation dates within the third dekad of September to the first dekad of October, and the length of rainy season was within 140-180 days. The bias in the rainfall onset, cessation and length of the rainy season was less than 10 days across the entire country, and the root mean square error (RMSE) was in the range of 5-25 days. These findings demonstrate that the onset derived from the cumulative rainfall amount and the rainy days are in consistent agreement. The wavelet power spectrum and its significant peaks showed evidence of variability in the rainfall onset and cessation dates across the country. The coastal and forest zones showed 2-8-and 2-4-year band variability in the onsets and cessations, whereas the onset and cessation variability of the transition and savannah zones were within 2-4 and 4-8 years. This result has adverse effects on rain-fed agricultural practices, disease control, water resource management, socioeconomic activities and food security in Ghana.

Research paper thumbnail of Assessment of urban heat island warming in the greater accra region

Scientific African, 2020

The Greater Accra region is the most urbanized region in Ghana. Over the last decade, the region ... more The Greater Accra region is the most urbanized region in Ghana. Over the last decade, the region has undergone rapid population shift and urban sprawl. This has modified the natural environment of the area and led to the formation and warming of Urban Heat Island (UHI). Previous studies have not established enough evidence on the existence of UHI phenomenon in the region. For this reason, this study examined the existence, magnitude, and spatial extent of UHI warming as well as its effect on temperature extremes in the region. The study used Landsat satellite imagery captured in 1991, 2002 and 2017, and in-situ daily minimum and maximum temperature data spanning the period 1980 to 2017. The satellite images were processed and analyzed using an integrated Geographic Information System (GIS) and remote sensing technique while extreme temperature indices were assessed with the ClimPACT2 software. The study found that UHI existed in the region with an increasing spatial coverage and a magnitude of about 4.07 • C, 5.79 • C, and 4.86 • C in 1991, 2002, and 2017 respectively. The built-up and bare land areas experienced the strongest effect of UHI warming. In addition, enhanced UHI warming effect caused an increase in the frequency and intensity of warm temperature extremes in the region. A faster increase in night time temperatures than day time resulted in a decrease in diurnal temperature range of the region. Considering the high rate of warming amidst rapid urban expansion, more warming is expected in the region. This is expected to exacerbate climate extreme events and weather-related health issues. It is also expected to increase energy consumption, air pollution and human discomfort.

Research paper thumbnail of Modelled and observed mean and seasonal relationships between climate, population density and malaria indicators in Cameroon

Malaria Journal, 2019

Background A major health burden in Cameroon is malaria, a disease that is sensitive to climate, ... more Background A major health burden in Cameroon is malaria, a disease that is sensitive to climate, environment and socio-economic conditions, but whose precise relationship with these drivers is still uncertain. An improved understanding of the relationship between the disease and its drivers, and the ability to represent these relationships in dynamic disease models, would allow such models to contribute to health mitigation and adaptation planning. This work collects surveys of malaria parasite ratio and entomological inoculation rate and examines their relationship with temperature, rainfall, population density in Cameroon and uses this analysis to evaluate a climate sensitive mathematical model of malaria transmission. Methods Co-located, climate and population data is compared to the results of 103 surveys of parasite ratio (PR) covering 18,011 people in Cameroon. A limited set of campaigns which collected year-long field-surveys of the entomological inoculation rate (EIR) are ex...

Research paper thumbnail of Variabilities in Rainfall Onset, Cessation and Length of Rainy Season for the Various Agro-Ecological Zones of Ghana

Climate, 2015

This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge... more This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge data from the Ghana Meteorological Agency (GMet) over the period of 1970-2012. The onset and cessation dates were determined from cumulative curves using the number of rainy days and rainfall amount. In addition, the inter-annual variability of the onset and cessation dates for each climatic zone was assessed using wavelet analysis. A clear distinction between the rainfall characteristics and the length of the rainy season in the various climatic zones is discussed. The forest and coastal zones in the south had their rainfall onset from the second and third dekads of March. The onset dates of the transition zone were from the second dekad of March to the third dekad of April. Late onset, which starts from the second dekad of April to the first dekad of May, was associated with the savannah zone. The rainfall cessation dates in the forest zone were in the third dekad of October to the first dekad of November, and the length of the rainy season was within 225-240 days. The cessation dates of the coastal zone were within the second and third dekad of October, and the length of rainy season was within 210-220 days. Furthermore, the transition zone had cessation dates in the second to third dekad of October, and the length of the rainy season was within 170-225 days. Lastly, the savannah zone had cessation dates within the third dekad of September to the first dekad of October, and the length of rainy season was within 140-180 days. The bias in the rainfall onset, cessation and length of the rainy season was less than 10 days across the entire country, and the root mean square error (RMSE) was in the range of 5-25 days. These findings demonstrate that the onset derived from the cumulative rainfall amount and the rainy days are in consistent agreement. The wavelet power spectrum and its significant peaks showed evidence of variability in the rainfall onset and cessation dates across the country. The coastal and forest zones showed 2-8-and 2-4-year band variability in the onsets and cessations, whereas the onset and cessation variability of the transition and savannah zones were within 2-4 and 4-8 years. This result has adverse effects on rain-fed agricultural practices, disease control, water resource management, socioeconomic activities and food security in Ghana.

Research paper thumbnail of Monthly Entomological Inoculation Rate Data for Studying the Seasonality of Malaria Transmission in Africa

Data

A comprehensive literature review was conducted to create a new database of 197 field surveys of ... more A comprehensive literature review was conducted to create a new database of 197 field surveys of monthly malaria Entomological Inoculation Rates (EIR), a metric of malaria transmission intensity. All field studies provide data at a monthly temporal resolution and have a duration of at least one year in order to study the seasonality of the disease. For inclusion, data collection methodologies adhered to a specific standard and the location and timing of the measurements were documented. Auxiliary information on the population and hydrological setting were also included. The database includes measurements that cover West and Central Africa and the period from 1945 to 2011, and hence facilitates analysis of interannual transmission variability over broad regions.

Research paper thumbnail of Article Variabilities in Rainfall Onset, Cessation and Length of Rainy Season for the Various Agro-Ecological Zones of Ghana

This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge... more This paper examines the onset and cessation dates of the rainy season over Ghana using rain gauge data from the Ghana Meteorological Agency (GMet) over the period of 1970-2012. The onset and cessation dates were determined from cumulative curves using the number of rainy days and rainfall amount. In addition, the inter-annual variability of the onset and cessation dates for each climatic zone was assessed using wavelet analysis. A clear distinction between the rainfall characteristics and the length of the rainy season in the various climatic zones is discussed. The forest and coastal zones in the south had their rainfall onset from the second and third dekads of March. The onset dates of the transition zone were from the second dekad of March to the third dekad of April. Late onset, which starts from the second dekad of April to the first dekad of May, was associated with the savannah zone. The rainfall cessation dates in the forest zone were in the third dekad of October to the first dekad of November, and the length of the rainy season was within 225-240 days. The cessation dates of the coastal zone were within the second and third dekad of October, and the length of rainy season was within 210-220 days. Furthermore, the transition zone had cessation dates in the second to third dekad of October, and the length of the rainy season was within 170-225 days. Lastly, the savannah zone had cessation dates within the third dekad of September to the first dekad of October, and the length of rainy season was within 140-180 days. The bias in the rainfall onset, cessation and length of the rainy season was less than 10 days across the entire country, and the root mean square error (RMSE) was in the range of 5-25 days. These findings demonstrate that the onset derived from the cumulative rainfall amount and the rainy days are in consistent agreement. The wavelet power spectrum and its significant peaks showed evidence of variability in the rainfall onset and cessation dates across the country. The coastal and forest zones showed 2-8-and 2-4-year band variability in the onsets and cessations, whereas the onset and cessation variability of the transition and savannah zones were within 2-4 and 4-8 years. This result has adverse effects on rain-fed agricultural practices, disease control, water resource management, socioeconomic activities and food security in Ghana.

Research paper thumbnail of Monthly entomological inoculation rates for studying malaria transmission seasonality in Africa

A comprehensive literature review is conducted to create a new database of malaria Entomological ... more A comprehensive literature review is conducted to create a new database of malaria Entomological Inoculation Rates (EIR), a metric of malaria transmission intensity. All field studies include data at a monthly temporal resolution and a duration of at least one year in order to be able to study seasonality variability in transmission. Care is taken to ensure the data collection methodologies adhere to a specific standard and that the location and timing of the measurements are well documented. Auxiliary information on the population and hydrological setting are included. The database includes measurements that cover Sub-Saharan Africa spanning from 1968 to 2013, thus also facilitating analysis of interannual transmission variability over broad regions.

Research paper thumbnail of Estimation of the return periods of maxima rainfall and floods at the Pra River Catchment, Ghana, West Africa using the Gumbel extreme value theory

Heliyon, 2021

The Pra river catchment in Ghana is adversely affected by perennial flooding from high-intensity ... more The Pra river catchment in Ghana is adversely affected by perennial flooding from high-intensity rainfall events. To aid in flood management at the catchment, the Gumbel extreme value distribution has been used to estimate the return periods of maxima rainfall, flood, and consecutive dry and wet days (CDD and CWD) for a period of 5 to 100 years. The results revealed an expected increase in maxima rainfall, CDD and CWD. Maxima rainfall favours the south of the catchment while the CDD decreases northward. Furthermore, an increase in the magnitude of CWD observed at the centre of the catchment had a maximum of approximately 30 days for the 100 year return period, while lower flood volumes had a higher recurrence of 50% to 100% for 1 to 2 year return periods. The inclusion of a projected increase in anthropogenic activities and climate factors at the catchment will slightly affect the magnitude of these variables for the various return periods. Nonetheless, the findings in this study wi...

Research paper thumbnail of Improvement and validation of dynamical malaria models in Africa

Overcoming the serious public health burden of malaria in Africa especially the sub-Saharan Afric... more Overcoming the serious public health burden of malaria in Africa especially the sub-Saharan Africa requires a detailed understanding of malaria epidemiology in the region. To contribute to this effect, this work embarked on several research steps. The first part of this study investigated the impact of climatic and environmental factors on seasonal malaria transmission in Africa. Monthly Entomological Inoculation Rate (EIRm) data initially gathered from different malaria locations across the region via a literature review was utilized for this purpose. The results revealed that rainfall was the primary climatic determinant of malaria seasonality at markedly seasonal rainfall areas such as Sahel and Eritrea. But its impact at bimodal rainfall distributed and more humid zones was more complex. Temperature was not a limiting factor of malaria seasonality in Africa except for East Africa where it can delay the impact of rainfall. The seasonal peaking characteristics of malaria were most...

Research paper thumbnail of Mechanisms of Rainfall Biases in two CORDEX-CORE Regional Climate Models at rainfall peaks over Central Equatorial Africa

Journal of Climate

Two regional climate models (RCMs) participating in the CORDEX-Coordinated Output for Regional Ev... more Two regional climate models (RCMs) participating in the CORDEX-Coordinated Output for Regional Evaluations (CORDEX-CORE) project feature a dipole-type rainfall bias during March-May (MAM) and September-November (SON) over Central Equatorial Africa (CEA), consisting in positive bias in West Central Equatorial Africa (WCEA) and negative bias in East Central Equatorial Africa (ECEA). One is the REgional MOdel version 2015 (REMO2015), and the other is the fourth version of the Regional Climate Model (RegCM4-v7). RCMs are nested in three Earth System Models (ESMs) from the Coupled Model Intercomparison Project phase 5 (CMIP5), and in the reanalysis ERA-Interim, at ~25 Km spacing-grid resolution. This study highlights misrepresented underlying physical processes associated with these rainfall biases through a process-based evaluation. Both RCMs produce a weaker Congo basin cell, associated with a weaker land-ocean zonal surface pressure gradient. Consequently, less water vapour enters the...

Research paper thumbnail of Low‐Level Cloud Development and Diurnal Cycle in Southern West Africa During the DACCIWA Field Campaign: Case Study of Kumasi Supersite, Ghana

Journal of Geophysical Research: Atmospheres

Research paper thumbnail of Endemicity of COVID-19 to Sub-Saharan Africa: A Review of the Past, Present and Future Risk

Research paper thumbnail of Monthly Entomological Inoculation Rate Data for Studying the Seasonality of Malaria Transmission in Africa

Data, 2020

A comprehensive literature review was conducted to create a new database of 197 field surveys of ... more A comprehensive literature review was conducted to create a new database of 197 field surveys of monthly malaria Entomological Inoculation Rates (EIR), a metric of malaria transmission intensity. All field studies provide data at a monthly temporal resolution and have a duration of at least one year in order to study the seasonality of the disease. For inclusion, data collection methodologies adhered to a specific standard and the location and timing of the measurements were documented. Auxiliary information on the population and hydrological setting were also included. The database includes measurements that cover West and Central Africa and the period from 1945 to 2011, and hence facilitates analysis of interannual transmission variability over broad regions.

Research paper thumbnail of Assessment of urban heat island warming in the greater accra region

The Greater Accra region is the most urbanized region in Ghana. Over the last decade, the region ... more The Greater Accra region is the most urbanized region in Ghana. Over the last decade, the region has undergone rapid population shift and urban sprawl. This has modified the natural environment of the area and led to the formation and warming of Urban Heat Island (UHI). Previous studies have not established enough evidence on the existence of UHI phenomenon in the region. For this reason, this study examined the existence, magnitude , and spatial extent of UHI warming as well as its effect on temperature extremes in the region. The study used Landsat satellite imagery captured in 1991, 2002 and 2017, and in-situ daily minimum and maximum temperature data spanning the period 1980 to 2017. The satellite images were processed and analyzed using an integrated Geographic Information System (GIS) and remote sensing technique while extreme temperature indices were assessed with the ClimPACT2 software. The study found that UHI existed in the region with an increasing spatial coverage and a magnitude of about 4.07 • C, 5.79 • C, and 4.86 • C in 1991, 2002, and 2017 respectively. The built-up and bare land areas experienced the strongest effect of UHI warming. In addition, enhanced UHI warming effect caused an increase in the frequency and intensity of warm temperature extremes in the region. A faster increase in night time temperatures than day time resulted in a decrease in diurnal temperature range of the region. Considering the high rate of warming amidst rapid urban expansion, more warming is expected in the region. This is expected to exacerbate climate extreme events and weather-related health issues. It is also expected to increase energy consumption, air pollution and human discomfort.