Papers by Souleymane Fall
15th Conference on Applied Climatology/13th Symposium on Meteorological Observations and Instrumentation, Jun 20, 2005
Climate variability over Senegal (West Africa) and its relationship to global climate are examine... more Climate variability over Senegal (West Africa) and its relationship to global climate are examined for the period 1979-1998. Monthly observed rainfall for 20 stations and monthly CPC merged analysis precipitation (CMAP) over Senegal were averaged for the months of June, July, August, and September in order to generate seasonal rainfall totals for the wet season, as well as climate indices averaged over the study period. The spatial distribution patterns are mapped and analyzed using ArcGIS Spatial Analyst. Rainfall distribution over Senegal is dominated by a N-S gradient. To investigate the climate variability over Senegal, an empirical orthogonal function (EOF) analysis is performed for the 1979-1998 period, using rain-gauge and CMAP rainfall data over Senegal, and CMAP data only for West Africa. The first West African mode agrees strongly with Lamb's rainfall index. One of our major findings is that EOF2 for West Africa is well correlated with EOF1 for rainfall in Senegal. This relationship is supported by the projection of winds on the EOF2 mode by the National Centers for Environmental Prediction (NCEP), as well as the grid-point correlation between the time series of EOF2 over West Africa and the Atlantic sea-surface temperature (SST). The typical circulation associated with positive anomalies over Senegal is a moisture convergence, which takes place over the Guinea Gulf, in conjunction with the warm waters in this area. The time series for rainfall over Senegal show positive correlations with the South Atlantic SST. Over the Pacific Ocean, the greatest correlation coefficients (up to −0.72) are observed during the April-July period, which provide a modest possibility of predicting Senegal's rainy season. Given the specificity of coastal West Africa, the traditional indices used by policy makers and end users for the whole Sahel-Sudan region will not work for Senegal. The CMAP data are robust and suitable for analyses over West Africa. On the basis of its reliability, CMAP data has proven to be a good validation for analyses based on rain-gauge precipitation.
Effectiveness of Utilizing Remote Sensing and GIS Techniques to Estimate the Exposure to Agricultural Pesticides Drift over Macon, Alabama
Agricultural workers utilize pesticides extensively on their farms to control weeds and insects, ... more Agricultural workers utilize pesticides extensively on their farms to control weeds and insects, as well as increase crop productivity. Despite these advantages, their excessive use poses a seri-ous threat, particularly to the population living at the nexus of urban and rural areas. Exposure to pesticide drift can be investigated using geospatial tools. Remote sensing technology and Geographic Information Systems (GIS) techniques have been used intensively and constitute trusted tools in different sectors, especially in agriculture. Remote sensing depends on pro-cessing the electromagnetic radiation reflected and emitted from the ground target and can be used to identify the spectral signature of crops exposed to pesticides. GIS has powerful tools for building a spatial geo-database of pesticide exposure drift. Therefore, the major objective of the research was to explore the effectiveness of using remote sensing and GIS techniques to estimate the exposure to pesticides in Macon Cou...
Agriculture
Pesticides have been widely used in agriculture, resulting in significant pollution that affects ... more Pesticides have been widely used in agriculture, resulting in significant pollution that affects both the environment and human health. This pollution is particularly prevalent in nearby agricultural areas, where sensitive resources are contaminated through spray drift exposure and surface runoff. Spray drift is a critical concern when it comes to environmental hazards. It poses health risks not only to farmers and pesticide applicators, but also to individuals living in nearby farm areas. To address this issue, developing reliable models and techniques for estimating spray drift and reducing its impact has become a crucial and efficient research topic. The current research has three primary objectives: firstly, to estimate the average pesticide application rates, trend analysis, and concentration distribution; secondly, to estimate the temporal variations of pesticide concentrations and identify the areas most likely to be affected by pesticide spray drift close to agricultural fie...
Agronomy
Farmers utilize pesticides extensively on their farms to control weeds and insects, as well as in... more Farmers utilize pesticides extensively on their farms to control weeds and insects, as well as increase crop productivity. Despite these advantages, their excessive use poses a serious threat, particularly to the population living at the nexus of urban and rural areas. Exposure to pesticide drift can be investigated using geospatial tools. Remote sensing technology and Geographic Information Systems (GIS) techniques have been used intensively and constitute trusted tools in different sectors, especially in agriculture. Remote sensing depends on processing the electromagnetic radiation reflected and emitted from the ground target and can be used to identify the main units of Land Use Land Cover (LULC), in addition to measuring crop areas exposed to pesticides. GIS has powerful tools for building a spatial geo-database of pesticide exposure drift. Therefore, the major objective of the research was to explore the effectiveness of using remote sensing and GIS techniques to estimate the ...
Abstract 5964: Integrating computational epidemiology and geographic information systems toos into cervical cancer research
Cancer Research, Jun 15, 2022
Background: Cancer control researchers seek to reduce the burden of cancer by studying interventi... more Background: Cancer control researchers seek to reduce the burden of cancer by studying interventions, their impact on defined populations, and the means by which they can be better used. The first step in cancer control is identifying where the cancer burden is elevated, which suggests locations where interventions are needed. Geographic information systems (GIS) and other spatial analytic methods provide such a solution and thus can play a major role in cancer control. Our objective is to combine computational epidemiological and GIS tools to identify, map and explain racial disparities in cervical cancer treatment in Alabama, especially in the Black Belt counties (BBCs) of Alabama. Methodology: Data obtained from ADPH/Cancer Registry were used in this study. ArcGIS 10.4 software was utilized to create maps along with graphs showing variation in cervical cancer treatment by race, stage at diagnosis, location and stratified by age groups and to measure geographical accessibility of cervical cancer patients to health care facilities. Accessibility was measured based on 10, 20, 30, 40 and50 miles multiple buffer distance from the city of Tuskegee, to sexually transmitted diseases (STD), clinics and hospitals. Results: Overall, Blacks and Whites Alabamians who were diagnosed with cervical cancer were significantly less likely to receive treatments (surgery, radiation, surgery and radiation and chemotherapy). Blacks, who were living in rural BBCs, diagnosed with four stages of cervical cancer, stratified by the age groups (17 to 49, 50 to 64, 65 to 74 and 75 to 100 years), and underwent the four above mentioned treatment, had the highest Prevalence Rates (PR) of cervical cancer compared to their White counterparts. The ideal distance for cancer patients to the hospital shall be less than 12.4 miles away to avoid pain and discomfort during the travel. Our results show that out of seven STD clinics, ten health care centers and six hospitals are located in Macon County, and nearby Alabama counties. There are only two health care centers, namely Macon County Health Department and Tuskegee Quality Health Care Medical Clinic, which have an ideal location (around 1.9 to 2.5 and 4.0 to 6.3 miles respectively from Macon County). However, it provides only Pap smear, but no treatment. Conclusion: We proved that disparity in outcomes result from unequal access to care and/or differences in the quality of care received. Also, factors that ultimately contribute to differences in outcome include access to timely treatment, factors which may be affected by race and age, as well as location differences. The findings could be used for planning better health care deliveries, especially in sparsely populated areas of Alabama. Citation Format: Ehsan Abdalla, David Nganwa, Souleymane Fall. Integrating computational epidemiology and geographic information systems toos into cervical cancer research [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5964.
Climate
This study presents an analysis of extreme temperature events over southeastern USA from 1978 to ... more This study presents an analysis of extreme temperature events over southeastern USA from 1978 to 2017. This region is part of the so-called ‘warming hole’ where long-term surface temperature trends are negative or non-significant, in contrast with the remainder of the country. This study examines whether this distinctive characteristic reflects on the region’s trends in temperature extremes. Daily maximum and minimum temperatures from the US Historical Climatology Network were used to compute extreme indices recommended by the Expert Team on Climate Change Detection and Indices. Temperature extreme indices computed for all stations using the RClimDex package were gridded onto a regular latitude–longitude grid, and a spatiotemporal analysis of associated trends was performed. The results point to a tendency toward warming due to increasing trends in the annual occurrence of the hottest day, the warmest night, warm days, warm nights, summer days, tropical nights, and warm spells, as w...
ISPRS International Journal of Geo-Information
The COVID-19 pandemic has posed an unprecedented challenge to public health across the world and ... more The COVID-19 pandemic has posed an unprecedented challenge to public health across the world and has further exposed health disparities and the vulnerability of marginal groups. Since the pandemic has exhibited marked regional differences, it is necessary to better understand the levels of vulnerability to the disease at local levels and provide policymakers with additional tools that will allow them to develop finely targeted policies. In this study, we develop for the State of Alabama (USA) a composite vulnerability index at county level that can be used as a tool that will help in the management of the pandemic. Twenty-four indicators were assigned to the following three categories: exposure, sensitivity, and adaptive capacity. The resulting subindices were aggregated into a composite index that depicts the vulnerability to COVID-19. A multivariate analysis was used to assign factor loadings and weights to indicators, and the results were mapped using Geographic Information Syste...
Climate
This study presents an analysis of extreme temperature events over southeastern USA from 1978 to ... more This study presents an analysis of extreme temperature events over southeastern USA from 1978 to 2017. This region is part of the so-called ‘warming hole’ where long-term surface temperature trends are negative or non-significant, in contrast with the remainder of the country. This study examines whether this distinctive characteristic reflects on the region’s trends in temperature extremes. Daily maximum and minimum temperatures from the US Historical Climatology Network were used to compute extreme indices recommended by the Expert Team on Climate Change Detection and Indices. Temperature extreme indices computed for all stations using the RClimDex package were gridded onto a regular latitude–longitude grid, and a spatiotemporal analysis of associated trends was performed. The results point to a tendency toward warming due to increasing trends in the annual occurrence of the hottest day, the warmest night, warm days, warm nights, summer days, tropical nights, and warm spells, as w...
Purdue Terrestrial Observatory, Rosen Cntr. for Advanced Computing
The authors present the utility of combining data from multiple earth observing satellites, with ... more The authors present the utility of combining data from multiple earth observing satellites, with complimentary spatial, temporal and spectral resolutions, together with landuse data, a digital elevation model and population data, for mitigation of selected vector-borne diseases. The literature with respect to identification of disease vector habitat, utilizing remote sensing, is examined. The potential benefits of heterogeneous data integration, for facilitating sustainable vector habitat mitigation, are presented, together with the recommended adjunct installations and initiatives required for implementation of a vital operational adjunct to public health surveillance. The applicability of such spatial data analysis and database development, incorporating both archival and real-time data to facilitate vulnerability assessment, is illustrated within the Nile River Delta.
Climate
This study presents an analysis of extreme temperature events over southeastern USA from 1978 to ... more This study presents an analysis of extreme temperature events over southeastern USA from 1978 to 2017. This region is part of the so-called ‘warming hole’ where long-term surface temperature trends are negative or non-significant, in contrast with the remainder of the country. This study examines whether this distinctive characteristic reflects on the region’s trends in temperature extremes. Daily maximum and minimum temperatures from the US Historical Climatology Network were used to compute extreme indices recommended by the Expert Team on Climate Change Detection and Indices. Temperature extreme indices computed for all stations using the RClimDex package were gridded onto a regular latitude–longitude grid, and a spatiotemporal analysis of associated trends was performed. The results point to a tendency toward warming due to increasing trends in the annual occurrence of the hottest day, the warmest night, warm days, warm nights, summer days, tropical nights, and warm spells, as w...
Climate
This study presents an analysis of extreme temperature events over southeastern USA from 1978 to ... more This study presents an analysis of extreme temperature events over southeastern USA from 1978 to 2017. This region is part of the so-called ‘warming hole’ where long-term surface temperature trends are negative or non-significant, in contrast with the remainder of the country. This study examines whether this distinctive characteristic reflects on the region’s trends in temperature extremes. Daily maximum and minimum temperatures from the US Historical Climatology Network were used to compute extreme indices recommended by the Expert Team on Climate Change Detection and Indices. Temperature extreme indices computed for all stations using the RClimDex package were gridded onto a regular latitude–longitude grid, and a spatiotemporal analysis of associated trends was performed. The results point to a tendency toward warming due to increasing trends in the annual occurrence of the hottest day, the warmest night, warm days, warm nights, summer days, tropical nights, and warm spells, as w...
ISPRS International Journal of Geo-Information
The COVID-19 pandemic has posed an unprecedented challenge to public health across the world and ... more The COVID-19 pandemic has posed an unprecedented challenge to public health across the world and has further exposed health disparities and the vulnerability of marginal groups. Since the pandemic has exhibited marked regional differences, it is necessary to better understand the levels of vulnerability to the disease at local levels and provide policymakers with additional tools that will allow them to develop finely targeted policies. In this study, we develop for the State of Alabama (USA) a composite vulnerability index at county level that can be used as a tool that will help in the management of the pandemic. Twenty-four indicators were assigned to the following three categories: exposure, sensitivity, and adaptive capacity. The resulting subindices were aggregated into a composite index that depicts the vulnerability to COVID-19. A multivariate analysis was used to assign factor loadings and weights to indicators, and the results were mapped using Geographic Information Syste...
ISPRS International Journal of Geo-Information
The COVID-19 pandemic has posed an unprecedented challenge to public health across the world and ... more The COVID-19 pandemic has posed an unprecedented challenge to public health across the world and has further exposed health disparities and the vulnerability of marginal groups. Since the pandemic has exhibited marked regional differences, it is necessary to better understand the levels of vulnerability to the disease at local levels and provide policymakers with additional tools that will allow them to develop finely targeted policies. In this study, we develop for the State of Alabama (USA) a composite vulnerability index at county level that can be used as a tool that will help in the management of the pandemic. Twenty-four indicators were assigned to the following three categories: exposure, sensitivity, and adaptive capacity. The resulting subindices were aggregated into a composite index that depicts the vulnerability to COVID-19. A multivariate analysis was used to assign factor loadings and weights to indicators, and the results were mapped using Geographic Information Syste...
ISPRS International Journal of Geo-Information
The COVID-19 pandemic has posed an unprecedented challenge to public health across the world and ... more The COVID-19 pandemic has posed an unprecedented challenge to public health across the world and has further exposed health disparities and the vulnerability of marginal groups. Since the pandemic has exhibited marked regional differences, it is necessary to better understand the levels of vulnerability to the disease at local levels and provide policymakers with additional tools that will allow them to develop finely targeted policies. In this study, we develop for the State of Alabama (USA) a composite vulnerability index at county level that can be used as a tool that will help in the management of the pandemic. Twenty-four indicators were assigned to the following three categories: exposure, sensitivity, and adaptive capacity. The resulting subindices were aggregated into a composite index that depicts the vulnerability to COVID-19. A multivariate analysis was used to assign factor loadings and weights to indicators, and the results were mapped using Geographic Information Syste...
Applied Climate Data Processing Using R
This paper presents a series of climate data processing procedures written in R. The workflows pr... more This paper presents a series of climate data processing procedures written in R. The workflows presented show that R can be used as a powerful and flexible tool for climate data analysis. Hourly reanalysis temperature from NASA’s Modern Era Retrospective-analysis for Research and Applications (MERRA) were used. MERRA data are individual daily data file in network common data form (NetCDF) with hourly temperature time series. Daily maximum and minimum temperatures were extracted from the individual NetCDF files, and then daily temperature ranges (DTR) were computed. The outputs were concatenated to obtain one single DTR file at daily time scale and written as a new NetCDF. The results were interpolated and compared to actual observations at specific locations. Also standard climatology procedures like cosine weighted time series anomalies, linear trends, spatial and temporal patterns (with user-defined thresholds) and computations of mean temperatures over time for each grid location...
Purdue Terrestrial Observatory, Rosen Cntr. for Advanced Computing
The authors present the utility of combining data from multiple earth observing satellites, with ... more The authors present the utility of combining data from multiple earth observing satellites, with complimentary spatial, temporal and spectral resolutions, together with landuse data, a digital elevation model and population data, for mitigation of selected vector-borne diseases. The literature with respect to identification of disease vector habitat, utilizing remote sensing, is examined. The potential benefits of heterogeneous data integration, for facilitating sustainable vector habitat mitigation, are presented, together with the recommended adjunct installations and initiatives required for implementation of a vital operational adjunct to public health surveillance. The applicability of such spatial data analysis and database development, incorporating both archival and real-time data to facilitate vulnerability assessment, is illustrated within the Nile River Delta.
Purdue Terrestrial Observatory, Rosen Cntr. for Advanced Computing
The authors present the utility of combining data from multiple earth observing satellites, with ... more The authors present the utility of combining data from multiple earth observing satellites, with complimentary spatial, temporal and spectral resolutions, together with landuse data, a digital elevation model and population data, for mitigation of selected vector-borne diseases. The literature with respect to identification of disease vector habitat, utilizing remote sensing, is examined. The potential benefits of heterogeneous data integration, for facilitating sustainable vector habitat mitigation, are presented, together with the recommended adjunct installations and initiatives required for implementation of a vital operational adjunct to public health surveillance. The applicability of such spatial data analysis and database development, incorporating both archival and real-time data to facilitate vulnerability assessment, is illustrated within the Nile River Delta.
Purdue Terrestrial Observatory, Rosen Cntr. for Advanced Computing
The authors present the utility of combining data from multiple earth observing satellites, with ... more The authors present the utility of combining data from multiple earth observing satellites, with complimentary spatial, temporal and spectral resolutions, together with landuse data, a digital elevation model and population data, for mitigation of selected vector-borne diseases. The literature with respect to identification of disease vector habitat, utilizing remote sensing, is examined. The potential benefits of heterogeneous data integration, for facilitating sustainable vector habitat mitigation, are presented, together with the recommended adjunct installations and initiatives required for implementation of a vital operational adjunct to public health surveillance. The applicability of such spatial data analysis and database development, incorporating both archival and real-time data to facilitate vulnerability assessment, is illustrated within the Nile River Delta.
Applied Climate Data Processing Using R
This paper presents a series of climate data processing procedures written in R. The workflows pr... more This paper presents a series of climate data processing procedures written in R. The workflows presented show that R can be used as a powerful and flexible tool for climate data analysis. Hourly reanalysis temperature from NASA’s Modern Era Retrospective-analysis for Research and Applications (MERRA) were used. MERRA data are individual daily data file in network common data form (NetCDF) with hourly temperature time series. Daily maximum and minimum temperatures were extracted from the individual NetCDF files, and then daily temperature ranges (DTR) were computed. The outputs were concatenated to obtain one single DTR file at daily time scale and written as a new NetCDF. The results were interpolated and compared to actual observations at specific locations. Also standard climatology procedures like cosine weighted time series anomalies, linear trends, spatial and temporal patterns (with user-defined thresholds) and computations of mean temperatures over time for each grid location...
Applied Climate Data Processing Using R
This paper presents a series of climate data processing procedures written in R. The workflows pr... more This paper presents a series of climate data processing procedures written in R. The workflows presented show that R can be used as a powerful and flexible tool for climate data analysis. Hourly reanalysis temperature from NASA’s Modern Era Retrospective-analysis for Research and Applications (MERRA) were used. MERRA data are individual daily data file in network common data form (NetCDF) with hourly temperature time series. Daily maximum and minimum temperatures were extracted from the individual NetCDF files, and then daily temperature ranges (DTR) were computed. The outputs were concatenated to obtain one single DTR file at daily time scale and written as a new NetCDF. The results were interpolated and compared to actual observations at specific locations. Also standard climatology procedures like cosine weighted time series anomalies, linear trends, spatial and temporal patterns (with user-defined thresholds) and computations of mean temperatures over time for each grid location...
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Papers by Souleymane Fall