Interannual, Monthly, and Regional Variability in the Wet Season Diurnal Cycle of Precipitation in Sub-Saharan Africa

Abstract. Sub-Saharan Africa (SSA) is a global hot spot for aerosol emissions, which affect the regional climate and air quality. In this paper, we use ground-based observations to address the large uncertainties in the source-resolved emission estimation of carbonaceous aerosols. Ambient fine fraction aerosol was collected on filters at the high-altitude (2590 m a.s.l.) Rwanda Climate Observatory (RCO), a SSA background site, during the dry and wet seasons in 2014 and 2015. The concentrations of both the carbonaceous and inorganic ion components show a strong seasonal cycle, with highly elevated concentrations during the dry season. Source marker ratios, including carbon isotopes, show that the wet and dry seasons have distinct aerosol compositions. The dry season is characterized by elevated amounts of biomass burning products, which approach ∼95 % for carbonaceous aerosols. An isotopic mass-balance estimate shows that the amount of the carbonaceous aerosol stemming from savanna fires may increase from 0.2 µg m−3 in the wet season up to 10 µg m−3 during the dry season. Based on these results, we quantitatively show that savanna fire is the key modulator of the seasonal aerosol composition variability at the RCO.

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Forecasting the global extent of invasion of the cereal pest Spodoptera frugiperda, the fall armyworm

NeoBiota ◽

10.3897/neobiota.40.28165 ◽

2018 ◽

Vol 40 ◽

pp. 25-50 ◽

Cited By ~ 54

Author(s):

Regan Early ◽

Pablo González-Moreno ◽

Sean T. Murphy ◽

Roger Day

Keyword(s):

Fall Armyworm ◽

Maize Yield ◽

Sub Saharan Africa ◽

Potential Range ◽

Wet Season ◽

Distribution Models ◽

Climate Conditions ◽

Temperature And Precipitation ◽

Sub Saharan ◽

Transportation Routes

Fall armyworm, Spodopterafrugiperda, is a crop pest native to the Americas, which has invaded and spread throughout sub-Saharan Africa within two years. Recent estimates of 20–50% maize yield loss in Africa suggest severe impact on livelihoods. Fall armyworm is still infilling its potential range in Africa and could spread to other continents. In order to understand fall armyworm’s year-round, global, potential distribution, we used evidence of the effects of temperature and precipitation on fall armyworm life-history, combined with data on native and African distributions to construct Species Distribution Models (SDMs). We also investigated the strength of trade and transportation pathways that could carry fall armyworm beyond Africa. Up till now, fall armyworm has only invaded areas that have a climate similar to the native distribution, validating the use of climatic SDMs. The strongest climatic limits on fall armyworm’s year-round distribution are the coldest annual temperature and the amount of rain in the wet season. Much of sub-Saharan Africa can host year-round fall armyworm populations, but the likelihoods of colonising North Africa and seasonal migrations into Europe are hard to predict. South and Southeast Asia and Australia have climate conditions that would permit fall armyworm to invade. Current trade and transportation routes reveal Australia, China, India, Indonesia, Malaysia, Philippines and Thailand face high threat of fall armyworm invasions originating from Africa.

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Spatial patterns of child mortality in Nanoro HDSS site, Burkina Faso

10.1101/2020.07.06.20147645 ◽

2020 ◽

Author(s):

Navideh Noori ◽

Karim Derra ◽

Innocent Valea ◽

Assaf P. Oron ◽

Aminata Welgo ◽

...

Keyword(s):

Burkina Faso ◽

Child Mortality ◽

Spatial Patterns ◽

Health Facilities ◽

Sub Saharan Africa ◽

Wet Season ◽

Inpatient Facility ◽

Child Deaths ◽

Sub Saharan ◽

Geographical Accessibility

AbstractBackgroundHalf of global child deaths occur in sub-Saharan Africa. Understanding child mortality patterns and risk factors will help inform interventions to reduce this heavy toll. The Nanoro Health and Demographic Surveillance System (HDSS), Burkina Faso was described previously, but spatial patterns of child mortality in the district had not been studied. Similar studies in other districts indicated accessibility to health facilities as a risk factor, usually without distinction between facility types.MethodsUsing Nanoro HDSS data from 2009 to 2013, we estimated the association between under-5 mortality and accessibility to inpatient and outpatient health facilities, seasonality of death, and age group.ResultsLiving in homes 40-60 minutes and >60 minutes travel time from an inpatient facility was associated with 1.52 (95% CI: 1.13-2.06) and 1.74 (1.27-2.40) greater hazard of under-5 mortality, respectively, than living in homes <20 minutes from an inpatient facility. No such association was found for outpatient facilities. Seasonality of death was significantly associated with under-5 mortality, and the wet season (July-November) was associated with 1.28 (1.07, 1.53) higher under-5 mortality than the dry season (December-June), likely reflecting the malaria season.ConclusionsOur results emphasize the importance of geographical accessibility to health care, and also distinguish between inpatient and outpatient facilities.

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Characterization of Spatio-Temporal Trends and Periodicity of Precipitation over Malawi during 1979–2015

Atmosphere ◽

10.3390/atmos11090891 ◽

2020 ◽

Vol 11 (9) ◽

pp. 891

Author(s):

Edwin Tadeyo ◽

Dan Chen ◽

Brian Ayugi ◽

Chunzhen Yao

Keyword(s):

Spatial Distribution ◽

Function Analysis ◽

Temporal Trends ◽

Sub Saharan Africa ◽

Spatial And Temporal Variability ◽

Wet Season ◽

Climate Change And Variability ◽

Spatio Temporal ◽

Sub Saharan ◽

Annual Scale

Precipitation remains the key climatic parameter in sub-Saharan Africa, as it drives the economy through rain-fed agricultural production. Malawi is one of the countries most susceptible to the impacts of climate change and variability. This paper presents the characteristics of spatio-temporal trends and periodicity of precipitation in Malawi in the period from 1979 to 2015. The analysis was based on recent rain ground gauge data. In total, 31 out of 36 rainfall stations, which include some key stations from the southeast of Malawi, were selected for the study after robust homogeneity tests were applied to the datasets. Spatial distribution of annual mean precipitation showed that high amounts of rainfall are located in areas along the lake and the southeast part of Malawi. The spatial distribution of the wet season (November to April) precipitation from EOF (Empirical Orthogonal Function) analysis revealed ten wet years (1985, 1986, 1989, 1996, 1997, 1999, 2001, 2006, 2007, and 2015) and ten dry years (1981, 1983, 1987, 1990, 1992, 1994, 1995, 2005, 2011, and 2014). In general, the temporal trends analyses of seasonal (wet season) and annual precipitations both displayed slight decreasing slopes during the 37 years. The trend of precipitation per decade displayed an increase in precipitation during 1980s and 1990s, followed by a decrease in the 21st century. Furthermore, the analysis of the spatial and temporal variability and trends of rainfall showed that northern and central Malawi displayed a clearer variability than southern Malawi. Although the trends of most of the stations are not significant at 95% confidence level, the decreasing rates of rainfall in the last decade and the decreasing trends on wet season and annual scale detected by Mann–Kendall tests require closer monitoring of rainfall changes in the near future. The stations which exhibited significant trends (Naminjiwa and Dedza stations) also call for closer monitoring, since the area relies heavily on rain-fed agriculture for economic sustenance.

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Influence of Subseasonal Variability on the Diurnal Cycle of Precipitation on a Mountainous Island: The Case of New Caledonia

Monthly Weather Review ◽

10.1175/mwr-d-19-0177.1 ◽

2019 ◽

Vol 148 (1) ◽

pp. 333-351 ◽

Cited By ~ 2

Author(s):

Damien Specq ◽

Gilles Bellon ◽

Alexandre Peltier ◽

Jérôme Lefèvre ◽

Christophe Menkes

Keyword(s):

Diurnal Cycle ◽

Large Scale ◽

New Caledonia ◽

Austral Summer ◽

Mountain Range ◽

Wet Season ◽

Diurnal Variability ◽

Synoptic Wind ◽

Diurnal Cycle Of Precipitation ◽

Wind Regimes

Abstract The relationship between the large-scale intraseasonal variability, synoptic wind regimes, and the local daily variability of precipitation over the main island of New Caledonia (southwest tropical Pacific) is investigated with a focus on the austral summer wet season (November–April). The average diurnal cycle of precipitation over the island is characterized by a sharp afternoon maximum around 1600 local time, with significant differences between the windward east coast, the leeward west coast, and the mountain range. The afternoon peak is related to the afternoon sea-breeze circulation and to the diurnal cycle of convection over land. In general, its magnitude follows the same evolution as the daily mean. In agreement with past studies, a clear modulation of the Madden–Julian oscillation (MJO) on both the diurnal cycle of precipitation and the probability of occurrence of four robust wind regimes can be identified in the New Caledonia region during the wet season. From the evidence that there is a qualitative correspondence between the effects of both the MJO phases and the wind regimes on features in the diurnal cycle of precipitation, a simple model is proposed to inspect the MJO forcing mediated by wind regimes on the diurnal variability of rain. The complete decomposition of the MJO impact shows that the modulation of diurnal cycle by the MJO relies on complex interactions between the MJO and synoptic winds that involve both large-scale MJO convective anomalies and MJO-induced modification of wind patterns.

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The influence of groundwater abstraction on interpreting climate controls and extreme recharge events from well hydrographs in semi-arid South Africa

Hydrogeology Journal ◽

10.1007/s10040-021-02391-3 ◽

2021 ◽

Author(s):

James P. R. Sorensen ◽

Jeff Davies ◽

Girma Y. Ebrahim ◽

John Lindle ◽

Ben P. Marchant ◽

...

Keyword(s):

South Africa ◽

Extreme Event ◽

Southern Oscillation ◽

Hierarchical Cluster ◽

Sub Saharan Africa ◽

Small Scale ◽

Groundwater Abstraction ◽

Wet Season ◽

Sub Saharan ◽

Semi Arid

AbstractThere is a scarcity of long-term groundwater hydrographs from sub-Saharan Africa to investigate groundwater sustainability, processes and controls. This paper presents an analysis of 21 hydrographs from semi-arid South Africa. Hydrographs from 1980 to 2000 were converted to standardised groundwater level indices and rationalised into four types (C1–C4) using hierarchical cluster analysis. Mean hydrographs for each type were cross-correlated with standardised precipitation and streamflow indices. Relationships with the El Niño–Southern Oscillation (ENSO) were also investigated. The four hydrograph types show a transition of autocorrelation over increasing timescales and increasingly subdued responses to rainfall. Type C1 strongly relates to rainfall, responding in most years, whereas C4 notably responds to only a single extreme event in 2000 and has limited relationship with rainfall. Types C2, C3 and C4 have stronger statistical relationships with standardised streamflow than standardised rainfall. C3 and C4 changes are significantly (p < 0.05) correlated to the mean wet season ENSO anomaly, indicating a tendency for substantial or minimal recharge to occur during extreme negative and positive ENSO years, respectively. The range of different hydrograph types, sometimes within only a few kilometres of each other, appears to be a result of abstraction interference and cannot be confidently attributed to variations in climate or hydrogeological setting. It is possible that high groundwater abstraction near C3/C4 sites masks frequent small-scale recharge events observed at C1/C2 sites, resulting in extreme events associated with negative ENSO years being more visible in the time series.

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Distribution of tsetse flies and its Trypanosoma species infection in Old Oyo National Park, Nigeria

Zoologist (The) ◽

10.4314/tzool.v18i1.6 ◽

2021 ◽

Vol 18 (1) ◽

pp. 33-38

Author(s):

A.O. Omonona ◽

S.A. Abioye ◽

P.O. Odeniran ◽

I.O. Ademola

Keyword(s):

National Parks ◽

National Park ◽

Ground Level ◽

Tsetse Fly ◽

Sub Saharan Africa ◽

Tsetse Flies ◽

Trypanosome Infection ◽

Wet Season ◽

Significant Difference ◽

Sub Saharan

Tsetse fly infestation in national parks is a major health risk to both the wildlife and tourists coming to sub-Saharan Africa. However, information on distribution and diversity of tsetse flies and trypanosome infection rate in Protected Areas like Old Oyo National Park in south-west Nigeria is largely unknown. Thus, the study evaluates distribution and diversity of tsetse flies in Magurba Range of Old Oyo National Park. Twelve Nzi traps were set at 50 m equidistance to capture Glossina species for a period of six months between February and August, 2019, considering both the altitudinal and ecological significance. A total of 136 tsetse flies belonging to four species; G. palpalis, G. tachinoides, G. morsitans and G. fusca; were captured. More Glossina species were captured during dry season 77.9% (70.0-84.6) than the wet season 22.1% (15.4-30.0). There was significant difference (p = 0.0001; x2 = 84.9; OR = 12.5) between the proportion of Glossina species captured at the riverine areas (106; 77.9%) and the woodland/forest areas (30; 22.1%). Glossina captured at ground level and 30 cm above ground were 71 (52.2 %) and 65 (47.8%) respectively. The overall prevalence of trypanosome infection (2.94%) was observed for Glossina spp. The presence of infected Glossina spp. indicated an urgent need to establish a concise strategic vector control in National Parks, in order to reduce the risk of transmission to both wildlife and humans in the area. The park is frequently visited by tourists, rangers, researchers and students for educational purposes. Keywords: Glossina spp.; Trypanosoma spp.; vector distribution; Old Oyo National Park

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Forecasting the global extent of invasion of the cereal pest Spodoptera frugiperda, the fall armyworm

10.1101/391847 ◽

2018 ◽

Cited By ~ 3

Author(s):

Regan Early ◽

Pablo González-Moreno ◽

Sean T. Murphy ◽

Roger Day

Keyword(s):

Spodoptera Frugiperda ◽

Fall Armyworm ◽

Maize Yield ◽

Sub Saharan Africa ◽

Potential Range ◽

Wet Season ◽

Distribution Models ◽

Temperature And Precipitation ◽

Sub Saharan ◽

Transportation Routes

AbstractFall armyworm, Spodoptera frugiperda, is a crop pest native to the Americas, which has invaded and spread throughout sub-Saharan Africa within two years. Recent estimates of 20-50% maize yield loss in Africa suggest severe damage to livelihoods. Fall armyworm is still infilling its potential range in Africa, and could spread to other continents. In order to understand fall armyworm’s year-round, global, potential distribution, we used evidence of the effects of temperature and precipitation on fall armyworm life-history, combined with data on native and African distributions to construct Species Distribution Models (SDMs). Fall armyworm has only invaded areas that have a climate similar to the native distribution, validating the use of climatic SDMs. The strongest climatic limits on fall armyworm’s year-round distribution are the coldest annual temperature and the amount of rain in the wet season. Much of sub-Saharan Africa can host year-round fall armyworm populations, but the likelihoods of colonising North Africa and seasonal migrations into Europe are hard to predict. South and Southeast Asia and Australia have climate that would permit fall armyworm to invade. Current trade and transportation routes reveal Australia, China, India, Indonesia, Malaysia, Philippines, and Thailand face high threat of fall armyworm invasions originating from Africa.

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Understanding the summertime diurnal cycle of precipitation over sub-Saharan West Africa: regions with daytime rainfall peaks in the absence of significant topographic features

Climate Dynamics ◽

10.1007/s00382-018-4315-z ◽

2018 ◽

Vol 52 (5-6) ◽

pp. 2903-2922 ◽

Cited By ~ 7

Author(s):

Edward K. Vizy ◽

Kerry H. Cook

Keyword(s):

West Africa ◽

Diurnal Cycle ◽

Topographic Features ◽

Diurnal Cycle Of Precipitation ◽

Sub Saharan

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RTS,S/AS01, a vaccine targeting pre-erythrocytic stages of Plasmodium falciparum

Emerging Topics in Life Sciences ◽

10.1042/etls20170101 ◽

2017 ◽

Vol 1 (6) ◽

pp. 533-537

Author(s):

Lorenz von Seidlein ◽

Borimas Hanboonkunupakarn ◽

Podjanee Jittmala ◽

Sasithon Pukrittayakamee

Keyword(s):

Protective Efficacy ◽

Age Groups ◽

Sub Saharan Africa ◽

Phase Iii ◽

European Medicines Agency ◽

Older Children ◽

Pivotal Phase ◽

Malaria Epidemiology ◽

Maximum Benefit ◽

Sub Saharan

RTS,S/AS01 is the most advanced vaccine to prevent malaria. It is safe and moderately effective. A large pivotal phase III trial in over 15 000 young children in sub-Saharan Africa completed in 2014 showed that the vaccine could protect around one-third of children (aged 5–17 months) and one-fourth of infants (aged 6–12 weeks) from uncomplicated falciparum malaria. The European Medicines Agency approved licensing and programmatic roll-out of the RTSS vaccine in malaria endemic countries in sub-Saharan Africa. WHO is planning further studies in a large Malaria Vaccine Implementation Programme, in more than 400 000 young African children. With the changing malaria epidemiology in Africa resulting in older children at risk, alternative modes of employment are under evaluation, for example the use of RTS,S/AS01 in older children as part of seasonal malaria prophylaxis. Another strategy is combining mass drug administrations with mass vaccine campaigns for all age groups in regional malaria elimination campaigns. A phase II trial is ongoing to evaluate the safety and immunogenicity of the RTSS in combination with antimalarial drugs in Thailand. Such novel approaches aim to extract the maximum benefit from the well-documented, short-lasting protective efficacy of RTS,S/AS01.

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