Skip to main content

Advertisement

SpringerLink
Log in

Fine-Mode Aerosol Loading Over a Sub-Sahel Location and Its Relation with the West African Monsoon

  • Original Paper
  • Published:
Aerosol Science and Engineering Aims and scope Submit manuscript

Abstract

The aerosol fine-mode fraction (FMF) at the sub-Sahel AErosol RObotic NETwork (AERONET) site at Ilorin (8°32′N; 4°34′E) is found to be the highest (FMFmean = 0.487) compared to six upper Sahel AERONET sites. The fine-mode aerosol population at the site dominates the coarse mode in core West African Monsoon months of June–July–August (FMFmean = 0.581; Angstrom exponent derivative = 0.44). Correlations (r) of aerosol optical depth (AOD) time series with corresponding seasonal zonal wind (ZW) and meridional wind (MW) speeds of the European Centre for Medium-Range Weather Forecasts at the seven AERONET sites reveal a uniquely strong positive value (r = 0.6) of wet-season AOD and MW at Ilorin. The wet-season FMF distribution at the site is bimodal with a broad mode (peak center = 0.685; half-width = 0.521) attributed to a wide range of industrial/urban aerosols and a narrow mode (peak center = 0.338; half-width = 0.136) attributed to fine dust aerosols, while the dry-season distribution is mono-modal, attributed to a fairly broad dust/biomass burning aerosol mixture (peak center = 0.484; half-width = 0.394). These are corroborated with 7-day back trajectories calculated for core wet- and dry-season months over 2 years indicating mainly high altitude maritime and continental air masses in the wet season and lower altitude Sahara and Sudanian air masses in the dry season. Comparison of inter-annual rainfall and FMF trends indicates coherence of intensifying rainfall in traditional dry-season months (December, January, and February) with decreasing FMF distribution means and increasing FMF distribution widths which are consistent with reducing dust and biomass burning aerosols and growing industrial and urban aerosol sources.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8

Source: Nigerian Meteorological Agency (NIMET) real-time rainfall gauge measurements

Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13

Similar content being viewed by others

References

  • Akoshile CO, Ajibola TB, Falaiye OA et al (2016) A BSRN Station in a developing country: need, challenge, effort and progress. In: 14th BSRN Workshop, April 26–29, 2016, Canberra, Australia

  • Andrade-Filho VS, Artaxo P, Hacon S et al (2013) Aerosols from biomass burning and respiratory diseases in children, Manaus, Northern Brazil. Rev Saúde Pública 47(2):1–8. https://doi.org/10.1590/S0034-8910.2013047004011

  • Ben-Ami Y, Koren I, Rudich Y et al (2010) Transport of North African dust from the Bodele depression to the Amazon Basin: a case study. Atmos Chem Phys 10:7533–7544

    Article  Google Scholar 

  • Bergstrom RW, Pilewskie P, Russell PB, Redemann J, Bond TC, Quinn PK, Sierau B (2007) Spectral absorption properties of atmospheric aerosols. Atmos Chem Phys 7:5937–5943

    Article  Google Scholar 

  • Boucher O, Randall D, Artaxo P et al (2013) Clouds and aerosols. In: Stocker TF, Qin D, Plattner G-K, Tignor M, Allen SK, Doschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Climate change 2013; the physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, pp 571–657. https://doi.org/10.1017/cbo9781107415324.016

    Google Scholar 

  • Cesnulyte V, Lindfors AV, Pitkänen MRA et al (2014) Comparing ECMWF AOD with AERONET observations at visible and UV wavelengths. Atmos Chem Phys 14:593–608

    Article  Google Scholar 

  • Charlson RJ, Schwartz SE, Hales JM et al (1992) Climate forcing by anthropogenic aerosols. Science 255(5043):423–430. https://doi.org/10.1126/science.255.5043.423

    Article  Google Scholar 

  • Chung CE, Chu J-E, Lee Y et al (2016) Global fine-mode aerosol radiative effect, as constrained by comprehensive observations. Atmos Chem Phys 16:8071–8080

    Article  Google Scholar 

  • Cowie SM, Knippert P, Marsham JH (2014) A climatology of dust emission events from northern Africa using long-term surface observations. Atmos Chem Phys 14:8579–8597

    Article  Google Scholar 

  • Dee DP, Uppala SM, Simmons AJ et al (2011) The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Q J R Meteorol Soc 137:553–597

    Article  Google Scholar 

  • Demographia (2017) Demographia World Urban Areas, 13th Annual Edition: 04

  • Dike VN, Shimizu MH, Diallo M, Lin Z, Nwofor OK, Chineke TC et al (2014) Modeling present and future African climate using CMIP5 scenarios in HadGEM2-ES. Int J Climatol. https://doi.org/10.1002/joc.4084

    Google Scholar 

  • Dong B, Sutton R (2015) Dominant role of greenhouse-gas forcing in the recovery of Sahel rainfall. Nat Clim Change 5:757–760

    Article  Google Scholar 

  • Eck TF, Holben BN, Sinyuk A et al (2010) Climatological aspects of the optical properties of fine/coarse mode aerosol mixtures. J Geophys Res 115:D1920. https://doi.org/10.1029/2010jd014002

    Article  Google Scholar 

  • Ezeh GC, Obioh IB, Asubiojo OI et al (2014) Elemental compositions of PM10-2.5 and PM2.5 aerosols of a Nigerian urban city using ion beam analytical techniques. Nucl Instrum Methods Phys Res B 334:28–33

    Article  Google Scholar 

  • Fawole O, Cai X, Levine J et al (2016) Detection of gas flaring signature in the AERONET optical properties of aerosols at a tropical station in West Africa. J Geophys Res Atmos 121(24):14513–14524

    Article  Google Scholar 

  • Flaounas E, Kotroni V, Lagouvardos K et al (2016) Assessing atmospheric dust modeling performance of WRF-Chem: over the semi-arid and arid regions around the Mediterranean. Atmos Chem Phys. https://doi.org/10.5194/acp-2016-307

    Google Scholar 

  • Fontaine B, Gaetani M, Ullman A (2011) Time evolution of observed July–September sea surface temperature-Sahel climate teleconnection with removed quasi-global effect (1900–2008). J Geophys Res 116:D041105. https://doi.org/10.1029/2010JD014843

    Google Scholar 

  • Giannini A, Saravanan R, Chang P (2003) Oceanic forcing of Sahel rainfall on interannual to interdecadal time scales. Science 302(5647):1027–1030. https://doi.org/10.1126/science.1089357

    Article  Google Scholar 

  • Giles DM, Holben BN, Eck TF et al (2012) An analysis of AERONET aerosol absorption properties and classifications representative of aerosol source regions. J Geophys Res 117:D17203. https://doi.org/10.1029/2012JD018127,2012

    Article  Google Scholar 

  • Holben BN, Eck TI, Slutsker I et al (1998) AERONET—a federated instrument network and data archive for aerosol characteristics. Remote Sens Environ 66:1–16

    Article  Google Scholar 

  • Holben BN, Tanre D, Smirnov A et al (2001) An emerging ground-based aerosol climatology: aerosol optical depth from AERONET 106. J Geophys Res 106(D11):12067–12097

    Article  Google Scholar 

  • Huang H, Thomas GE, Grainger RG (2010) Relationship between wind speed and aerosol optical depth over remote ocean. Atmos Chem Phys 10:5943–5950. https://doi.org/10.5194/acp-10-5943-2010

    Article  Google Scholar 

  • Huete A, Justice C, van Leeuwen W (1999) MODIS vegetation index (MOD 13) algorithm, theoretical basis, document version 3. University of Virginia Department of Environmental Sciences, Charlottesville, p 22903

    Google Scholar 

  • Hui WJ, Cook BI, Jose SR, Fuentes D, D’Odorico P (2008) Dust-rainfall feedbacks in the West African Sahel. Water Resour Res 44:W05202. https://doi.org/10.1029/2008wr006885,2008

    Article  Google Scholar 

  • Husar RB (2005) The emergence of the bimodal distribution concept. In: Sem GJ, Boulaud D, Brimblecombe P, Ensor ES, Gentry JW, Marijnissen JCM, Preining O (eds) History & reviews of aerosol science. American Association for Aerosol Research, Reston

  • Kaskaoutis DG, Kambezidis HD (2006) Investigation into the wavelength dependence of the aerosol optical depth in the Athens area. Q J R Meteorol Soc 132:2217–2234. https://doi.org/10.1256/qj.05.183

    Article  Google Scholar 

  • Kaskaoutis DG, Kambezidis HD, Hatzianastassiou N et al (2007) Aerosol climatology: dependence of the Angstrom exponent on wavelength over four AERONET sites. Atmos Chem Phys Discuss 7:7347–7397

    Article  Google Scholar 

  • Lee C-G, Yuan C-S, Chang J-C et al (2005) Effects of aerosol species on atmospheric visibility in Kaohsiung City, Taiwan. J Air Waste Manage Assoc 55:1031–1041

    Article  Google Scholar 

  • Lesins G, Lohmann U (2003) GCM aerosol radiative effects using geographically varying aerosol sizes deduced from AERONET measurements. J Atmos Sci 60:2747–2763

    Article  Google Scholar 

  • Liousse C, Guillaume B, Gregoire JM et al (2010) Updated African biomass burning emission inventories in the framework of the AMMA-IDAF program with an evaluation of combustion aerosols. Atmos Chem Phys 10:9631–9646

    Article  Google Scholar 

  • Manish K, Raju MP, Banerjee T (2017) Impact of drought and normal monsoon scenarios on aerosol induced radiative forcing and atmospheric heating in Varanasi over middle Indo-Gangetic Plain. J Aerosol Sci 113:95–107

    Article  Google Scholar 

  • Myhre G, Hoyle CR, Berglen TF et al (2008) Modeling of the solar radiative impact of biomass burning aerosols during the Dust and Biomass-burning Experiment (DABEX). J Geophys Res 113:D00c16. https://doi.org/10.1029/2008jd009857

    Article  Google Scholar 

  • Myhre G, Shindell D, Bréon F-M et al (2013) Anthropogenic and natural radiative forcing. In: Stocker TF, Qin D, Plattner G-K, Tignor M, Allen SK, Boschung J, Nauels A, Xia Y, Bex V, Midgley PM (eds) Climate change 2013: the physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge

    Google Scholar 

  • Nicholson SE (2013) The West African Sahel: a review of recent studies on the rainfall regime and its interannual variability. ISRN Meteorol. https://doi.org/10.1155/2013/453521 (Article ID 453521)

    Google Scholar 

  • Nwofor OK, Chineke TC, Pinker RT (2007) Seasonal characteristics of spectral aerosol optical properties at a sub-Saharan site. Atmos Res 85:38–51

    Article  Google Scholar 

  • O’Neill NT, Dubovik O, Eck T (2001) Modified Angstrom Exponent for the characterization of sub-micrometer aerosols. Appl Opt 40:2368–2375

    Article  Google Scholar 

  • O’Neill NT, Eck TF, Smirnov A et al (2003) Spectral discrimination of coarse and fine mode optical depth. J Geophys Res 108(D17):4559–4573. https://doi.org/10.1029/2002JD002975

    Article  Google Scholar 

  • Onyeuwaoma ND, Nwofor OK, Chineke TC et al (2015) Implications of MODIS impression of aerosol loading over urban and rural settlements in Nigeria: possible links to energy consumption patterns in the country. Atmos Pollut Res 6:484–494

    Article  Google Scholar 

  • Pandithurai G, Pinker RT, Dubovik O, Holben BN, Aro TO (2001) Remote sensing of aerosol optical characteristics in sub-Sahel West Africa. J Geophys Res 106(D22):28347–28356

    Article  Google Scholar 

  • Park J, Bader J, Matei D (2016) Anthropogenic Mediterranean warming; essential driver for present and future Sahel rainfall. Nat Clim Change. https://doi.org/10.1038/nclimate3065

    Google Scholar 

  • Pinker RT, Idemudia G, Aro TO (1994) Characteristic aerosol optical depths during the Harmattan season on Sahara Africa. Geophys Res Lett 21(8):685–688

    Article  Google Scholar 

  • Pinker RT, Liu H, Osborne SR (2010) Radiative affects of aerosols in sub-Sahel Africa: dust and biomass burning. J Geophys Res 115:D15205. https://doi.org/10.1029/2009JD013335

    Article  Google Scholar 

  • Raman A, Arellano AF Jr, Sorooshian A (2016) Decreasing aerosol loading in the North American monsoon region. Atmosphere. https://doi.org/10.3390/atmos7020024

    Google Scholar 

  • Remer LA, Chin M, DeCola P et al (2009) Executive Summary. In: Chin M, Kahn RA, Schwartz SE (eds) Atmospheric aerosol properties and climate impacts, a report by the US Climate Change Science Program and the Subcommittee on Global Change Research. National Aeronautics and Space Administration, Washington, DC

  • Roberts G, Wooster MJ, Lagoudakis E (2009) Annual and diurnal African biomass burning temporal dynamics. Biogeosciences 6:849–866

    Article  Google Scholar 

  • Rolph G, Stein A, Stunder B (2017) Real-time environmental applications and display sYstem: READY. environmental modeling and software. 95: 210–228. https://doi.org/10.1016/j.envsoft.2017.06.025. http://www.sciencedirect.com/science/article/pii/S1364815217302360

  • Salack S, Klein C, Giannini A et al (2016) Global warming induced hybrid rainy seasons in the Sahel. Environ Res Lett 11:104008. https://doi.org/10.1088/1748-9326/11/10/104008

    Article  Google Scholar 

  • Schneider U, Becker A, Finger P, Meyer-Christoffer A, Rudolf B, Ziese M (2011) GPCC full data reanalysis version 6.0 at 0.5°: monthly land-surface precipitation from rain-gauges built on GTS-based and historic data. https://doi.org/10.5676/dwd_gpcc/fd_m_v7_050

  • Schuster GL, Dubovik O, Holben B (2006) Angstrom exponent and bimodal aerosol size distribution. J Geophys Res 111:D07207

    Article  Google Scholar 

  • Smirnov A, Holben BN, Eck TF et al (2000) Cloud screening and quality control algorithm for the AERONET database. Remote Sens Environ 73:334–337

    Article  Google Scholar 

  • Smith DM, Booth BB, Dunstone NJ et al (2016) Role of volcanic and anthropogenic aerosols in the recent global surface warming slowdown. Nat Clim Change 6:936–940. https://doi.org/10.1038/nclimate3058

    Article  Google Scholar 

  • Soni K, Singh S, Bano T et al (2011) Wavelength dependence of the aerosol Angstrom exponent and its implications over Delhi, India. Aerosol Sci Technol 45(12):1488–1498

    Article  Google Scholar 

  • Stein AF, Draxler RR, Rolph GD, Stunder BJB, Cohen MD, Ngan F (2015) NOAA’s HYSPLIT atmospheric transport and dispersion modeling system. Bull Am Meteorol Soc 96:2059–2077. https://doi.org/10.1175/BAMS-D-14-00110.1

    Article  Google Scholar 

  • Sylla MB, Diallo I, Pal JS (2013) West African Monsoon in state-of-the-science regional climate models. In: Climate variability—regional and thematic patterns. http://www.intechopen.com/books/climate-variability-regionaland-thematic-patterns

  • Szopa S, Balkanski Y, Schulz M et al (2013) Aerosol and ozone changes as forcing for climate evolution between 1850 and 2100. Clim Dyn 40(9):2223–2250

    Article  Google Scholar 

  • Tie X, Wu D, Brasseur G (2009) Lung cancer mortality and exposure to atmospheric aerosol particles in Guangzhou. China Atmos Environ 43(14):2375–2377

    Article  Google Scholar 

  • Tiwari S, Mishra AK, Singh AK (2016) Aerosol climatology over the bay of Bengal and Arabian sea inferred from space-borne radiometers and lidar observations. Aerosol Air Qual Res 16:2855–2868

    Article  Google Scholar 

  • Vernier J-P, Fairlie TD, Natarajan M, Wienhld FG, Bian J, Martisnsson BG, Crumeyrolle S, Thomason LW, Bedka KM (2015) Increase in upper tropospheric and lower stratospheric aerosol levels and its potential connection with Asian monsoon. J Geophys Res Atmos 120:1608–1619. https://doi.org/10.1002/2014JD022372.l

    Article  Google Scholar 

  • Wang J, Zhao Q, Cui S et al (2012) Assessment of aerosol modes used in the MODIS ocean aerosol retrieval. J Atmos Sci 69:3595–3605

    Article  Google Scholar 

  • Zhang Y, Li Z, Qie L et al (2016) Retrieval of aerosol fine-mode fraction from intensity and polarization measurements by PARASOL over East Asia. Remote Sens 8(5):417. https://doi.org/10.3390/rs8050417

    Article  Google Scholar 

  • Zuluaga MD, Webster PJ, Hoyos CD et al (2012) Variability of aerosols in the tropical Atlantic Ocean relative to African Easterly Waves and their relationship with atmospheric and oceanic environments. J Geophys Res Atmos 117:D16207. https://doi.org/10.1029/2011JD017181

    Article  Google Scholar 

Download references

Acknowledgements

The authors are grateful to the Principal Investigators of the Sahel AERONET sites used in the study for the data and for maintaining the stations. The authors gratefully acknowledge the NOAA Air Resources Laboratory (ARL) for the provision of the HYSPLIT transport and dispersion model and/or READY website (http://www.ready.noaa.gov) used in this publication and other agencies whose data sets were employed. This study was undertaken during Okechukwu K. Nwofor’s stay at the International Center for Climate and Environment Sciences (ICCES), Institute of Atmospheric Physics (IAP), Chinese Academy of Science (CAS) in 2016 under the support of President’s International Fellowship Initiative (PIFI) from the Chinese Academy of Science. The support from the Chinese Academy of Sciences’ “The Belt and Road Initiatives” Program on International Cooperation (No. 134111KYSB20160010)is also appreciated. The authors thank the reviewers for their comments and suggestions which led to considerable improvement in the presentation of the ideas and results of this paper.

Author information

Authors and Affiliations

  1. Atmospheric Physics Group, Department of Physics and Industrial Physics, Imo State University, PMB 2000, Owerri, Nigeria

    Okechukwu K. Nwofor & Victor N. Dike

  2. International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China

    Victor N. Dike & Zhaohui Lin

  3. Energy, Climate and Environment Science Group, Imo State Polytechnic Umuagwo, Ohaji, PMB 1472, Owerri, Imo State, Nigeria

    Victor N. Dike

  4. Department of Atmospheric and Oceanic Science, University of Maryland, College Park, Maryland, USA

    Rachel T. Pinker

  5. Center for Basic Space Science (CBSS), National Space Research and Development Agency (NASRDA), Federal Ministry of Science and Technology, University of Nigeria, Nsukka, PMB 2022, Nsukka, Enugu State, Nigeria

    Nnaemeka D. Onyeuwaoma

Authors
  1. Okechukwu K. Nwofor
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Victor N. Dike
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Zhaohui Lin
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Rachel T. Pinker
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Nnaemeka D. Onyeuwaoma
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Okechukwu K. Nwofor.

Ethics declarations

Conflict of interest

There are no conflicts of interest declared.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Nwofor, O.K., Dike, V.N., Lin, Z. et al. Fine-Mode Aerosol Loading Over a Sub-Sahel Location and Its Relation with the West African Monsoon. Aerosol Sci Eng 2, 74–91 (2018). https://doi.org/10.1007/s41810-018-0024-6

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s41810-018-0024-6

Keywords

Search

Navigation