Dust-Storm Source Areas Determined by the Total Ozone Monitoring Spectrometer and Surface Observations

Washington, Richard; Todd, Martin C.; Middleton, Nick; Goudie, Andrew

doi:10.1111/1467-8306.9302003

Cited by 635 publications

(569 citation statements)

References 86 publications

(72 reference statements)

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“…The associated spatial pattern also shows reversed signs for the northern and southern hemispheres. The dust source regions [e.g., Washington et al, 2003], including North Africa (Sahara desert), Middle East, and Northeast China (Taklamakan desert) have the strongest signals in EOF 1. PC 2 also has an annual cycle but peaks at northern hemisphere autumn (September to November).…”

Section: Analysis Of Aod Datamentioning

confidence: 99%

Application of spectral analysis techniques in the intercomparison of aerosol data: 1. An EOF approach to analyze the spatial‐temporal variability of aerosol optical depth using multiple remote sensing data sets

Carlson

Lacis

2013

JGR Atmospheres

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Many remote sensing techniques and passive sensors have been developed to measure global aerosol properties. While instantaneous comparisons between pixel‐level data often reveal quantitative differences, here we use Empirical Orthogonal Function (EOF) analysis, also known as Principal Component Analysis, to demonstrate that satellite‐derived aerosol optical depth (AOD) data sets exhibit essentially the same spatial and temporal variability and are thus suitable for large‐scale studies. Analysis results show that the first four EOF modes of AOD account for the bulk of the variance and agree well across the four data sets used in this study (i.e., Aqua MODIS, Terra MODIS, MISR, and SeaWiFS). Only SeaWiFS data over land have slightly different EOF patterns. Globally, the first two EOF modes show annual cycles and are mainly related to Sahara dust in the northern hemisphere and biomass burning in the southern hemisphere, respectively. After removing the mean seasonal cycle from the data, major aerosol sources, including biomass burning in South America and dust in West Africa, are revealed in the dominant modes due to the different interannual variability of aerosol emissions. The enhancement of biomass burning associated with El Niño over Indonesia and central South America is also captured with the EOF technique.

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Section: Analysis Of Aod Datamentioning

confidence: 99%

Application of spectral analysis techniques in the intercomparison of aerosol data: 1. An EOF approach to analyze the spatial‐temporal variability of aerosol optical depth using multiple remote sensing data sets

Carlson

Lacis

2013

JGR Atmospheres

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“…The Bodélé Depression (north-central Africa) is Earth's most prolific dust producer and may be key component to the global radiative budget of the atmosphere as well as to long-range nutrient transport to the Amazon rainforest (e.g., Prospero et al, 2002;Washington et al, 2003;Giles, 2005;Goudie and Middleton, 2006;Warren et al, 2007;Bristow et al, 2009Bristow et al, , 2010Hudson-Edwards et al, 2014;Yu et al, 2015). The Bodélé dust-source region consists mainly of diatomaceous lake beds overridden by dunes and other aeolian deposits (e.g., Warren et al, 2007;Bristow et al, 2009), which are driven by dominant northeasterly winds (Washington and Todd, 2005;Washington et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Iron oxide minerals in dust-source sediments from the Bodélé Depression, Chad: Implications for radiative properties and Fe bioavailability of dust plumes from the Sahara

et al. 2016

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Atmospheric mineral dust can influence climate and biogeochemical cycles. An important component of mineral dust is ferric oxide minerals (hematite and goethite) which have been shown to influence strongly the optical properties of dust plumes and thus affect the radiative forcing of global dust. Here we report on the iron mineralogy of dust-source samples from the Bodélé Depression (Chad, north-central Africa), which is estimated to be Earth's most prolific dust producer and may be a key contributor to the global radiative budget of the atmosphere as well as to long-range nutrient transport to the Amazon Basin. By using a combination of magnetic property measurements, Mössbauer spectroscopy, reflectance spectroscopy, chemical analysis, and scanning electron microscopy, we document the abundance and relative amounts of goethite, hematite, and magnetite in dust-source samples from the Bodélé Depression. The partition between hematite and goethite is important to know to improve models for the radiative effects of ferric oxide minerals in mineral dust aerosols. The combination of methods shows (1) the dominance of goethite over hematite in the source sediments, (2) the abundance and occurrences of their nanosize components, and (3) the ubiquity of magnetite, albeit in small amounts. Dominant goethite and subordinate hematite together compose about 2% of yellowreddish dust-source sediments from the Bodélé Depression and contribute strongly to diminution of reflectance in bulk samples. These observations imply that dust plumes from the Bodélé Depression that are derived from goethite-dominated sediments strongly absorb solar radiation. The presence of ubiquitous magnetite (0.002-0.57 wt. %) is also noteworthy for its potentially higher solubility relative to ferric oxide and for its small sizes, including PM<0.1m. For all examined samples, the average iron apportionment is estimated at about 33% in ferric oxide minerals, 1.4 % in magnetite, and 65% in ferric silicates. Structural iron in clay minerals may account for much of the iron in the ferric silicates. We estimate that the mean ferric oxides flux exported from the Bodélé Depression is 0.9 Tg/yr with greater than 50% exported as ferric oxide nanoparticles (<0.1m). The high surface-to-volume ratios of ferric oxide nanoparticles once entrained into dust plumes may facilitate increased atmospheric chemical and physical processing and affect iron solubility and bioavailability to marine and terrestrial ecosystems.

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“…However, studies addressing these problems all agree that North Africa is the main source area (over 50 %) (see, e.g. Ginoux et al 2004;Washington et al 2003). Regions of the world in the path of dust-laden wind record increased ambient air dust concentrations that are temporally associated with deteriorations in air quality and the strong possibility of negative impacts on human health (Engelstaedter et al 2006;Kellogg et al 2004;Ozer et al 2005).…”

Section: Introductionmentioning

confidence: 99%

“…The ultimate aim was to investigate the need to undertake such studies in West Africa, near the Sahara, the most important global dust source (e.g. Engelstaedter et al 2006;Washington et al 2003). Due to the large quantity of PM emanating from this source (more than 50 % of the total emitted into the atmosphere), the potential risk to health is higher for populations in West Africa.…”

Section: Introductionmentioning

confidence: 99%

Desert dust impacts on human health: an alarming worldwide reality and a need for studies in West Africa

et al. 2012

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High desert dust concentrations raise concerns about adverse health effects on human populations. Based on a systematic literature review, this paper aims to learn more about the relationship between desert dust and human health in the world and to analyse the place of West Africa as a study area of interest. Papers focussing on the potential relationship between dust and health and showing quantitative analyses, published between January 1999 and September 2011, were identified using the ISI Web of Knowledge database (N050). A number of adverse health effects, including respiratory, cardiovascular and cardiopulmonary diseases, are associated with dust. This survey highlights obvious dust impacts on human health independently of the study area, health outcomes and method. Moreover, it reveals an imbalance between the areas most exposed to dust and the areas most studied in terms of health effects. None of these studies has been conducted in West Africa, despite the proximity of the Sahara, which produces about half of the yearly global mineral dust. In view of the alarming results in many parts of the world (Asia, Europe, America), this paper concludes by stressing the importance of carrying out impact studies of Saharan dust in West Africa, where dust events are more frequent and intense than anywhere else.

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Dust-Storm Source Areas Determined by the Total Ozone Monitoring Spectrometer and Surface Observations

Cited by 635 publications

References 86 publications

Application of spectral analysis techniques in the intercomparison of aerosol data: 1. An EOF approach to analyze the spatial‐temporal variability of aerosol optical depth using multiple remote sensing data sets

Application of spectral analysis techniques in the intercomparison of aerosol data: 1. An EOF approach to analyze the spatial‐temporal variability of aerosol optical depth using multiple remote sensing data sets

Iron oxide minerals in dust-source sediments from the Bodélé Depression, Chad: Implications for radiative properties and Fe bioavailability of dust plumes from the Sahara

Desert dust impacts on human health: an alarming worldwide reality and a need for studies in West Africa

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