Airborne dust collected at Barbados

Delany, Audrey C.; Parkin, David; Griffin, John J.; Goldberg, Edward D.; Reimann, Bernhard E. F.

doi:10.1016/s0016-7037(67)80037-1

Cited by 284 publications

(113 citation statements)

References 6 publications

Supporting

Mentioning

108

Contrasting

Order By: Relevance

“…In this respect, they are in accordance with previously published papers for dust collected in Africa (Kandler et al, 2009) or after long-range transport (Delany et al, 1967;Kiefert et al, 1996;Glaccum and Prospero, 1980;Caquineau et al, 2002). These measurements, however, tend to indicate that the clay fraction accounts for ∼ 60-70 % of the dust weight, whereas our measurements suggest higher values (80-90 %).…”

Section: Comparison With Other Data Setssupporting

confidence: 93%

Mapping the physico-chemical properties of mineral dust in western Africa: mineralogical composition

et al. 2014

View full text Add to dashboard Cite

Abstract. In the last few years, several ground-based and airborne field campaigns have allowed the exploration of the properties and impacts of mineral dust in western Africa, one of the major emission and transport areas worldwide. In this paper, we explore the synthesis of these observations to provide a large-scale quantitative view of the mineralogical composition and its variability according to source region and time after transport.This work reveals that mineral dust in western Africa is a mixture of clays, quartz, iron and titanium oxides, representing at least 92 % of the dust mass. Calcite ranged between 0.3 and 8.4 % of the dust mass, depending on the origin. Our data do not show a systematic dependence of the dust mineralogical composition on origin; this is to be the case as, in most of the instances, the data represent the composition of the atmospheric burden after 1-2 days after emission, when air masses mix and give rise to a more uniform dust load. This has implications for the representation of the mineral dust composition in regional and global circulation models and in satellite retrievals.Iron oxides account for 58 ± 7 % of the mass of elemental Fe and for between 2 and 5 % of the dust mass. Most of them are composed of goethite, representing between 52 and 78 % of the iron oxide mass. We estimate that titanium oxides account for 1-2 % of the dust mass, depending on whether the dust is of Saharan or Sahelian origin.The mineralogical composition is a critical parameter for estimating the radiative and biogeochemical impact of mineral dust. The results regarding dust composition have been used to estimate the optical properties as well as the iron fractional solubility of Saharan and Sahelian dust.Data presented in this paper are provided in numerical form upon email request while they are being turned into a public database, the Dust-Mapped Archived Properties (DUST-MAP), which is an open repository for compositional data from other source regions in Africa and worldwide.

show abstract

Section: Comparison With Other Data Setssupporting

confidence: 93%

Mapping the physico-chemical properties of mineral dust in western Africa: mineralogical composition

et al. 2014

View full text Add to dashboard Cite

show abstract

“…In addition, Lohmann and Diehl (2006) found that there was a strong sensitivity to dust type, using parameterisations based upon experimental data of freezing due to montmorillonite and kaolinite. Although montmorillonite and kaolinite are both present in the atmosphere, illite has often been observed to be the most abundant airborne clay mineral (Chester et al, 1972;Glaccum and Prospero, 1980;Delany et al, 1967;Arnold et al, 1998). This is illustrated in Fig.…”

Section: S L Broadley Et Al: Immersion Mode Heterogeneous Ice Nuclmentioning

confidence: 98%

Immersion mode heterogeneous ice nucleation by an illite rich powder representative of atmospheric mineral dust

et al. 2012

View full text Add to dashboard Cite

Abstract. Atmospheric dust rich in illite is transported globally from arid regions and impacts cloud properties through the nucleation of ice. We present measurements of ice nucleation in water droplets containing known quantities of an illite rich powder under atmospherically relevant conditions. The illite rich powder used here, NX illite, has a similar mineralogical composition to atmospheric mineral dust sampled in remote locations, i.e. dust which has been subject to long range transport, cloud processing and sedimentation. Arizona Test Dust, which is used in other ice nucleation studies as a model atmospheric dust, has a significantly different mineralogical composition and we suggest that NX illite is a better surrogate of natural atmospheric dust.Using optical microscopy, heterogeneous nucleation in the immersion mode by NX illite was observed to occur dominantly between 246 K and the homogeneous freezing limit. In general, higher freezing temperatures were observed when larger surface areas of NX illite were present within the drops. Homogenous nucleation was observed to occur in droplets containing low surface areas of NX illite. We show that NX illite exhibits strong particle to particle variability in terms of ice nucleating ability, with ∼1 in 10 5 particles dominating ice nucleation when high surface areas were present. In fact, this work suggests that the bulk of atmospheric mineral dust particles may be less efficient at nucleating ice than assumed in current model parameterisations.For droplets containing ≤2×10 −6 cm 2 of NX illite, freezing temperatures did not noticeably change when the cooling rate was varied by an order of magnitude. The data obtained during cooling experiments (surface area ≤2×10 −6 cm 2 ) is shown to be inconsistent with the single component stochastic model, but is well described by the singular model (n s (236.2 K≤T ≤247.5 K) = exp(6.53043×10 4 − 8.2153088. However, droplets continued to freeze when the temperature was held constant, which is inconsistent with the time independent singular model. We show that this apparent discrepancy can be resolved using a multiple component stochastic model in which it is assumed that there are many types of nucleation sites, each with a unique temperature dependent nucleation coefficient. Cooling rate independence can be achieved with this time dependent model if the nucleation rate coefficients increase very rapidly with decreasing temperature, thus reconciling our measurement of nucleation at constant temperature with the cooling rate independence.

show abstract

“…Potassium and its main mineralogical carrier illite are frequently used to infer the supply of terrigenous material to marine sediments (e.g., Fütterer, 1983;Sirocko et al, 2000;Yarincik et al, 2000), for climatic (arid/humid) changes of the source region (Schneider et al, 1997;Kuhlmann et al, 2004) and for identification of source regions of aeolian dust (Delany et al, 1967;Caquineau et al, 1998;Goudie and Middleton, 2001;Caquineau et al, 2002;Stuut et al, 2005). In the investigated area near the coast of NW Africa river discharge has to be considered as a transport process of terrigenous material as described before.…”

Section: Potassiummentioning

confidence: 99%

Geochemical distribution patterns as indicators for productivity and terrigenous input off NW Africa

Plewa

Meggers

Kuhlmann

et al. 2012

Deep Sea Research Part I: Oceanographic Research Papers

View full text Add to dashboard Cite

a b s t r a c tOne hundred and twenty-eight surface-sediment samples collected off North-West Africa were studied geochemically to detect the expressions of different meridional climate regimes and zonal productivity gradients in the surface sediments. This geochemical multi-tracer approach, coupled with additional information on the bulk carbonate and TOC contents makes it possible to characterise the sedimentological regime in detail. Typical terrigenous elements like Al, K and Fe mirror the importance of the humid (fluvial) influence in the north of the study area and the dominance of aeolian input in the south. Furthermore, the distributions of Ti and Fe in the surface sediments serve as tracers for the supply of eolian volcanic material from the Canary Islands. The spatial variability of the TOC contents in the surface sediments closely follows the ocean surface productivity patterns, whereas the CaCO 3 contents are mainly controlled by dilution with terrigenous matter. The potential productivity proxy Ba is not a reliable tracer for productivity in this region, since it is mainly supplied by terrigenous input (coupled with aluminosilicates).

show abstract

Airborne dust collected at Barbados

Cited by 284 publications

References 6 publications

Mapping the physico-chemical properties of mineral dust in western Africa: mineralogical composition

Mapping the physico-chemical properties of mineral dust in western Africa: mineralogical composition

Immersion mode heterogeneous ice nucleation by an illite rich powder representative of atmospheric mineral dust

Geochemical distribution patterns as indicators for productivity and terrigenous input off NW Africa

Contact Info

Product

Resources

About