Saharan calima dust contains FeO in addition to Fe2O3.
the verdict
INSUFFICIENT LEANING
refutedsupported
the weight of evidence
2 sources for · 0 against
The retrieved literature references iron oxide phases such as hematite (Fe2O3) in Saharan and atmospheric dust, but does not provide evidence supporting the presence of FeO.
Abstract. In aerosol chamber experiments optical properties of airborne mineral dust samples of defined size distribution were measured. Extinction coefficients (bext) and mass specific extinction cross sections (σext) were determined for Saharan dust samples from different locations. The results for σext were not very sensitive to the type of dust and varied at λ=550 nm between 3.3±0.4 m2 g−1 and 3.7±0.4 m2 g−1. The absorption coefficients (babs) and mass specific absorption cross sections (σabs) were determined with a novel multi-wavelength photo-acoustic absorption spectrometer (PAS). Between λ=266 nm and λ=1064 nm the derived single scattering albedos (SSA) ranged from 0.63±0.04 to 0.99±0.01. Additionally the chemical and mineralogical composition of the dust samples was analysed with special regard to the iron oxide phases hematite and goethite. At λ=266 nm the mineral dust sample without any detectable iron oxides showed a significantly higher SSA compared to the sample with a hematite content of 0.6 wt-%.
Inferring iron-oxide species content in atmospheric mineral dust from DSCOVR EPIC observations - NASA Technical Reports Server (NTRS)
NTRS NTRS - NASA Technical Reports Server Search more_vert Collections About News Help Login Press Enter or click the Search button to begin your search. Back to Results Inferring iron-oxide species content in atmospheric mineral dust from DSCOVR EPIC observations The iron-oxide content of dust in the atmosphere and most notably its apportionment between hematite (α-Fe2O3) and goethite (α-FeOOH) are key determinants in quantifying dust’s light absorption, its top of atmosphere UV radiances used for dust monitoring, and ultimately shortwave dust direct radiative effects (DRE). Hematite and goethite column mass concentrations and iron-oxide mass fractions of total dust mass concentration were retrieved from the DeepSpace Climate Observatory (DSCOVR) Earth Polychromatic Imaging Camera (EPIC) measurements in the ultraviolet–visible (UV–Vis) channels. The retrievals were performed for dust-identified aerosol plumes over land using aerosol optical depth (AOD) and spectral imaginary refractive index provided by the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm over six continental regions (North America, North Africa, West Asia, Central Asia, EastAsia, and Australia). The dust particles are represented as an internal mixture of non-absorbing host and absorbing hematite and goethite. We use the Maxwell–Garnett effective medium approximation with carefully selected complex refractive indices of hematite and goethite that produce mass fractions of iron oxides species consistent with in situ values found in the literature to derive the hematite and goethite volumetric/mass concentrations from MAIAC EPIC products. We compared the retrieved hematite and goethite concentrations with in situ dust aerosol mineralogical content measurements, as well as with published data. Our data display variations within the published range
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