Predictions for particle deposition on natural waters

Slinn, S.A.; Slinn, W.G.N.

doi:10.1016/0004-6981(80)90032-3

Cited by 585 publications

(391 citation statements)

References 8 publications

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“…Suppose also that the grain size distribution is given in Table 1b (the data refer to a sample collected in Niger in 2005; the values are typical for mineral dust near a desert surface). If we take the mean diameter of each grain size class when calculating the deposition velocities then the v d values are those shown in Table 1c (we used Slinn and Slinn's [1980] model, which accounts for the particle density, the wind velocity and the friction velocity; see Appendix A for the formula). With these data, deposition can be calculated; see Table 1d.…”

Section: Interpretation and Discussionmentioning

confidence: 99%

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Relationships between horizontal transport flux and vertical deposition flux during dry deposition of atmospheric dust particles

Goossens

2008

J. Geophys. Res.

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[1] Wind tunnel experiments were conducted to investigate the relationships between vertically settling dust and the horizontal dust flow from which the particles originate. The study primarily focused on the grain size characteristics and on the horizontal and vertical sediment fluxes. Simultaneous samplings of vertical deposition flux and horizontal transport flux were carried out at an almost identical altimetric level (a very narrow layer immediately above a water surface generating no resuspension). This made it possible to relate deposition flux to the horizontal transport flux and to study how deposition alters the sedimentological characteristics of horizontally moving dust. The use of water as a deposition surface implied that the dust was subjected to some degree of dispersion after the settling. This restricted the analysis to grains >10 mm, but the trends for grains <10 mm were easy to reconstruct. The experiments show that deposited dust is generally coarser than the parent dust from which it originates but only for friction velocities below 0.34 m s À1 . For higher wind speeds the median grain diameter of settling dust does not differ from that of the parent dust. Similar observations were made for the horizontal and vertical dust fluxes. At a constant horizontal transport flux (Fh) vertical deposition flux (Fs) drops with wind speed; however, from the same critical friction velocity of 0.34 m s À1 the ratio Fs/Fh remains constant. It was also found that the relationships between Fh and Fs depend on the grain size of the particles but only for sufficiently fine particles. Particles >50 mm no longer affect these relationships. Vertical mixing created by the turbulent nature of the flow strongly affects deposition of atmospheric dust. Mixing significantly hampers deposition of the grains, especially the small ones. The wind tunnel experiments allowed the magnitude of the effect mixing exerts on deposition to be calculated. For coarse grains the effect is small, but for fine grains mixing may hamper deposition by several dozen per cent. Theoretical dust deposition models should thus consider vertical mixing or otherwise include it in the numerical value of the velocity of deposition v d . Citation: Goossens, D. (2008), Relationships between horizontal transport flux and vertical deposition flux during dry deposition of atmospheric dust particles,

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Section: Interpretation and Discussionmentioning

confidence: 99%

“…[47] The formula for v d in Slinn and Slinn's [1980] model is as follows: /n); n kinematic viscosity of air; D Brownian or molecular diffusivity; t particle relaxation time.…”

Section: Discussionmentioning

confidence: 99%

Relationships between horizontal transport flux and vertical deposition flux during dry deposition of atmospheric dust particles

Goossens

2008

J. Geophys. Res.

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“…For this reason, we adopted the ±50% uncertainty associated with the average values assumed by Gao (2002). We acknowledge that higher uncertainty levels with a range of 0.001 -2 cm s -1 are possible as suggested by other researchers (Slinn and Slinn, 1980;Williams, 1982;Clark and Kremer, 2005). These deposition velocities were previously used within the same study region.…”

Section: Atmospheric Flux Calculationsmentioning

confidence: 99%

Atmospheric nitrogen deposition to the Mullica River-Great Bay Estuary

Ayars¹,

Gao

2007

Marine Environmental Research

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“…The zone (latitude up to 5 • N) and the period of interest (early March 1999) are dry enough to state that wet processes can be neglected. Moreover, aerosols observed over the ocean during INDOEX mainly exhibit a diameter smaller than 2 µm (De Reus et al, 2001), characterized by weak sedimentation velocities (Slinn and Slinn, 1980) Finally, since we mainly study the transport of tracers over stable oceanic areas or in altitude, turbulent dry deposition at the surface is considered to be negligible, as well.…”

Section: Tracer Simulationsmentioning

confidence: 99%

The structure of the haze plume over the Indian Ocean during INDOEX: tracer simulations and LIDAR observations

et al. 2006

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Abstract. Three-dimensional, nested tracer simulations of a pollution plume originating from the Indian sub-continent over the Indian Ocean, in the framework of the Indian Ocean Experiment (INDOEX), between 5 and 9 March 1999, were performed with the Regional Atmospheric Modeling System (RAMS), to provide insight into the transport patterns of the pollutants, as well as to investigate the dynamical mechanisms controlling the vertical structure of the plume and its evolution in the vicinity of the Maldives Islands. Airborne and ground-based LIDAR observations of the structure of the haze plume made on 7 March 1999 were used to assess the quality of the simulations, as well as the impact of grid resolution on the vertical structure of the simulated plume. It is shown that, over the Arabian Sea, in the vicinity of the Maldives Islands, the pollutants composing the plume observed by the airborne LIDAR essentially originated from the city of Madras and that the vertical structure of the plume was controlled by the diurnal cycle of the continental boundary layer depth. A combination of tracer simulations and remote sensing observations (airborne LIDAR, ship-borne photometer, ground-based LIDAR in Goa) was used to analyse the diurnal evolution of the haze plume over the sea. We find evidence that the sea breeze circulation and orographic lifting taking place in the southern part of the Indian sub-continent during the daytime play a crucial role in the modulation of the continental boundary layer depth, and in turn, the haze plume depth. The eastward shift of the subtropical high from central India to the Bay of Bengal after 6 March lead to an increase in the tracer concentrations simulated over the Arabian Sea, in the region of intensive observations north of the Maldives, as transport pathways form Hyderabad and Madras were modified significantly. The nesting of a high horizontal resolution Correspondence to: G. Forêt (foret@lisa.univ-paris12.fr) domain (5 km, with 39 vertical levels below 4000 m above mean seal level) allows for a better representation of local dynamics, the circulation of sea and mountains breezes, and therefore a noticeable improvement in the representation of the pollutants' plume in the simulation.

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Predictions for particle deposition on natural waters

Cited by 585 publications

References 8 publications

Relationships between horizontal transport flux and vertical deposition flux during dry deposition of atmospheric dust particles

Relationships between horizontal transport flux and vertical deposition flux during dry deposition of atmospheric dust particles

Atmospheric nitrogen deposition to the Mullica River-Great Bay Estuary

The structure of the haze plume over the Indian Ocean during INDOEX: tracer simulations and LIDAR observations

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