E&ES > Geography > Research projects > Atmospheric and Aeolian Processes
Atmospheric and Aeolian Processes
| Researcher: | Dr. Dirk Goossens |
Keywords:
| wind, aerosol, aeolian processes, dust, desert, air pollution |
Research abstract:
 Research activities focus on atmospheric processes, with a strong link to various environmental disciplines including geomorphology, meteorology, air pollution and desert science. Central research topic is the dynamics of natural aerosols. The work includes theoretical modelling (development of dust deposition models), physical simulations (experimental studies in an aeolian dust wind tunnel), field experiments (in various regions in Europe, the Middle East, Africa and North America), and monitoring of aerosol dynamics in various ecosystems in Europe, the Middle East and the USA (agricultural landscapes, drift-sand landscapes, desert areas). Themes currently under study are: the quantification of aeolian erosion, aeolian transport and aeolian deposition in various climates; the effect of landforms and complex topography on the dynamics of aerosols; short-term and long-term effects of aeolian dust deposition and accumulation on the desert ecosystem; the effect of aerosols on the performance of photovoltaic and thermic solar collectors; monitoring the emission, airborne concentration, transport and deposition of natural aerosols in dry and wet ecosystems; quantifying dust emissions caused by off-road driving, the effect of rock fragments and stone layers on the deposition and accumulation of atmospheric dust in deserts; the study of aeolian landforms; and the development and calibration of aerosol measuring equipment. |
The mechanics of dust erosion, dust transport and dust deposition is studied using physical simulations in a dust wind tunnel. The picture shows part of the wind tunnel's test channel.
The effects topography exerts on dust erosion and dust deposition is investigated by simulating these processes on topographic scale models (in the wind tunnel) and measuring the patterns at full scale (during field measurements). The picture shows a deposition pattern on one of the scale models.
Dust accumulating on solar collectors’ panels and mirrors reduces the collectors’ performance. The picture shows a scale model of a thermic collector, tested in Leuven’s dust wind tunnel.
Rock fragments strongly affect the patterns of dust deposition. The upper photo shows the deposition pattern around a semicircular rock fragment resting on the surface. The lower photo shows the deposition pattern after the same rock fragment has become embedded in the surface (75% embedding). Note the large differences in the patterns.
Wind erosion is a major process in North-European lowland plains. The picture shows sand and dust being transported during a wind erosion event on an agricultural field in northern Germany. Events like the one shown in the picture are monitored using specially designed sand and dust collectors.
Aeolian dust station on an agricultural field in northern Germany.
Left: dust mast with MDCO dust collectors
Right: meteorological mast with sensors for wind speed, wind direction, temperature, radiation and precipitation
Measuring aeolian sediment dynamics on field plots in a drift-sand area at Kootwijkerzand, the Netherlands. The photo shows various instruments: erosion pins (for measuring temporal and spatial changes of the field level), MWAC catchers (for measuring the horizontal sediment flux) and MDCO collectors (for measuring deposition and accumulation).
Various aeolian dust samplers have been tested and calibrated in the Leuven wind tunnel. These include samplers for measuring dust transport as well as deposition. Two examples calibrated in the Leuven tunnel are shown below.
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Left: BSNE sampler |
Right: Inverted frisbee filled with marbles and surrounded by an aerodynamic flow deflector ring |
Erosion, transport and deposition of atmospheric dust are important processes on other celestial bodies of the solar system such as Mars, Venus, Titan and Triton. Simulations of aeolian structures on Mars and Venus have been performed in the Leuven wind tunnel. Two examples are shown below.
Trilobate dust accumulation streak downwind of a 2-km crater NW of Memnonia (Mars)
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A: Mariner-9 image |
B: wind tunnel simulation |
Dust sedimentation parabola NW of Alpha Regio (Venus)
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A: Magellan image |
B: wind tunnel simulation |
Dust emission by off-road driving is studied for a large number of soils and for various types of vehicles. The effects off-road driving has on the topsoil are studied as well. The photo shows an experiment with a quad. Dust is collected at various elevations to sample the entire dust cloud.