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Dust Events (dust + event)

Distribution by Scientific Domains

Earth and Environmental Science	100%

Selected Abstracts

The development of a new dust uplift scheme in the Met Office Unified ModelÔ

METEOROLOGICAL APPLICATIONS, Issue 4 2009
D. Ackerley
Abstract Aeolian mineral dust aerosol is an important consideration in the Earth's radiation budget as well as a source of nutrients to oceanic and land biota. The modelling of aeolian mineral dust has been improving consistently despite the relatively sparse observations to constrain them. This study documents the development of a new dust emissions scheme in the Met Office Unified ModelÔ (MetUM) based on the Dust Entrainment and Deposition (DEAD) module. Four separate case studies are used to test and constrain the model output. Initial testing was undertaken on a large dust event over North Africa in March 2006 with the model constrained using AERONET data. The second case study involved testing the capability of the model to represent dust events in the Middle East without being re-tuned from the March 2006 case in the Sahara. While the model is unable to capture some of the daytime variation in AERONET AOD there is good agreement between the model and observed dust events. In the final two case studies new observations from in situ aircraft data during the Dust Outflow and Deposition to the Ocean (DODO) campaigns in February and August 2006 were used. These recent observations provided further data on dust size distributions and vertical profiles to constrain the model. The modelled DODO cases were also compared to AERONET data to make sure the radiative properties of the dust were comparable to observations. Copyright © 2009 Royal Meteorological Society and Crown Copyright [source]

Effects of spatial variations in source areas upon dust concentration profiles during three wind erosion events in Australia

EARTH SURFACE PROCESSES AND LANDFORMS, Issue 10 2001
H. J. Butler
Abstract Dust storms are a major contributor to soil erosion in inland Australia, and the Simpson Desert,Channel Country region is one of the most active wind erosion regions. While information is available on wind erosion rates at the land-type level, little is known about the influence that spatial variations in the erodibility within a land type have on the resulting dust concentration profile. A Gaussian plume model, DSIS, is presented along with tower-based dust data, to describe the influence of different spatial combinations of dust source areas, during three dust events on the Diamantina River floodplain in Western Queensland, Australia. Copyright © 2001 John Wiley & Sons, Ltd. [source]

Suspended dust over southeastern Mediterranean and its relation to atmospheric circulations

INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 7 2008
Uri Dayan
Abstract The Middle East deserts are often subjected to dust, which reduces horizontal visibility to 5 km, and sometimes even to < 1 km. The present study examines the annual and inter-annual occurrences of dust events based on 37 years of visibility observations from Hazerim (near Beer Sheba) correlated with PM10 dust concentration. The visibility data was converted to PM10 dust concentration, using concurrent data for three years. We then analyse the linkage between dust and synoptic- to global-scale weather systems. The monthly data indicate that the dust season starts in October and ends in May, with a maximum in March. More than 89% of the total annual dust is accumulated between December and May, the ,high dust season'. The annual totals vary as much as an order of magnitude from year to year. The synoptic system that produces the majority of the dust over the northern Negev is the Cyprus Low, contributing 2/3 of both the total yearly dust yield and of the number of dust observations. This suggests that a positive relationship exists between the dust in the Negev and rainfall in north Israel, both of which are generated by Cyprus Lows. Indeed, a significant (at 0.05 level) correlation of + 0.30 was found between the two. Correlation maps evidence that in dust-rich years the cyclonic activity over the Mediterranean is abnormally high and in poor-dust years it is low. A highly significant negative correlation (,0.66) was found between the dust yield and the intensity of the North Atlantic oscillation (NAO), which modulates the cyclonic activity over Europe and the northern Mediterranean. This may also imply that periods in which more dust accumulated as loess in the northern Negev may indicate the existence of negative NAO phase, and concurrently, warmer conditions over the Sahara, colder conditions over Europe and enhanced rainfall over the Mediterranean Basin. Copyright © 2007 Royal Meteorological Society [source]

Evolution of the southern Mu US desert in north China over the past 50 years: an analysis using proxies of human activity and climate parameters

LAND DEGRADATION AND DEVELOPMENT, Issue 4 2005
X. Wang
Abstract Many previous studies have attributed the degradation in the Mu Us Desert in China to many centuries of human activity. The present study includes analysis of proxies of human activity such as arable land area, population and livestock number, and variations of precipitation, evaporation, temperature, sand-driving wind and dust events, covering the period since 1950. It is demonstrated that desertification and vegetation rehabilitation during this period were principally related to the climatic variation, especially correlated to sand-driving winds. It also suggests that the desert evolution in the past 2000 years was controlled by climate change rather than human activity. Although human activity was significant in the desert evolution processes over the past 50 years, the impacts seems to be overestimated in previous studies. Desertification and desert evolution in the Mu Us Desert are mainly in response to climatic trends and fluctuations. Copyright © 2005 John Wiley & Sons, Ltd. [source]