نتایج جستجو برای: dust deposition

تعداد نتایج: 133067  

2004
Song-Miao Fan Larry W. Horowitz Hiram Levy Walter J. Moxim

[1] Mineral dust aerosols originating from arid regions are simulated in an atmospheric global chemical transport model. Based on model results and observations of dust concentration, we hypothesize that air pollution increases the scavenging of dust by producing high levels of readily soluble materials on the dust surface, which makes dust aerosols effective cloud condensation nuclei (CCN). Th...

2003
Y. J. Kaufman I. Koren L. A. Remer D. Tanré P. Ginoux S. Fan

Meteorological observations, in situ data and satellite images of dust episodes were used already in the 1970s to estimate that 100 tg of dust are transported from Africa over the Atlantic Ocean every year between June and August and deposited in the Atlantic Ocean and the Americas. Desert dust is a main source of nutrients to oceanic biota and the Amazon forest, but deteriorates air quality as...

Journal: :Indoor air 2000
B Croxford K W Tham A Young T Oreszczyn D Wyon

The impact of electrostatic precipitation as a useful form of particulate filtration in the breathing zone is investigated in an intervention study in an air-conditioned commercial office in central London. Surface dust deposition and airborne dust levels are measured in the open plan zones of two floors--a control floor and a floor where the intervention is effected. The intervention consists ...

2003
Charles S. Zender Huisheng Bian David Newman

[1] We describe a model for predicting the size-resolved distribution of atmospheric dust for climate and chemistry-related studies. The dust distribution from 1990 to 1999 is simulated with our mineral aerosol entrainment and deposition module embedded in a chemical transport model. Mobilization processes include entrainment thresholds for saltation, moisture inhibition, drag partitioning, and...

2006
P. R. Field O. Möhler P. Connolly M. Krämer R. Cotton A. J. Heymsfield

The large (7 m×4 m cylinder, 84 m3) AIDA (Aerosol Interactions and Dynamics in the Atmosphere) cloud chamber facility at Forschungszentrum, Karlsruhe, Germany was used to test the ice nucleating ability of two desert dust samples from the Sahara and Asia. Aerosol samples were lognormally distributed with a mode diameter of 0.4(±0.1)μm and geometric standard deviation of ∼1.7(±0.2). At temperatu...

2007
Marith C. Reheis

Dust samples collected annually for 5 years from 55 sites in southern Nevada and California provide the first regional source of information on modem rates of dust deposition, grain size, and mineralogical and chemical composition relative to climate and to type and lithology of dust source. The average silt and clay flux (rate of deposition) in southern Nevada and southeastern California range...

2010
T. D. Fairlie D. J. Jacob J. E. Dibb B. Alexander M. A. Avery A. van Donkelaar

We use a 3-D global chemical transport model (GEOS-Chem) to interpret aircraft observations of nitrate and sulfate partitioning in transpacific dust plumes during the INTEX-B campaign of April–May 2006. The model includes explicit transport of size-resolved mineral dust and its alkalinity, nitrate, and sulfate content. The observations show that particulate nitrate is primarily associated with ...

ژورنال: سلامت و محیط زیست 2017

Background and Objective: The aim of this study was to investigate the physico-chemical properties, size distribution and shape of the falling mineral dusts over Masjed Soleyman and to identify their origins. Also, seasonal and annual variations of climatic parameters and their relation with dust storm occurrence were investigated. Materials and Methods: The collected samples were as result ...

2017
Stanley R. Herwitz Daniel R. Muhs Joseph M. Prospero Shannon Mahan Bruce Vaughn

Red clayey paleosols that are chiefly the product of aerosolic dust deposition are interbedded in the Quaternary carbonate formations of the Bermuda oceanic island system. These paleosols provide a basis for reconstructing Quaternary atmospheric circulation patterns in the northwestern Atlantic. Geochemical analyses were performed on representative paleosol samples to identify their parent dust...

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