Size-resolved chemical composition of Australian dust aerosol during winter

2011 ◽  
Vol 8 (3) ◽  
pp. 248 ◽  
Author(s):  
M. Radhi ◽  
M. A. Box ◽  
G. P. Box ◽  
M. D. Keywood ◽  
D. D. Cohen ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Mineral Dust ◽  
Ion Beam ◽  
Dust Aerosol ◽  
Back Trajectory ◽  
The South ◽  
Transport Pathway ◽  
Dust Transport ◽  
Back Trajectory Analysis ◽  
Two Samples

Environmental contextMineral dust aerosol is both an efficient scatterer of solar radiation, potentially cooling the planet, and a moderate absorber, potentially warming it: the exact balance is both uncertain, and geographically variable. Australian desert soils are noticeably more reddish than most Northern Hemisphere deserts, most probably a result of enhanced iron mineralogy. This paper contains results from a field campaign designed to increase our understanding of the chemistry of Australian mineral dust aerosol, especially in relation to iron and salt. AbstractAustralia is the dominant source of mineral dust aerosol in the Southern Hemisphere, yet the physical, chemical and optical properties of this aerosol remain poorly understood. Four sets of size-resolved aerosol samples were collected at a site on the edge of the Lake Eyre Basin (LEB), in the south-east dust transport pathway. Back trajectory analysis shows that three samples were sourced from the LEB (one during a rare winter dust storm), and one from coastal regions to the south. All samples were subjected to both ion beam analysis and ion chromatography. A Fe/Al ratio of 0.9 was found, consistent with results from our other campaigns to sites in the LEB, significantly higher than typical Northern Hemisphere values (~0.45–0.6). This confirms the iron-rich character of central Australian soils. Clear evidence of marine advection in the fourth sample was also found, and evidence of chloride depletion by nitric acid in two samples.

scholarly journals Optical, physical and chemical characteristics of Australian continental aerosols: results from a field experiment

2010 ◽  
Vol 10 (13) ◽  
pp. 5925-5942 ◽  
Author(s):  
M. Radhi ◽  
M. A. Box ◽  
G. P. Box ◽  
R. M. Mitchell ◽  
D. D. Cohen ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Ion Chromatography ◽  
Biomass Burning ◽  
Mineral Dust ◽  
Ion Beam ◽  
Water Soluble ◽  
Size Distributions ◽  
Ion Beam Analysis ◽  
Beam Analysis ◽  
Scatter Plots

Abstract. Mineral dust is one of the major components of the world's aerosol mix, having a number of impacts within the Earth system. However, the climate forcing impact of mineral dust is currently poorly constrained, with even its sign uncertain. As Australian deserts are more reddish than those in the Northern Hemisphere, it is important to better understand the physical, chemical and optical properties of this important aerosol. We have investigated the properties of Australian desert dust at a site in SW Queensland, which is strongly influenced by both dust and biomass burning aerosol. Three years of ground-based monitoring of spectral optical thickness has provided a statistical picture of gross aerosol properties. The aerosol optical depth data showed a clear though moderate seasonal cycle with an annual mean of 0.06 ± 0.03. The Angstrom coefficient showed a stronger cycle, indicating the influence of the winter-spring burning season in Australia's north. AERONET size distributions showed a generally bimodal character, with the coarse mode assumed to be mineral dust, and the fine mode a mixture of fine dust, biomass burning and marine biogenic material. In November 2006 we undertook a field campaign which collected 4 sets of size-resolved aerosol samples for laboratory analysis – ion beam analysis and ion chromatography. Ion beam analysis was used to determine the elemental composition of all filter samples, although elemental ratios were considered the most reliable output. Scatter plots showed that Fe, Al and Ti were well correlated with Si, and Co reasonably well correlated with Si, with the Fe/Al ratio somewhat higher than values reported from Northern Hemisphere sites (as expected). Scatter plots for Ca, Mn and K against Si showed clear evidence of a second population, which in some cases could be identified with a particular sample day or size fraction. These data may be used to attempt to build a signature of soil in this region of the Australian interior. Ion chromatography was used to quantify water soluble ions for 2 of our sample sets, complementing the picture provided by ion beam analysis. The strong similarities between the MSA and SO42− size distributions argue strongly for a marine origin of much of the SO42−. The similarity of the Na+, Cl− and Mg2+ size distributions also argue for a marine contribution. Further, we believe that both NO3− and NH4+ are the result of surface reactions with appropriate gases.

scholarly journals Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean

2010 ◽  
Vol 10 (11) ◽  
pp. 27283-27320
Author(s):  
M. S. Johnson ◽  
N. Meskhidze ◽  
V. P. Kiliyanpilakkil ◽  
S. Gassó
Keyword(s):  
Mineral Dust ◽  
Low Pressure ◽  
Remotely Sensed ◽  
South Atlantic ◽  
The South ◽  
Remotely Sensed Data ◽  
Pressure System ◽  
Transport Pathways ◽  
Dust Transport ◽  
Chl A

Abstract. The supply of bioavailable iron to the high-nitrate low-chlorophyll (HNLC) waters of the Southern Ocean through atmospheric pathways could stimulate phytoplankton blooms and have major implications for the global carbon cycle. In this study, model results and remotely-sensed data are analyzed to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of iron-laden mineral dust deposition on marine biological productivity in the surface waters of the South Atlantic Ocean (SAO). Model simulations for the atmospheric transport and deposition of mineral dust and bioavailable iron are carried out for two large dust outbreaks originated at the source regions of Northern Patagonia during the austral summer of 2009. Model-simulated horizontal and vertical transport pathways of Patagonian dust plumes are in reasonable agreement with remotely-sensed data. Simulations indicate that the synoptic meteorological patterns of high and low pressure systems are largely accountable for dust transport trajectories over the SAO. According to model results and retrievals from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), synoptic flows caused by opposing pressure systems (a high pressure system located to the east or north-east of a low pressure system) elevate the South American dust plumes well above the marine boundary layer. Under such conditions, the bulk concentration of mineral dust can quickly be transported around the low pressure system in a clockwise manner, follow the southeasterly advection pathway, and reach the HNLC waters of the SAO and Antarctica in ~3–4 days after emission from the source regions of Northern Patagonia. Two different mechanisms for dust-iron mobilization into a bioavailable form are considered in this study. A global 3-D chemical transport model (GEOS-Chem), implemented with an iron dissolution scheme, is employed to estimate the atmospheric fluxes of soluble iron, while a dust/biota assessment tool (Boyd et al., 2010) is applied to evaluate the amount of bioavailable iron formed through the slow and sustained leaching of dust in the ocean mixed layer. The effect of iron-laden mineral dust supply on surface ocean biomass is investigated by comparing predicted surface chlorophyll-a concentration ([Chl-a]) to remotely-sensed data. As the dust transport episodes examined here represent large summertime outflows of mineral dust from South American continental sources, this study suggests that (1) atmospheric fluxes of mineral dust from Patagonia are not likely to be the major source of bioavailable iron to ocean regions characterized by high primary productivity; (2) even if Patagonian dust plumes may not cause visible algae blooms, they could still influence background [Chl-a] in the South Atlantic sector of the Southern Ocean.

scholarly journals Study of Persistent Pollution in Hefei during Winter Revealed by Ground-Based LiDAR and the CALIPSO Satellite

2021 ◽  
Vol 13 (2) ◽  
pp. 875
Author(s):  
Zhiyuan Fang ◽  
Hao Yang ◽  
Ye Cao ◽  
Kunming Xing ◽  
Dong Liu ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Eastern China ◽  
Northwest China ◽  
Back Trajectory ◽  
Observation Data ◽  
Transport Pathway ◽  
Back Trajectory Analysis ◽  
Maximum Value ◽  
Heavy Pollution ◽  
Ground Based Lidar

LiDAR and CALIPSO satellites are effective tools for detecting air pollution, and by employing PM2.5 observation data, ground-based LiDAR measurements, CALIPSO satellite data, meteorological data, and back-trajectory analysis, we analyzed the process of pollution (moderate pollution, heavy pollution, excellent weather, and dust transmission weather) in Hefei, China from 24 to 27 January 2019 and analyzed the meteorological conditions and pollutants causing heavy pollution. Observation data from the ground station showed that the concentrations of PM10 and PM2.5 increased significantly on 25 January; the maximum value of PM10 was 175 µg/m3, and the maximum value of PM2.5 was 170 µg/m3. In this study, aerosol transboundary transport was observed using a combination of ground-based LiDAR and CALIPSO satellite observations. This method showed that aerosols were distributed at a height of 3–4 km over Hefei at 12:00 on 26 January, and it was found that the aerosols came from the desert region in northwest China. Moreover, we determined its transport pathway based on the backward trajectory, and the transportation of pollutants from the surrounding important industrial cities in central and eastern China led to severe pollution after aggregating and mixing with local aerosols in Hefei in the winter. Therefore, the method proposed in this paper can effectively monitor the optical properties and transportation process of aerosols, help to explore the causes of pollution under complex conditions, and improve environmental quality.

scholarly journals Understanding the transport of Patagonian dust and its influence on marine biological activity in the South Atlantic Ocean

2011 ◽  
Vol 11 (6) ◽  
pp. 2487-2502 ◽  
Author(s):  
M. S. Johnson ◽  
N. Meskhidze ◽  
V. P. Kiliyanpilakkil ◽  
S. Gassó
Keyword(s):  
Mineral Dust ◽  
Low Pressure ◽  
Remotely Sensed ◽  
South Atlantic ◽  
The South ◽  
Remotely Sensed Data ◽  
Pressure System ◽  
Transport Pathways ◽  
Dust Transport ◽  
Chl A

Abstract. The supply of bioavailable iron to the high-nitrate low-chlorophyll (HNLC) waters of the Southern Ocean through atmospheric pathways could stimulate phytoplankton blooms and have major implications for the global carbon cycle. In this study, model results and remotely-sensed data are analyzed to examine the horizontal and vertical transport pathways of Patagonian dust and quantify the effect of iron-laden mineral dust deposition on marine biological productivity in the surface waters of the South Atlantic Ocean (SAO). Model simulations for the atmospheric transport and deposition of mineral dust and bioavailable iron are carried out for two large dust outbreaks originated at the source regions of northern Patagonia during the austral summer of 2009. Model-simulated horizontal and vertical transport pathways of Patagonian dust plumes are in reasonable agreement with remotely-sensed data. Simulations indicate that the synoptic meteorological patterns of high and low pressure systems are largely accountable for dust transport trajectories over the SAO. According to model results and retrievals from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), synoptic flows caused by opposing pressure systems (a high pressure system located to the east or north-east of a low pressure system) elevate the South American dust plumes well above the marine boundary layer. Under such conditions, the bulk concentration of mineral dust can quickly be transported around the low pressure system in a clockwise manner, follow the southeasterly advection pathway, and reach the HNLC waters of the SAO and Antarctica in ~3–4 days after emission from the source regions of northern Patagonia. Two different mechanisms for dust-iron mobilization into a bioavailable form are considered in this study. A global 3-D chemical transport model (GEOS-Chem), implemented with an iron dissolution scheme, is employed to estimate the atmospheric fluxes of soluble iron, while a dust/biota assessment tool (Boyd et al., 2010) is applied to evaluate the amount of bioavailable iron formed through the slow and sustained leaching of dust in the ocean mixed layer. The effect of iron-laden mineral dust supply on surface ocean biomass is investigated by comparing predicted surface chlorophyll-a concentration ([Chl-a]) to remotely-sensed data. As the dust transport episodes examined here represent large summertime outflows of mineral dust from South American continental sources, this study suggests that (1) atmospheric fluxes of mineral dust from Patagonia are not likely to be the major source of bioavailable iron to ocean regions characterized by high primary productivity; (2) even if Patagonian dust plumes may not cause visible algae blooms, they could still influence background [Chl-a] in the South Atlantic sector of the Southern Ocean.

scholarly journals Continuous observations of synoptic-scale dust transport at the Nepal Climate Observatory-Pyramid (5079 m a.s.l.) in the Himalayas

2011 ◽  
Vol 11 (2) ◽  
pp. 4229-4261 ◽  
Author(s):  
R. Duchi ◽  
P. Cristofanelli ◽  
A. Marinoni ◽  
P. Laj ◽  
S. Marcq ◽  
...  
Keyword(s):  
Mineral Dust ◽  
Monsoon Season ◽  
Three Dimensional ◽  
Temporal Variations ◽  
Number Concentration ◽  
Back Trajectory ◽  
Synoptic Scale ◽  
Data Set ◽  
Dust Transport ◽  
Coarse Aerosol

Abstract. This study presents two years of continuous observations of physical aerosol properties at the GAW-WMO global station "Nepal Climate Observatory – Pyramid" (NCO-P, 27°57' N, 86°48' E), sited at 5079 m a.s.l. in the high Himalayan Khumbu Valley (Nepal). Measurements of aerosol number size distribution, aerosol optical depth (AOD) and single scattering albedo (SSA) are analysed from March 2006 to February 2008. By studying the temporal variations of coarse (1 μm < Dp ≤ 10 μm) particle number concentration, 53 mineral Dust Transport Events (DTEs) are identified, accounting for 22.2% of the analysed data-set. Such events occurred prevalently during pre-monsoon (for 30.6% of the period) and winter (22.1%) seasons. However, uncommon cases of mineral dust transport are observed even during the monsoon season. The main sources of mineral dust reaching NCO-P are identified in the arid regions not far from the measurement site, i.e. from Tibetan Plateau, and Lot-Thar deserts, which account for 52% of the dust transport days. Moreover, a non-negligible contribution can be attributed to the Arabian Peninsula (17%) and the Indo-Gangetic Plains (16%), as indicated by three dimensional (3-D) back-trajectory analyses performed with LAGRANTO model. The observed DTEs lead to significant enhancements in the coarse aerosol number concentration (+513%) and coarse aerosol mass (+655%), as compared with average values observed in "dust-free" conditions ( 0.05 ± 0.11 cm−3 and 3.4 ± 3.7 μg m−3, respectively). During DTEs, SSA is higher (0.84–0.89) than on "dust-free" days (0.75–0.83), confirming the importance of this class of events as a driver of the radiative features of the regional Himalayan climate. Considering the dust events, a significant seasonal AOD increase (+37.5%) is observed in the post-monsoon, whereas lower increase (less than +11.1%) characterises the pre-monsoon and winter seasons confirming the influence of synoptic-scale mineral dust transports on the aerosol optical properties observed at NCO-P.

scholarly journals Role of sea surface temperature responses in simulation of the climatic effect of mineral dust aerosol

2011 ◽  
Vol 11 (12) ◽  
pp. 6049-6062 ◽  
Author(s):  
X. Yue ◽  
H. Liao ◽  
H. J. Wang ◽  
S. L. Li ◽  
J. P. Tang
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Radiative Forcing ◽  
Mineral Dust ◽  
Dust Aerosol ◽  
Sea Surface ◽  
Climatic Effect ◽  
Radiative Effects ◽  
Climate Simulations

Abstract. Mineral dust aerosol can be transported over the nearby oceans and influence the energy balance at the sea surface. The role of dust-induced sea surface temperature (SST) responses in simulations of the climatic effect of dust is examined by using a general circulation model with online simulation of mineral dust and a coupled mixed-layer ocean model. Both the longwave and shortwave radiative effects of mineral dust aerosol are considered in climate simulations. The SST responses are found to be very influential on simulated dust-induced climate change, especially when climate simulations consider the two-way dust-climate coupling to account for the feedbacks. With prescribed SSTs and dust concentrations, we obtain an increase of 0.02 K in the global and annual mean surface air temperature (SAT) in response to dust radiative effects. In contrast, when SSTs are allowed to respond to radiative forcing of dust in the presence of the dust cycle-climate interactions, we obtain a global and annual mean cooling of 0.09 K in SAT by dust. The extra cooling simulated with the SST responses can be attributed to the following two factors: (1) The negative net (shortwave plus longwave) radiative forcing of dust at the surface reduces SST, which decreases latent heat fluxes and upward transport of water vapor, resulting in less warming in the atmosphere; (2) The positive feedback between SST responses and dust cycle. The dust-induced reductions in SST lead to reductions in precipitation (or wet deposition of dust) and hence increase the global burden of small dust particles. These small particles have strong scattering effects, which enhance the dust cooling at the surface and further reduce SSTs.

A new generator for mineral dust aerosol production from soil samples in the laboratory: GAMEL

2014 ◽  
Vol 15 ◽  
pp. 319-334 ◽  
Author(s):  
Sandra Lafon ◽  
Stéphane C. Alfaro ◽  
Servanne Chevaillier ◽  
Jean Louis Rajot
Keyword(s):  
Mineral Dust ◽  
Soil Samples ◽  
Dust Aerosol

Water Interaction with Mineral Dust Aerosol: Particle Size and Hygroscopic Properties of Dust

2018 ◽  
Vol 2 (4) ◽  
pp. 376-386 ◽  
Author(s):  
Sara Ibrahim ◽  
Manolis N. Romanias ◽  
Laurent Y. Alleman ◽  
Mohamad N. Zeineddine ◽  
Giasemi K. Angeli ◽  
...  
Keyword(s):  
Particle Size ◽  
Aerosol Particle ◽  
Mineral Dust ◽  
Dust Aerosol ◽  
Water Interaction ◽  
Hygroscopic Properties ◽  
Aerosol Particle Size

scholarly journals Use of Low-Cost Ambient Particulate Sensors in Nablus, Palestine with Application to the Assessment of Regional Dust Storms

Atmosphere ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 539
Author(s):  
Abdelhaleem Khader ◽  
Randal S. Martin
Keyword(s):  
Low Cost ◽  
Dust Storms ◽  
Air Pollutant ◽  
World Health ◽  
Back Trajectory ◽  
Hysplit Model ◽  
Air Masses ◽  
Palestinian Territories ◽  
Back Trajectory Analysis ◽  
Lower Elevation

Few air pollutant studies within the Palestinian territories have been reported in the literature. In March–April and May–June of 2018, three low-cost, locally calibrated particulate monitors (AirU’s) were deployed at different elevations and source areas throughout the city of Nablus in Northern West Bank, Palestine. During each of the three-week periods, high but site-to-site similar particulate matter less than 2.5 µm in aerodynamic diameter (PM2.5) and less than 10 µm (PM10) concentrations were observed. The PM2.5 concentrations at the three sampling locations and during both sampling periods averaged 38.2 ± 3.6 µg/m3, well above the World Health Organization’s (WHO) 24 h guidelines. Likewise, the PM10 concentrations exceeded or were just below the WHO’s 24 h guidelines, averaging 48.5 ± 4.3 µg/m3. During both periods, short episodes were identified in which the particulate levels at all three sites increased substantially (≈2×) above the regional baseline. Air mass back trajectory analyses using U.S. National Oceanic and Atmospheric Administration’s (NOAA) Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggested that, during these peak episodes, the arriving air masses spent recent days over desert areas (e.g., the Saharan Desert in North Africa). On days with regionally low PM2.5 concentrations (≈20 µg/m3), back trajectory analysis showed that air masses were directed in from the Mediterranean Sea area. Further, the lower elevation (downtown) site often recorded markedly higher particulate levels than the valley wall sites. This would suggest locally derived particulate sources are significant and may be beneficial in the identification of potential remediation options.

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