scholarly journals Roles of saltation, sandblasting, and wind speed variability on mineral dust aerosol size distribution during the Puerto Rican Dust Experiment (PRIDE)

2004 ◽  
Vol 109 (D7) ◽  
Author(s):  
Alf Grini
Keyword(s):  
Wind Speed ◽  
Puerto Rican ◽  
Size Distribution ◽  
Mineral Dust ◽  
Dust Aerosol ◽  
Aerosol Size Distribution

scholarly journals Modeling of Mineral Dust Emissions with a Weibull Wind Speed Distribution Including Subgrid-Scale Orography Variance

2018 ◽  
Vol 35 (6) ◽  
pp. 1221-1236
Author(s):  
Laurent Menut
Keyword(s):  
Wind Speed ◽  
Mineral Dust ◽  
Aerosol Size Distribution ◽  
Test Case ◽  
Subgrid Scale ◽  
Dust Emissions ◽  
Speed Distribution ◽  
Wind Speed Distribution ◽  
Main Driver ◽  
Dust Modeling

AbstractThe modeling of mineral dust emissions requires an extensive knowledge of the wind speed close to the surface. In regional and global models, Weibull distributions are often used to better represent the subgrid-scale variability of the wind speed. This distribution mainly depends on a k parameter, itself currently parameterized as a function of the wind speed value. In this study we propose to add the potential impact of the orography variance in the wind speed distribution by changing the k parameter value. Academic test cases are designed to estimate the parameters of the scheme. A realistic test case is performed over a large domain encompassing the northern part of Africa and Europe and for the period 1 January–1 May 2012. The results of the simulations are compared to particulate matter (PM10) surface concentrations and Aerosol Robotic Network (AERONET) aerosol optical depth and aerosol size distribution. We show that with the orography variance, the simulation results are closer to the ones without variance, showing that this additional variability is not the main driver of possible errors in mineral dust modeling.

scholarly journals Dust plume formation in the free troposphere and aerosol size distribution during the Saharan Mineral Dust Experiment in North Africa

Tellus B ◽  
2015 ◽  
Vol 67 (1) ◽  
pp. 27170 ◽  
Author(s):  
Basit Khan ◽  
Georgiy Stenchikov ◽  
Bernadett Weinzierl ◽  
Stoitchko Kalenderski ◽  
Sergey Osipov
Keyword(s):  
Size Distribution ◽  
North Africa ◽  
Mineral Dust ◽  
Aerosol Size Distribution ◽  
Free Troposphere

scholarly journals The evolution of biomass-burning aerosol size distributions due to coagulation: dependence on fire and meteorological details and parameterization

2016 ◽  
Author(s):  
K. M. Sakamoto ◽  
R. G. Stevens ◽  
J. R. Pierce
Keyword(s):  
Wind Speed ◽  
Size Distribution ◽  
Biomass Burning ◽  
Independent Set ◽  
Aerosol Size Distribution ◽  
Size Distributions ◽  
Atmospheric Conditions ◽  
Mixing Depth ◽  
Fire Area ◽  
Biomass Burning Aerosol

Abstract. Biomass-burning aerosols have a significant effect on global and regional aerosol climate forcings. To model the magnitude of these effects accurately requires knowledge of the size distribution of the emitted and evolving aerosol particles. Current biomass-burning inventories do not include size distributions, and global and regional models generally assume a fixed size distribution from all biomass-burning emissions. However, biomass-burning size distributions evolve in the plume due to coagulation and net organic aerosol (OA) evaporation or formation, and the plume processes occur on spacial scales smaller than global/regional-model grid boxes. The extent of this size-distribution evolution is dependent on a variety of factors relating to the emission source and atmospheric conditions. Therefore, to account for biomass-burning aerosol size in global models accurately requires an effective aerosol size distribution that accounts for this sub-grid evolution and can be derived from available emissions-inventory and meteorological parameters. In this paper, we perform a detailed investigation of the effects of coagulation on the aerosol size distribution in biomass-burning plumes. We compare the effect of coagulation to that of OA evaporation and formation. We develop coagulation-only parameterizations for effective biomass-burning size distributions using the SAM-TOMAS large-eddy simulation plume model. For the most-sophisticated parameterization, we use the Gaussian Emulation Machine for Sensitivity Analysis (GEM-SA) to build a parameterization of the aged size distribution based on the SAM-TOMAS output and seven inputs: emission median dry diameter, emission distribution modal width, mass emissions flux, fire area, mean boundary-layer wind speed, plume mixing depth, and time/distance since emission. This parameterization was tested against an independent set of SAM-TOMAS simulations, and yields R2 values of 0.83 and 0.89 for Dpm and modal width, respectively. The aged size distribution is particularly sensitive to the mass emissions flux, fire area, wind speed, and time, and we provide simplified fits of the aged size distribution to just these input variables. These fits may be used in global and regional aerosol models. Finally, we show that variability in coagulation may lead to greater variability in the particle size distribution than does OA evaporation/formation using estimates of OA production/loss from the literature.

scholarly journals Accounting for dust aerosol size distribution in radiative transfer

2015 ◽  
Vol 120 (13) ◽  
pp. 6537-6550 ◽  
Author(s):  
Jiangnan Li ◽  
Qilong Min ◽  
Yiran Peng ◽  
Zhian Sun ◽  
Jian-Qi Zhao
Keyword(s):  
Radiative Transfer ◽  
Size Distribution ◽  
Dust Aerosol ◽  
Aerosol Size Distribution

scholarly journals The evolution of biomass-burning aerosol size distributions due to coagulation: dependence on fire and meteorological details and parameterization

2016 ◽  
Vol 16 (12) ◽  
pp. 7709-7724 ◽  
Author(s):  
Kimiko M. Sakamoto ◽  
James R. Laing ◽  
Robin G. Stevens ◽  
Daniel A. Jaffe ◽  
Jeffrey R. Pierce
Keyword(s):  
Wind Speed ◽  
Size Distribution ◽  
Biomass Burning ◽  
Independent Set ◽  
Aerosol Size Distribution ◽  
Size Distributions ◽  
Atmospheric Conditions ◽  
Mixing Depth ◽  
Fire Area ◽  
Biomass Burning Aerosol

Abstract. Biomass-burning aerosols have a significant effect on global and regional aerosol climate forcings. To model the magnitude of these effects accurately requires knowledge of the size distribution of the emitted and evolving aerosol particles. Current biomass-burning inventories do not include size distributions, and global and regional models generally assume a fixed size distribution from all biomass-burning emissions. However, biomass-burning size distributions evolve in the plume due to coagulation and net organic aerosol (OA) evaporation or formation, and the plume processes occur on spacial scales smaller than global/regional-model grid boxes. The extent of this size-distribution evolution is dependent on a variety of factors relating to the emission source and atmospheric conditions. Therefore, accurately accounting for biomass-burning aerosol size in global models requires an effective aerosol size distribution that accounts for this sub-grid evolution and can be derived from available emission-inventory and meteorological parameters. In this paper, we perform a detailed investigation of the effects of coagulation on the aerosol size distribution in biomass-burning plumes. We compare the effect of coagulation to that of OA evaporation and formation. We develop coagulation-only parameterizations for effective biomass-burning size distributions using the SAM-TOMAS large-eddy simulation plume model. For the most-sophisticated parameterization, we use the Gaussian Emulation Machine for Sensitivity Analysis (GEM-SA) to build a parameterization of the aged size distribution based on the SAM-TOMAS output and seven inputs: emission median dry diameter, emission distribution modal width, mass emissions flux, fire area, mean boundary-layer wind speed, plume mixing depth, and time/distance since emission. This parameterization was tested against an independent set of SAM-TOMAS simulations and yields R2 values of 0.83 and 0.89 for Dpm and modal width, respectively. The size distribution is particularly sensitive to the mass emissions flux, fire area, wind speed, and time, and we provide simplified fits of the aged size distribution to just these input variables. The simplified fits were tested against 11 aged biomass-burning size distributions observed at the Mt. Bachelor Observatory in August 2015. The simple fits captured over half of the variability in observed Dpm and modal width even though the freshly emitted Dpm and modal widths were unknown. These fits may be used in global and regional aerosol models. Finally, we show that coagulation generally leads to greater changes in the particle size distribution than OA evaporation/formation does, using estimates of OA production/loss from the literature.

scholarly journals Does the size distribution of mineral dust aerosols depend on the wind speed at emission?

2011 ◽  
Vol 11 (7) ◽  
pp. 19995-20012 ◽  
Author(s):  
J. F. Kok
Keyword(s):  
Wind Speed ◽  
Size Distribution ◽  
Mineral Dust ◽  
Dust Emission ◽  
Dust Deposition ◽  
Dust Aerosols ◽  
Wind Speeds ◽  
Dust Size Distribution ◽  
Emission Models ◽  
Mineral Dust Aerosols

Abstract. The size distribution of mineral dust aerosols greatly affects their interactions with clouds, radiation, ecosystems, and other components of the Earth system. Several theoretical dust emission models predict that the dust size distribution depends on the wind speed at emission, with larger wind speeds predicted to produce smaller aerosols. The present study investigates this prediction using a compilation of published measurements of the size-resolved vertical dust flux emitted by eroding soils. Surprisingly, these measurements indicate that the size distribution of naturally emitted dust aerosols is independent of the wind speed. This finding is consistent with the recently formulated brittle fragmentation theory of dust emission, but inconsistent with other theoretical dust emission models. The independence of the emitted dust size distribution with wind speed simplifies both the parameterization of dust emission in atmospheric circulation models as well as the interpretation of geological records of dust deposition.

scholarly journals Ozone and aerosol tropospheric concentrations variability analyzed using the ADRIMED measurements and the WRF and CHIMERE models

2015 ◽  
Vol 15 (11) ◽  
pp. 6159-6182 ◽  
Author(s):  
L. Menut ◽  
S. Mailler ◽  
G. Siour ◽  
B. Bessagnet ◽  
S. Turquety ◽  
...  
Keyword(s):  
Size Distribution ◽  
Mineral Dust ◽  
Regional Climate ◽  
Mediterranean Area ◽  
Network Size ◽  
Ozone Production ◽  
Aerosol Size Distribution ◽  
Pollution Transport ◽  
Fine Mode ◽  
The Mediterranean

Abstract. During the months of June and July 2013, over the Euro–Mediterranean area, the ADRIMED (Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) project was dedicated to characterize the ozone and aerosol concentrations in the troposphere. It is first shown that this period was not highly polluted compared to previous summers in this region, with a moderate ozone production, no significant vegetation fire events and several precipitation periods scavenging the aerosol. The period is modeled with the WRF (Weather Research and Forecasting) and CHIMERE models, and their ability to quantify the observed pollution transport events is presented. The CHIMERE model simulating all kinds of sources (anthropogenic, biogenic, mineral dust, vegetation fires); the aerosol speciation, not available with the measurements, is presented: during the whole period, the aerosol was mainly constituted by mineral dust, sea salt and sulfates close to the surface and mainly by mineral dust in the troposphere. Compared to the AERONET (Aerosol Robotic Network) size distribution, it is shown that the model underestimates the coarse mode near mineral dust sources and overestimates the fine mode in the Mediterranean area, highlighting the need to improve the model representation of the aerosol size distribution both during emissions, long-range transport and deposition.

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