Modeling of particle size distribution and its influence on the radiative properties of mineral dust aerosol

1996 ◽  
Vol 101 (D14) ◽  
pp. 19237-19244 ◽  
Author(s):  
Ina Tegen ◽  
Andrew A. Lacis
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Mineral Dust ◽  
Dust Aerosol ◽  
Radiative Properties

scholarly journals U.K. HiGEM: Impacts of Desert Dust Radiative Forcing in a High-Resolution Atmospheric GCM

2014 ◽  
Vol 27 (15) ◽  
pp. 5907-5928 ◽  
Author(s):  
M. J. Woodage ◽  
S. Woodward
Keyword(s):  
Particle Size ◽  
High Resolution ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Radiative Forcing ◽  
Mineral Dust ◽  
West African Monsoon ◽  
Radiative Properties ◽  
Saharan Dust ◽  
Dust Particles

Abstract This work investigates the impacts of mineral dust aerosol on climate using the atmospheric component of the U.K. High-Resolution Global Environmental Model (HiGEM) with an interactive embedded mineral dust scheme. It extends earlier work by Woodage et al. in which direct radiative forcing due to dust was calculated and in which it was reported that the global total dust burden was increased when this was included in the model. Here this result is analyzed further and the regional and global impacts are investigated. It is found that particle size distribution is critically important: In regions where large, more absorbent dust particles are present, burdens are increased because of the enhanced heating aloft, which strengthens convection, whereas, in areas where smaller, more scattering particles dominate, the surface layers are stabilized and dust emissions are decreased. The consequent changes in dust load and particle size distribution when radiative effects are included make the annual mean global forcing more positive at the top of the atmosphere (0.33 versus 0.05 W m−2). Impacts on the West African monsoon are also considered, where Saharan dust brings about a northward shift in the summertime intertropical convergence zone with increased precipitation on its northern side. This contrasts with results from some other studies, but the authors’ findings are supported by recent observational data. They argue that the impacts depend crucially on the size distribution and radiative properties of the dust particles, which are poorly known on a global scale and differ here from those used in other models.

scholarly journals Investigation of Radiative Properties of a Multi-particle Cloud with Non-uniform Particle Size Distribution

2021 ◽  
Vol 701 (1) ◽  
pp. 012025
Author(s):  
Z M Cheng ◽  
F Q Wang ◽  
D Y Gong ◽  
H X Liang ◽  
Y Shuai ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Radiative Properties ◽  
Particle Cloud ◽  
Uniform Particle Size

scholarly journals Impact of particle size, refractive index, and shape on the determination of the particle scattering coefficient – an optical closure study evaluating different nephelometer angular truncation and illumination corrections

2021 ◽  
Author(s):  
Marilena Teri ◽  
Thomas Müller ◽  
Josef Gasteiger ◽  
Sara Valentini ◽  
Helmuth Horvath ◽  
...  
Keyword(s):  
Particle Size ◽  
Refractive Index ◽  
Optical Properties ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Mineral Dust ◽  
Scattering Coefficient ◽  
Particle Scattering ◽  
Aerosol Optical Properties ◽  
Angular Correction

Abstract. Aerosol particles in the atmosphere interact with solar radiation through scattering and absorption. Accurate aerosol optical properties are needed to reduce the uncertainties of climate predictions. The aerosol optical properties can be obtained via optical modeling based on the measured particle size distribution. This approach requires knowledge or assumptions on the particle refractive index and shape. Meanwhile, integrating nephelometry provides information on the aerosol scattering properties directly. However, their measurements are affected by angular non-idealities, and their data need to be corrected for angular truncation and illumination to provide the particle scattering coefficient. We performed an extensive closure study, including a laboratory and a simulated experiment, aiming to compare different nephelometer angular truncation and illumination corrections (further referred to as "angular corrections"). We focused on coarse mode irregularly shaped aerosols, such as mineral dust, a worldwide abundant aerosol component. The angular correction of irregular particles is found to be only ~2 % higher than the angular correction of volume equivalent spheres. If the angular correction is calculated with Mie theory, the particle size distribution is needed. Our calculations show that if the particle size distribution is retrieved from optical particle spectrometer measurements and the irregular shape effect is not considered, the angular correction can be overestimated by about 5 % and up to 22 %. For mineral dust, the traditional angular correction based on the wavelength dependency of the scattering coefficient seems more accurate. We propose a guideline to establish the most appropriate angular correction depending on the aerosol type and the investigated size range.

scholarly journals Particle Size Distribution Analysis of Mineral Dust in Polar Snow Using a Coulter Counter

2014 ◽  
Vol 36 (4) ◽  
pp. 319-326
Author(s):  
Jung-Ho Kang ◽  
Heejin Hwang ◽  
Sang Bum Hong ◽  
Soon Do Hur
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Mineral Dust ◽  
Coulter Counter ◽  
Distribution Analysis ◽  
Polar Snow

scholarly journals Aerosol optical properties during dust and biomass burning episodes retrieved from sun-photometer over Shanghai

2013 ◽  
Vol 6 (6) ◽  
pp. 11011-11054 ◽  
Author(s):  
C. Shi ◽  
S. Wang ◽  
R. Zhou ◽  
D. Li ◽  
H. Zhao ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Biomass Burning ◽  
Dust Aerosol ◽  
Asymmetry Factor ◽  
Optical Extinction ◽  
Biomass Smoke ◽  
Fine Mode ◽  
Average Condition

Abstract. Ground-based observation over Shanghai was carried out from 28 March to 25 June 2013 in an urban site at Fudan University (31°18' N, 121°29' E). Utilizing a sun/sky radiometer (CE318), aerosol properties including thickness, scattering, asymmetry, and particle size distribution were inversed for two types (dust and biomass burning). Dust aerosol showed large optical depth (AOD at 440 nm ~ 1.06) with small value of Ångström parameter (α) around 0.74, indicating the strong optical extinction capability of large-size particles. Aerosol loading (~ 0.72 at 440 nm) was discovered to be coupled with large α (> 1.05) for biomass smoke. The particle size distribution was dominated by the coarse mode for dust with high concentration ratio between coarse and fine mode (VC/VF ~ 3.76). Biomass burning particle primarily accumulated around 0.17 μm and performed smaller VC/VF (~ 0.99). Aerosol in fine mode mainly accounted for the optical extinction process in Shanghai as its volume concentration was well-correlated with AOD (R ~ 0.88 in average condition). The value of single scattering albedo (SSA) during agricultural residue burning displayed variation from 0.902 to 0.922 with a descending trend at 670–1020 nm while SSA increased at all wavelengths for dust aerosol. The negative correlation between SSA · AOD and α was analyzed to capture the order of scattering capability: urban/industrial < biomass < dust aerosol. Higher value of asymmetry factor at 1020 nm (~ 0.652) of dust aerosol was found compared to average condition and biomass smoke (both were equaled to 0.625), imposing the enhanced forward scattering of dust particles in NIR band. The validation of AOD vs. MODIS showed errors in dust and biomass samples, which may be attributed to the variable SSA in YRD. The ascending deviation also existed in clear condition, which could be caused by the overestimation of ground reflectance in MODIS algorithm.

scholarly journals Evaluation of natural aerosols in CRESCENDO-ESMs: Mineral Dust

2020 ◽  
Author(s):  
Ramiro Checa-Garcia ◽  
Yves Balkanski ◽  
Samuel Albani ◽  
Tommi Bergman ◽  
Ken Carslaw ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Dust Particle ◽  
Mineral Dust ◽  
Radiative Effects ◽  
Dust Emissions ◽  
Dust Sources ◽  
Global Consistency ◽  
The Difference

Abstract. This paper presents an analysis of the mineral dust aerosol modelled by five Earth System Models (ESM) within the Coordinated Research in Earth Systems and Climate: Experiments, kNowledge, Dissemination and Outreach (CRESCENDO) project. We quantify the global dust cycle described by each model in terms of global emissions together with dry and wet depositions, reporting large differences in ratio of dry over wet deposition across the models not directly correlated with the range of particle sizes emitted. The multi-model mean dust emissions was 2954 Tg yr−1 but with a large uncertainty due mainly to the difference in maximum dust particle size emitted. For the subset of ESMs without particles larger than 10 μm we obtained 1664 (σ = 650) Tg yr−1. Total dust emissions with identical nudged winds from reanalysis give us better consistency between models with 1530 (σ = 282) Tg yr−1. Significant discrepancies in the globally averaged dust mass extinction efficiency explain why even models with relatively similar dust load global budgets can display strong differences in dust optical depths. The comparison against observations has been done in terms of dust optical depths based on MODIS satellite products, showing a global consistency in terms of preferential dust sources and transport across the Atlantic. However, we found regional and seasonal differences between models and observations when we quantified the cross-correlation of time-series over dust emitting regions. To faithfully compare local emissions between models we introduce a re-gridded normalization method, that also can be compared with satellite products derived from dust events frequencies. Dust total depositions are compared with instrumental network to assess global and regional differences. We found that models agree with observations distant from dust sources within a factor 10, but the approximations of dust particle size distribution at emission contributed to a misrepresentation of the actual range of deposition values when instruments are close to dust emitting regions. The observational dust surface concentrations also are reproduced within a factor 10. The comparison of total aerosol optical depths with AERONETv3 stations where dust is dominant shows large differences between models, however with an increase of the inter-model consistency when the simulations are conducted with nudged-winds. The increase of the model ensemble consistency also means a better agreement with observations, which we have ascertained for dust total deposition, surface concentrations and optical depths (against both AERONETv3 and MODIS-DOD retrievals). We estimated the direct radiative effects of a multi-modal representation of the dust particle size distribution that includes the largest particles measured at FENNEC experiment. We introduced a method to ascertain the contributions per mode consistent with the multimodal direct radiative effects.

Effects of Particle Size Distribution on Corrosion Rate of Carbon Steel in Soil

2020 ◽  
Vol 69 (4) ◽  
pp. 102-106
Author(s):  
Shota Ohki ◽  
Shingo Mineta ◽  
Mamoru Mizunuma ◽  
Soichi Oka ◽  
Masayuki Tsuda
Keyword(s):  
Particle Size ◽  
Carbon Steel ◽  
Corrosion Rate ◽  
Particle Size Distribution ◽  
Size Distribution

Zooplankton grazing and egestion shifts particle size distribution in natural communities

2017 ◽  
Vol 575 ◽  
pp. 43-56 ◽  
Author(s):  
K Stamieszkin ◽  
NJ Poulton ◽  
AJ Pershing
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Zooplankton Grazing ◽  
Natural Communities
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