scholarly journals A general database of hydrometeor single scattering properties at microwave and sub-millimetre wavelengths

2018 ◽  
Author(s):  
Patrick Eriksson ◽  
Robin Ekelund ◽  
Jana Mendrok ◽  
Manfred Brath ◽  
Oliver Lemke ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Single Scattering ◽  
Particle Orientation ◽  
Maximum Diameter ◽  
Particle Sizes ◽  
Orientation Data ◽  
Different Types ◽  
Rain Drops ◽  
Cloud Ice ◽  
Random Particle

Abstract. A main limitation today in simulations and inversions of microwave observations of ice hydrometeors (cloud ice, snow, hail ...) is the lack of data describing the interaction between electromagnetic waves and the particles. To improve the situation, the development of a comprehensive dataset of such "scattering properties" has been started. The database aims at giving a broad coverage in both frequency (1 to 886 GHz) and temperature (190 to 270 K), to support both passive and active current and planned measurements, and to provide data corresponding to the full Stokes vector. This first version of the database is restricted to totally random particle orientation. Data for 34 particle sets, i.e. habits, have been generated. About 17 of the habits can be classified as single crystals, three habits can be seen as heavily rimed particles, and remaining habits are aggregates of different types, representing e.g. snow and hail. The particle sizes considered vary between the habits, but a maximum diameter of 10 and 20 mm are typical values for the largest single crystal and aggregate particles, respectively, and the number of sizes per habit is at least 30. Particles containing liquid water are also inside the scope of the database, but this phase of water is so far only represented by a liquid sphere habit. The database is built upon the netCDF4 file format. Interfaces to browse, extract and convert data for selected radiative transfer models are provided in Matlab and Python. The database and associated tools are publically available from Zenedo (https://doi.org/10.5281/zenodo.1175572 and https://doi.org/10.5281/zenodo.1175588, respectively). Planned extensions include non-spherical rain drops, melting particles and a second orientation case that can be denoted as azimuthally random.

scholarly journals A general database of hydrometeor single scattering properties at microwave and sub-millimetre wavelengths

2018 ◽  
Vol 10 (3) ◽  
pp. 1301-1326 ◽  
Author(s):  
Patrick Eriksson ◽  
Robin Ekelund ◽  
Jana Mendrok ◽  
Manfred Brath ◽  
Oliver Lemke ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Single Scattering ◽  
Particle Orientation ◽  
Particle Sizes ◽  
File Format ◽  
Orientation Data ◽  
Liquid Sphere ◽  
Different Types ◽  
Cloud Ice ◽  
Random Particle

Abstract. A main limitation today in simulations and inversions of microwave observations of ice hydrometeors (cloud ice, snow, hail, etc.) is the lack of data describing the interaction between electromagnetic waves and the particles. To improve the situation, the development of a comprehensive dataset of such scattering properties has been started. The database aims at giving a broad coverage in both frequency (1 to 886 GHz) and temperature (190 to 270 K), to support both passive and active current and planned measurements, and to provide data corresponding to the full Stokes vector. This first version of the database is restricted to totally random particle orientation. Data for 34 particle sets, i.e. habits, have been generated. About 17 of the habits can be classified as single crystals, three habits can be seen as heavily rimed particles, and the remaining habits are aggregates of different types, e.g. snow and hail. The particle sizes considered vary between the habits, but maximum diameters of 10 and 20 mm are typical values for the largest single crystal and aggregate particles, respectively, and the number of sizes per habit is at least 30. Particles containing liquid water are also inside the scope of the database, but this phase of water is so far only represented by a liquid sphere habit. The database is built upon the netCDF4 file format. Interfaces to browse, extract and convert data for selected radiative transfer models are provided in MATLAB and Python. The database and associated tools are publicly available from Zenodo (https://doi.org/10.5281/zenodo.1175572, Ekelund et al., 2018b), and https://doi.org/10.5281/zenodo.1175588, Mendrok et al., 2018, respectively). Planned extensions include non-spherical raindrops, melting particles and a second orientation case that can be denoted as azimuthally random.

scholarly journals On cloud ice induced absorption and polarisation effects in microwave limb sounding

2011 ◽  
Vol 4 (2) ◽  
pp. 1493-1531
Author(s):  
P. Eriksson ◽  
B. Rydberg
Keyword(s):  
Significant Degree ◽  
Single Scattering ◽  
Particle Sizes ◽  
Ice Clouds ◽  
Oblate Spheroids ◽  
Orthogonal Components ◽  
Ice Water Content ◽  
Combine Information ◽  
Cloud Ice ◽  
Ice Water

Abstract. Detailed simulations of microwave limb sounding in the presence of ice clouds have been performed. It is clarified that, while particle absorption normally gives no significant change of the measured radiance for down-looking measurements, this is not the case for limb sounding. The particles were treated as horizontally aligned oblate spheroids and for this assumption on particle shape, and comparable situations, no significant degree of circular polarisation is generated. Differences between the brightness temperature of the ±45° polarisation components up to 4 K were found, but this difference appears to be small as long as single scattering conditions apply. The cloud extinction is the smallest for the vertically polarised component, but it should be more beneficial to observe any of the ±45° and circularly polarised components if ice water content is also a target of the retrievals. These latter pairs of orthogonal components also make it easier to combine information measured from different positions and with different polarisations. The results indicate that single scattering can be assumed for cloud optical thicknesses below about 0.1, which is thus an important threshold with respect to the complexity and accuracy of retrievals. The representation of particle sizes during the retrieval is discussed.

scholarly journals Size-segregated characteristics of organic carbon (OC), elemental carbon (EC) and organic matter in particulate matter (PM) emitted from different types of ships in China

2020 ◽  
Vol 20 (3) ◽  
pp. 1549-1564 ◽  
Author(s):  
Fan Zhang ◽  
Hai Guo ◽  
Yingjun Chen ◽  
Volker Matthias ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
Elemental Carbon ◽  
Fine Particles ◽  
Particle Mass ◽  
Fuel Oil ◽  
Chemical Compositions ◽  
Particle Sizes ◽  
Heavy Fuel Oil ◽  
Different Types ◽  
Marine Diesel

Abstract. Studies of detailed chemical compositions in particles with different size ranges emitted from ships are in serious shortage. In this study, size-segregated distributions and characteristics of particle mass, organic carbon (OC), elemental carbon (EC), 16 EPA polycyclic aromatic hydrocarbons (PAHs) and 25 n-alkanes measured aboard 12 different vessels in China are presented. The results showed the following. (1) More than half of the total particle mass, OC, EC, PAHs and n-alkanes were concentrated in fine particles with aerodynamic diameter (Dp) < 1.1 µm for most of the tested ships. The relative contributions of OC, EC, PAH and alkanes to the size-segregated particle mass are decreasing with the increase in particle size. However, different types of ships showed quite different particle-size-dependent chemical compositions. (2) In fine particles, the OC and EC were the dominant components, while in coarse particles, OC and EC only accounted for very small proportions. With the increase in particle size, the OC / EC ratios first decreased and then increased, having the lowest values for particle sizes between 0.43 and 1.1 µm. (3) Out of the four OC fragments and three EC fragments obtained in thermal–optical analysis, OC1, OC2 and OC3 were the dominant OC fragments for all the tested ships, while EC1 and EC2 were the main EC fragments for ships running on heavy fuel oil (HFO) and marine-diesel fuel, respectively; different OC and EC fragments presented different distributions in different particle sizes. (4) The four-stroke low-power diesel fishing boat (4-LDF) had much higher PAH emission ratios than the four-stroke high-power marine-diesel vessel (4-HMV) and two-stroke high-power heavy-fuel-oil vessel (2-HHV) in fine particles, and 2-HHV had the lowest values. (5) PAHs and n-alkanes showed different profile patterns for different types of ships and also between different particle-size bins, which meant that the particle size should be considered when source apportionment is conducted. It is also noteworthy from the results in this study that the smaller the particle size, the more toxic the particle was, especially for the fishing boats in China.

scholarly journals A Polarimetric Scattering Database for Non-spherical Ice Particles at MicrowaveWavelengths

2016 ◽  
Author(s):  
Yinghui Lu ◽  
Zhiyuan Jiang ◽  
Kultegin Aydin ◽  
Johannes Verlinde ◽  
Eugene E. Clothiaux ◽  
...  
Keyword(s):  
Incident Radiation ◽  
Single Scattering ◽  
Particle Orientation ◽  
Particle Scattering ◽  
Particle Properties ◽  
Ice Particles ◽  
Science Community ◽  
Fixed Orientation ◽  
Radiative Scattering

Abstract. The atmospheric science community has entered a period in which radiative scattering properties in the microwave of realistically constructed ice particles are necessary for making progress on a number of fronts. One front includes retrieval of ice-particle properties and signatures from ground-, airborne- and satellite-based radar and radiometer observations. Another front is evaluation of model microphysics by application of forward operators to their outputs and comparison to observations during case study periods. Yet a third front is data assimilation, where again forward operators are applied to databases of ice-particle scattering properties and the results compared to observations, with their differences leading to corrections of the model state. Over the past decade investigators have developed databases of ice-particle scattering properties in the microwave and made them openly available. Motivated by and complementing these earlier efforts, a database containing polarimetric single-scattering properties of various types of ice particles at millimeter to centimeter wavelengths is presented. While the database presented here contains only single-scattering properties of ice particles in a fixed orientation, ice-particle scattering properties are computed for many different directions of the radiation incident on them. These results are useful for understanding the dependence of ice-particle scattering properties on ice-particle orientation with respect to the incident radiation. For ice particles small compared to the wavelength, the number of incident directions of the radiation is sufficient to compute reasonable estimates of their (randomly) orientation-averaged scattering properties. This database is complementary to earlier ones in that it contains complete (polarimetric) scattering property information for each ice particle – 44 plates, 30 columns, 405 branched planar crystals, 660 aggregates, and 640 conical graupel – and direction of incident radiation but is limited to four frequencies (W-, Ka-, Ku- and X-bands), does not include temperature dependencies of the single-scattering properties and does not include scattering properties averaged over randomly oriented ice particles. Rules for constructing the morphologies of ice particles from one database to the next often differ; consequently, analyses that incorporate all of the different databases will contain the most variability, while illuminating important differences between them. Publication of this database is in support of future analyses of this nature and comes with the hope that doing so helps contribute to the development of a database standard for ice-particle scattering properties, like the NetCDF CF (Climate and Forecast) or NetCDF CF Radial metadata conventions.

A comprehensive database of the optical properties of irregular aerosol particles for radiative transfer simulations

2021 ◽  
Author(s):  
Masanori Saito ◽  
Ping Yang ◽  
Jiachen Ding ◽  
Xu Liu
Keyword(s):  
Optical Properties ◽  
Radiative Transfer ◽  
Aerosol Particle ◽  
Volcanic Ash ◽  
Aerosol Particles ◽  
Single Scattering ◽  
Dust Aerosol ◽  
Index Of Refraction ◽  
Particle Sizes

AbstractA database (TAMUdust2020) of the optical properties of irregular aerosol particles is developed for applications to radiative transfer simulations involving aerosols, particularly dust and volcanic ash particles. The particle shape model assumes an ensemble of irregular hexahedral geometries to mimic complex aerosol particle shapes in nature. State-of-the-art light scattering computational capabilities are employed to compute the single-scattering properties of these particles for wide ranges of values of the size parameter, the index of refraction, and the degree of sphericity. The database therefore is useful for various radiative transfer applications over a broad spectral region from ultraviolet to infrared. Overall, agreement between simulations and laboratory/in-situ measurements is achieved for the scattering phase matrix and backscattering of various dust aerosol and volcanic ash particles. Radiative transfer simulations of active and passive spaceborne sensor signals for dust plumes with various aerosol optical depths and the effective particle sizes clearly demonstrate the applicability of the database for aerosol studies. In particular, the present database includes, for the first time, robust backscattering of nonspherical particles spanning the entire range of aerosol particle sizes, which shall be useful to appropriately interpret lidar signals related to the physical properties of aerosol plumes. Furthermore, thermal infrared simulations based on in-situ measured refractive indices of dust aerosol particles manifest the effects of the regional variations of aerosol optical properties. This database includes a user-friendly interface to obtain user-customized aerosol single-scattering properties with respect to spectrally dependent complex refractive index, size, and the degree of sphericity.

Influence of Sulfur Precursor Solutions on Crystallinity of CuInS2 Nanocrystals Fabricated with Hot-Injection Method

2020 ◽  
Vol 20 (7) ◽  
pp. 4533-4536
Author(s):  
Chong Deng ◽  
Bowen Fu ◽  
Lili Li ◽  
Yanlai Wang ◽  
Lin Yang
Keyword(s):  
Chalcopyrite Structure ◽  
Particle Sizes ◽  
Copper Iodide ◽  
Metal Chalcogenide ◽  
Injection Method ◽  
Metal Precursors ◽  
Hot Injection ◽  
Different Types ◽  
Ternary Metal ◽  
Enhanced Luminescence

The hot-injection method was used for the synthesis of ternary metal chalcogenide nanocrystals (NCs) CuInS2 (CIS); this was achieved by using the metal precursors (copper iodide and indium acetate) and four different types of sulfur precursor solutions. It was discovered that CIS NCs synthesized with different sulfur precursor solutions exhibited the chalcopyrite structure with similar particle sizes of ~4.2 nm. As a comparison, CIS NCs synthesized using ODE-S precursor displayed an enhanced luminescence intensity and a long PL decay lifetime, which could be considered as an evidence of improved interior crystallinity.

Effects of Sand Particle Size and Gradation on Strength of Reactive Powder Concrete

2011 ◽  
Vol 261-263 ◽  
pp. 208-211 ◽  
Author(s):  
Tao Ji ◽  
Bao Chun Chen ◽  
Yi Zhou Zhuang ◽  
Feng Li ◽  
Zhi Bin Huang ◽  
...  
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Strength Test ◽  
Reactive Powder Concrete ◽  
Sand Particle ◽  
Particle Sizes ◽  
Test Results ◽  
Sand Mixture ◽  
Different Types ◽  
Reactive Powder

After modification, Toufar model was used to calculate the packing degrees of sand mixtures with different particle sizes. For four gradations of sands, the weight ratios of different types of sands with different size ranges, which achieve maximum packing degrees, have been obtained using the modified Toufar model. A strength test of reactive powder concretes (RPCs) with the four gradations of sands was reported. The test results show that the strength of RPC is related to both the maximum grain size and the packing degree of sand mixture. The smaller maximum grain size and larger packing degree of sand mixture can achieve the higher strength of RPC.

scholarly journals A polarimetric scattering database for non-spherical ice particles at microwave wavelengths

2016 ◽  
Vol 9 (10) ◽  
pp. 5119-5134 ◽  
Author(s):  
Yinghui Lu ◽  
Zhiyuan Jiang ◽  
Kultegin Aydin ◽  
Johannes Verlinde ◽  
Eugene E. Clothiaux ◽  
...  
Keyword(s):  
Electromagnetic Scattering ◽  
Incident Radiation ◽  
Single Scattering ◽  
Particle Orientation ◽  
Particle Scattering ◽  
Microwave Frequencies ◽  
Particle Properties ◽  
Ice Particles ◽  
Science Community ◽  
Fixed Orientation

Abstract. The atmospheric science community has entered a period in which electromagnetic scattering properties at microwave frequencies of realistically constructed ice particles are necessary for making progress on a number of fronts. One front includes retrieval of ice-particle properties and signatures from ground-based, airborne, and satellite-based radar and radiometer observations. Another front is evaluation of model microphysics by application of forward operators to their outputs and comparison to observations during case study periods. Yet a third front is data assimilation, where again forward operators are applied to databases of ice-particle scattering properties and the results compared to observations, with their differences leading to corrections of the model state. Over the past decade investigators have developed databases of ice-particle scattering properties at microwave frequencies and made them openly available. Motivated by and complementing these earlier efforts, a database containing polarimetric single-scattering properties of various types of ice particles at millimeter to centimeter wavelengths is presented. While the database presented here contains only single-scattering properties of ice particles in a fixed orientation, ice-particle scattering properties are computed for many different directions of the radiation incident on them. These results are useful for understanding the dependence of ice-particle scattering properties on ice-particle orientation with respect to the incident radiation. For ice particles that are small compared to the wavelength, the number of incident directions of the radiation is sufficient to compute reasonable estimates of their (randomly) orientation-averaged scattering properties. This database is complementary to earlier ones in that it contains complete (polarimetric) scattering property information for each ice particle – 44 plates, 30 columns, 405 branched planar crystals, 660 aggregates, and 640 conical graupel – and direction of incident radiation but is limited to four frequencies (X-, Ku-, Ka-, and W-bands), does not include temperature dependencies of the single-scattering properties, and does not include scattering properties averaged over randomly oriented ice particles. Rules for constructing the morphologies of ice particles from one database to the next often differ; consequently, analyses that incorporate all of the different databases will contain the most variability, while illuminating important differences between them. Publication of this database is in support of future analyses of this nature and comes with the hope that doing so helps contribute to the development of a database standard for ice-particle scattering properties, like the NetCDF (Network Common Data Form) CF (Climate and Forecast) or NetCDF CF/Radial metadata conventions.

Breakage of Carbon-Rubber Networks by Applied Stress

1952 ◽  
Vol 25 (4) ◽  
pp. 808-842 ◽  
Author(s):  
A. F. Blanchard ◽  
D. Parkinson
Keyword(s):  
Chemical Nature ◽  
Weak Type ◽  
Chain Structure ◽  
Strength Distribution ◽  
Particle Sizes ◽  
Carbon Particles ◽  
Different Types ◽  
Filler Particles ◽  
Mode Of Attachment ◽  
Rubber Filler

Abstract The results of this investigation strongly support previous conclusions by the authors that the softening of reinforced rubber when it is stressed to moderate extensions owes little to breakdown of filler chain structure and is due primarily to rupture of attachments between the filler and the rubber molecules. This means that the stiffness of reinforced rubber is influenced greatly by the mode of attachment of filler to rubber, and the conclusion reached is that such stiffening by finely divided fillers is largely a consequence of linkages between rubber molecules formed through the filler particles by rubber-filler bonds and assisted by the presence of coherent chain structure of the filler particles themselves. The work further suggests that the linkages formed through carbon particles are of two kinds : one a relatively weak type linkage due to physical (van der Waals) attachments, the other a strong type linkage due to chemisorptive attachments which remain unbroken by stressing. The strong linkages are relatively few and have not been found with fillers other than carbon black, but the strength distribution of the weaker type does not depend on the chemical nature or type of filler, although differences are found in the total number of such relatively weak attachments. The weak linkages are substantially all broken in the course of stressing to high elongations and the stiffening at the highest elongations is a consequence of the relatively small number of strong linkages. It is to be expected that among the fully reinforcing carbon blacks, where the particle sizes of the different types are roughly equivalent, those providing the greatest number of strong linkages will have the greatest reinforcing ability, and it may be significant in this connection that HAF black vulcanizates are recognized to have better abrasion resistance than MPC vulcanizates, in keeping with a larger number of strong linkages.

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