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GIST-PM-Asia v1: development of a numerical system to improve particulate matter forecasts in South Korea using geostationary satellite-retrieved aerosol optical data over Northeast Asia
摘要： To improve short-term particulate matter (PM) forecasts in South Korea, the initial distribution of PM composition, particularly over the upwind regions, is primarily important. To prepare the initial PM composition, the aerosol optical depth (AOD) data retrieved from a geostationary equatorial orbit (GEO) satellite sensor, GOCI (Geostationary Ocean Color Imager) which covers a part of Northeast Asia (113–146? E; 25–47? N), were used. Although GOCI can provide a higher number of AOD data in a semicontinuous manner than low Earth orbit (LEO) satellite sensors, it still has a serious limitation in that the AOD data are not available at cloud pixels and over high-re?ectance areas, such as desert and snow-covered regions. To overcome this limitation, a spatiotemporal-kriging (STK) method was used to better prepare the initial AOD distributions that were converted into the PM composition over Northeast Asia. One of the largest advantages in using the STK method in this study is that more observed AOD data can be used to prepare the best initial AOD ?elds compared with other methods that use single frame of observation data around the time of initialization. It is demonstrated in this study that the short-term PM forecast system developed with the application of the STK method can greatly improve PM10 predictions in the Seoul metropolitan area (SMA) when evaluated with ground-based observations. For example, errors and biases of PM10 predictions decreased by ～ 60 and ～ 70%, respectively, during the ?rst 6 h of short-term PM forecasting, compared with those without the initial PM composition. In addition, the in?uences of several factors on the performances of the short-term PM forecast were explored in this study. The in?uences of the choices of the control variables on the PM chemical composition were also investigated with the composition data measured via PILS-IC (particle-into-liquid sampler coupled with ion chromatography) and low air-volume sample instruments at a site near Seoul. To improve the overall performances of the short-term PM forecast system, several future research directions were also discussed and suggested.
关键词： particulate matter,short-term forecast,geostationary satellite,spatiotemporal-kriging,aerosol optical depth
更新于2025-09-04 15:30:14
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Towards on-chip mid infrared photonic aerosol spectroscopy
摘要： We propose an on-chip mid-infrared (MIR) photonic spectroscopy platform for aerosol characterization to obtain highly discriminatory information on the chemistry of aerosol particles. Sensing of aerosols is crucial for various environmental, climatic, warfare threat detection, and pulmonary healthcare applications. Currently, chemical characterization of aerosols is performed using FTIR spectroscopy, yielding chemical ?ngerprinting because most of the vibrational and rotational transitions of chemical molecules fall in the IR range, and Raman spectroscopy. Both techniques use free space bench-top geometries. Here, we propose miniaturized on-chip MIR photonics-based aerosol spectroscopy consisting of a broadband spiral-waveguide sensor that signi?cantly enhances the particle-light interaction to improve sensitivity. The spiral waveguides are made of a chalcogenide glass material (Ge23Sb7S70) which shows a broad transparency over the IR range (1–10 lm). We demonstrate the sensing of N-methyl aniline-based aerosol particles with the device. We anticipate that the sensor will readily complement existing photonic resonator-based particle sizing and counting techniques to develop a uni?ed framework for on-chip integrated photonic aerosol spectroscopy.
关键词： N-methyl aniline,chalcogenide glass,on-chip mid-infrared photonic spectroscopy,aerosol characterization,spiral-waveguide sensor
更新于2025-09-04 15:30:14
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Formation of silver films for advanced electrical properties by using aerosol deposition process
摘要： A simple room temperature aerosol deposition (AD) process was used to fabricate silver thick films for high efficiency metallization that can be applied to decrease the resistance–capacitance delay and increase the signal propagation speed in integrated circuits. To obtain more advanced performance than aerosol-deposited silver films reported in previous studies, experimental parameters (orifice size of nozzle and gas consumption) that could directly affect electrical resistivity were optimized in advance. The proper small orifice size was selected for facilitated reduction of electrical resistivity by activating the percolation effect and making more conduction channels. High gas consumption also reduced the electrical resistivity of the silver films, forming plenty of metal clusters. Using experimental parameters that showed the lowest resistivity, silver thick films were fabricated via the AD process and their properties were analyzed. The results of the X-ray diffraction confirmed that the silver particles underwent impact-induced plastic deformation. As the film thickness was thickened up to 12 scans, the collided particles filled up the rough alumina substrate. After 12 scans, the silver films became densified due to severe plastic deformation of the as-deposited silver particles. Therefore, the growth mechanism suggests that most silver particles in the initial deposition step contribute to mechanical interlocking, and the subsequent particles could lead to film densification.
关键词： aerosol deposition,electrical resistivity,silver films,metallization,integrated circuits
更新于2025-09-04 15:30:14
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All Printed Low-Power Metal Oxide Gas Sensors on Polymeric Substrates
摘要： This paper presents a novel approach for fabrication of miniaturized and fully printed metal oxide (MOX) gas sensors on polyimide substrate by using digital manufacturing of the functional layers, namely aerosol jet and inkjet printing technologies. We are reporting for the first time a stacking approach for all-printed metal-oxide sensors. High resolution (~20 μm) printing of metallic patterns is enabled by aerosol jet of gold (Au) nanoparticles in solution, which leads to printed resistive thermal transducers with a reduced size of 500×500 μm2. Wide area printing feature of the aerosol jet is also applied for printing thin (~2 μm) inter-dielectric polyimide layer in between the heater and gold electrodes. The gas sensing layer, i.e. Pd-doped Tin Oxide (SnO2) nanoparticles, is deposited through drop on demand inkjet printing. Proper operation of the printed sensors is evaluated in both dry and humid conditions under reducing and oxidizing gases i.e. CO and NO2, respectively. All the tests are performed at 250 oC, produced by the integrated micro-hotplate at a low power consumption of ~78mW. The chemo-resistive responses of the sensors towards both the gases are found to be in the acceptable range as compared to conventional metal-oxide gas sensor responses. These results are very promising for future integration of metal-oxide gas sensors notably in smart printed electronics, disposable systems and wearables.
关键词： Aerosol Jet,Metal Oxide,Printing,Gas Sensors,Micro-hotplates,Inkjet
更新于2025-09-04 15:30:14
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[IEEE 2018 7th Electronic System-Integration Technology Conference (ESTC) - Dresden, Germany (2018.9.18-2018.9.21)] 2018 7th Electronic System-Integration Technology Conference (ESTC) - Compact LTCC Packaging and Printing Technologies for Sub–THz Modules
摘要： Low Temperature Co-fired Ceramics (LTCC) is a ceramic multilayer material with properties that suit well as both as a substrate and packaging material. LTCCs multilayer capabilities, excellent electrical properties, extremely high reliability and full hermetic nature suit it to a wide range of RF applications. Several frequency bands of interest from 100 GHz up to 300 GHz could potentially benefit from the use of LTCC system in package devices. To test the ability of LTCC materials at these frequencies, several grounded coplanar waveguide (GCPW) on 35-60 μm thick LTCC substrates were manufactured with the help of high-resolution Aerosol Jet printing technique and measured from 1-320 GHz (Ferro A6M-E) and 1-220 GHz, respectively (DuPont 9k7). For the first time, LTCC material are characterized as mm-wave circuit substrates at the frequency band of 220-320 GHz.
关键词： high frequency,MMIC,high resolution,LTCC,thick-film,Aerosol Jet printing,H-Band,radar
更新于2025-09-04 15:30:14
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Combined sphere-spheroid particle model for the retrieval of the microphysical aerosol parameters via regularized inversion of lidar data
摘要： In this work we propose a two-step advancement of the Mie spherical-particle model accounting for particle non-sphericity. First, a naturally two-dimensional (2D) generalized model (GM) is made, which further triggers analogous 2D re-definitions of microphysical parameters. We consider a spheroidal-particle approach where the size distribution is additionally dependent on aspect ratio. Second, we incorporate the notion of a sphere-spheroid particle mixture (PM) weighted by a non-sphericity percentage. The efficiency of these two models is investigated running synthetic data retrievals with two different regularization methods to account for the inherent instability of the inversion procedure. Our preliminary studies show that a retrieval with the PM model improves the fitting errors and the microphysical parameter retrieval and it has at least the same efficiency as the GM. While the general trend of the initial size distributions is captured in our numerical experiments, the reconstructions are subject to artifacts. Finally, our approach is applied to a measurement case yielding acceptable results.
关键词： regularization,microphysical parameters,aerosol,lidar,spheroidal-particle model
更新于2025-09-04 15:30:14
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Retrieval of aerosol optical depth in the visible range with a Brewer spectrophotometer in Athens
摘要： A MkIV Brewer spectrophotometer has been operating in Athens since 2004. Direct-sun measurements originally scheduled for nitrogen dioxide retrievals were reprocessed to provide aerosol optical depths (AODs) at a wavelength of about 440 nm. A novel retrieval algorithm was specifically developed and the resulting AODs were compared to those obtained from a collocated Cimel filter radiometer belonging to the Aerosol Robotic Network (AERONET). The series are perfectly correlated, with Pearson’s correlation coefficients being as large as 0.996 and with 90 % of AOD deviations between the two instruments being within the World Meteorological Organisation (WMO) traceability limits. In order to reach such a high agreement, several instrumental factors impacting the quality of the Brewer retrievals must be taken into account, including sensitivity to the internal temperature, and the state of the external optics and pointing accuracy must be carefully checked. Furthermore, the long-term radiometric stability of the Brewer was investigated and the performances of in situ Langley extrapolations as a way to track the absolute calibration of the Brewer were assessed. Other sources of error, such as slight shifts of the wavelength scale, are discussed and some recommendations to Brewer operators are drawn. Although MkIV Brewers are rarely employed to retrieve AODs in the visible range, they represent a key source of information about aerosol changes in the past three decades and a potential worldwide network for present and future coordinated AOD measurements. Moreover, a better understanding of the AOD retrieval at visible wavelengths will also contribute in improving similar techniques in the more challenging UV range.
关键词： Cimel sun-sky photometer,AERONET,aerosol optical depth,Athens,Brewer spectrophotometer
更新于2025-09-04 15:30:14
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Polarimetric remote sensing in oxygen A and B bands: sensitivity study and information content analysis for vertical profile of aerosols
摘要： Theoretical analysis is conducted to reveal the information content of aerosol vertical profile in space-borne measurements of the backscattered radiance and degree of linear polarization (DOLP) in oxygen (O2) A and B bands. Assuming a quasi-Gaussian shape for aerosol vertical profile characterized by peak height H and half width γ (at half maximum), the Unified Linearized Vector Radiative Transfer Model (UNL-VRTM) is used to simulate the Stokes four-vector elements of upwelling radiation at the top of atmosphere (TOA) and their Jacobians with respect to H and γ. Calculations for different aerosol types and different combinations of H and γ values show that the wide range of gas absorption optical depth in O2 A and B band enables the sensitivity of backscattered DOLP and radiance at TOA to the aerosol layer at different altitudes. Quantitatively, DOLP in O2 A and B bands is found to be more sensitive to H and γ than radiance, especially over the bright surfaces (with large visible reflectance). In many O2 absorption wavelengths, the degree of freedom of signal (DFS) for retrieving H (or γ) generally increases with H (and γ) and can be close to unity in many cases, assuming that the composite uncertainty from surface and aerosol scattering properties as well as measurements is less than 5 %. Further analysis demonstrates that DFS needed for simultaneous retrieval of H and γ can be obtained from a combined use of DOLP measurements at ～ 10–100 O2 A and B absorption wavelengths (or channels), depending on the specific values of H. The higher the aerosol layer, the fewer number of channels for DOLP measurements in O2 A and B bands are needed for characterizing H and γ. Future hyperspectral measurements of DOLP in O2 A and B bands are needed to continue studying their potential and their combination with radiance and DOLP in atmospheric window channels for retrieving the vertical profiles of aerosols, especially highly scattering aerosols, over land.
关键词： oxygen A and B bands,radiative transfer model,aerosol vertical profile,polarimetric remote sensing,degree of linear polarization
更新于2025-09-04 15:30:14
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - OLCI/SLSTR SYN L2 Algorithm and Products Overview
摘要： The Sentinel-3 SYNERGY (SYN) processing branch has been designed as a combination of the acquisition of the two optical instruments, the Ocean and Land Color Instrument (OLCI) and the Sea and Land Surface Temperature Radiometer (SLSTR), with the main objective to provide surface vegetation products similar to those obtained from the VEGETATION instrument on SPOT. Synergistic and collocated measurements from both OLCI and SLSTR are ingested in an aerosol retrieval module. Then for each 300m pixel, Aerosol optical thickness data and Surface directional reflectances are retrieved and outputted in S3 SYNERGY L2 products. A description of the whole processing chain from OLCI/SLSTR L1 products to SYN L2 ones will be provided followed by a detailed description of the SYN L2 products. Quality assessment of these products, performed by the S3 MPC consortium and using in situ comparisons with AERONET data and with PROBA-V data will be discussed. Finally, a third section will be dedicated to the development of a future global aerosol products and the possible evolutions of this SYNERGY processing branch. More details about the whole S3 algorithms and products can be found in the Sentinel 3 Handbook [1]
关键词： Land products,Synergy,Sentinel-3,Aerosol parameters,collocated measurements
更新于2025-09-04 15:30:14
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The Role of Humidity in Tuning the Texture and Electrical Properties of Cu <sub/>2</sub> O Thin Films Deposited via Aerosol‐Assisted CVD
摘要： A study on the effect of carrier gas (CG) humidity on the texture and the resulting electronic properties of Cu2O thin films deposited using aerosol-assisted chemical vapor deposition (AA-CVD) at low temperatures (<365 °C) is reported. By increasing the CG humidity, the preferred orientation of the films can be tuned from [110] to [111]. By studying the initial stages of film deposition, a different growth mode is found for dry and humid conditions, which in turn directs the final texture of the films. The analysis of the electric properties of the films by Hall effect shows that carrier concentration remains in the order of 1015 cm?3 when using both dry and humid conditions. Conversely, Cu2O samples deposited with humid CG generally present a higher mobility, up to 17 cm2 V?1 s?1. [111]-textured Cu2O films with high mobility were used to fabricate a diode by depositing a ZnO layer on top using atmospheric pressure spatial atomic layer deposition (AP-SALD). The diode shows an excellent rectifying behavior with a high asymmetry close to 104 between ?1 and +1 V.
关键词： textured thin films,copper oxides,aerosol-assisted CVD,carrier mobility,atmospheric pressure processing
更新于2025-09-04 15:30:14