Aerosol Impacts on Thermally Driven Orographic Convection

Abstract Observations from the Dominica Experiment (DOMEX) field campaign clearly show aerosols having an impact on cloud microphysical properties in thermally driven orographic clouds. It is hypothesized that when convection is forced by island surface heating, aerosols from the mostly forested island surface are lofted into the clouds, resulting in the observed high concentration of aerosols and the high concentration of small cloud droplets. When trying to understand the impact of these surface-based aerosols on precipitation, however, observed differences in cloud-layer moisture add to the complexity. The WRF Model with the aerosol-aware Thompson microphysics scheme is used to study six idealized scenarios of thermally driven island convection: with and without a surface aerosol source, with a relatively dry cloud layer and with a moist cloud layer, and with no wind and with a weak background wind. It is found that at least a weak background wind is needed to ensure Dominica-relevant results and that the effect of cloud-layer moisture on cloud and precipitation formation dominates over the effect of aerosol. The aerosol impact is limited by the dominance of precipitation formation through accretion. Nevertheless, in order to match observed cloud microphysical properties and precipitation, both a relatively dry cloud layer and a surface aerosol source are needed. The impact of a surface aerosol source on precipitation is strongest when the environment is not conducive to cloud growth.

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A Case Study of Radar Observations and WRF LES Simulations of the Impact of Ground-Based Glaciogenic Seeding on Orographic Clouds and Precipitation. Part I: Observations and Model Validations

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-14-0017.1 ◽

2014 ◽

Vol 53 (10) ◽

pp. 2264-2286 ◽

Cited By ~ 30

Author(s):

Xia Chu ◽

Lulin Xue ◽

Bart Geerts ◽

Roy Rasmussen ◽

Daniel Breed

Keyword(s):

Vertical Plane ◽

Vertical Motion ◽

Radar Data ◽

Mountain Range ◽

Motion Field ◽

Microphysics Scheme ◽

Seeding Effect ◽

Orographic Clouds ◽

Glaciogenic Seeding ◽

The Impact

AbstractProfiling airborne radar data and accompanying large-eddy-simulation (LES) modeling are used to examine the impact of ground-based glaciogenic seeding on cloud and precipitation in a shallow stratiform orographic winter storm. This storm occurred on 18 February 2009 over a mountain in Wyoming. The numerical simulations use the Weather Research and Forecasting (WRF) Model in LES mode with horizontal grid spacings of 300 and 100 m in a domain covering the entire mountain range, and a glaciogenic seeding parameterization coupled with the Thompson microphysics scheme. A series of non-LES simulations at 900-m resolution, each with different initial/boundary conditions, is validated against sounding, cloud, and precipitation data. The LES runs then are driven by the most representative 900-m non-LES simulation. The 100-m LES results compare reasonably well to the vertical-plane radar data. The modeled vertical-motion field reveals a turbulent boundary layer and gravity waves above this layer, as observed. The storm structure also validates well, but the model storm thins and weakens more rapidly than is observed. Radar reflectivity frequency-by-altitude diagrams suggest a positive seeding effect, but time- and space-matched model reflectivity diagrams only confirm this in a relative sense, in comparison with the trend in the control region upwind of seeding generators, and not in an absolute sense. A model sensitivity run shows that in this case natural storm weakening dwarfs the seeding effect, which does enhance snow mass and snowfall. Since the kinematic and microphysical structure of the storm is simulated well, future Part II of this study will examine how glaciogenic seeding impacts clouds and precipitation processes within the LES.

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Impact of the Variability in Vertical Separation between Biomass-Burning Aerosols and Marine Stratocumulus on Cloud Microphysical Properties over the Southeast Atlantic

10.5194/acp-2020-1039 ◽

2020 ◽

Author(s):

Siddhant Gupta ◽

Greg M. McFarquhar ◽

Joseph R. O'Brien ◽

David J. Delene ◽

Michael R. Poellot ◽

...

Keyword(s):

Biomass Burning ◽

Cloud Droplet ◽

Liquid Water Content ◽

Droplet Evaporation ◽

Cloud Layer ◽

Aerosol Layer ◽

Marine Stratocumulus ◽

Microphysical Properties ◽

Cloud Tops ◽

The Impact

Abstract. Marine stratocumulus cloud properties over the southeast Atlantic Ocean are impacted by contact between above-cloud biomass-burning aerosols and cloud tops. Different vertical separations (0 to 2000 m) between the aerosol layer and cloud tops were observed on six research flights in September 2016 during the NASA ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) field campaign. There were 30 contact profiles where the aerosol layer with aerosol concentration (Na) > 500 cm−3 was within 100 m of cloud tops, and 41 separated profiles where the aerosol layer with Na > 500 cm−3 was located more than 100 m above cloud tops. For contact profiles, the average cloud droplet concentration (Nc) in the cloud layer was up to 68 cm−3 higher, the effective radius (Re) up to 1.3 µm lower and the liquid water content (LWC) within 0.01 g m−3 compared to separated profiles. Free tropospheric humidity was higher in the presence of biomass-burning aerosols and contact profiles had a smaller decrease in humidity (and positive buoyancy) across cloud tops due to higher median above-cloud Na (895 cm−3) compared to separated profiles (30 cm−3). Due to droplet evaporation from entrainment mixing of warm, dry free tropospheric air into the clouds, the median Nc and LWC for contact profiles decreased with height by 21 % and 9 % in the top 20 % of the cloud layer. The impact of droplet evaporation was stronger during separated profiles as a greater decrease in humidity (and negative buoyancy) across cloud tops led to greater decreases in median Nc (30 %) and LWC (16 %) near cloud tops. Below-cloud Na was sampled during 61 profiles, and most contact profiles (20 out of 28) were within high-Na (> 350 cm−3) boundary layers while most separated profiles (22 out of 33) were within low-Na (

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A statistical subgrid-scale algorithm for precipitation formation in stratiform clouds in the ECHAM5 single column model

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-9335-2011 ◽

2011 ◽

Vol 11 (3) ◽

pp. 9335-9374 ◽

Cited By ~ 5

Author(s):

S. Jess ◽

P. Spichtinger ◽

U. Lohmann

Keyword(s):

Cloud Cover ◽

Climate Model ◽

Global Climate Model ◽

Subgrid Scale ◽

Column Model ◽

Microphysical Properties ◽

Single Column ◽

Single Column Model ◽

The Impact ◽

Precipitation Formation

Abstract. Cloud properties are usually assumed to be homogeneous within the cloudy part of the grid-box, i.e. subgrid-scale inhomogeneities in cloud cover and/or microphysical properties are often neglected. However, precipitation formation is initiated by large particles. Thus mean values are not representative and could lead to a delayed onset of precipitation. For a more physical description of the subgrid-scale structure of clouds we introduce a new statistical sub-column algorithm to study the impact of cloud inhomogeneities on stratiform precipitation. Each model column is divided into N independent sub-columns with sub-boxes in each layer, which are completely clear or cloudy. The cloud cover is distributed over the sub-columns depending on the diagnosed cloud fraction. Mass and number concentrations of cloud droplets and ice crystals are distributed randomly over the cloudy sub-columns according to prescribed probability distributions. Shapes and standard deviations of the distributions are obtained from aircraft observations. We have implemented this sub-column algorithm into the ECHAM5 global climate model to take subgrid variability of cloud cover and microphysical properties into account. Simulations with the Single Column Model version of ECHAM5 were carried out for one period of the Mixed-Phase Polar Arctic Cloud Experiment (MPACE) campaign as well as for the Eastern Pacific Investigation of climate Processes (EPIC) campaign. Results with the new algorithm show an earlier onset of precipitation for the EPIC campaign and a higher conversion of liquid to ice for the MPACE campaign, which reduces the liquid water path in better agreement with the observations than the original version of the ECHAM5 model.

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Submikroninių aerozolio dalelių kilmės ir fizikinių-cheminių parametrų įtaka atmosferos šiluminei pusiausvyrai

10.15388/vu.thesis.102 ◽

2020 ◽

Author(s):

◽

Julija Pauraitė-Dudek

Keyword(s):

Chemical Parameters ◽

Radiative Balance ◽

Submicron Aerosol ◽

Physical Chemical ◽

The Impact ◽

Aerosol Source

The impact of submicron aerosol source and physical-chemical parameters on atmospheric radiative balance

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Faculty Opinions recommendation of Randomized controlled trial to assess the impact of high concentration intraurethral lidocaine on urodynamic voiding parameters.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.736515166.793575195 ◽

2020 ◽

Author(s):

Linda Cardozo

Keyword(s):

Randomized Controlled Trial ◽

Controlled Trial ◽

High Concentration ◽

Randomized Controlled ◽

The Impact

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Chemical Composition and Metal Speciation in Porewaters from the Upper Qu’Appelle River Basin, Saskatchewan

Water Quality Research Journal ◽

10.2166/wqrj.1993.005 ◽

1993 ◽

Vol 28 (1) ◽

pp. 83-110 ◽

Cited By ~ 1

Author(s):

Richard E. Farrell ◽

Jae E. Yang ◽

P. Ming Huang ◽

Wen K. Liaw

Keyword(s):

Amino Acids ◽

Trace Metal ◽

River Basin ◽

Drainage Basin ◽

Metal Speciation ◽

Anthropogenic Activities ◽

High Concentration ◽

Metal Concentrations ◽

Carbonate Equilibria ◽

The Impact

Abstract Porewater samples from the upper Qu’Appelle River basin in Saskatchewan, Canada, were analyzed to obtain metal, inorganic ligand and amino add profiles. These data were used to compute the aqueous speciation of the metals in each porewater using the computer program GEOCHEM-PC. The porewaters were classified as slightly to moderately saline. Metal concentrations reflected both the geology of the drainage basin and the impact of anthropogenic activities. Whereas K and Na were present almost entirely as the free aquo ions, carbonate equilibria dominated the speciation of Ca. Mg and Mn (the predominant metal ligand species were of the type MCO3 (s). MCO30. and MHCO3+). Trace metal concentrations were generally within the ranges reported for non-polluted freshwater systems. Whereas the speciation of the trace metals Cr(III) and Co(II) was dominated by carbonate equilibria, Hg(II)-, Zn(II)- and Fe(II)-speciation was dominated by hydroxy-metal complexes of the type M(OH)+ and M(OH)2°. The speciation of Fe(III) was dominated by Fe(OH)3 (s). In porewaters with high chloride concentrations (> 2 mM), however, significant amounts of Hg(II) were bound as HgCl20 and HgClOH0. The aqueous speciation of Al was dominated by Al(OH)4− and Al2Si2O4(OH)6 (s). Total concentrations of dissolved free amino acids varied from 15.21 to 25.17 umole L−1. The most important metal scavenging amino acids were histidine (due to high stability constants for the metal-histidine complexes) and tryptophan (due to its relatively high concentration in the porewaters. i.e., 5.96 to 7.73 umole L−1). Secondary concentrations of various trace metal-amino add complexes were computed for all the porewaters, but metal-amino acid complexes dominated the speciation of Cu(II) in all the porewaters and Ni(II) in two of the porewaters.

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The impact of the microphysical properties of aerosol on the atmospheric correction of hyperspectral data in coastal waters

Atmospheric Measurement Techniques ◽

10.5194/amt-8-1593-2015 ◽

2015 ◽

Vol 8 (3) ◽

pp. 1593-1604 ◽

Cited By ~ 12

Author(s):

C. Bassani ◽

C. Manzo ◽

F. Braga ◽

M. Bresciani ◽

C. Giardino ◽

...

Keyword(s):

Accuracy Assessment ◽

Atmospheric Correction ◽

Solar Spectrum ◽

Hyperspectral Data ◽

High Spectral Resolution ◽

Quality Analysis ◽

Microphysical Properties ◽

Quantitative Remote Sensing ◽

The Impact ◽

Aerosol Types

Abstract. Hyperspectral imaging provides quantitative remote sensing of ocean colour by the high spectral resolution of the water features. The HICO™ (Hyperspectral Imager for the Coastal Ocean) is suitable for coastal studies and monitoring. The accurate retrieval of hyperspectral water-leaving reflectance from HICO™ data is still a challenge. The aim of this work is to retrieve the water-leaving reflectance from HICO™ data with a physically based algorithm, using the local microphysical properties of the aerosol in order to overcome the limitations of the standard aerosol types commonly used in atmospheric correction processing. The water-leaving reflectance was obtained using the HICO@CRI (HICO ATmospherically Corrected Reflectance Imagery) atmospheric correction algorithm by adapting the vector version of the Second Simulation of a Satellite Signal in the Solar Spectrum (6SV) radiative transfer code. The HICO@CRI algorithm was applied on to six HICO™ images acquired in the northern Mediterranean basin, using the microphysical properties measured by the Acqua Alta Oceanographic Tower (AAOT) AERONET site. The HICO@CRI results obtained with AERONET products were validated with in situ measurements showing an accuracy expressed by r2 = 0.98. Additional runs of HICO@CRI on the six images were performed using maritime, continental and urban standard aerosol types to perform the accuracy assessment when standard aerosol types implemented in 6SV are used. The results highlight that the microphysical properties of the aerosol improve the accuracy of the atmospheric correction compared to standard aerosol types. The normalized root mean square (NRMSE) and the similar spectral value (SSV) of the water-leaving reflectance show reduced accuracy in atmospheric correction results when there is an increase in aerosol loading. This is mainly when the standard aerosol type used is characterized with different optical properties compared to the local aerosol. The results suggest that if a water quality analysis is needed the microphysical properties of the aerosol need to be taken into consideration in the atmospheric correction of hyperspectral data over coastal environments, because aerosols influence the accuracy of the retrieved water-leaving reflectance.

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Postharvest Burning of Crop Residues in Home Stoves in a Rural Site of Daejeon, Korea: Its Impact to Atmospheric Carbonaceous Aerosol

Atmosphere ◽

10.3390/atmos12020257 ◽

2021 ◽

Vol 12 (2) ◽

pp. 257

Author(s):

Jin Sang Jung ◽

Ji Hwan Kang

Keyword(s):

Urban Area ◽

Rural Area ◽

Crop Residues ◽

Sampling Period ◽

Carbonaceous Aerosol ◽

Rural Site ◽

Carbonaceous Aerosols ◽

High Concentration ◽

Crop Residue Burning ◽

The Impact

To investigate the impact of burning postharvest crop residues in home stoves, PM2.5 samples (particulate matter with a diameter of <2.5 μm) were collected every 3 h at a rural site in Daejeon, Korea during the postharvest season in 2014. A high concentration of levoglucosan was observed with a peak value of 3.8 µg/m3 during the sampling period. The average mannosan/levoglucosan ratio (0.18) at the rural site during a severe BB episode (levoglucosan > 1 μg/m3) was similar to burnings of pepper stems (0.19) and bean stems (0.18) whereas the average OC/levoglucosan ratio (9.9) was similar to burning of pepper stems (10.0), implying that the severe BB episode was mainly attributed to burning of pepper stems. A very strong correlation was observed between levoglucosan and organic carbon (OC) (R2 = 0.81) during the entire sampling period, suggesting that the emission of organic aerosols at the rural site was strongly associated with the burning of crop residues in home stoves. The average mannosan/levoglucosan ratio (0.17 ± 0.06) in the rural area was similar to that in a nearby urban area in Daejeon (0.16 ± 0.04). It was concluded that crop residue burning in a home stove for space heating is one of the important sources of carbonaceous aerosols not only in a rural area but also in the urban area of Daejeon, Korea during the postharvest season.

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Pharmacologic modulation of 5-fluorouracil by folinic acid and high-dose pyridoxine for treatment of patients with digestive tract carcinomas

Scientific Reports ◽

10.1038/s41598-021-92110-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

David Machover ◽

Wathek Almohamad ◽

Vincent Castagné ◽

Christophe Desterke ◽

Léa Gomez ◽

...

Keyword(s):

Folinic Acid ◽

Digestive Tract ◽

Vitamin B6 ◽

Colorectal Adenocarcinoma ◽

High Dose ◽

High Concentration ◽

Carcinoma Of The Esophagus ◽

Pancreas Adenocarcinoma ◽

The Impact ◽

High Dose Vitamin

AbstractSupplementation of cancer cells exposed to 5-fluorouracil (FUra) and folinic acid (FA) with high concentration pyridoxal 5′-phosphate, the cofactor of vitamin B6, potentiates the cytotoxicity of FUra in a synergistic interaction mode. We report a pilot study in 13 patients with previously untreated advanced carcinoma of the digestive tract to assess the impact of high-dose pyridoxine (PN) on the antitumor activity of regimens comprising FUra and FA. Five patients had colorectal adenocarcinoma (CRC); 5 had pancreas adenocarcinoma (PC); and 3 had squamous cell carcinoma of the esophagus (EC). Patients with CRC and with PC received oxaliplatin, irinotecan, FUra and FA, and patients with EC had paclitaxel, carboplatin, FUra and FA. PN iv from 1000 to 3000 mg/day preceded each administration of FA and FUra. Eleven patients responded. Two patients with CRC attained CRs and 3 had PRs with reduction rates ≥ 78%. Two patients with PC attained CRs, and 2 had PRs with reduction rates ≥ 79%. Responders experienced disappearance of most metastases. Of 3 patients with EC, 2 attained CRs. Median time to attain a response was 3 months. Unexpected toxicity did not occur. Results suggest that high-dose vitamin B6 enhances antitumor potency of regimens comprising FUra and FA.

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Photocrosslinking and photopatterning of magneto-optical nanocomposite sol–gel thin film under deep-UV irradiation

Scientific Reports ◽

10.1038/s41598-021-84376-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

C. Bidaud ◽

D. Berling ◽

D. Jamon ◽

E. Gamet ◽

S. Neveu ◽

...

Keyword(s):

Uv Irradiation ◽

Cobalt Ferrite ◽

Sol Gel ◽

Optical Devices ◽

High Concentration ◽

Nanocomposite Thin Films ◽

Deep Uv ◽

High Concentrations ◽

193 Nm ◽

The Impact

AbstractThis paper is aimed at investigating the process of photocrosslinking under Deep-UV irradiation of nanocomposite thin films doped with cobalt ferrite magnetic nanoparticles (MNPs). This material is composed of a hybrid sol–gel matrix in which MNP can be introduced with high concentrations up to 20 vol%. Deep-UV (193 nm) is not only interesting for high-resolution patterning but we also show an efficient photopolymerization pathway even in the presence of high concentration of MNPs. In this study, we demonstrate that the photocrosslinking is based on the free radical polymerization of the methacrylate functions of the hybrid precursor. This process is initiated by Titanium-oxo clusters. The impact of the nanoparticles on the photopolymerization kinetic and photopatterning is investigated. We finally show that the photosensitive nanocomposite is suitable to obtain micropatterns with sub-micron resolution, with a simple and versatile process, which opens many opportunities for fabrication of miniaturized magneto-optical devices for photonic applications.

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