scholarly journals Sub 500 nm refractory carbonaceous particles in the polar stratosphere

2017 ◽  
Author(s):  
Katharina Schütze ◽  
James C. Wilson ◽  
Stephan Weinbruch ◽  
Nathalie Benker ◽  
Martin Ebert ◽  
...  
Keyword(s):  
Standard Deviation ◽  
High Resolution ◽  
Polar Vortex ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
Particle Volume ◽  
Carbonaceous Particles ◽  
Minor Elements ◽  
Validation Experiment ◽  
Polar Stratosphere

Abstract. Eleven particle samples collected in the polar stratosphere during SOLVE (SAGE III Ozone loss and validation experiment) from January until March 2000 were characterized in detail by high-resolution transmission and scanning electron microscopy (TEM/SEM) combined with energy-dispersive X-ray microanalysis. A total number of 4175 particles (TEM = 3845; SEM = 330) was analyzed from these samples which were collected mostly inside the polar vortex in the altitude range between 17.3 and 19.9 km. By particle volume, all samples are dominated by volatile particles (ammonium sulfates/hydrogen sulfates). By number, approximately 28–82 % of the particles are refractory carbonaceous with sizes between 20–830 nm. Internal mixtures of refractory carbonaceous and volatile particles comprise up to 16 %, individual volatile particles about 9 to 72 %. Most of the refractory carbonaceous particles are completely amorphous, a few of the particles are partly ordered with a graphene sheet separation distance of 0.37 ± 0.06 nm (mean value ± standard deviation). Carbon and oxygen are the only detected major elements with an atomic O / C ratio of 0.11 ± 0.07. Minor elements observed include Si, S, Fe, Cr and Ni with the following atomic ratios relative to C: Si / C: 0.010 ± 0.011; S / C: 0.0007 ± 0.0015; Fe / C: 0.0052 ± 0.0074; Cr / C: 0.0012 ± 0.0017; Ni / C: 0.0006 ± 0.0011 (all mean values ± standard deviation). High resolution element distribution images reveal that the minor elements are distributed within the carbonaceous matrix, i.e., heterogeneous inclusions are not observed. No difference in size, nanostructure and elemental composition was found between particles collected inside and outside the polar vortex. Based on chemistry and nanostructure, aircraft exhaust, volcanic emissions and biomass burning can certainly be excluded as source. The same is true for the less probable, but globally important sources: wood burning, coal burning, diesel engines and ship emissions. Rocket exhaust and carbonaceous material from interplanetary dust particles remain as possible sources of the refractory carbonaceous particles studied. However, additional work is required in order to identify the sources unequivocally.

scholarly journals Sub-micrometer refractory carbonaceous particles in the polar stratosphere

2017 ◽  
Vol 17 (20) ◽  
pp. 12475-12493 ◽  
Author(s):  
Katharina Schütze ◽  
James Charles Wilson ◽  
Stephan Weinbruch ◽  
Nathalie Benker ◽  
Martin Ebert ◽  
...  
Keyword(s):  
High Resolution ◽  
Polar Vortex ◽  
Median Number ◽  
Major Elements ◽  
Separation Distance ◽  
Volcanic Emissions ◽  
Carbonaceous Particles ◽  
Minor Elements ◽  
Validation Experiment ◽  
Polar Stratosphere

Abstract. Eleven particle samples collected in the polar stratosphere during SOLVE (SAGE III Ozone loss and validation experiment) from January until March 2000 were characterized in detail by high-resolution transmission and scanning electron microscopy (TEM/SEM) combined with energy-dispersive X-ray microanalysis. A total of 4202 particles (TEM  =  3872; SEM  =  330) were analyzed from these samples, which were collected mostly inside the polar vortex in the altitude range between 17.3 and 19.9 km. Particles that were volatile in the microscope beams contained ammonium sulfates and hydrogen sulfates and dominated the samples. Some particles with diameters ranging from 20 to 830 nm were refractory in the electron beams. Carbonaceous particles containing additional elements to C and O comprised from 72 to 100 % of the refractory particles. The rest were internal mixtures of these materials with sulfates. The median number mixing ratio of the refractory particles, expressed in units of particles per milligram of air, was 1.1 (mg air)−1 and varied between 0.65 and 2.3 (mg air)−1. Most of the refractory carbonaceous particles are completely amorphous, a few of the particles are partly ordered with a graphene sheet separation distance of 0.37 ± 0.06 nm (mean value ± standard deviation). Carbon and oxygen are the only detected major elements with an atomic O∕C ratio of 0.11 ± 0.07. Minor elements observed include Si, S, Fe, Cr and Ni with the following atomic ratios relative to C: Si∕C: 0.010 ± 0.011; S∕C: 0.0007 ± 0.0015; Fe∕C: 0.0052 ± 0.0074; Cr∕C: 0.0012 ± 0.0017; Ni∕C: 0.0006 ± 0.0011 (all mean values ± standard deviation).High-resolution element distribution images reveal that the minor elements are distributed within the carbonaceous matrix; i.e., heterogeneous inclusions are not observed. No difference in size, nanostructure and elemental composition was found between particles collected inside and outside the polar vortex. Based on chemistry and nanostructure, aircraft exhaust, volcanic emissions and biomass burning can certainly be excluded as sources. The same is true for the less probable but globally important sources: wood burning, coal burning, diesel engines and ship emissions. Recondensed organic matter and extraterrestrial particles, potentially originating from ablation and fragmentation, remain as possible sources of the refractory carbonaceous particles studied. However, additional work is required in order to identify the sources unequivocally.

High resolution PIXE analyses of interplanetary dust particles with the new Heidelberg proton microprobe

1995 ◽  
Vol 43 (3-4) ◽  
pp. 411-428 ◽  
Author(s):  
Jörg Bohsung ◽  
Peter Arndt ◽  
Elmar K. Jessberger ◽  
Mischa Maetz ◽  
Kurt Traxel ◽  
...  
Keyword(s):  
High Resolution ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
Proton Microprobe

Study of putative microfossils in space dust from the stratosphere

2010 ◽  
Vol 9 (3) ◽  
pp. 183-189 ◽  
Author(s):  
Kani Rauf ◽  
Anthony Hann ◽  
Max Wallis ◽  
Chandra Wickramasinghe
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
High Resolution ◽  
Aromatic Hydrocarbons ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
Space Dust ◽  
Prominent Peak ◽  
Scanning Electron

AbstractInterplanetary dust particles (IDPs) were recovered from the stratosphere by a cryosampler flown below a balloon flying at altitudes of 20–41 km. The present study uses high-resolution scanning electron microscopy (SEM) and ultraviolet-visible (UV-Vis) spectrophotometry to examine fresh samples collected at 38–41 km. The SEM observations confirm the presence of 7–32 μm sized clusters of coccoidal (0.4–1.3 μm in diameter) and rod-shaped (0.6–2.5 μm in length) objects as components of the IDP complex. Many single globules (1.6–9.0 μm in diameter) are also observed, some of which exhibit a rough surface with filamentous features of variable lengths. The spectrophotometry of the particles in aggregate reveals a prominent peak centred at 216 nm, which is remarkably similar to that of diatoms and close to the UV astronomical feature of 217.5 nm that has been identified as the spectral characteristic of aromatic hydrocarbons. The evidence presented here suggests that the stratospheric particles are IDPs comprising an assortment of materials among which are included microfossil-like features in variable sizes and forms, such as coccoids, rods and filaments.

High Resolution Observations of Ion-Milling Induced Transformation in Synthetic Hollandses

1981 ◽  
Vol 39 ◽  
pp. 114-115 ◽  
Author(s):  
T. J. Headley
Keyword(s):  
High Resolution ◽  
Radioactive Waste Disposal ◽  
Ion Milling ◽  
Minor Elements ◽  
Waste Forms ◽  
Carbon Substrates ◽  
Structural Differences ◽  
Oxide Phases ◽  
Argon Ions ◽  
High Resolution Microscopy

Oxide phases having the hollandite structure have been identified in multiphase ceramic waste forms being developed for radioactive waste disposal. High resolution studies of phases in the waste forms described in Ref. [2] were initiated to examine them for fine scale structural differences compared to natural mineral analogs. Two hollandites were studied: a (Ba,Cs,K)-titan-ate with minor elements in solution that is produced in the waste forms, and a synthesized BaAl2Ti6O16 phase containing ∼ 4.7 wt% Cs2O. Both materials were consolidated by hot pressing at temperatures above 1100°C. Samples for high resolution microscopy were prepared both by ion-milling (7kV argon ions) and by crushing and dispersing the fragments on holey carbon substrates. The high resolution studies were performed in a JEM 200CX/SEG operating at 200kV.

IDENTIFICATION AND ANALYSIS OF INTERPLANETARY DUST PARTICLES FILTERED FROM ANTARCTIC AIR

2018 ◽  
Author(s):  
Katherine Burgess ◽  
◽  
David Bour ◽  
Rhonda M. Stroud ◽  
Anais Bardyn ◽  
...  
Keyword(s):  
Interplanetary Dust ◽  
Dust Particles ◽  
Interplanetary Dust Particles

scholarly journals On Two Mechanisms of X-Ray Generation in Comets

1985 ◽  
Vol 85 ◽  
pp. 365-368
Author(s):  
S. Ibadov
Keyword(s):  
High Temperature ◽  
Interplanetary Dust ◽  
Dust Particles ◽  
Interplanetary Dust Particles ◽  
Temperature Plasma ◽  
X Ray ◽  
Plasma Generation ◽  
High Temperature Plasma

AbstractThe intensity of solar X-radiation scattered by a comet is calculated and compared to the proper X-radiation of the comet due to impacts of cometary and interplanetary dust particles. Detection of X-radiation of dusty comets at small heliocentric distances (R ≤ 1 a.u.) is found to be an indicator of high-temperature plasma generation as result of grain collisions.

scholarly journals Assessment of High Resolution Air Temperature Fields at Rocky Mountain National Park by Combining Scarce Point Measurements with Elevation and Remote Sensing Data

2020 ◽  
Vol 13 (1) ◽  
pp. 113
Author(s):  
Antonio-Juan Collados-Lara ◽  
Steven R. Fassnacht ◽  
Eulogio Pardo-Igúzquiza ◽  
David Pulido-Velazquez
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Air Temperature ◽  
Land Surface ◽  
National Park ◽  
Rocky Mountain ◽  
Rocky Mountain National Park ◽  
Temperature Fields ◽  
Lapse Rate ◽  
Validation Experiment

There is necessity of considering air temperature to simulate the hydrology and management within water resources systems. In many cases, a big issue is considering the scarcity of data due to poor accessibility and limited funds. This paper proposes a methodology to obtain high resolution air temperature fields by combining scarce point measurements with elevation data and land surface temperature (LST) data from remote sensing. The available station data (SNOTEL stations) are sparse at Rocky Mountain National Park, necessitating the inclusion of correlated and well-sampled variables to assess the spatial variability of air temperature. Different geostatistical approaches and weighted solutions thereof were employed to obtain air temperature fields. These estimates were compared with two relatively direct solutions, the LST (MODIS) and a lapse rate-based interpolation technique. The methodology was evaluated using data from different seasons. The performance of the techniques was assessed through a cross validation experiment. In both cases, the weighted kriging with external drift solution (considering LST and elevation) showed the best results, with a mean squared error of 3.7 and 3.6 °C2 for the application and validation, respectively.

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