Log in

Relevant bibliographies by topics / Loaded origin in clouds / Journal articles

Journal articles on the topic 'Loaded origin in clouds'

To see the other types of publications on this topic, follow the link: Loaded origin in clouds.

Author: Grafiati

Published: 4 June 2021

Last updated: 17 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Loaded origin in clouds.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Gao, F., S. Stanič, K. Bergant, T. Bolte, F. Coren, T. Y. He, A. Hrabar, et al. "Monitoring presence and streaming patterns of Icelandic volcanic ash during its arrival to Slovenia." Biogeosciences Discussions 8, no. 2 (April 14, 2011): 3863–98. http://dx.doi.org/10.5194/bgd-8-3863-2011.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract. The eruption of the Eyjafjallajökull volcano starting on 14 April 2010 resulted in the spreading of volcanic ash over most parts of Europe. In Slovenia, the presence of volcanic ash was monitored using ground-based in-situ measurements, lidar-based remote sensing and airborne in-situ measurements. Volcanic origin of the detected aerosols was confirmed by subsequent spectral and chemical analysis of the collected samples. The initial arrival of volcanic ash to Slovenia was detected at ground level using in-situ measurements during the night of 17 April 2010, but was not observed via lidar-based remote sensing due to the presence of clouds at lower altitudes while the streaming height of ash-loaded air masses was above 5 km a.s.l. The second arrival of volcanic ash on 20 April 2010 was detected by both lidar-based remote sensing and airborne in-situ measurement, revealing two or more elevated atmospheric aerosol layers above Slovenia. Identification of samples from ground-based in-situ and airborne in-situ measurements based on energy-dispersive X-ray spectroscopy confirmed that a fraction of particles was volcanic ash from the Eyjafjallajökull eruption. We performed simulations of airflow trajectories to explain the arrival of the air masses containing volcanic ash to Slovenia.

2

Cainey, Jill M. "Understanding the origin of clouds." Environmental Chemistry 4, no. 3 (2007): 141. http://dx.doi.org/10.1071/en07010.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Vogt, Mario H. J., Joost W. van den Muijsenberg, Els Goulmy, Eric Spierings, Petra Kluck, Michel G. Kester, Ronald A. van Soest, Jan W. Drijfhout, Roel Willemze, and J. H. Frederik Falkenburg. "The DBY gene codes for an HLA-DQ5–restricted human male-specific minor histocompatibility antigen involved in graft-versus-host disease." Blood 99, no. 8 (April 15, 2002): 3027–32. http://dx.doi.org/10.1182/blood.v99.8.3027.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract Graft rejection or graft-versus-host (GVH) disease after HLA-identical stem cell transplantation is the result of recognition of minor histocompatibility antigens (mHags) by immunocompetent T lymphocytes from recipient or donor origin, respectively. Cytolytic T lymphocyte (CTL) clones can be isolated during graft rejection and GVH disease to identify mHags and their corresponding genes. Thus far, all human mHags identified appeared to be HLA class I–restricted. Here, we report the characterization of the first human HLA class II–restricted sex-linked mHag involved in GVH disease. Previously, we isolated an HLA-DQ5–restricted CD4+ CTL clone from a male patient with chronic myeloid leukemia who developed acute GVH disease grade III-IV after transplantation of HLA genotypically identical female stem cells. Using a panel of female HLA-DQ5+ EBV cells that we stably transfected with Y chromosome–specific genes, we determined that the HLA class II male-specific mHag (H-Y) was encoded by the Y chromosome–specific gene DBY. The H-Y epitope was localized in the DBY protein using female HLA-DQ5+peripheral blood mononuclear cells loaded with DBY protein fragments. The minimal peptide sequence leading to maximal recognition by the specific HLA-DQ5–restricted CTL clone was characterized as the 12–amino acid sequence HIENFSDIDMGE. Although the epitope differed by 3 amino acids from its X-homolog DBX, only 2 polymorphisms were shown to be essential for recognition by the CTL clone.

4

Price, R. J., S. Viti, and D. A. Williams. "On the origin of diffuse clouds." Monthly Notices of the Royal Astronomical Society 343, no. 4 (August 21, 2003): 1257–62. http://dx.doi.org/10.1046/j.1365-8711.2003.06762.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Shchekinov, Yu A., and I. I. Zinchenko. "The origin of giant molecular clouds." Astronomy Reports 48, no. 8 (August 2004): 629–37. http://dx.doi.org/10.1134/1.1787065.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Valdivia, Valeska, Benjamin Godard, Patrick Hennebelle, Maryvonne Gerin, Pierre Lesaffre, and Jacques Le Bourlot. "Origin of CH+ in diffuse molecular clouds." Astronomy & Astrophysics 600 (April 2017): A114. http://dx.doi.org/10.1051/0004-6361/201629905.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Context. Molecular clouds are known to be magnetised and to display a turbulent and complex structure where warm and cold phases are interwoven. The turbulent motions within molecular clouds transport molecules, and the presence of magnetic fields induces a relative velocity between neutrals and ions known as the ion-neutral drift (vd). These effects all together can influence the chemical evolution of the clouds. Aims. This paper assesses the roles of two physical phenomena which have previously been invoked to boost the production of CH+ under realistic physical conditions: the presence of warm H2 and the increased formation rate due to the ion-neutral drift. Methods. We performed ideal magnetohydrodynamical (MHD) simulations that include the heating and cooling of the multiphase interstellar medium (ISM), and where we treat dynamically the formation of the H2 molecule. In a post-processing step we compute the abundances of species at chemical equilibrium using a solver that we developed. The solver uses the physical conditions of the gas as input parameters, and can also prescribe the H2 fraction if needed. We validate our approach by showing that the H2 molecule generally has a much longer chemical evolution timescale compared to the other species. Results. We show that CH+ is efficiently formed at the edge of clumps, in regions where the H2 fraction is low (0.3−30%) but nevertheless higher than its equilibrium value, and where the gas temperature is high (≳ 300 K). We show that warm and out of equilibrium H2 increases the integrated column densities of CH+ by one order of magnitude up to values still ~ 3−10 times lower than those observed in the diffuse ISM. We balance the Lorentz force with the ion-neutral drag to estimate the ion-drift velocities from our ideal MHD simulations. We find that the ion-neutral drift velocity distribution peaks around ~ 0.04 km s-1, and that high drift velocities are too rare to have a significant statistical impact on the abundances of CH+. Compared to previous works, our multiphase simulations reduce the spread in vd, and our self-consistent treatment of the ionisation leads to much reduced vd. Nevertheless, our resolution study shows that this velocity distribution is not converged: the ion-neutral drift has a higher impact on CH+ at higher resolution. On the other hand, our ideal MHD simulations do not include ambipolar diffusion, which would yield lower drift velocities. Conclusions. Within these limitations, we conclude that warm H2 is a key ingredient in the efficient formation of CH+ and that the ambipolar diffusion has very little influence on the abundance of CH+, mainly due to the small drift velocities obtained. However, we point out that small-scale processes and other non-thermal processes not included in our MHD simulation may be of crucial importance, and higher resolution studies with better controlled dissipation processes are needed.

7

Gorbatskii, V. G. "Origin of clouds of the lα forest." Astrophysics 43, no. 1 (January 2000): 1–5. http://dx.doi.org/10.1007/bf02683941.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Nilges, Katja, Hanni Höhn, Henryk Pilch, Claudia Neukirch, Kirsten Freitag, P. J. Talbot, and Markus J. Maeurer. "Human Papillomavirus Type 16 E7 Peptide-Directed CD8+ T Cells from Patients with Cervical Cancer Are Cross-Reactive with the Coronavirus NS2 Protein." Journal of Virology 77, no. 9 (May 1, 2003): 5464–74. http://dx.doi.org/10.1128/jvi.77.9.5464-5474.2003.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

ABSTRACT Human papillomavirus type 16 (HPV16) E6 and E7 oncoproteins are required for cellular transformation and represent candidate targets for HPV-specific and major histocompatibility complex class I-restricted CD8+-T-cell responses in patients with cervical cancer. Recent evidence suggests that cross-reactivity represents the inherent nature of the T-cell repertoire. We identified HLA-A2 binding HPV16 E7 variant peptides from human, bacterial, or viral origin which are able to drive CD8+-T-cell responses directed against wild-type HPV16 E7 amino acid 11 to 19/20 (E711-19/20) epitope YMLDLQPET(T) in vitro. CD8+ T cells reacting to the HLA-A2-presented peptide from HPV16 E711-19(20) recognized also the HLA-A2 binding peptide TMLDIQPED (amino acids 52 to 60) from the human coronavirus OC43 NS2 gene product. Establishment of coronavirus NS2-specific, HLA-A2-restricted CD8+-T-cell clones and ex vivo analysis of HPV16 E7 specific T cells obtained by HLA-A2 tetramer-guided sorting from PBL or tumor-infiltrating lymphocytes obtained from patients with cervical cancer showed that cross-reactivity with HPV16 E711-19(20) and coronavirus NS252-60 represents a common feature of this antiviral immune response defined by cytokine production. Zero of 10 patients with carcinoma in situ neoplasia and 3 of 18 patients with cervical cancer showed ≥0.1% HPV16 E7-reactive T cells in CD8+ peripheral blood lymphocytes. In vivo priming with HPV16 was confirmed in patients with cervical cancer or preinvasive HPV16-positive lesions using HLA-A2 tetramer complexes loaded with the E6-derived epitope KLPQLCTEL. In contrast, we could not detect E6-reactive T cells in healthy individuals. These data imply that the measurement of the HPV16 E711-19(20) CD8+-T-cell response may reflect cross-reactivity with a common pathogen and that variant peptides may be employed to drive an effective cellular immune response against HPV.

9

Wolf, Veronika, Thomas Kuhn, Mathias Milz, Peter Voelger, Martina Krämer, and Christian Rolf. "Arctic ice clouds over northern Sweden: microphysical properties studied with the Balloon-borne Ice Cloud particle Imager B-ICI." Atmospheric Chemistry and Physics 18, no. 23 (December 7, 2018): 17371–86. http://dx.doi.org/10.5194/acp-18-17371-2018.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract. Ice particle and cloud properties such as particle size, particle shape and number concentration influence the net radiation effect of cirrus clouds. Measurements of these features are of great interest for the improvement of weather and climate models, especially for the Arctic region. In this study, balloon-borne in situ measurements of Arctic cirrus clouds have been analysed for the first time with respect to their origin. Eight cirrus cloud measurements have been carried out in Kiruna (68∘ N), Sweden, using the Balloon-borne Ice Cloud particle Imager (B-ICI). Ice particle diameters between 10 and 1200 µm have been found and the shape could be recognized from 20 µm upwards. Great variability in particle size and shape is observed. This cannot simply be explained by local environmental conditions. However, if sorted by cirrus origin, wind and weather conditions, the observed differences can be assessed. Number concentrations between 3 and 400 L−1 have been measured, but the number concentration has reached values above 100 L−1 only for two cases. These two cirrus clouds are of in situ origin and have been associated with waves. For all other measurements, the maximum ice particle concentration is below 50 L−1 and for one in situ origin cirrus case only 3 L−1. In the case of in situ origin clouds, the particles are all smaller than 350 µm diameter. The PSDs for liquid origin clouds are much broader with particle sizes between 10 and 1200 µm. Furthermore, it is striking that in the case of in situ origin clouds almost all particles are compact (61 %) or irregular (25 %) when examining the particle shape. In liquid origin clouds, on the other hand, most particles are irregular (48 %), rosettes (25 %) or columnar (14 %). There are hardly any plates in cirrus regardless of their origin. It is also noticeable that in the case of liquid origin clouds the rosettes and columnar particles are almost all hollow.

10

Pulido, F. A., B. R. McNamara, A. C. Edge, M. T. Hogan, A. N. Vantyghem, H. R. Russell, P. E. J. Nulsen, I. Babyk, and P. Salomé. "The Origin of Molecular Clouds in Central Galaxies." Astrophysical Journal 853, no. 2 (February 5, 2018): 177. http://dx.doi.org/10.3847/1538-4357/aaa54b.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Koyama, Hiroshi, and Shu-ichiro Inutsuka. "An Origin of Supersonic Motions in Interstellar Clouds." Astrophysical Journal 564, no. 2 (January 10, 2001): L97—L100. http://dx.doi.org/10.1086/338978.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Nagai, Tomoya, Shu‐ichiro Inutsuka, and Shoken M. Miyama. "An Origin of Filamentary Structure in Molecular Clouds." Astrophysical Journal 506, no. 1 (October 10, 1998): 306–22. http://dx.doi.org/10.1086/306249.

Full text

APA, Harvard, Vancouver, ISO, and other styles

13

Huo, Juan, Yufang Tian, Xue Wu, Congzheng Han, Bo Liu, Yongheng Bi, Shu Duan, and Daren Lyu. "Properties of ice cloud over Beijing from surface Ka-band radar observations during 2014–2017." Atmospheric Chemistry and Physics 20, no. 22 (November 27, 2020): 14377–92. http://dx.doi.org/10.5194/acp-20-14377-2020.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract. The physical properties and radiative role of ice clouds remain one of the uncertainties in the Earth–atmosphere system. In this study, we present a detailed analysis of ice cloud properties based on 4 years of surface millimeter-wavelength radar measurements in Beijing, China, where the summer monsoon from the ocean and the winter monsoon from the continent prevail alternately, resulting in various ice clouds. More than 6300 ice cloud clusters were studied to quantify the properties of ice clouds, such as the height, optical depth and horizontal extent, which can serve as a reference for parameterization and characterization in global climate models. In addition, comparison between ice cloud clusters formed under the summer monsoon and the winter monsoon indicates the different formation and evolution mechanisms of cirrus clouds. Statistically, temperatures of more than 95 % of ice radar bins are below −15 ∘C and more than 80 % of ice clouds are above 7 km. The dependence of the radar reflectivity of ice particles on height and temperature was also observed in this study, indicating that the reflectivity of ice bins increases (decreases) as the temperature (height) increases. In addition, it is found that there is a strong linear relationship between the mean reflectivity and the ice cloud depth. Due to various synoptic circumstances, the ice clouds in summer are warmer, higher and thicker, with larger reflectivity than that in winter; in particular, the mean cloud-top height of ice clouds in summer is 2.2 km higher than that in winter. Our analysis indicates that in spring, in situ-origin cirrus clouds are more common than liquid-origin cirrus clouds, while in summer liquid-origin cirrus clouds are more frequent; in autumn and winter, most cirrus clouds are of in situ origin.

14

Gadsden, M. "Noctilucent clouds seen at 60°N: origin and development." Journal of Atmospheric and Solar-Terrestrial Physics 60, no. 18 (December 1998): 1763–72. http://dx.doi.org/10.1016/s1364-6826(98)00154-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Simion, Iulia T., Vasily Belokurov, and Sergey E. Koposov. "Common origin for Hercules-Aquila and Virgo Clouds inGaiaDR2." Monthly Notices of the Royal Astronomical Society 482, no. 1 (October 9, 2018): 921–28. http://dx.doi.org/10.1093/mnras/sty2744.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Takahashi, Sanemichi Z., Kengo Tomida, Masahiro N. Machida, and Shu-ichiro Inutsuka. "The origin of rotation profiles in star-forming clouds." Monthly Notices of the Royal Astronomical Society 463, no. 2 (September 16, 2016): 1390–99. http://dx.doi.org/10.1093/mnras/stw1994.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Mossop, S. C. "The Origin and Concentration of Ice Crystals in Clouds." Bulletin of the American Meteorological Society 66, no. 3 (March 1985): 264–73. http://dx.doi.org/10.1175/1520-0477(1985)066<0264:toacoi>2.0.co;2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Wagenblast, R., D. A. Williams, T. J. Millar, and L. A. M. Nejad. "On the origin of NH in diffuse interstellar clouds." Monthly Notices of the Royal Astronomical Society 260, no. 2 (January 15, 1993): 420–24. http://dx.doi.org/10.1093/mnras/260.2.420.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Surdin, V. G. "On the origin of stellar aggregates in molecular clouds." Astronomische Nachrichten: A Journal on all Fields of Astronomy 310, no. 5 (1989): 381–83. http://dx.doi.org/10.1002/asna.2113100516.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Van Woerden, Hugo, Ulrich J. Schwarz, and Aad N. M. Hulsbosch. "Highlights of high-velocity clouds." Symposium - International Astronomical Union 106 (1985): 387–408. http://dx.doi.org/10.1017/s0074180900242824.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Twenty years after their first discovery at Dwingeloo (Muller, Oort and Raimond 1963), the nature and origin of high-velocity clouds (HVCs) remain enigmatic. Yet, much important progress has been made in the study of their properties, and prospects are brightening that the problem of their distances, which holds the key to their understanding, may soon be solved.

21

Clube, S. V. M. "Molecular clouds: comet factories?" International Astronomical Union Colloquium 83 (1985): 19–30. http://dx.doi.org/10.1017/s0252921100083779.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

AbstractRecent discoveries seem to indicate a catastrophic history of terrestrial evolution, explicable in terms of Oort cloud disturbance by molecular clouds in the Galactic disc. The problem of Oort cloud replenishment thus assumes considerable significance and reasons are given for supposing comet exchange takes place during actual penetration of molecular clouds. The number density of comets in molecular clouds, thereby implied, seems to suggest primary condensations of ≤103km in a dense precursor state of spiral arms. If chemical and/or isotopic signatures of comets should indicate an extra-Solar System source, the theory of terrestrial catastrophism may place new constraints on our understanding of the origin of molecular clouds.

22

Schnaiter, M., E. Järvinen, P. Vochezer, A. Abdelmonem, R. Wagner, O. Jourdan, G. Mioche, et al. "Cloud chamber experiments on the origin of ice crystal complexity in cirrus clouds." Atmospheric Chemistry and Physics Discussions 15, no. 21 (November 4, 2015): 30511–61. http://dx.doi.org/10.5194/acpd-15-30511-2015.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract. This study reports on the origin of ice crystal complexity and its influence on the angular light scattering properties of cirrus clouds. Cloud simulation experiments were conducted at the AIDA (Aerosol Interactions and Dynamics in the Atmosphere) cloud chamber of the Karlsruhe Institute of Technology (KIT). A new experimental procedure was applied to grow and sublimate ice particles at defined super- and subsaturated ice conditions and for temperatures in the −40 to −60 °C range. The experiments were performed for ice clouds generated via homogeneous and heterogeneous initial nucleation. Ice crystal complexity was deduced from measurements of spatially resolved single particle light scattering patterns by the latest version of the Small Ice Detector (SID-3). It was found that a high ice crystal complexity is dominating the microphysics of the simulated clouds and the degree of this complexity is dependent on the available water vapour during the crystal growth. Indications were found that the crystal complexity is influenced by unfrozen H2SO4/H2O residuals in the case of homogeneous initial ice nucleation. Angular light scattering functions of the simulated ice clouds were measured by the two currently available airborne polar nephelometers; the Polar Nephelometer (PN) probe of LaMP and the Particle Habit Imaging and Polar Scattering (PHIPS-HALO) probe of KIT. The measured scattering functions are featureless and flat in the side- and backward scattering directions resulting in low asymmetry parameters g around 0.78. It was found that these functions have a rather low sensitivity to the crystal complexity for ice clouds that were grown under typical atmospheric conditions. These results have implications for the microphysical properties of cirrus clouds and for the radiative transfer through these clouds.

23

Schnaiter, Martin, Emma Järvinen, Paul Vochezer, Ahmed Abdelmonem, Robert Wagner, Olivier Jourdan, Guillaume Mioche, et al. "Cloud chamber experiments on the origin of ice crystal complexity in cirrus clouds." Atmospheric Chemistry and Physics 16, no. 8 (April 25, 2016): 5091–110. http://dx.doi.org/10.5194/acp-16-5091-2016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract. This study reports on the origin of small-scale ice crystal complexity and its influence on the angular light scattering properties of cirrus clouds. Cloud simulation experiments were conducted at the AIDA (Aerosol Interactions and Dynamics in the Atmosphere) cloud chamber of the Karlsruhe Institute of Technology (KIT). A new experimental procedure was applied to grow and sublimate ice particles at defined super- and subsaturated ice conditions and for temperatures in the −40 to −60 °C range. The experiments were performed for ice clouds generated via homogeneous and heterogeneous initial nucleation. Small-scale ice crystal complexity was deduced from measurements of spatially resolved single particle light scattering patterns by the latest version of the Small Ice Detector (SID-3). It was found that a high crystal complexity dominates the microphysics of the simulated clouds and the degree of this complexity is dependent on the available water vapor during the crystal growth. Indications were found that the small-scale crystal complexity is influenced by unfrozen H2SO4 / H2O residuals in the case of homogeneous initial ice nucleation. Angular light scattering functions of the simulated ice clouds were measured by the two currently available airborne polar nephelometers: the polar nephelometer (PN) probe of Laboratoire de Métérologie et Physique (LaMP) and the Particle Habit Imaging and Polar Scattering (PHIPS-HALO) probe of KIT. The measured scattering functions are featureless and flat in the side and backward scattering directions. It was found that these functions have a rather low sensitivity to the small-scale crystal complexity for ice clouds that were grown under typical atmospheric conditions. These results have implications for the microphysical properties of cirrus clouds and for the radiative transfer through these clouds.

24

Dudorov, A. E. "MHD instabilities and fragmentation of molecular clouds." Symposium - International Astronomical Union 147 (1991): 402–4. http://dx.doi.org/10.1017/s0074180900199164.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Dudorov, A. E. "MHD instabilities and fragmentation of molecular clouds." Symposium - International Astronomical Union 147 (1991): 402–4. http://dx.doi.org/10.1017/s0074180900239788.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Chiar, Jean E., and Yvonne J. Pendleton. "The origin and evolution of interstellar organics." Proceedings of the International Astronomical Union 4, S251 (February 2008): 35–44. http://dx.doi.org/10.1017/s1743921308021133.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

AbstractOver the last decade, we have made great strides in better understanding dust composition and evolution in dense clouds and the diffuse interstellar medium (ISM). Thanks to improvements in IR detector sensitivity on ground-based telescopes and the Spitzer Space Telescope mission, we are no longer limited to a handful of bright background stars in order to study dust composition in quiescent dense clouds and the diffuse ISM. More thorough sampling of lines of sight in these regions has highlighted the dichotomy of the nature and composition of dust in these environments. In addition, successes in recreating interstellar processes and dust-analogs in the laboratory have helped us to understand the differences in dust absorption features we observe in the ISM. In this article, we focus on the organic components of interstellar dust, reviewing past work and highlighting the most recent observations and laboratory experiments.

27

Petrukhin, A. A., and S. Yu Matveev. "Gamma-Rays from magellanic clouds and origin of cosmic rays." Bulletin of the Russian Academy of Sciences: Physics 73, no. 5 (May 2009): 584–87. http://dx.doi.org/10.3103/s1062873809050153.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Höfner, Susanne, and Bernd Freytag. "Exploring the origin of clumpy dust clouds around cool giants." Astronomy & Astrophysics 623 (March 2019): A158. http://dx.doi.org/10.1051/0004-6361/201834799.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Context. Dust grains forming in the extended atmospheres of AGB stars are critical for the heavy mass loss of these cool luminous giants, as they provide radiative acceleration for the stellar winds. Characteristic mid-IR spectral features indicate that the grains consist mainly of silicates and corundum. The latter species seems to form in a narrow zone within about 2 stellar radii, preceding the condensation of silicate dust, which triggers the outflow. Recent high-angular-resolution observations show clumpy, variable dust clouds at these distances. Aims. We explore possible causes for the formation of inhomogeneous dust layers, using 3D dynamical simulations. Methods. We modeled the outer convective envelope and the dust-forming atmosphere of an M-type AGB star with the CO5BOLD radiation-hydrodynamics code. The simulations account for frequency-dependent gas opacities, and include a time-dependent description of grain growth and evaporation for corundum (Al2O3) and olivine-type silicates (Mg2SiO4). Results. In the inner, gravitationally bound, and corundum-dominated layers of the circumstellar envelope, a patchy distribution of the dust emerges naturally, due to atmospheric shock waves that are generated by large-scale convective flows and pulsations. The formation of silicate dust at somewhat larger distances probably indicates the outer limit of the gravitationally bound layers. The current models do not describe wind acceleration, but the cloud formation mechanism should also work for stars with outflows. Timescales of atmospheric dynamics and grain growth are similar to observed values. In spherical averages of dust densities, more easily comparable to unresolved observations and 1D models, the variable 3D morphology manifests itself as cycle-to-cycle variations. Conclusions. Grain growth in the wake of large-scale non-spherical shock waves, generated by convection and pulsations, is a likely mechanism for producing the observed clumpy dust clouds, and for explaining their physical and dynamical properties.

29

Sorrell, Wilfred H. "Origin of Amino Acids and Organic Sugars in Interstellar Clouds." Astrophysical Journal 555, no. 2 (July 10, 2001): L129—L132. http://dx.doi.org/10.1086/322525.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

WANG, Yu-Ming, Pin-Zhong YE, and Shui WANG. "An Interplanetary Origin of Great Geomagnetic Storms: Multiple Magnetic Clouds." Chinese Journal of Geophysics 47, no. 3 (May 2004): 417–23. http://dx.doi.org/10.1002/cjg2.502.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Elmegreen, Bruce G., and Edith Falgarone. "A Fractal Origin for the Mass Spectrum of Interstellar Clouds." Astrophysical Journal 471, no. 2 (November 10, 1996): 816–21. http://dx.doi.org/10.1086/178009.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Smirnov, V. V., D. A. Gillette, G. S. Golitsyn, and D. J. MacKinnon. "The origin and evolution of dust clouds in Central Asia." Atmospheric Research 34, no. 1-4 (June 1994): 169–76. http://dx.doi.org/10.1016/0169-8095(94)90088-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Danly, Laura, and Chris Blades. "Ultraviolet Observations of Halo Clouds." International Astronomical Union Colloquium 120 (1989): 408–15. http://dx.doi.org/10.1017/s0252921100024179.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Since the earliest optical absorption line studies of Munch and Zirin (1961) identified clouds of gas located at large distances from the galactic plane, considerable effort has gone into trying to understand the origin and nature of Milky Way halo gas. Subsequent high resolution optical absorption studies (Albert 1981; Blades et al 1989) have expanded on the early results, demonstrating clearly that (1) halo clouds are more likely to have velocities outside the range allowed by galactic rotation and (2) halo clouds show smaller depletion of refractory elements compared to their disk counterparts (i.e. the Spitzer-Routley effect).

34

Luebke, A. E., A. Afchine, A. Costa, J. Meyer, C. Rolf, N. Spelten, L. M. Avallone, D. Baumgardner, and M. Krämer. "The origin of midlatitude ice clouds and the resulting influence on their microphysical properties." Atmospheric Chemistry and Physics Discussions 15, no. 23 (December 7, 2015): 34243–81. http://dx.doi.org/10.5194/acpd-15-34243-2015.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract. The radiative role of ice clouds in the atmosphere is known to be important, but uncertainties remain concerning the magnitude and net effects. However, through measurements of the microphysical properties of cirrus clouds, we can better characterize them, which can ultimately allow for their radiative properties to be more accurately ascertained. It has recently been proposed that there are two types of cirrus clouds – in situ and liquid origin. In this study, we present observational evidence to show that two distinct types of cirrus do exist. Airborne, in situ measurements of cloud ice water content (IWC), ice crystal concentration (Nice), and ice crystal size from the 2014 ML-CIRRUS campaign provide cloud samples that have been divided according to their origin type. The key features that set liquid origin cirrus apart from the in situ origin cirrus are a higher frequency of high IWC (> 100 ppmv), higher Nice values, and larger ice crystals. A vertical distribution of Nice shows that the in situ origin cirrus clouds exhibit a median value of around 0.1 cm−3, while the liquid origin concentrations are slightly, but notably higher. The median sizes of the crystals contributing the most mass are less than 200 μm for in situ origin cirrus, with some of the largest crystals reaching 550 μm in size. The liquid origin cirrus, on the other hand, were observed to have median diameters greater than 200 μm, and crystals that were up to 750 μm. An examination of these characteristics in relation to each other and their relationship to temperature provides strong evidence that these differences arise from the dynamics and conditions in which the ice crystals formed. Additionally, the existence of these two groups in cirrus cloud populations may explain why a bimodal distribution in the IWC-temperature relationship has been observed. We hypothesize that the low IWC mode is the result of in situ origin cirrus and the high IWC mode is the result of liquid origin cirrus.

35

Luebke, Anna E., Armin Afchine, Anja Costa, Jens-Uwe Grooß, Jessica Meyer, Christian Rolf, Nicole Spelten, Linnea M. Avallone, Darrel Baumgardner, and Martina Krämer. "The origin of midlatitude ice clouds and the resulting influence on their microphysical properties." Atmospheric Chemistry and Physics 16, no. 9 (May 12, 2016): 5793–809. http://dx.doi.org/10.5194/acp-16-5793-2016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract. The radiative role of ice clouds in the atmosphere is known to be important, but uncertainties remain concerning the magnitude and net effects. However, through measurements of the microphysical properties of cirrus clouds, we can better characterize them, which can ultimately allow for their radiative properties to be more accurately ascertained. Recently, two types of cirrus clouds differing by formation mechanism and microphysical properties have been classified – in situ and liquid origin cirrus. In this study, we present observational evidence to show that two distinct types of cirrus do exist. Airborne, in situ measurements of cloud ice water content (IWC), ice crystal concentration (Nice), and ice crystal size from the 2014 ML-CIRRUS campaign provide cloud samples that have been divided according to their origin type. The key features that set liquid origin cirrus apart from the in situ origin cirrus are higher frequencies of high IWC ( > 100 ppmv), higher Nice values, and larger ice crystals. A vertical distribution of Nice shows that the in situ origin cirrus clouds exhibit a median value of around 0.1 cm−3, while the liquid origin concentrations are slightly, but notably higher. The median sizes of the crystals contributing the most mass are less than 200 µm for in situ origin cirrus, with some of the largest crystals reaching 550 µm in size. The liquid origin cirrus, on the other hand, were observed to have median diameters greater than 200 µm, and crystals that were up to 750 µm. An examination of these characteristics in relation to each other and their relationship to temperature provides strong evidence that these differences arise from the dynamics and conditions in which the ice crystals formed. Additionally, the existence of these two groups in cirrus cloud populations may explain why a bimodal distribution in the IWC-temperature relationship has been observed. We hypothesize that the low IWC mode is the result of in situ origin cirrus and the high IWC mode is the result of liquid origin cirrus.

36

Pudritz, Ralph E., and N. K. R. Kevlahan. "Shock interactions, turbulence and the origin of the stellar mass spectrum." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 371, no. 2003 (November 28, 2013): 20120248. http://dx.doi.org/10.1098/rsta.2012.0248.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Supersonic turbulence is an essential element in understanding how structure within interstellar gas is created and shaped. In the context of star formation, many computational studies show that the mass spectrum of density and velocity fluctuations within dense clouds, as well as the distribution of their angular momenta, trace their origin to the statistical and physical properties of gas that is lashed with shock waves. In this paper, we review the observations, simulations and theories of how turbulent-like processes can account for the structures we see in molecular clouds. We then compare traditional ideas of supersonic turbulence with a simpler physical model involving the effects of multiple shock waves and their interactions in the interstellar medium. Planar intersecting shock waves produce dense filaments and generate vortex sheets that are essential to create the broad range of density and velocity structure in clouds. As an example, the lower-mass behaviour of the stellar initial mass function can be traced to the tendency of a collection of shock waves to build up a lognormal density distribution (or column density). Vorticity—which is essential to produce velocity structure over a very broad range of length scales in shocked clouds—can also be generated by the passage of curved shocks or intersecting planar shocks through such media. Two major additional physical forces affect the structure of star-forming gas—gravity and feedback processes from young stars. Both of these can produce power-law tails at the high-mass end of the initial mass function.

37

Mathewson, D. S., S. R. Wayte, V. L. Ford, and K. Ruan. "The ‘High Velocity Cloud’ Origin of the Magellanic System." Publications of the Astronomical Society of Australia 7, no. 1 (1987): 19–25. http://dx.doi.org/10.1017/s1323358000021755.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

AbstractIt is believed that the splitting of the SMC into two fragments and the production of the Inter-Cloud gas and the Magellanic Stream occurred in the one event 4 × 108 years ago. This event was a collision between the LMC and SMC. This time is too short for the Stream to be tidal, or be the result of stripping of the Inter-Cloud gas by a diffuse gaseous halo. It is proposed that the clouds in the Stream are the results of collisions between the Inter-Cloud gas and HVCs in the Galactic halo. A model of this process accounts for all of the observational features of the Stream. Observations of HVCs in the path of the Magellanic Clouds are used to predict the development of the Stream. The HVCs in our halo are thought to be a result of a collision of a galaxy with our Galaxy 6 × 109 years ago.

38

Schappert, Sebastian, and Volkmar Wirth. "Origin and Flow History of Air Parcels in Orographic Banner Clouds." Journal of the Atmospheric Sciences 72, no. 9 (September 1, 2015): 3389–403. http://dx.doi.org/10.1175/jas-d-14-0300.1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract Banner clouds are clouds in the lee of steep mountains or sharp ridges. Previous work suggests that the main formation mechanism is vertical uplift in the lee of the mountain. On the other hand, little is known about the Lagrangian behavior of air parcels as they pass the mountain, which motivates the current investigation. Three different diagnostics are applied in the framework of large-eddy simulations of airflow past an isolated pyramid-shaped obstacle: Eulerian tracers indicating the initial positions of the parcels, streamlines along the time-averaged wind field, and online trajectories computed from the instantaneous wind field. All three methods diagnose a plume of large vertical uplift in the immediate lee of the mountain. According to the time-mean Eulerian tracers, the cloudy parcels originated within a fairly small coherent area at the inflow boundary. In contrast, the time-mean streamlines indicate a bifurcation into two distinct classes of air parcels with very different characteristics. The parcels in the first class originate at intermediate altitudes, pass the obstacle close to its summit, and proceed directly into the cloud. By contrast, the parcels in the second class start at low altitude and take a fairly long time before they reach the cloud on a spiraling path. A humidity tracer quantifies mixing, revealing partial moistening for the first class of parcels and drying for the second class of parcels. For the online trajectories, the originating location of parcels is more scattered, but the results are still consistent with the basic features revealed by the other two diagnostics.

39

Krolik, Julian H. "The origin of broad emission line clouds in active galactic nuclei." Astrophysical Journal 325 (February 1988): 148. http://dx.doi.org/10.1086/165990.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Connors, Tim W., Daisuke Kawata, Jeremy Bailin, Jason Tumlinson, and Brad K. Gibson. "On the Origin of Anomalous Velocity Clouds in the Milky Way." Astrophysical Journal 646, no. 1 (July 18, 2006): L53—L56. http://dx.doi.org/10.1086/506519.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Hoyle, C. R., B. P. Luo, and T. Peter. "The Origin of High Ice Crystal Number Densities in Cirrus Clouds." Journal of the Atmospheric Sciences 62, no. 7 (July 1, 2005): 2568–79. http://dx.doi.org/10.1175/jas3487.1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract Recent measurements with four independent particle instruments in cirrus clouds, which formed without convective or orographic influence, report high number densities of ice particles (as high as nice = 50 cm−3) embedded in broad density distributions (nice = 0.1–50 cm−3). It is shown here that small-scale temperature fluctuations related to gravity waves, mechanical turbulence, or other small-scale air motions are required to explain these observations. These waves have typical peak-to-peak amplitudes of 1–2 K and frequencies of up to 10 h−1, corresponding to instantaneous cooling rates of up to 60 K h−1. Such waves remain unresolved in even the most advanced state-of-the-art global atmospheric models. Given the ubiquitous nature of these fluctuations, it is suggested that the character of young in situ forming cirrus clouds is mostly determined by homogeneous freezing of ice in solution droplets, driven by a broad range of small-scale fluctuations (period ∼a few minutes) with moderate to high cooling rates (1–100 K h−1).

42

Jog, Chanda J., and Jeremiah P. Ostriker. "The velocity dispersion of the giant molecular clouds - A viscous origin." Astrophysical Journal 328 (May 1988): 404. http://dx.doi.org/10.1086/166302.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Bothmer, V., and R. Schwenn. "The structure and origin of magnetic clouds in the solar wind." Annales Geophysicae 16, no. 1 (January 31, 1998): 1–24. http://dx.doi.org/10.1007/s00585-997-0001-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract. Plasma and magnetic field data from the Helios 1/2 spacecraft have been used to investigate the structure of magnetic clouds (MCs) in the inner heliosphere. 46 MCs were identified in the Helios data for the period 1974–1981 between 0.3 and 1 AU. 85% of the MCs were associated with fast-forward interplanetary shock waves, supporting the close association between MCs and SMEs (solar mass ejections). Seven MCs were identified as direct consequences of Helios-directed SMEs, and the passage of MCs agreed with that of interplanetary plasma clouds (IPCs) identified as white-light brightness enhancements in the Helios photometer data. The total (plasma and magnetic field) pressure in MCs was higher and the plasma-β lower than in the surrounding solar wind. Minimum variance analysis (MVA) showed that MCs can best be described as large-scale quasi-cylindrical magnetic flux tubes. The axes of the flux tubes usually had a small inclination to the ecliptic plane, with their azimuthal direction close to the east-west direction. The large-scale flux tube model for MCs was validated by the analysis of multi-spacecraft observations. MCs were observed over a range of up to ~60° in solar longitude in the ecliptic having the same magnetic configuration. The Helios observations further showed that over-expansion is a common feature of MCs. From a combined study of Helios, Voyager and IMP data we found that the radial diameter of MCs increases between 0.3 and 4.2 AU proportional to the distance, R, from the Sun as R0.8 (R in AU). The density decrease inside MCs was found to be proportional to R–2.4, thus being stronger compared to the average solar wind. Four different magnetic configurations, as expected from the flux-tube concept, for MCs have been observed in situ by the Helios probes. MCs with left- and right-handed magnetic helicity occurred with about equal frequencies during 1974–1981, but surprisingly, the majority (74%) of the MCs had a south to north (SN) rotation of the magnetic field vector relative to the ecliptic. In contrast, an investigation of solar wind data obtained near Earth's orbit during 1984–1991 showed a preference for NS-clouds. A direct correlation was found between MCs and large quiescent filament disappearances (disparition brusques, DBs). The magnetic configurations of the filaments, as inferred from the orientation of the prominence axis, the polarity of the overlying field lines and the hemispheric helicity pattern observed for filaments, agreed well with the in situ observed magnetic structure of the associated MCs. The results support the model of MCs as large-scale expanding quasi-cylindrical magnetic flux tubes in the solar wind, most likely caused by SMEs associated with eruptions of large quiescent filaments. We suggest that the hemispheric dependence of the magnetic helicity structure observed for solar filaments can explain the preferred orientation of MCs in interplanetary space as well as their solar cycle behavior. However, the white-light features of SMEs and the measured volumes of their interplanetary counterparts suggest that MCs may not simply be just Hα-prominences, but that SMEs likely convect large-scale coronal loops overlying the prominence axis out of the solar atmosphere.

44

Dieball, A., and E. K. Grebel. "Binary Clusters in the Magellanic Clouds." Symposium - International Astronomical Union 190 (1999): 440–42. http://dx.doi.org/10.1017/s0074180900118492.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Binary clusters account for more than 10% of the cluster population in the Magellanic Clouds. Statistically fewer than 50% of the found pairs are expected to be chance superpositions. We are studying binary cluster candidates in the Magellanic Clouds to investigate whether the cluster pairs are of common origin and if they show evidence for interaction. We determine ages for the cluster components through isochrone fitting (isochrone models based on Schaerer et al. 1993, and Bertelli et al. 1994) to the colour magnitude diagrams (CMDs). We investigate the stellar spatial density in the surroundings of the clusters to look for signs of possible interactions between the components.

45

Krämer, M., C. Rolf, A. Luebke, A. Afchine, N. Spelten, A. Costa, M. Zöger, et al. "A microphysics guide to cirrus clouds – Part 1: Cirrus types." Atmospheric Chemistry and Physics Discussions 15, no. 21 (November 11, 2015): 31537–86. http://dx.doi.org/10.5194/acpd-15-31537-2015.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract. The microphysical and radiative properties of cirrus clouds continue to be beyond understanding and thus still represent one of the largest uncertainties in the prediction of the Earth's climate (IPCC, 2013). Our study aims to provide a guide to cirrus microphysics, which is compiled from an extensive set of model simulations, covering the broad range of atmospheric conditions for cirrus formation and evolution. The model results are portrayed in the same parameter space as field measurements, i.e. in the Ice Water Content-Temperature (IWC-T) parameter space. We validate this cirrus analysis approach by evaluating cirrus data sets from seventeen aircraft campaigns, conducted in the last fifteen years, spending about 94 h in cirrus over Europe, Australia, Brazil as well as Southern and Northern America. Altogether, the approach of this study is to track cirrus IWC development with temperature by means of model simulations, compare with observations and then assign, to a certain degree, cirrus microphysics to the observations. Indeed, the field observations show characteristics expected from the simulated cirrus guide. For example, high/low IWCs are found together with high/low ice crystal concentrations Nice. An important finding from our study is the classification of two types of cirrus with differing formation mechanisms and microphysical properties: the first cirrus type is rather thin with lower IWCs and forms directly as ice (in-situ origin cirrus). The second type consists predominantly of thick cirrus originating from mixed phase clouds (i.e. via freezing of liquid droplets – liquid origin cirrus), which are completely glaciated while lifting to the cirrus formation temperature region (< 235 K). In the European field campaigns, in-situ origin cirrus occur frequently at slow updrafts in low and high pressure systems, but also in conjunction with faster updrafts. Also, liquid origin cirrus mostly related to warm conveyor belts are found. In the US and tropical campaigns, thick liquid origin cirrus which are formed in large convective systems are detected more frequently.

46

Young, Judith S. "Molecular clouds in external galaxies." Symposium - International Astronomical Union 106 (1985): 183–92. http://dx.doi.org/10.1017/s0074180900242381.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Observations of the large-scale distribution of molecular clouds in external galaxies offer a unique opportunity for investigating galactic evolution. New generations of stars form in these dense regions, and the most massive of these stars recycle their processed interiors into the interstellar medium. Early observations of the CO distribution in the Milky Way (Scoville and Solomon 1975; Burton and Gordon 1976) indicated that there is intense emission at the center of our Galaxy, very little gas between 1 and 4 kpc radius, and a “molecular ring” feature between 4 and 8 kpc. Observations of molecular clouds in external galaxies of a variety of Hubble types and luminosities will enable us to more clearly understand the origin of this distribution. Although no other galaxies are observed to contain CO distributions precisely like that in the Milky Way, the differences which are present provide important clues to the structure and evolution of galaxies.

47

Inutsuka, Shu-ichiro. "The role of magnetic field in the formation and evolution of filamentary molecular clouds." Proceedings of the International Astronomical Union 14, A30 (August 2018): 100. http://dx.doi.org/10.1017/s1743921319003557.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

AbstractRecent observations have emphasized the importance of the formation and evolution of magnetized filamentary molecular clouds in the process of star formation. Theoretical and observational investigations have provided convincing evidence for the formation of molecular cloud cores by the gravitational fragmentation of filamentary molecular clouds. In this review we summarize our current understanding of various processes that are required in describing the filamentary molecular clouds. Especially we can explain a robust formation mechanism of filamentary molecular clouds in a shock compressed layer, which is in analogy to the making of “Sushi.” We also discuss the origin of the mass function of cores.

48

Krämer, Martina, Christian Rolf, Anna Luebke, Armin Afchine, Nicole Spelten, Anja Costa, Jessica Meyer, et al. "A microphysics guide to cirrus clouds – Part 1: Cirrus types." Atmospheric Chemistry and Physics 16, no. 5 (March 16, 2016): 3463–83. http://dx.doi.org/10.5194/acp-16-3463-2016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

Abstract. The microphysical and radiative properties of cirrus clouds continue to be beyond understanding and thus still represent one of the largest uncertainties in the prediction of the Earth's climate (IPCC, 2013). Our study aims to provide a guide to cirrus microphysics, which is compiled from an extensive set of model simulations, covering the broad range of atmospheric conditions for cirrus formation and evolution. The model results are portrayed in the same parameter space as field measurements, i.e., in the Ice Water Content-Temperature (IWC-T) parameter space. We validate this cirrus analysis approach by evaluating cirrus data sets from 17 aircraft campaigns, conducted in the last 15 years, spending about 94 h in cirrus over Europe, Australia, Brazil as well as South and North America. Altogether, the approach of this study is to track cirrus IWC development with temperature by means of model simulations, compare with observations and then assign, to a certain degree, cirrus microphysics to the observations. Indeed, the field observations show characteristics expected from the simulated Cirrus Guide. For example, high (low) IWCs are found together with high (low) ice crystal concentrations Nice. An important finding from our study is the classification of two types of cirrus with differing formation mechanisms and microphysical properties: the first cirrus type forms directly as ice (in situ origin cirrus) and splits in two subclasses, depending on the prevailing strength of the updraft: in slow updrafts these cirrus are rather thin with lower IWCs, while in fast updrafts thicker cirrus with higher IWCs can form. The second type consists predominantly of thick cirrus originating from mixed phase clouds (i.e., via freezing of liquid droplets – liquid origin cirrus), which are completely glaciated while lifting to the cirrus formation temperature region (< 235 K). In the European field campaigns, slow updraft in situ origin cirrus occur frequently in low- and high-pressure systems, while fast updraft in situ cirrus appear in conjunction with jet streams or gravity waves. Also, liquid origin cirrus mostly related to warm conveyor belts are found. In the US and tropical campaigns, thick liquid origin cirrus which are formed in large convective systems are detected more frequently.

49

Black, John H., and Ewine F. van Dishoeck. "Chemistry and small-scale structure of diffuse and translucent clouds." Symposium - International Astronomical Union 147 (1991): 139–50. http://dx.doi.org/10.1017/s0074180900198857.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

The small, thin diffuse and translucent molecular clouds are excellent laboratories for studying the ways in which small—scale structure and interstellar chemistry affect each other. Variations of density or column density and chemical stratification can be found on scales as small as 0.01 pc. The origin of such structures and the evolutionary states of small clouds remain elusive.

50

Black, John H., and Ewine F. van Dishoeck. "Chemistry and small-scale structure of diffuse and translucent clouds." Symposium - International Astronomical Union 147 (1991): 139–50. http://dx.doi.org/10.1017/s0074180900239478.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Abstract:

The small, thin diffuse and translucent molecular clouds are excellent laboratories for studying the ways in which small—scale structure and interstellar chemistry affect each other. Variations of density or column density and chemical stratification can be found on scales as small as 0.01 pc. The origin of such structures and the evolutionary states of small clouds remain elusive.