scholarly journals Tracking microphysical variations in emissions from Karymsky volcano using MISR multi-angle imagery, and implications for volcano geologic interpretation

2017 ◽  
Author(s):  
Verity J. B. Flower ◽  
Ralph A. Kahn
Keyword(s):  
Atmospheric Aerosols ◽  
Thermal Anomaly ◽  
Remote Locations ◽  
Microphysical Properties ◽  
Stereo Imagery ◽  
Geologic Interpretation ◽  
Particle Property ◽  
Karymsky Volcano ◽  
Activity Cycles ◽  
Over Time

Abstract. Space-based, operational instruments are in unique positions to monitor volcanic activity globally, especially in remote locations or where suborbital observing conditions are hazardous. The Multi-angle Imaging SpectroRadiometer (MISR) provides hyper-stereo imagery, from which the altitude and microphysical properties of suspended atmospheric aerosols can be derived. These capabilities are applied to plumes emitted at Karymsky volcano from 2000 to 2017. Plumes from Karymsky were predominantly emitted to an altitude of 2–4 km, with occasional events exceeding 6 km. MISR plume observations were most common when volcanic surface manifestations were high, such as lava flows identified by satellite-based thermal anomaly detection. The plumes contained large, strongly absorbing particles indicative of ash-rich eruptions. Differences between the retrievals for Karymsky volcano's ash-rich plumes and the sulfur-rich plumes from the 2014–2015 eruption of Bárðarbunga (Iceland) highlight the ability of MISR to distinguish particle types from such events. Plumes emitted at Karymsky prior to 2010 contain the sulfate proxy. After 2011, plumes contain similar particle components, but with varying fractions of absorption linked to timing within respective eruption phases. From the 1.1 km spatial-resolution retrievals within 30–220 km plumes, particle fallout, physical aggregation, and chemical evolution are indicated by the particle property variations observed downwind. In addition, changes in plume properties retrieved from the remote-sensing observations over time are interpreted in terms of activity cycles within the volcano itself, corroborated to the extent possible with suborbital data.

scholarly journals Karymsky volcano eruptive plume properties based on MISR multi-angle imagery and the volcanological implications

2018 ◽  
Vol 18 (6) ◽  
pp. 3903-3918 ◽  
Author(s):  
Verity J. B. Flower ◽  
Ralph A. Kahn
Keyword(s):  
Atmospheric Aerosols ◽  
Thermal Anomaly ◽  
Effective Radius ◽  
Particle Properties ◽  
Remote Locations ◽  
Microphysical Properties ◽  
Event Timing ◽  
Stereo Imagery ◽  
Karymsky Volcano ◽  
Over Time

Abstract. Space-based operational instruments are in unique positions to monitor volcanic activity globally, especially in remote locations or where suborbital observing conditions are hazardous. The Multi-angle Imaging SpectroRadiometer (MISR) provides hyper-stereo imagery, from which the altitude and microphysical properties of suspended atmospheric aerosols can be derived. These capabilities are applied to plumes emitted at Karymsky volcano from 2000 to 2017. Observed plumes from Karymsky were emitted predominantly to an altitude of 2–4 km, with occasional events exceeding 6 km. MISR plume observations were most common when volcanic surface manifestations, such as lava flows, were identified by satellite-based thermal anomaly detection. The analyzed plumes predominantly contained large (1.28 µm effective radius), strongly absorbing particles indicative of ash-rich eruptions. Differences between the retrievals for Karymsky volcano's ash-rich plumes and the sulfur-rich plumes emitted during the 2014–2015 eruption of Holuhraun (Iceland) highlight the ability of MISR to distinguish particle types from such events. Observed plumes ranged from 30 to 220 km in length and were imaged at a spatial resolution of 1.1 km. Retrieved particle properties display evidence of downwind particle fallout, particle aggregation and chemical evolution. In addition, changes in plume properties retrieved from the remote-sensing observations over time are interpreted in terms of shifts in eruption dynamics within the volcano itself, corroborated to the extent possible with suborbital data. Plumes emitted at Karymsky prior to 2010 display mixed emissions of ash and sulfate particles. After 2010, all plumes contain consistent particle components, indicative of entering an ash-dominated regime. Post-2010 event timing, relative to eruption phase, was found to influence the optical properties of observed plume particles, with light absorption varying in a consistent sequence as each respective eruption phase progressed.

scholarly journals Optical and microphysical properties of natural mineral dust and anthropogenic soil dust near dust source regions over northwestern China

2018 ◽  
Vol 18 (3) ◽  
pp. 2119-2138 ◽  
Author(s):  
Xin Wang ◽  
Hui Wen ◽  
Jinsen Shi ◽  
Jianrong Bi ◽  
Zhongwei Huang ◽  
...  
Keyword(s):  
Atmospheric Aerosols ◽  
Mineral Dust ◽  
Particle Diameter ◽  
Northwestern China ◽  
Soil Dust ◽  
Dust Source ◽  
Dust Aerosols ◽  
Microphysical Properties ◽  
Source Regions ◽  
Anthropogenic Soil

Abstract. Mineral dust aerosols (MDs) not only influence the climate by scattering and absorbing solar radiation but also modify cloud properties and change the ecosystem. From 3 April to 16 May 2014, a ground-based mobile laboratory was deployed to measure the optical and microphysical properties of MDs near dust source regions in Wuwei, Zhangye, and Dunhuang (in chronological order) along the Hexi Corridor over northwestern China. Throughout this dust campaign, the hourly averaged (±standard deviation) aerosol scattering coefficients (σsp, 550 nm) of the particulates with aerodynamic diameters less than 2.5 µm (PM2.5) at these three sites were sequentially 101.5 ± 36.8, 182.2 ± 433.1, and 54.0 ± 32.0 Mm−1. Correspondingly, the absorption coefficients (σap, 637 nm) were 9.7 ± 6.1, 6.0 ± 4.6, and 2.3 ± 0.9 Mm−1; single-scattering albedos (ω, 637 nm) were 0.902 ± 0.025, 0.931 ± 0.037, and 0.949 ± 0.020; and scattering Ångström exponents (Åsp, 450–700 nm) of PM2.5 were 1.28 ± 0.27, 0.77 ± 0.51, and 0.52 ± 0.31. During a severe dust storm in Zhangye (i.e., from 23 to 25 April), the highest values of σsp2.5 (∼ 5074 Mm−1), backscattering coefficient (σbsp2.5, ∼ 522 Mm−1), and ω637 (∼ 0.993) and the lowest values of backscattering fraction (b2.5, ∼ 0.101) at 550 nm and Åsp2.5 (∼ −0.046) at 450–700 nm, with peak values of aerosol number size distribution (appearing at the particle diameter range of 1–3 µm), exhibited that the atmospheric aerosols were dominated by coarse-mode dust aerosols. It is hypothesized that the relatively higher values of mass scattering efficiency during floating dust episodes in Wuwei and Zhangye are attributed to the anthropogenic soil dust produced by agricultural cultivations.

Temporal Dominance: Controlling Activity Cycles When Time Is Scarce, Sudden, and Squeezed

2021 ◽  
pp. 089331892110234
Author(s):  
Jared T. Jensen ◽  
Shelbey L. Rolison ◽  
Joshua B. Barbour
Keyword(s):  
Health Research ◽  
Communication Theory ◽  
Research Organization ◽  
Team Members ◽  
Domains Of Life ◽  
Temporal Structures ◽  
Activity Cycles ◽  
And Control ◽  
Temporal Dominance ◽  
Over Time

Constant interaction, digital interruptions, and shrinking time to think and act characterize much of present-day communication. The management of time pressures is a key concern for contemporary workers as work responsibilities encroach on each other and other domains of life. This study focuses on how individuals and collectives try to exert control over time through communication. An analysis of observational and interview data ( N = 26) at a health research organization revealed that workers encountered cyclical, pervasive temporal structures marked by commotion: a blur of jarring, immediate tasks that require intense communication. As workers sought to make time for sustained focus, these pervasive temporal structures stymied their efforts. The findings contribute to communication theory by illuminating relationships among organizing, time, and control. This study provides metalanguage that facilitates the description and examination of temporal activity, and it describes a form of temporal control that was evident across hierarchal roles. Power differences explained the efficacy and agency of team members’ choices to manage busy, disrupted, and fast-paced work.

scholarly journals Assessing remote polarimetric measurements sensitivities to aerosol emissions using the GEOS-Chem adjoint model

2013 ◽  
Vol 6 (3) ◽  
pp. 5447-5493
Author(s):  
B. S. Meland ◽  
X. Xu ◽  
D. K. Henze ◽  
J. Wang
Keyword(s):  
Atmospheric Aerosols ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Microphysical Properties ◽  
Upper Limits ◽  
Radiative Impacts ◽  
Aerosol Sources ◽  
Absorbing Aerosols ◽  
New Applications ◽  
Aerosol Emissions

Abstract. Uncertainties in aerosol sources, microphysical properties, and global distributions undermine efforts to evaluate the radiative impacts of atmospheric aerosols. In this work, we investigate the feasibility of using remote polarimetric measurements for constraining aerosol and aerosol precursor emissions in light of these uncertainties. A model that incorporates a radiative transfer model with forward and adjoint chemical transport models has been applied to quantify the sensitivity of the reflectance at the top of atmosphere to aerosol emissions and microphysical properties. A set of simulated satellite observations, one intensity based and one capable of polarimetric measurements, are used to illustrate differences in the assimilation potential between the two. It is found that the sensitivity of the polarized reflectance to aerosol and aerosol precursor emissions tends to be significantly higher than that of the intensity for cases of non-absorbing aerosols. This is true even when the polarimetric sampling scheme is spatially sparser than that of the intensity sampling. This framework allows us to quantify upper limits on the uncertainties in the aerosol microphysical properties for which a 50% change in aerosol emissions is detectable using these simulated observations. It was found that although typical current remote sensing instrumentation provides retrievals of the refractive index and effective radius with accuracies within acceptable limits to detect a 50% change in emissions, retrievals of the effective variance contain uncertainties too large to detect these changes in emissions. These results may guide new applications of polarimetric measurements to constrain aerosol sources, and thus reduce uncertainty in our broader understanding of the impacts of aerosols on climate.

scholarly journals Impact of in-cloud aqueous processes on the chemical compositions and morphology of individual atmospheric aerosols

2020 ◽  
Vol 20 (22) ◽  
pp. 14063-14075
Author(s):  
Yuzhen Fu ◽  
Qinhao Lin ◽  
Guohua Zhang ◽  
Yuxiang Yang ◽  
Yiping Yang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Atmospheric Aerosols ◽  
Chemical Reactivity ◽  
Chemical Compositions ◽  
Refractory Mixture ◽  
Cloud Processing ◽  
Microphysical Properties ◽  
Heterogeneous Chemical ◽  
Individual Particles

Abstract. The composition, morphology, and mixing structure of individual cloud residues (RES) and interstitial particles (INT) at a mountaintop site were investigated. Eight types of particles were identified, including sulfate-rich (S-rich), S-organic matter (OM), aged soot, aged mineral dust, aged fly ash, aged metal, refractory, and aged refractory mixture. A shift of dominant particle types from S-rich (29 %) and aged soot (27 %) in the INT to aged refractory mixture (23 %) and S-OM (22 %) in the RES is observed. In particular, particles with organic shells are enriched in the RES (27 %) relative to the INT (12 %). Our results highlight that the formation of more oxidized organic matter in the cloud contributes to the existence of organic shells after cloud processing. The fractal dimension (Df), a morphologic parameter to represent the branching degree of particles, for soot particles in the RES (1.82 ± 0.12) is lower than that in the INT (2.11 ± 0.09), which indicates that in-cloud processes may result in less compact soot. This research emphasizes the role of in-cloud processes in the chemistry and microphysical properties of individual particles. Given that organic coatings may determine the particle hygroscopicity, activation ability, and heterogeneous chemical reactivity, the increase of OM-shelled particles upon in-cloud processes should have considerable implications.

scholarly journals Renewable-based electrification for remote locations. Does short-term success endure over time? A case study in Peru

2021 ◽  
Vol 146 ◽  
pp. 111177
Author(s):  
M. Juanpera ◽  
B. Domenech ◽  
L. Ferrer-Martí ◽  
A. Garzón ◽  
R. Pastor
Keyword(s):  
Short Term ◽  
Remote Locations ◽  
Over Time

scholarly journals Remote sensing of aerosol in the terrestrial atmosphere from space: new missions

2015 ◽  
Vol 5 (1) ◽  
pp. 11-16 ◽  
Author(s):  
G. Milinevsky ◽  
Ya. Yatskiv ◽  
O. Degtyaryov ◽  
I. Syniavskyi ◽  
Yu. Ivanov ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Atmospheric Aerosols ◽  
Climate Models ◽  
Global Scale ◽  
Climate Impact ◽  
Quality Of Data ◽  
Anthropogenic Aerosol ◽  
Terrestrial Atmosphere ◽  
Microphysical Properties ◽  
Cloud Properties

The distribution and properties of atmospheric aerosols on a global scale are not well known in terms of determination of their effects on climate. This mostly is due to extreme variability of aerosol concentrations, properties, sources, and types. Aerosol climate impact is comparable to the effect of greenhouse gases, but its influence is more difficult to measure, especially with respect to aerosol microphysical properties and the evaluation of anthropogenic aerosol effect. There are many satellite missions studying aerosol distribution in the terrestrial atmosphere, such as MISR/Terra, OMI/Aura, AVHHR, MODIS/Terra and Aqua, CALIOP/CALIPSO. To improve the quality of data and climate models, and to reduce aerosol climate forcing uncertainties, several new missions are planned. The gap in orbital instruments for studying aerosol microphysics has arisen after the Glory mission failed during launch in 2011. In this review paper, we describe several planned aerosol space missions, including the Ukrainian project Aerosol-UA that obtains data using a multi-channel scanning polarimeter and wide-angle polarimetric camera. The project is designed for remote sensing of the aerosol microphysics and cloud properties on a global scale.

scholarly journals Aerosol-Precipitation Interactions over India: Review and Future Perspectives

2013 ◽  
Vol 2013 ◽  
pp. 1-20 ◽  
Author(s):  
S. Ramachandran ◽  
S. Kedia
Keyword(s):  
Chemical Composition ◽  
Atmospheric Aerosols ◽  
Bay Of Bengal ◽  
Hydrological Cycle ◽  
Cloud Condensation Nuclei ◽  
Longwave Radiation ◽  
Microphysical Properties ◽  
Cloud Properties ◽  
Aerosol Distribution ◽  
Size Type

Atmospheric aerosols can interact with clouds and influence the hydrological cycle by acting as cloud condensation nuclei. The current study reviews the results obtained on aerosol-precipitation interactions over India and the surrounding oceanic regions. An analysis of aerosol and cloud characteristics over the Arabian Sea, India, and the Bay of Bengal during summer monsoon in the last decade reveals large regional, intraseasonal, and interannual variations. Aerosol optical depth (AOD) and aerosol absorbing index (AAI) in 2002 (a drought year) are higher over India when compared to normal monsoon years. Cloud effective radius (CER) and cloud optical thickness exhibit a negative correlation with AOD over India, which agrees well with the indirect radiative effects of aerosols. Over Bay of Bengal CER is positively correlated with AOD suggesting an inverse aerosol indirect effect. In future, observatories to measure aerosol characteristics (amount, size, type, chemical composition, mixing, vertical and horizontal distributions), and cloud properties (number and size) over several locations in India, and intense observational campaigns involving aircraft and ships are crucial to unravel the quantitative impact that aerosols have on Indian monsoon. Satellite remote sensing of aerosol distribution, their chemical composition, microphysical properties of clouds, solar irradiance, and terrestrial longwave radiation is important.

scholarly journals Temporal Variation of Aerosol Optical Properties at Măgurele, Romania

2011 ◽  
Vol 28 (10) ◽  
pp. 1307-1316 ◽  
Author(s):  
Laura Mihai ◽  
Sabina Stefan
Keyword(s):  
Optical Properties ◽  
Atmospheric Aerosols ◽  
Fine Particles ◽  
Temporal Variations ◽  
Saharan Dust ◽  
Optical Parameters ◽  
Aerosol Optical Properties ◽  
Total Scattering ◽  
Local Pollution ◽  
Microphysical Properties

Abstract Even though much research has been conducted regarding the study of atmospheric aerosols, significant uncertainties still exist in this direction. The uncertainties are related to different physical and microphysical properties of these fine particles, but they are also related to the complex processes of interactions between aerosols and other atmospheric components, such as water droplets in the clouds or gaseous molecules. Therefore, it is mandatory to understand aerosol physics with maximum precision in real time all over the world. In this paper, the results of the statistical analysis of atmospheric aerosol optical properties as the total scattering and the backscattering coefficients, the Ångström parameter, and the aerosol optical depth from Măgurele (Ilfov, Romania) are presented. The analysis covers the period between 1 June 2008 and 31 December 2009. The results showed significant differences in temporal variations of the optical parameters for the winter of 2008 and 2009. From spring 2009 to the winter of this year, a decreasing tendency of the total scattering coefficient and an increasing trend for the Ångström exponent were observed. The size-increase tendency, over 1 μm, appears during the spring of 2008 and the summers of 2008 and 2009, coinciding with the local pollution or Saharan dust intrusion episodes. From the seasonal analysis, a certain monthly variation of the optical parameters was noticed. The results of the diurnal optical properties variations for the Măgurele area showed visible differences between the maximal and minimal values for the spring and summer seasons.

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