scholarly journals Observations of Volcanic Clouds in Their First Few Days of Atmospheric Residence: The 1992 Eruptions of Crater Peak, Mount Spurr Volcano, Alaska

2001 ◽  
Vol 109 (6) ◽  
pp. 677-694 ◽  
Author(s):  
William I. Rose ◽  
Gregg J. S. Bluth ◽  
David J. Schneider ◽  
Gerald G. J. Ernst ◽  
Colleen M. Riley ◽  
...  
Keyword(s):  
Volcanic Clouds ◽  
Mount Spurr

scholarly journals Revisiting the Agung 1963 volcanic forcing – impact of one or two eruptions

2019 ◽  
Author(s):  
Ulrike Niemeier ◽  
Claudia Timmreck ◽  
Kirstin Krüger
Keyword(s):  
Radiative Forcing ◽  
Injection Rate ◽  
Data Sets ◽  
Meridional Transport ◽  
Emission Data ◽  
Volcanic Clouds ◽  
Different Seasons ◽  
Future Emission ◽  
Volcanic Emission ◽  
The Individual

Abstract. In 1963 a series of eruptions of Mt. Agung, Indonesia, resulted in the 3rd largest eruption of the 20th century and claimed about 1900 lives. Two eruptions of this series injected SO2 into the stratosphere, a requirement to get a long lasting stratospheric sulfate layer. The first eruption on March 17th injected 4.7 Tg SO2 into the stratosphere, the second eruption 2.3 Tg SO2 on May, 16th. In recent volcanic emission data sets these eruption phases are merged together to one large eruption phase for Mt. Agung in March 1963 with an injection rate of 7 Tg SO2. The injected sulfur forms a sulfate layer in the stratosphere. The evolution of sulfur is non-linear and depends on the injection rate and aerosol background conditions. We performed ensembles of two model experiments, one with a single and a second one with two eruptions. The two smaller eruptions result in a lower burden, smaller particles and 0.1 to 0.3 Wm−2 (10–20 %) lower radiative forcing in monthly mean global average compared to the individual eruption experiment. The differences are the consequence of slightly stronger meridional transport due to different seasons of the eruptions, lower injection height of the second eruption and the resulting different aerosol evolution. The differences between the two experiments are significant but smaller than the variance of the individual ensemble means. Overall, the evolution of the volcanic clouds is different in case of two eruptions than with a single eruption only. We conclude that there is no justification to use one eruption only and both climatic eruptions should be taken into account in future emission datasets.

scholarly journals A comparison of AIRS, MODIS and OMI sulphur dioxide retrievals in volcanic clouds

2011 ◽  
Vol 2 (3) ◽  
pp. 217-232 ◽  
Author(s):  
Helen E. Thomas ◽  
I. Matthew Watson ◽  
Simon A. Carn ◽  
Alfredo J. Prata ◽  
Vincent J. Realmuto
Keyword(s):  
Sulphur Dioxide ◽  
Volcanic Clouds

scholarly journals The Influence of Particle Concentration on the Formation of Settling-Driven Gravitational Instabilities at the Base of Volcanic Clouds

2021 ◽  
Vol 9 ◽  
Author(s):  
Allan Fries ◽  
Jonathan Lemus ◽  
Paul A. Jarvis ◽  
Amanda B. Clarke ◽  
Jeremy C. Phillips ◽  
...  
Keyword(s):  
Volcanic Ash ◽  
Particle Concentration ◽  
Initial Conditions ◽  
Initial Density ◽  
Fluid Phase ◽  
Dimensionless Number ◽  
Narrow Region ◽  
Gravitational Instabilities ◽  
Volcanic Clouds ◽  
Particle Imaging

Settling-driven gravitational instabilities observed at the base of volcanic ash clouds have the potential to play a substantial role in volcanic ash sedimentation. They originate from a narrow, gravitationally unstable region called a Particle Boundary Layer (PBL) that forms at the lower cloud-atmosphere interface and generates downward-moving ash fingers that enhance the ash sedimentation rate. We use scaled laboratory experiments in combination with particle imaging and Planar Laser Induced Fluorescence (PLIF) techniques to investigate the effect of particle concentration on PBL and finger formation. Results show that, as particles settle across an initial density interface and are incorporated within the dense underlying fluid, the PBL grows below the interface as a narrow region of small excess density. This detaches upon reaching a critical thickness, that scales with (ν2/g′)1/3, where ν is the kinematic viscosity and g′ is the reduced gravity of the PBL, leading to the formation of fingers. During this process, the fluid above and below the interface remains poorly mixed, with only small quantities of the upper fluid phase being injected through fingers. In addition, our measurements confirm previous findings over a wider set of initial conditions that show that both the number of fingers and their velocity increase with particle concentration. We also quantify how the vertical particle mass flux below the particle suspension evolves with time and with the particle concentration. Finally, we identify a dimensionless number that depends on the measurable cloud mass-loading and thickness, which can be used to assess the potential for settling-driven gravitational instabilities to form. Our results suggest that fingers from volcanic clouds characterised by high ash concentrations not only are more likely to develop, but they are also expected to form more quickly and propagate at higher velocities than fingers associated with ash-poor clouds.

scholarly journals Early in-flight detection of SO<sub>2</sub> via Differential Optical Absorption Spectroscopy: a feasible aviation safety measure to prevent potential encounters with volcanic plumes

2011 ◽  
Vol 4 (3) ◽  
pp. 2827-2881 ◽  
Author(s):  
L. Vogel ◽  
B. Galle ◽  
C. Kern ◽  
H. Delgado Granados ◽  
V. Conde ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Volcanic Ash ◽  
Lower Troposphere ◽  
Differential Optical Absorption Spectroscopy ◽  
Cumulative Exposure ◽  
Optical Absorption Spectroscopy ◽  
Volcanic Plumes ◽  
Volcanic Clouds ◽  
Volcanic Cloud

Abstract. Volcanic ash constitutes a risk to aviation, mainly due to its ability to cause jet engines to fail. Other risks include the possibility of abrasion of windshields and potentially serious damage to avionic systems. These hazards have been widely recognized since the early 1980s, when volcanic ash provoked several incidents of engine failure in commercial aircraft. In addition to volcanic ash, volcanic gases also pose a threat. Prolonged and/or cumulative exposure to sulphur dioxide (SO2) or sulphuric acid (H2SO4) aerosols potentially affects e.g. windows, air frame and may cause permanent damage to engines. SO2 receives most attention among the gas species commonly found in volcanic plumes because its presence above the lower troposphere is a clear proxy for a volcanic cloud and indicates that fine ash could also be present. Up to now, remote sensing of SO2 via Differential Optical Absorption Spectroscopy (DOAS) in the ultraviolet spectral region has been used to measure volcanic clouds from ground based, airborne and satellite platforms. Attention has been given to volcanic emission strength, chemistry inside volcanic clouds and measurement procedures were adapted accordingly. Here we present a set of experimental and model results, highlighting the feasibility of DOAS to be used as an airborne early detection system of SO2 in two spatial dimensions. In order to prove our new concept, simultaneous airborne and ground-based measurements of the plume of Popocatépetl volcano, Mexico, were conducted in April 2010. The plume extended at an altitude around 5250 m above sea level and was approached and traversed at the same altitude with several forward looking DOAS systems aboard an airplane. These DOAS systems measured SO2 in the flight direction and at ± 40 mrad (2.3°) angles relative to it in both, horizontal and vertical directions. The approaches started at up to 25 km distance to the plume and SO2 was measured at all times well above the detection limit. In combination with radiative transfer studies, this study indicates that an extended volcanic cloud with a concentration of 1012 molecules cm−3 at typical flight levels of 10 km can be detected unambiguously at distances of up to 80 km away. This range provides enough time (approx. 5 min) for pilots to take action to avoid entering a volcanic cloud in the flight path, suggesting that this technique can be used as an effective aid to prevent dangerous aircraft encounters with potentially ash rich volcanic clouds.

scholarly journals Revisiting the Agung 1963 volcanic forcing – impact of one or two eruptions

2019 ◽  
Vol 19 (15) ◽  
pp. 10379-10390 ◽  
Author(s):  
Ulrike Niemeier ◽  
Claudia Timmreck ◽  
Kirstin Krüger
Keyword(s):  
Mass Flux ◽  
Radiative Forcing ◽  
Aerosol Particles ◽  
Injection Rate ◽  
Meridional Transport ◽  
The Third ◽  
Volcanic Clouds ◽  
Different Seasons ◽  
Future Emission ◽  
The Individual

Abstract. In 1963 a series of eruptions of Mt. Agung, Indonesia, resulted in the third largest eruption of the 20th century and claimed about 1900 lives. Two eruptions of this series injected SO2 into the stratosphere, which can create a long-lasting stratospheric sulfate layer. The estimated mass flux of the first eruption was about twice as large as the mass flux of the second eruption. We followed the estimated emission profiles and assumed for the first eruption on 17 March an injection rate of 4.7 Tg SO2 and 2.3 Tg SO2 for the second eruption on 16 May. The injected sulfur forms a sulfate layer in the stratosphere. The evolution of sulfur is nonlinear and depends on the injection rate and aerosol background conditions. We performed ensembles of two model experiments, one with a single eruption and a second one with two eruptions. The two smaller eruptions result in a lower sulfur burden, smaller aerosol particles, and 0.1 to 0.3 Wm−2 (10 %–20 %) lower radiative forcing in monthly mean global average compared to the individual eruption experiment. The differences are the consequence of slightly stronger meridional transport due to different seasons of the eruptions, lower injection height of the second eruption, and the resulting different aerosol evolution. Overall, the evolution of the volcanic clouds is different in case of two eruptions than with a single eruption only. The differences between the two experiments are significant. We conclude that there is no justification to use one eruption only and both climatic eruptions should be taken into account in future emission datasets.

Rise and flow of volcanic clouds observed from the ground and from satellites

2000 ◽  
Vol 3 (1) ◽  
pp. 71-78 ◽  
Author(s):  
K. Kinoshita ◽  
H. Togoshi
Keyword(s):  
Volcanic Clouds
Sign in / Sign up

Export Citation Format

Share Document