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At least 343 records · Page 19

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NASA NTRS2021

Tracking aerosols and SO2 clouds from the Raikoke eruption: 3D view from satellite observations

The 21 June 2019 eruption of the Raikoke volcano (Kuril Islands, Russia; 48° N, 153° E) produced significant amounts of volcanic aerosols (sulfate and ash) and sulfur dioxide (SO2) gas that penetrated into the lower stratosphere. The dispersed SO2 and sulfate aerosols in the stratosphere were still detectable by multiple satellite sensors for many months after the eruption. For this study of SO2 and aerosol clouds we use data obtained from two of the Ozone Mapping and Profiler Suite sensors on the Suomi National Polar-orbiting Partnership satellite: total column SO2 from the Nadir Mapper and aerosol extinction profiles from the Limb Profiler as well as other satellite data sets. We evaluated the limb viewing geometry effect (the “arch effect”) in the retrieval of the LP standard aerosol extinction product at 674 nm. It was shown that the amount of SO2 decreases with a characteristic period of 8–18 d and the peak of stratospheric aerosol optical depth recorded at a wavelength of 674 nm lags the initial peak of SO2 mass by 1.5 months. Using satellite observations and a trajectory model, we examined the dynamics of an unusual atmospheric feature that was observed, a stratospheric coherent circular cloud of SO2 and aerosol from 18 July to 22 September 2019.

Eruption of the Raikoke volcano↗

NASA NTRS2022

Stratospheric Circulation Changes Associated with the Hunga Tonga-Hunga Ha'apai Eruption

The 15 January 2022 eruption of the Hunga Tonga-Hunga Ha'apai underwater volcano (20.5°S, 175.4°W) injected a record amount of water directly into the stratosphere. This study attempts to quantify this impact on the temperature, as well as the subsequent changes to the stratospheric circulation, during the months following the eruption based on reanalysis fields. The extreme nature of the temperature, wind, and circulation changes are tracked through comparisons of the first six months of 2022 with the previous 42 years. Examination of the data assimilation process shows that at 20 hPa the thermal observations are forcing significant cooling, compensating for the absence of the excess stratospheric moisture in the model used for the reanalysis. In response to this cooling the atmosphere adjusts by creating strong westerly winds above the temperature anomaly and large changes to the downward and poleward mean meridional circulation.

Volcano↗

DOE OSTI2025

Could the chemical industry mitigate rapid global cooling from a catastrophic volcanic eruption?

Abstract Estimates based on historical data place the probability of a catastrophic volcanic eruption in the next 100 years at around one in six. Large volcanic eruptions can lead to significant global cooling for 2–4 years, with potentially devastating impacts on global agriculture. In principle, the negative impacts of volcano‐induced cooling could be reduced by deliberate emission of short‐lived chemicals with high greenhouse gas intensity into the atmosphere. This article examines the physical feasibility of this concept for a wide range of short‐lived climate pollutants, using the global chemical industry for context. Deliberate emission of any known chemical species would require gigatons of material, which would have to be produced and stored far in advance of the volcanic event. The cost of this undertaking would be immense. In addition to these daunting logistical challenges, a range of other uncertainties and complications associated with this concept are discussed.

Sholl, David S. [University of Tennessee‐Oak Ridge↗

DOE OSTI2024

Quasi-periodic X-ray eruptions years after a nearby tidal disruption event

Abstract Quasi-periodic eruptions (QPEs) are luminous bursts of soft X-rays from the nuclei of galaxies, repeating on timescales of hours to weeks 1–5 . The mechanism behind these rare systems is uncertain, but most theories involve accretion disks around supermassive black holes (SMBHs) undergoing instabilities 6–8 or interacting with a stellar object in a close orbit 9–11 . It has been suggested that this disk could be created when the SMBH disrupts a passing star 8,11 , implying that many QPEs should be preceded by observable tidal disruption events (TDEs). Two known QPE sources show long-term decays in quiescent luminosity consistent with TDEs 4,12 and two observed TDEs have exhibited X-ray flares consistent with individual eruptions 13,14 . TDEs and QPEs also occur preferentially in similar galaxies 15 . However, no confirmed repeating QPEs have been associated with a spectroscopically confirmed TDE or an optical TDE observed at peak brightness. Here we report the detection of nine X-ray QPEs with a mean recurrence time of approximately 48 h from AT2019qiz, a nearby and extensively studied optically selected TDE 16 . We detect and model the X-ray, ultraviolet (UV) and optical emission from the accretion disk and show that an orbiting body colliding with this disk provides a plausible explanation for the QPEs.

Science & Technology - Other Topics↗

DOE OSTI2024

Applying Automated Detectors for Regional Infrasound Signals to Global Networks: A Case Study Using the 2022 Hunga Tonga Volcanic Eruption

The January 15, 2022 Tonga Hunga volcanic eruption was the largest event to be recorded across the International Monitoring System infrasound network. Signals from the eruption were identified at all 53 operational stations by International Data Centre analysts. This report contains descriptors for signal detection bulletins produced by infrasound researchers at Sandia National Laboratories and Los Alamos National Laboratory. Manual detection bulletins were produced by laboratory staff. Automated detection bulletins were produced using automated infrasound processing tools developed at both laboratories. Initial results are provided to evaluate the utility of extending tools developed for regional infrasound event analysis to global-scale events.

58 GEOSCIENCES↗

DOE OSTI2024

Identifying Northern Hemisphere Stratospheric and Surface Temperature Responses to the Mt. Pinatubo Eruption within E3SMv2-SPA

The Mt. Pinatubo eruption on 15 June 1991 is often associated with surface warming in the subsequent Northern Hemisphere winter. Employing E3SMv2 with prognostic aerosol modifications, we generated an ensemble of simulations initialized on 1 June 1991 to limit the intra-ensemble variability at the time of the eruption and a more traditional ensemble representing the full range of intra-ensemble variability. For each ensemble member we generated a paired counterfactual simulation with the Pinatub forcing removed allowing for isolation of the Pinatubo impact. In general, the limited variability ensemble has greater coherence in the Pinatubo impact across ensemble members which leads to more statistically robust signals compared to the full variability ensemble. Stratospheric warming patterns from Pinatubo were approximately zonally symmetric and confined between 30°S and 50°N. Isolating localized surface temperature impacts was more difficult, but the limited variability simulation did identify a preferential region of cooling between 20°S to 50°N.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2025

Kink-driven Magnetic Reconnection as the Driver of a Laboratory Plasma Eruption

We report that kink-driven magnetic reconnection serves as an eruption mechanism for a laboratory jet. A flux rope is formed and becomes a filamentary jet. The jet becomes unstable due to kink instability when the Kruskal–Shafranov instability criterion is met, leading to an inflow of reconnecting fields. As a result of kink-driven magnetic reconnection, ions are substantially energized, resulting in enhanced acceleration of the jet. Based on the evidence observed from this laboratory experiment, we propose that kink-driven magnetic reconnection might act as a key driver for laboratory jet eruptions and might be relevant to solar jets associated with kink instability and magnetic reconnection.

Solar magnetic reconnection↗

DOE OSTI2025

Comparing multi-model ensemble simulations with observations and decadal projections of upper atmospheric variations following the Hunga eruption

The Hunga Tonga–Hunga Ha'apai Model–Observation Comparison (HTHH–MOC) project aims to comprehensively investigate the evolution of volcanic water vapor and sulfur emissions and their subsequent atmospheric impacts and underlying response mechanisms using state-of-the-art global climate models. This study evaluates multi-model ensemble simulations participating in the HTHH–MOC free-run experiment with climate projections for 10 years (2022–2032). Model results are evaluated against satellite observations to assess their ability to reproduce the observed evolution of stratospheric water vapor, aerosols, temperature, and ozone from 2022 to 2024. The participating models accurately capture the observed distribution patterns and associated upper atmospheric responses, providing confidence for their future projections. Model simulations suggest that the Hunga eruption-induced stratospheric water vapor anomaly lasts 4–7 years, with a water vapor e-folding time of 31–43 months. This prolonged water vapor perturbation leads to significant stratospheric and mesospheric cooling, resulting in significant ozone loss in the upper stratosphere and lower mesosphere for 7–10 years. Comparisons between simulations with both SO 2 and H 2 O emissions and those with H 2 O-only emissions indicate that the pronounced dipole response with upper-stratospheric cooling and lower-stratospheric warming is driven by the combined effects of SO 2 and H 2 O injections. These results highlight the prolonged atmospheric impacts of the Hunga eruption and the potential critical role of stratospheric water vapor in modulating long-term atmospheric chemistry and dynamics.

Zhuo, Zhihong [Univ. of Quebec, Montreal, QC (Cana↗

NASA NTRS1971

Possible effects on the stratosphere of the 1963 Mt. Agung volcanic eruption.

Previous studies of atmospheric pollution resulting from the 1963 eruption of Mt. Agung have shown that the volcanic dust caused temperature increases in the lower stratosphere over Australia. The present study provides time series of monthly-mean lower stratospheric temperatures for eight tropical stations on both sides of the equator. The data have been smoothed by taking 12-month running means. The results suggest that any effect of the eruption may be impossible to isolate. Some features of the quasi-biennial oscillation in zonal winds and temperatures are pointed out which must be considered in any attempt to explain the peculiarities in the curves of monthly mean temperatures.

Mcinturff, R. M.↗

NASA NTRS1978

Mount Agung eruption provides test of global climatic perturbation

The Mount Agung volcanic eruption in 1963 provides the best-documented global radiative perturbation to the earth's atmosphere currently available. Data on stratospheric aerosols produced by this eruption have been used as input to a model for the atmospheric thermal structure. The computed magnitude, sign, and phase lag of the temperature changes in both the stratosphere and the troposphere are in good agreement with observations, providing evidence that the climatic response to a global radiative perturbation is significant as well as support for the use of theoretical models to predict climatic effects.

Hansen, J. E.↗

NASA NTRS1978

Similar explosive eruptions of lunar and terrestrial volcanoes

A mathematical model of one-dimensional, steady duct flow of a mixture of gas and small solid particles (rock), has been applied to the earth and the moon under geometrically and dynamically similar conditions to simulate explosive eruption conditions. Numerical results for equilibrium two-phase flows for lunar and terrestrial explosive eruptions under similar conditions indicate that: (1) a lunar explosive vent is much larger than the corresponding terrestrial vent, (2) the exit velocity from the lunar explosive flow may be higher than the lunar escape velocity, but the exit velocity of terrestrial explosive flow is much less than that of the lunar case (this result supports the hypothesis that Australian tektites came from the moon as a stream of a mixture of rock and gas of extremely high speed), and (3) the thermal effects on the lunar explosive flows are much larger than those of the terrestrial case.

Pai, S. I.↗

NASA NTRS1980

Determination of the total grain size distribution in a vulcanian eruption column, and its implications to stratospheric aerosol perturbation

The total grain distribution of tephra from the eruption by the Fuego volcano in Guatemala on Oct. 14, 1974 was determined by grain size analysis. The region within each isopach has a grain distribution which was weighted proportionally to its percentage volume; the total distribution had a median grain size of 0.6 mm and a sorting coefficient of 2.3. The ash composed of fine particles did not fall in the volcano area as part of the recognizable tephra blanket; the eruption column reached well into the stratosphere to the height of 10-12 km above sea level, with mass flux rate estimated altitudes of 18-23 km

Murrow, P. J.↗

NASA NTRS1981

Size distributions and mineralogy of ash particles in the stratosphere from eruptions of Mount St. Helens

Samples from the stratosphere obtained by U-2 aircraft after the first three major eruptions of Mount St. Helens contained large globules of liquid acid and ash. Because of their large size, these globules had disappeared from the lower stratosphere by late June 1980, leaving behind only smaller acid droplets. Particle size distributions and mineralogy of the stratospheric ash grains demonstrate inhomogeneity in the eruption clouds.

Farlow, N. H.↗

NASA NTRS1981

Eruption mechanics on the earth, moon and Mars

A survey is provided of recent comparative studies on the character of eruption mechanics on earth, the moon and Mars. Among the relevant determinations made are: (1) a source depth for lunar basaltic magmas deeper, at 100 km, than most terrestrial ones; (2) the rising of both lunar and terrestrial magmas to less than 2 km below the surface before gases begin to exsolve; (3) carbon monoxide concentrations in lunar basalts are an order of magnitude lower than the average volatile contents of terrestrial basalts; and (4) unequivocal proof is lacking for the existence of ignimbrites in Martian volcanic formations, which would be formed by the collapse of large eruption columns.

Wadge, G.↗

NASA NTRS1982

Steady state volcanism - Evidence from eruption histories of polygenetic volcanoes

Cumulative volcano volume curves are presented as evidence for steady-state behavior at certain volcanoes and to develop a model of steady-state volcanism. A minimum criteria of five eruptions over a year was chosen to characterize a steady-state volcano. The subsequent model features a constant head of magmatic pressure from a reservoir supplied from depth, a sawtooth curve produced by the magma arrivals or discharge from the subvolcanic reservoir, large volume eruptions with long repose periods, and conditions of nonsupply of magma. The behavior of Mts. Etna, Nyamuragira, and Kilauea are described and show continuous levels of plasma output resulting in cumulative volume increases. Further discussion is made of steady-state andesitic and dacitic volcanism, long term patterns of the steady state, and magma storage, and the lack of a sufficient number of steady-state volcanoes in the world is taken as evidence that further data is required for a comprehensive model.

Wadge, G.↗

NASA NTRS1982

Fine particles in the Soufriere eruption plume

The size distributions of fine particles measured at tropospheric altitudes in the periphery of the eruption plume formed during the April 17, 1979 eruption of Soufriere Volcano and in the low-level effluents on May 15, 1979 were found to be bimodal, having peak concentrations at geometric mean diameters of 1.1 and 0.23 micrometers. Scanning electron microscopy and energy-dispersive X-ray analysis of the samples revealed an abundance of aluminum and silicon and traces of sodium, magnesium, chlorine, potassium, calcium, and iron in the large-particle mode. The submicrometer-sized particles were covered with liquid containing sulfur, assumed to be in the form of liquid sulfuric acid.

Woods, D. C.↗

NASA NTRS1982

Analysis of long-period seismic waves excited by the May 18, 1980, eruption of Mount St. Helens - A terrestrial monopole

The eruption of Mount St. Helens on May 18, 1980, excited long-period seismic waves, and high-quality digital seismograms were recorded. The present investigation is concerned with the results of detailed analyses of Rayleigh and Love waves excited by this eruption. Since the elastic response of the earth is very accurately known, it is possible to retrieve the source parameters of this unique event from observations at far-field. It is shown that the source can be represented by a nearly horizontal single force. The conducted analysis is concerned with only long-period characteristics of the source. The short-period behavior of the source is difficult to determine from surface waves because the available knowledge of the earth's response is less accurate than at long periods.

Kanamori, H.↗

NASA NTRS1982

Atmospheric Effects and Potential Climatic Impact of the 1980 Eruptions of Mount St. Helens

Measurements and studies of the 1980 Mount St. Helens volcanic eruptions and their atmospheric effects and climatic impact are addressed. Specific areas discussed include: (1) nature and impact of volcanic eruptions; (2) in situ measurements of effluents; (3) remote sensing measurements; (4) transport and dispersion of volcanic effluents; (5) chemistry of volcanic effluents; and (6) weather and potential climate impact.

Adarsh Deepak↗