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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Flux Cancelation as the Trigger of Quiet-Region Coronal Jet Eruptions

Coronal jets are frequent magnetically channeled narrow eruptions. They occur in various solar environments: quiet regions, coronal holes and active regions. All coronal jets observed in EUV (Extreme UltraViolet) and X-ray images show a bright spire with a base brightening, also known as jet bright point (JBP). Recent studies show that coronal jets are driven by small-scale filament eruptions. Sterling et al. 2015 did extensive study of 20 polar coronal hole jets and found that X-ray jets are mainly driven by the eruption of minifilaments. What leads to these minifilament eruptions?

Panesar, Navdeep K.↗
NASA NTRS2019

Monitoring Volcanic Eruptions by OMI/OMPS, ASTER, and MERRA-2

Volcanic lava flows and/or the gas eruptions are the most common characteristics that can be remotely monitored with satellite technology in the global perspective and on different timescales. Atmospheric Sulfur Dioxide (SO2), one of the most abundant gases from volcanic eruptions apart from atmospheric common gases Carbon Dioxide and water vapor, can be directly detected by space-based sensors on satellites. The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) is one of the 12 Distributed Active Archive Centers (DAACs) within NASA's Earth Observing System Data and Information System (EOSDIS), which archives SO2 data sets from the Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) in 1978, till the ongoing Ozone Monitoring Instrument (OMI) on NASA's EOS-Aura satellite, the Ozone Mapping Profiler Suite (OMPS) Nadir Mapper (NM) on both the Suomi National Polar-Orbiting Partnership (Suomi-NPP or SNPP) and the Joint Polar-orbiting Satellite System-1 (JPSS-1) satellites, into the future JPSS missions. In addition to the standard OMI/Aura and OMPS/S-NPP SO2 products, SO2 products created under the charter of the Making Earth System Data Records for Use in Research Environments (MEaSUREs) project, are also archived at GES DISC, through which NASA enacts to expand understanding the Earth system using consistent data records. The Land Processes Distributed Active Archive Center (LP DAAC) is another EOSDIS's DAAC that provides land data products and operates as a partnership with the U.S. Geological Survey (USGS). The LP DAAC has been archiving the satellite imagery from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard NASA's EOS-Terra satellite, a high spatial resolution (15 meters) and 14 band multispectral instrument. The ASTER imagery is one of the land products contributing to the application for monitoring hot spots and land terrain changes caused by volcanic eruption events. The data potential in GES DISC and LP DAAC to monitor volcanic sources of SO2 and the influence of wind fields on the gas plume spread will be demonstrated with the most recent 2018 May-July Kilauea Volcano eruption.

Zeng, Jian↗
NASA NTRS2022

Kink Oscillation of a Flux Rope During a Failed Solar Eruption

We report a decaying kink oscillation of a flux rope during a confined eruptive flare, observed off the solar limb by SDO/AIA, that lacked a detectable white-light coronal mass ejection. The erupting flux rope underwent kinking, rotation, and apparent leg–leg interaction during the event. The oscillations were observed simultaneously in multiple AIA channels at 304, 171, and 193 Å, indicating that multithermal plasma was entrained in the rope. After reaching the overlying loops in the active region, the flux rope exhibited large-amplitude, decaying kink oscillations with an apparent initial amplitude of 30 Mm, period of about 16 min, and decay time of about 17 min. We interpret these oscillations as a fundamental standing kink mode of the flux rope. The oscillation polarization has a clear vertical component, while the departure of the detected waveform from a sinusoidal signal suggests that the oscillation could be circularly or elliptically polarized. The estimated kink speed is 1080 km s−1, corresponding to an Alfv'en speed of about 760 km s−1. This speed, together with the estimated electron density in the rope from our DEM analysis, ne ≈ (1.5–2.0) ×109 cm−3, yields a magnetic field strength of about 15 G. To the best of our knowledge, decaying kink oscillations of a flux rope with non-horizontal polarization during a confined eruptive flare have not been reported before. These oscillations provide unique opportunities for indirect measurements of the magnetic-field strength in low-coronal flux ropes during failed eruptions.

Pankaj Kumar↗
NASA NTRS2022

Future High-Resolution and High-Cadence Observations for Unraveling Eruptive Solar Features

Many of the key advances in solar science over recent decades have been strongly influenced by imaging with increasing resolution and cadence of the Sun’s atmosphere from space. There is still much room for further advances in this area in the coming decades. Here we demonstrate this potential using recent advances in observation and understanding of the features known as solar coronal jets. Modern jet studies started in the 1990s, but have progressed substantially over the past ten years. Much of this progress is due to improved resolution and cadence in imaging, along with concurrent improved magnetic field and spectroscopic observations. Moreover, it is now clear that jets are smaller-size-scale, shorter-time-scale versions of less-frequent larger solar eruptions. Jets are also likely representative of yet more numerous eruptions occurring on smaller size scales. We propose development of instrumentation focused on multi-wavelength observations of jet-sized-scale eruptive solar activity, as a window to understanding both larger-scale and smaller-scale eruptive solar events.

Alphonse C. Sterling↗
NASA NTRSDate not supplied

Coupled Aerosol-Chemistry Simulations of the January 2022 Eruptions of Hunga Tonga-Hunga Ha’apai in the NASA GEOS Earth System Model

The January 2022 eruptions of the underwater Hunga Tonga-Hunga Ha’apai volcano injected more than 100 Tg of water vapor and approximately 0.5 Tg of sulfur dioxide into the stratosphere. Injected materials reached as high as ~55 km in altitude, while the main plume from the eruption travelled west over Australia and the Indian Ocean between about 20 – 30 km altitude. We investigate the transport and the impact of the erupted materials in coupled aerosol-chemistry simulations performed with the NASA Goddard Earth Observing System (GEOS) Earth system model. A sulfur mechanism introduced into the Global Modeling Initiative (GMI) stratospheric-tropospheric chemistry package allows for an interactive simulation of the water vapor-chemistry impacts, and the large water vapor perturbation results in rapid conversion of sulfur dioxide to sulfate aerosol in our aerosol mechanism. We report on the results of a multi-year ensemble of simulations performed with this system that include a control ensemble (no eruption), a water vapor-only injection ensemble, and a water vapor and sulfur dioxide injection ensemble. Simulations of the near-field aerosol and chemistry transport are compared to available measurements from OMPS-LP, OMPS-NM, CALIOP, MLS, and other sensors. The extended impact of the volcanic materials on the stratospheric composition and chemistry over the next several years is further investigated in forecast simulations.

Peter Colarco↗
NASA NTRSDate not supplied

Breakout Reconnection and Eruption in a Double Null-point Topology

Basic Question: Why are some eruptions successful while others remain confined? • We analyzed an eruption associated with a C-class flare in a null-point topology (fan-spine/embedded bipole configuration) within NOAA AR 11791, embedded within a large pseudostreamer between two coronal holes. • About 4 hours prior, interchange reconnection at the null produced a faint jet and a B-class flare without any filament eruption. • Continued reconnection below the filament built a flux rope (FR) that rose slowly and later generated the C1.4 flare. The flux rope reconnected with pseudostreamer flux near inner null, producing a remote (third) ribbon at the base of the fan and partial ejection of the flux rope. • Multiple plasmoids appeared in two places: above the rising flux rope in the breakout current sheet (the deformed null), and in a vertical flare current sheet below the flux rope (quasiperiodic flare reconnection). • Weak, narrow, coronal and interplanetary Type-III radio bursts were also detected, suggesting that electron beams from the null were ejected into the heliosphere. • The partial FR ejected from the inner system encountered the overlying arcade and null of the big pseudostreamer higher in the corona and oscillated, but did not escape. • EUV and coronagraph images revealed a wave and a faint ejection from the pseudostreamer that propagated laterally southward with ~270 km s-1. • We suggest that the main factors leading to the confined filament eruption are (i) lack of significant breakout reconnection between the rising flux rope and the overlying arcade due to an unfavorable relative orientation of these flux systems; and/or (ii) insufficient free energy of the flux rope to overcome the tension forces of the overlying arcades.

J Karpen↗
NASA NTRS2023

Plasmoids, Flows, and Jets During Magnetic Reconnection in a Failed Solar Eruption

We report a detailed analysis of a failed eruption and flare in active region 12018 on 2014 April 3 using multiwavelength observations from the Solar Dynamics Observatory/Atmospheric Imaging Assembly, IRIS, STEREO, and Hinode/Solar Optical Telescope. At least four jets were observed to emanate from the cusp of this small active region (large bright point) with a null-point topology during the 2 hr prior to the slow rise of a filament. During the filament slow rise multiple plasma blobs were seen, most likely formed in a null-point current sheet near the cusp. The subsequent filament eruption, which was outside the IRIS field of view, was accompanied by a flare but remained confined. During the explosive flare reconnection phase, additional blobs appeared repetitively and moved bidirectionally within the flaring region below the erupting filament. The filament kinked, rotated, and underwent leg–leg reconnection as it rose, yet it failed to produce a coronal mass ejection. Tiny jet-like features in the fan loops were detected during the filament slow rise/preflare phase. We interpret them as signatures of reconnection between the ambient magnetic field and the plasmoids leaving the null-point sheet and streaming along the fan loops. We contrast our interpretation of these tiny jets, which occur within the large-scale context of a failed filament eruption, with the local nanoflare-heating scenario proposed by Antolin et al.

Sun: jets↗
NASA NTRS2022

Measurement of Surface Deformation Related to the December 2018 Mt. Etna Eruption Using Time-Series Interferometry and Magma Modeling for Hazard Zone Mapping

Mount Etna has erupted several times since it was first formed. Recently, Mount Etna began erupting again over 24–27 December 2018. Because it erupts frequently, Mount Etna should be observed on a frequent basis. From June 2018 to October 2019, 34 and 56 interferometric synthetic aperture radar (InSAR) images were acquired from the ascending and descending tracks of the Sentinel-1 satellite, respectively. We employed the Stanford Method for Persistent Scatterers (StaMPS) and a refined small baseline subset (SBAS) InSAR method to produce a surface deformation time-series map. In the time-series analysis, the phase signal remained unaltered with time. The Okada model was then applied to the result to generate a modeled interferogram, and the Q-LavHA program was run to generate a lava flow prediction model. A direct comparison of the results showed that Persistent Scatterers Interferometry (PSI)-StaMPS and the refined SBAS technique were comparable in terms of the displacement pattern, with slightly different velocity values obtained for individual points. In particular, a velocity range of −25 to 21 cm/yr was obtained from PSI-StaMPS, whereas a range of −30 to 25 cm/yr was obtained from the refined SBAS method. Upon computation of the vertical and east-west displacement components based on ascending and descending track data using both methods, deformation velocities of 51.5 and 52.5 cm/yr in the westerly direction on the western flank of Mount Etna were obtained from PSI-StaMPS and the refined SBAS method, respectively, whereas on the eastern flank, deformation toward the east was estimated to occur at a velocity of 50.1 or 54.2 cm/yr, respectively. PSIStaMPS estimated a vertical deformation velocity of −5.3 to 18.3 cm/yr, whereas the refined SBAS method produced a velocity range of approximately −7 to 19 cm/yr. The interferogram obtained via Okada modeling showed two fault sources in the 2018 Mount Etna eruption and a total volume change of approximately 12.39 × 10 6 m 3 . From the modeling results, a lava flow prediction model was generated using the Q-LavHA program. The approaches described in this study can be used by government officials, authorities, and other decision-makers to monitor and assess the risk of volcanic activity in the region.

Suci Ramayanti↗
NASA NTRS2023

Dispersion and Aging of Volcanic Aerosols after the La Soufriere Eruption in April 2021

Volcanic aerosols change the atmospheric composition and thereby affect weather and climate. Aerosol dynamic processes such as nucleation, condensation, and coagulation modify the shape, size, and mass of aerosol particles, which influence their atmospheric lifetime and radiative properties. Nevertheless, most models omit these processes for ash particles. In this work, we explore the ash aerosol aging and sulfate production during the first 4 days following the 2021 La Soufrière (St. Vincent) eruption with the ICON-ART model (ICOsahedral Nonhydrostatic model with Aerosol and Reactive Trace gases). Online coupling of ICON-ART with a one-dimensional volcanic plume model calculates volcanic emission, which makes it possible to resolve the different eruption phases of the noncontinuous La Soufrière eruption. We compared our simulated aerosol distribution and composition with observations from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument, the Multiangle Imaging SpectroRadiometer (MISR) Research Aerosol (RA) Algorithm, and the Barbados Cloud Observatory (BCO). We show that online coupling is essential to adequately model the emissions and plume development close to the volcano. The modeled aerosol aging is in very good agreement with observations from MISR near the emission source and with CALIOP at larger distances. Furthermore, particle aging occurs faster in the troposphere than in the stratosphere due to the availability of water vapor and OH, but a layer of coated ash appears at the plume top due to faster oxidation of SO2 and lofting by aerosol-radiation interaction. This paper gives the first direct comparison of aerosol aging in volcanic eruption plumes between simulations and observations

volcanic aerosols↗
NASA NTRS2024

Large-scale Coronal Dimming Foreshadowing a Solar Eruption on 2011 October 1

Understanding large-scale solar eruptions requires detailed investigation of the entire system's evolution, including the magnetic environment enveloping the source region and searches for precursor activity prior to event onset. We combine stereoscopic observations from the Solar Dynamics Observatory (SDO) and STEREO-B spacecraft for several hours before a filament ejection, M1.2-class eruptive flare, and coronal mass ejection (CME) originating in NOAA active region (AR) 11305 on 2011 October 1. Two episodes of significant preeruption coronal dimming that occurred well to the southeast of the ejected filament are identified. The CME subsequently took off with a substantial component of velocity toward the dimming, which became very pronounced during eruption. We used SDO/Helioseismic and Magnetic Imager (HMI) data to reconstruct the magnetic environment of the system and found that it contains a null point near the dimming region. AR 11305 had quite complex connections to nearby ARs 11302 and 11306, as well as to other regions of decayed AR flux. The intensifying and spatially expanding precursor dimming was accompanied by southeastward rising motions of loops toward the null point and northeastward and southwestward motions of loops retracting away. These motions and the dimming are consistent with persistent magnetic reconnection occurring at the null point as it moved upward and southeastward, thereby removing a strapping magnetic field high above AR 11305. Eventually, the filament was ejected explosively toward the null point. We conclude that the breakout model for solar eruptions provides a compelling account of this event. Furthermore, we conjecture that preeruption dimmings may be much more frequent than currently recognized.

solar flares↗
NASA NTRS2024

Evolving Particles in the 2022 Hunga-Tonga Hunga-Ha’apai Volcano Eruption Plume

The Multi-angle Imaging SpectroRadiometer (MISR) aboard NASA’s Terra satellite observed the Hunga Tonga—Hunga Ha’apai (HTHH) 15 January eruption plume on eight occasions between 15 and 23 January 2022. From the MISR multi-angle, multi-spectral imagery we retrieve aerosol plume height geometrically, along with plume-level motion vectors, and derive radiometrically constraints on particle effective size, shape, and light-absorption properties. Parts of two downwind aerosol layers were observed in different places and times, one concentrated in the upper troposphere (11-18 km ASL), and a mid-stratosphere layer~23 –30+ km ASL. After the initial day (1/15), the retrievals identified only spherical, non-light-absorbing particles, typical of volcanic sulfate/water particles. The near-tropopause plume particles show constant, medium-small (several tenths of a micron) effective size over four days. The mid-stratosphere particles were consistently smaller, but retrieved effective particle size increased between 1/17 and 1/23, though they might have decreased slightly on 1/22. As a vast amount of water was also injected into the stratosphere by this eruption, models predicted relatively rapid sulfate particle growth from the modest amounts of SO2 gas injected by the eruption to high altitudes along with the water (Zhu et al, 2022). MISR observations up to ten days after the eruption are consistent with these model predictions. The possible decrease in stratospheric particle size after initial growth was likely caused by evaporation, as the plume mixed with drier, ambient air. Particles in the lower-elevation plume observed on 1/15 were larger than all the downwind aerosols and contained significant non-spherical (likely ash) particles.

aerosol plume height↗
DOE OSTI2023

Lightning Rings and Gravity Waves: Insights Into the Giant Eruption Plume From Tonga's Hunga Volcano on 15 January 2022

Abstract On 15 January 2022, Hunga Volcano in Tonga produced the most violent eruption in the modern satellite era, sending a water‐rich plume at least 58 km high. Using a combination of satellite‐ and ground‐based sensors, we investigate the astonishing rate of volcanic lightning (>2,600 flashes min −1 ) and what it reveals about the dynamics of the submarine eruption. In map view, lightning locations form radially expanding rings. We show that the initial lightning ring is co‐located with an internal gravity wave traveling >80 m s −1 in the stratospheric umbrella cloud. Buoyant oscillations of the plume's overshooting top generated the gravity waves, which enhanced turbulent particle interactions and triggered high‐current electrical discharges at unusually high altitudes. Our analysis attributes the intense lightning activity to an exceptional mass eruption rate (>5 × 10 9 kg s −1 ), rapidly expanding umbrella cloud, and entrainment of abundant seawater vaporized from magma‐water interaction at the submarine vent.

58 GEOSCIENCES↗
NASA NTRS2016

Analysis of an Anemone-Type Eruption in an On-Disk Coronal Hole

We report on an eruption seen in a very small coronal hole (about 120 arcseconds across), beginning at approximately 19:00 Universal Time on March 3, 2016. The event was initially observed by an amateur astronomer (RW) in an H-alpha movie from the Global Oscillation Network Group (GONG); the eruption attracted the attention of the observer because there was no nearby active region. To examine the region in detail, we use data from the Solar Dynamics Observatory (SDO), provided by the Atmospheric Imaging Assembly (AIA) in wavelengths 193 angstroms, 304 angstroms, and 94 angstroms, and the Helioseismic and Magnetic Imager (HMI). Data analysis and calibration activities such as scaling, rotation so that north is up, and removal of solar rotation are accomplished with SunPy. The eruption in low-cadence HMI data begins with the appearance of a bipole in the location of the coronal hole, followed by (apparent) expansion outwards when the intensity of the AIA wavelengths brighten; as the event proceeds, the coronal hole disappears. From high-cadence data, we will present results on the magnetic evolution of this structure, how it is related to intensity brightenings seen in the various SDO/AIA wavelengths, and how this event compares with the standard-anemone picture.

anemone↗
NASA NTRS2016

How Did Climate and Humans Respond to Past Volcanic Eruptions?

To predict and prepare for future climate change, scientists are striving to understand how global-scale climatic change manifests itself on regional scales and also how societies adapt or don't to sometimes subtle and complex climatic changes. In this regard, the strongest volcanic eruptions of the past are powerful test cases, showcasing how the broad climate system responds to sudden changes in radiative forcing and how societies have responded to the resulting climatic shocks. These issues were at the heart of the inaugural workshop of the Volcanic Impacts on Climate and Society (VICS) Working Group, convened in June 2016 at the Lamont-Doherty Earth Observatory of Columbia University in Palisades, N.Y. The 3-day meeting gathered approximately 50 researchers, who presented work intertwining the history of volcanic eruptions and the physical processes that connect eruptions with human and natural systems on a global scale.

societies↗
NASA NTRS1994

Volcanic Eruptions on Io: Heat Flow, Resurfacing, and Lava Composition

In this paper we consider the infrared outbursts on Io reported over the last 15 years and examine the implications for resurfacing rates and heat flow using a recent, well observed, eruption sequence. A large change was observed in Io's infrared emission on January 9, 1990 at several different wavelengths. We model this event as due to a large actively erupting lava flow. The flow increased its area at a rate of 1.5 x 10 5 m 2 s -1 and cooled from 1225 K to 555 K over about 2.6 hours. This event is consistent with other Io infrared outbursts and is used in this paper to estimate the more general characteristics of Ionian volcanism, resurfacing, and heat flow. The inferred eruption rate of 3 x 10 5 m 3 s -1 is very high, but is not unprecedented on the Earth.

Io↗
NASA NTRS2022

Volcanic Eruption of Cumbre Vieja, La Palma, Spain: A First Insight to the Particulate Matter Injected in the Troposphere

The volcanic eruption of Cumbre Vieja (La Palma Island, Spain), started on 19 September, 2021, and was declared terminated on 25 December, 2021. A complete set of aerosol measurements were deployed around the volcano within the first month of the eruptive activity. This paper describes the results of the observations made at Tazacorte on the west bank of the island where a polarized micro pulse lidar was deployed. The two and a half months analyzed (16 October – 31 December) reveal that the peak height of the lowermost and strongest volcanic plume did not exceed 3 km (mean of 1.43±0.45 km over the whole period) and was highly variable. It steadily increased until week 11 after the eruption start (and 3 weeks before its end) and started decreasing afterwards. The ash mass concentration has been assessed with a method based on the polarization capability of the instrument. Considering the limitation of current remote sensing techniques to detect large to giant particles, the ash mass concentration on one of the days with the highest ash load is estimated to have peaked in the range 800-3200 μg m(exp -3) in the lowermost layer below 2.5 km.

Cumbre Vieja↗
NASA NTRS2023

The Cross Equatorial Transport of the Hunga Tonga-Hunga Ha'apai Eruption Plume

On 15 January 2022, the Hunga Tonga-Hunga Ha'apai (HT) eruption injected SO 2 and water into the middle stratosphere. Shortly after the eruption, the water vapor anomaly moved northward toward and across the equator. This northward movement appears to be due to equatorial Rossby waves forced by the excessive infrared water vapor cooling. Following the early eruption stage, persistent mid-stratospheric water vapor and aerosol layers were mostly confined to Southern Hemisphere tropics (Eq. to 30°S). However, during the spring of 2022, the westerly phase of the tropical quasi-biennial oscillation (QBO) descended through the tropics. The HT water vapor and aerosol anomalies were observed to again move across the equator coincident with the shift in the Brewer-Dobson circulation and the descent of the QBO shear zone.

water↗
NASA NTRSDate not supplied

Reassessing Post-Eruption Precipitation Anomalies in the Context of Natural Variability

Several studies have reported anomalous precipitation in the years that follow large volcanic eruptions. Here we assess precipitation anomalies in post-eruption years according to their rarity in non-volcanic periods. Using global simulations of climate over the last millennium, we reevaluate the response of precipitation to volcanic aerosols in terms of novel metrics. In this approach, the magnitude of the precipitation response is contextualized through comparisons to internal variability. We also examine the connections between global and regional-scale precipitation anomalies. Finally, we assess to what extent a unique ‘fingerprint’ of eruptions can be seen in the observational precipitation record in spite of concurrent internal variability.

volcanic eruptions↗