nasa-gesdisc/es-publications-researchareas huggingface dataset:
Satellite-based global volcanic SO2emissions and sulfate direct radiative forcing during 2005-2012 (2016)

An 8 year volcanic SO<SUB>2</SUB> emission inventory for 2005-2012 is obtained based on satellite measurements of SO<SUB>2</SUB> from OMI (Ozone Monitoring Instrument) and ancillary information from the Global Volcanism Program. It includes contributions from global volcanic eruptions and from eight persistently degassing volcanoes in the tropics. It shows significant differences in the estimate of SO<SUB>2</SUB> amount and injection height for medium to large volcanic eruptions as compared to the counterparts in the existing volcanic SO<SUB>2</SUB> database. Emissions from Nyamuragira (DR Congo) in November 2006 and Grímsvötn (Iceland) in May 2011 that were not included in the Intergovernmental Panel on Climate Change 5 (IPCC) inventory are included here. Using the updated emissions, the volcanic sulfate (SO<SUB>4</SUB><SUP>2-</SUP>) distribution is simulated with the global transport model Goddard Earth Observing System (GEOS)-Chem. The simulated time series of sulfate aerosol optical depth (AOD) above 10 km captures every eruptive volcanic sulfate perturbation with a similar magnitude to that measured by Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO). The 8 year average contribution of eruptive SO<SUB>4</SUB><SUP>2-</SUP> to total SO<SUB>4</SUB><SUP>2-</SUP> loading above 10 km is ~10% over most areas of the Northern Hemisphere, with a maxima of 30% in the tropics where the anthropogenic emissions are relatively smaller. The persistently degassing volcanic SO<SUB>4</SUB><SUP>2-</SUP> in the tropics barely reaches above 10 km, but in the lower atmosphere it is regionally dominant (60%+ in terms of mass) over Hawaii and other oceanic areas northeast of Australia. Although the 7 year average (2005-2011) of eruptive volcanic sulfate forcing of -0.10 W m<SUP>-2</SUP> in this study is comparable to that in the 2013 IPCC report (-0.09 W m<SUP>-2</SUP>), significant discrepancies exist for each year. Our simulations also imply that the radiative forcing per unit AOD for volcanic eruptions can vary from -40 to -80 W m<SUP>-2</SUP>, much higher than the -25 W m<SUP>-2</SUP> implied in the IPCC calculations. In terms of sulfate forcing efficiency with respect to SO<SUB>2</SUB> emission, eruptive volcanic sulfate is 5 times larger than anthropogenic sulfate. The sulfate forcing efficiency from degassing volcanic sources is close to that of anthropogenic sources. This study highlights the importance of characterizing both volcanic emission amount and injection altitude as well as the key role of satellite observations in maintaining accurate volcanic emissions inventories.

Research areas: Volcanic Eruptions
Significant Ionospheric Hole and Equatorial Plasma Bubbles After the 2022 Tonga Volcano Eruption (2022)

This paper investigates the local and global ionospheric responses to the 2022 Tonga volcano eruption, using ground-based Global Navigation Satellite System total electron content (TEC), Swarm in situ plasma density measurements, the Ionospheric Connection Explorer (ICON) Ion Velocity Meter (IVM) data, and ionosonde measurements. The main results are as follows: (a) A significant local ionospheric hole of more than 10 TECU depletion was observed near the epicenter ∼45 min after the eruption, comprising of several cascading TEC decreases and quasi-periodic oscillations. Such a deep local plasma hole was also observed by space-borne in situ measurements, with an estimated horizontal radius of 10-15° and persisted for more than 10 hr in ICON-IVM ion density profiles until local sunrise. (b) Pronounced post-volcanic evening equatorial plasma bubbles (EPBs) were continuously observed across the wide Asia-Oceania area after the arrival of volcano-induced waves; these caused a N<SUB>e</SUB> decrease of 2-3 orders of magnitude at Swarm/ICON altitude between 450 and 575 km, covered wide longitudinal ranges of more than 140°, and lasted around 12 hr. (c) Various acoustic-gravity wave modes due to volcano eruption were observed by accurate Beidou geostationary orbit (GEO) TEC, and the huge ionospheric hole was mainly caused by intense shock-acoustic impulses. TEC rate of change index revealed globally propagating ionospheric disturbances at a prevailing Lamb-wave mode of ∼315 m/s; the large-scale EPBs could be seeded by acoustic-gravity resonance and coupling to less-damped Lamb waves, under a favorable condition of volcano-induced enhancement of dusktime plasma upward E×B drift and postsunset rise of the equatorial ionospheric F-layer.

Research areas: Volcanic Eruptions
Improved estimation of volcanic SO<sub>2</sub> injections from satellite retrievals and Lagrangian transport simulations: the 2019 Raikoke eruption (2022)

Abstract. Monitoring and modeling of volcanic plumes are important for understanding the impact of volcanic activity on climate and for practical concerns, such as aviation safety or public health. Here, we apply the Lagrangian transport model Massive-Parallel Trajectory Calculations (MPTRAC) to estimate the SO2 injections into the upper troposphere and lower stratosphere by the eruption of the Raikoke volcano (48.29 N, 153.25 E) in June 2019 and its subsequent long-range transport and dispersion. First, we used SO2 retrievals from the AIRS (Atmospheric Infrared Sounder) and TROPOMI (TROPOspheric Monitoring Instrument) satellite instruments together with a backward trajectory approach to estimate the altitude-resolved SO2 injection time series. Second, we applied a scaling factor to the initial estimate of the SO2 mass and added an exponential decay to simulate the time evolution of the total SO2 mass. By comparing the estimated SO2 mass and the mass from TROPOMI retrievals, we show that the volcano injected 2.1  0.2 Tg SO2, and the e-folding lifetime of the SO2 was about 13 to 17 d. The reconstructed SO2 injection time series are consistent between using the AIRS nighttime and the TROPOMI daytime products. Further, we compared forward transport simulations that were initialized by AIRS and TROPOMI SO2 products with a constant SO2 injection rate. The results show that the modeled SO2 change, driven by chemical reactions, captures the SO2 mass variations from TROPOMI retrievals. In addition, the forward simulations reproduce the SO2 distributions in the first 10 d after the eruption. However, diffusion in the forward simulations is too strong to capture the internal structure of the SO2 clouds, which is further quantified in the simulation of the compact SO2 cloud from late July to early August. Our study demonstrates the potential of using combined nadir satellite retrievals and Lagrangian transport simulations to further improve SO2 time- and height-resolved injection estimates of volcanic eruptions.

Research areas: Volcanic Eruptions
Fluid Fluxing and Accumulation Drive Decadal and Short-Lived Explosive (2021)

Abstract
            Some volcanoes are known for repeatedly producing explosive but short-lived eruptions (< half a day) every decade or so. These eruptions are often preceded by limited unrest signals and short run-up times to eruption (a few hours to months), and thus they are difficult to anticipate. Some well-documented examples are the 1990 and 2014 eruptions of Kelud volcano in Indonesia, or the 2015 Calbuco eruption in Chile. Here we interrogate the rock record and obtain insights into the processes and pre-eruptive conditions that led to the 1990 Kelud eruption, which we integrate with monitoring data (seismicity, lake temperature and hydro-acoustics, sulfur emissions) towards a conceptual model for this type of events. Mineral-melt geothermobarometers indicate that the basaltic andesite magma carried a crystal cargo from as deep as 1519 km, and reached volatile saturation at 49 km with 24 wt.% water in the melt. The textures and compositional zoning of orthopyroxene and plagioclase do not support intrusion of more primitive magma as the driver for the eruption, and we instead propose that pre-eruptive fluid accumulation and high-temperature fluid fluxing from depth (likely dominated by CO2) played a major role in priming the eruption to occur. Such pre-eruptive gas accumulation is also supported by mass balance calculation of the emitted excess SO2 gas. Mg-Fe diffusion profiles in reversely zoned pyroxenes constrain timescales of weeks to months before eruption for fluid addition to the reservoir, and such events may be recorded in the monitoring signals, especially in the change of hydroacoustics and water lake temperature, and probably in the seismic swarms. We propose that fluid exsolution and accumulation in the shallow reservoir plays a crucial role in modulating and triggering short-lived explosive eruptions with brief unrest at Kelud and probably other volcanoes worldwide.

Research areas: Volcanic Eruptions
Satellite Detection of a Massive Phytoplankton Bloom Following the 2022 Submarine Eruption of the Hunga Tonga‐Hunga Haʻapai Volcano (2022)

The largest submarine volcanic eruption of this century led to a dramatic phytoplankton bloom north of the island of Tongatapu, in the Kingdom of Tonga. In the absence of shipboard observations, we reconstructed the dynamics of this event by using a suite of satellite observations. Two independent bio-optical approaches confirmed that the phytoplankton bloom was a robust observation and not an optical artifact due to volcanogenic material. Furthermore, the timing, size, and position of the phytoplankton bloom suggest that plankton growth was primarily stimulated by nutrients released from volcanic ash rather than by nutrients upwelled through submarine volcanic activity. The appearance of a large region with high chlorophyll a concentrations &lt;48 hr after the largest eruptive phase indicates a fast ecosystem response to nutrient fertilization. However, net phytoplankton growth probably initiated before the main eruption, when weaker volcanism had already fertilized the ocean.

Research areas: Volcanic Eruptions
Shallow ground temperature measurements on the highest volcano on Earth (2019)

Mt. Ojos del Salado (6893 m a.s.l.) lies within the Andean Arid Diagonal, on the Chilean–Argentinean border. Due to the extremely arid climate, surface ice is not widespread on Mt. Ojos del Salado and at similar high‑altitude massifs in the region, although ice‑bearing permafrost might be present. However, the thermal regime of the ground is relatively unknown in the region, especially outside of rock glaciers at high elevations north of 30°S. To study ground thermal regimes, in‑situ shallow ground temperature and snow coverage from satellite imagery have been surveyed for four years (2012–2016) at six sites between the elevations of 4200–6893 m a.s.l. on Mt. Ojos del Salado (27°07′S, 68°32′W). According to the ground temperature and snow coverage data at the six monitoring sites, the presence of permafrost is unlikely below 4550 m a.s.l. but likely above 5250 m a.s.l. on Mt. Ojos del Salado. In addition, the active layer becomes extremely thin around 6750 m a.s.l.

Research areas: Cryospheric Indicators
Investigations on the Global Spread of the Hunga Tonga-Hunga Ha'apai Volcanic Eruption Using Space-Based Observations and Lagrangian Transport … (2022)

On 15 January 2022, the Hunga Tonga-Hunga Haapai (HTHH) (175.38 W, 20.54 S) volcano erupted explosively. It is considered the most explosive volcanic eruption during the past 140 years. The HTHH volcanic eruption caused intense ripples, Lamb waves, and gravity waves in the atmosphere which encircled the globe several times, as reported by different studies. In this study, using OMI, SAGE-III/ISS, and CALIPSO satellite observations, we investigated the spread of the volcanic SO2 cloud due to the HTHH eruption and subsequent formation of sulfuric acid clouds in the stratosphere. It took about 1921 days for the stratospheric SO2 injections of the HTHH to encircle the globe longitudinally due to a dominant westward jet with wind speeds of ~2500 km/day, and it slowly dispersed over the whole globe within several months due to poleward spread. The formation of sulfuric acid clouds intensified after about a month, causing the more frequent occurrence of high aerosol optical depth elevated layers in the stratosphere at an altitude of about 2026 km. This study deals with the dynamics of volcanic plume spread in the stratosphere, knowledge of which is essential in estimating the accurate radiative effects caused by perturbations in the earthatmosphere system due to a volcanic eruption. In addition, this knowledge provides important input for studies related to the geo-engineering of the earths atmosphere by injecting particulates and gases into the stratosphere.

Research areas: Volcanic Eruptions
Inflating shallow plumbing system of Bezymianny volcano, Kamchatka, studied by InSAR and seismicity data prior to the 20 December 2017 eruption (2021)

Explosive eruptions at steep-sided volcanoes may develop with complex precursor activity occurring in a poorly-understood magma plumbing system so that timelines and possible interactions with the geologic surrounding are often unresolved. Here we investigate the episode prior to the energetic December 20, 2017 eruption at Bezymianny volcano, Kamchatka. We compare degassing activity inferred from time-lapse camera images, seismicity and real-time seismic amplitude (RSAM) data derived from a temporary station network, as well as high-resolution InSAR displacement maps. Results show that the first changes can be identified in low-frequency seismicity and degassing at least 90 days before the eruption, while the first volcano-tectonic (VT) seismicity occurred 50 days before the eruption. Coinciding with significant changes of the RSAM, surface displacements affect the volcanic flanks at least 9 days prior to the eruption. Inversion modeling of the pre-eruptive surface deformation as well as deflation-type, co-eruptive surface changes indicate the presence of a shallow and transient reservoir. We develop a conceptual model for Bezymianny volcano initiating with deep seismicity, followed by shallow events, rockfalls, steaming and an inflating reservoir. The eruption is then associated with subsidence, caused by deflation of the same reservoir. This sequence and conceivable causality of these observations are providing a valuable contribution to our understanding of the shallow magma plumbing system beneath Bezymianny and may have relevance for volcano monitoring and early warning strategies at similar volcanoes elsewhere.

Research areas: Volcanic Eruptions
The first evaluation of the FY-3D/MERSI-2 sensor's thermal infrared capabilities for deriving land surface temperature in volcanic regions: a case study of Mount Etna (2022)

In November 2017, the China Meteorological Administration launched a new polar orbiting satellite in its Fengyun (FY) series: FY-3D. With its main purpose being the collection of meteorological data, FY-3D featured a comprehensive payload that is equally exploitable by various Earth Science disciplines. One of its sensors, the MEdium Resolution Spectral Imager-2 (MERSI-2), provides visible and infrared imagery at spatial resolutions of 250  1000 m. These characteristics make MERSI-2 suitable for volcanological remote sensing and make it comparable to the National Aeronautics and Space Administrations (NASAs) Moderate Resolution Imaging Spectroradiometer (MODIS) sensors which themselves, have been widely used in volcanological applications. This paper evaluates the first clear and near-coincident MODIS  MERSI-2 images of Mount Etna (Italy) during an active volcanic phase in 2019 and in turn, provides the first assessment of MERSI-2s utility in observing volcanic activity in the Thermal InfraRed (TIR). To ensure the comparability of both scenes, data from each were converted to Land Surface Temperature (LST) and comparisons were encouraging, with an r2 of 0.92, a mean temperature discrepancy of 0.26 K and a root mean squared error of 0.75 K. Having ascertained comparability, we focussed on the absolute temperatures detected at the eruption site, with the highest being 317.3 K and 328.1 K for MODIS and MERSI-2, respectively. The 20 minute gap between the acquisitions is the most likely the cause of this temperature discrepancy, suggesting variations in lava effusion rates and activity were occurring at Mount Etna over such timescales. This study confirms the applicability of MERSI-2 for observing volcanic activity and emphasises the significance of TIR volcanic monitoring and the importance that additional spaceborne platforms might have in reducing temporal gaps between image acquisitions. Given its unique characteristics, future studies should investigate the applicability of MERSI-2 in more varied volcanic settings.

Research areas: Volcanic Eruptions
Geochronology of volcanically associated hydrocarbon charge in the pre-salt carbonates of the Namibe Basin, Angola (2021)

In volcanic rifted margins, the timing of hydrocarbon charge is difficult to predict, but is important in understanding fluid genesis. We investigated whether igneous activity was linked to hydrocarbon charge in the prolific South Atlantic pre-salt petroleum system. To do this, we applied in situ carbonate U-Pb geochronology, a relatively novel tool for dating hydrocarbon migration, to bituminous veins in pre-salt travertines from the rifted onshore Namibe Basin (Angola). To test if fluid flow was synchronous with known volcanic pulses, we also obtained new 40Ar/39Ar geochronology from a nearby volcanic complex. Bitumen is associated with calcite in a first generation of veins and vugs, and with dolomite in younger veins. The dated calcite veins yielded a pooled U-Pb age of 86.2  2.4 Ma, which overlaps the volcanism 40Ar/39Ar age of 89.9  1.8 Ma. The overlapping dates and the localized bitumen occurrence around the dated volcanic center show a clear genetic relationship between Late Cretaceous igneous activity and hydrocarbon charge. The dolomite was dated at 56.8  4.8 Ma, revealing a previously unknown Paleocene/Eocene fluid-flow phase in the basin.

Research areas: Volcanic Eruptions
Atmospheric and Ionospheric Signatures Associated with the 15 January 2022 Cataclysmic Hunga-Tonga Volcanic Eruption: A Multi-layer Observation (2022)

The Hunga-Tonga volcanic eruption occurred on 15 January 2022 generated different modes of atmospheric and ionospheric waves. Using the Geostationary Operational Environment Satellite-17 (GOES-17), Aqua and Global Positioning System (GPS) satellite observations, an atmospheric and ionospheric multi-layer study of the Tonga volcano induced signatures over the New Zealand region is performed. The visible and infrared channel data of GOES-17 and Atmospheric Infrared Sounder (AIRS) data from NASA Aqua satellite confirm the presence of a highly convective zone and occurrence of concentric Lamb and gravity waves at lower atmospheric altitudes. The Total Electron Content (TEC) derived from 175 GPS stations covering the entire New Zealand region brings out two dominant modes of Travelling Ionospheric Disturbances (TIDs) having periodicity between 30 and 50 min. These two different modes having the phase speeds of 542 m/s and 354 m/s are allied to atmospheric gravity waves and Lamb wave triggered gravity waves respectively and are observed to propagate towards the south-west direction over the New Zealand region.

Research areas: Volcanic Eruptions
Climate disaster and the resilience of local maritime networks: Two examples from the Aegean Bronze Age (2021)

This paper investigates changing patterns of maritime small-world networks among the Cycladic islands of the southern Aegean Sea in the context of two climate disasters in the Bronze Age (ca. 3200 BCE - 1100 BCE): the 4.2 ka event at the end of the Early Bronze Age and the eruption of Thera in the late 17th century BCE in the Late Bronze Age. The 4.2 ka event is a period where changing environmental conditions  including landscape degradation, deforestation, and increased drought  correlate with drastically reduced maritime connectivity and increased settlement isolation. Previous archaeological study of the eruption of the Theran volcano (Santorini) has shown the persistence of regional-scale communication networks for a period of up to a century after the eruption. This paper examines the effect of the eruption on local-scale maritime networks. The archaeological study of both climate events is complicated by chronological discrepancies and, in the case of the 4.2 ka event, reliance on indirect environmental data. This paper addresses the questions: a) what effect did these two climate disasters have on small-world maritime networks in the Bronze Age Cyclades, and b) how did the island inhabitants adapt within a context of disruptive environmental phenomena? GIS modeling reveals that small-world networks in the Early Bronze Age Cyclades were substantially altered in the face of the 4.2 ka climate event, while in response to the eruption of Thera, small-world networks were resilient. Variables influencing the differing network responses include the temporality of the climate disasters, the availability of the sail as a technology of resilience, and varying environmental and social vulnerabilities.

Research areas: Volcanic Eruptions
The evolution and dynamics of the Hunga TongaHunga Ha'apai sulfate aerosol plume in the stratosphere (2022)

Abstract. We use a combination of spaceborne instruments to study the unprecedented stratospheric plume after the Tonga eruption of 15 January 2022. The aerosol plume was initially formed of two clouds at 30 and 28 km, mostly composed of submicron-sized sulfate particles, without ash, which is washed out within the first day following the eruption. The large amount of injected water vapour led to a fast conversion of SO2 to sulfate aerosols and induced a descent of the plume to 2426 km over the first 3 weeks by radiative cooling. Whereas SO2 returned to background levels by the end of January, volcanic sulfates and water still persisted after 6 months, mainly confined between 35 S and 20 N until June due to the zonal symmetry of the summer stratospheric circulation at 2226 km. Sulfate particles, undergoing hygroscopic growth and coagulation, sediment and gradually separate from the moisture anomaly entrained in the ascending branch BrewerDobson circulation. Sulfate aerosol optical depths derived from the IASI (Infrared Atmospheric Sounding Interferometer) infrared sounder show that during the first 2 months, the aerosol plume was not simply diluted and dispersed passively but rather organized in concentrated patches. Space-borne lidar winds suggest that those structures, generated by shear-induced instabilities, are associated with vorticity anomalies that may have enhanced the duration and impact of the plume.

Research areas: Volcanic Eruptions