nasa-gesdisc/es-publications-researchareas huggingface dataset:
Infrasound Observations of Atmospheric Disturbances Due to a Sequence of Explosive Eruptions at Mt. Shinmoedake in Japan on March 2018 (2020)

Thirty infrasound sensors have been operated over Japan since 2015. We developed the irregular array data processing in order to detect and estimate the parameters of the arrival source waves by using infrasound data related to the sequence of the volcanic eruption at Mt. Shinmoedake in March 2018. We found that the apparent velocity at the ground was equal to the acoustic velocity at particular reflection levels. The results were confirmed through a comparison of the findings of the apparent velocity with a wave propagation simulation on the basis of the azimuth, infrasound time arrivals, and the state of the atmospheric background using global atmospheric models. In addition, simple ideas for estimating horizontal wind speeds at certain atmospheric altitudes based on infrasound observation data and their validation and comparison were presented. The calculated upper wind speed and wind observed by radiosonde measurements were found to have a qualitative agreement. Propagation modeling for these events estimated celerities in the propagation direction to the sensors that were consistent with the tropospheric and stratospheric ducting. This study could inspire writers, in particular, and readers, in general, to take advantage of the benefits of infrasound wave remote-sensing for the study of the Earths atmospheric dynamics.

Research areas: Volcanic Eruptions
First Detection of the Pekeris Internal Global Atmospheric Resonance: Evidence from the 2022 Tonga Eruption and from Global Reanalysis Data (2022)

Abstract We used observations and model simulation to examine the atmospheric pulses that dominate the far field in the hours after the January 2022 Tonga eruption. We analyzed radiance observations taken from the Himawari-8 geostationary satellite and showed that both a Lamb wave front with the expected horizontal phase speed 315 m s1 and a distinct front with phase speed 245 m s1 can be detected. The slower phase speed is consistent with that expected for the global internal resonant mode that had been proposed by Pekeris in 1937 and in other idealized theoretical studies over the past century, but which had never been detected in the atmosphere. A simulation of the eruption aftermath was performed with a high-resolution atmospheric general circulation model. A hot anomaly over the volcano location was introduced instantaneously to the model fields and the model was integrated for another 12 h. This produced a simulated wave pulse that, in the far field, agreed reasonably well with barograph observations of the Lamb wave. The model results also showed the presence of the slower pulse and that this disturbance had a vertical structure with a 180 phase shift in the stratosphere, in agreement with the theoretical prediction for the internal resonant mode. An implication is that the continuously ringing Lamb wave global normal modes that have been seen in analyses of long observational records ought to have lower-frequency internal Pekeris mode counterparts, a prediction that we confirm though analysis of 67 years of hourly global reanalysis data. Significance Statement Our demonstration that both a surface-trapped Lamb wave and a slower horizontal phase speed internal Pekeris wave can be realized as normal modes of the global atmosphere resolves a very long-standing and fundamental issue in dynamical meteorology. Our result also has broader implications. The 2022 Tonga eruption produced a surprisingly large ocean tsunami even in a remote ocean basin, and it is possible that the slower atmospheric Pekeris mode can play a role in exciting the remarkable ocean response. Also the spectral peaks seen in atmospheric variability corresponding to the Pekeris normal mode provide features for comparison with global model simulations of the atmosphere, along with the Lamb modes detected in earlier studies.

Research areas: Volcanic Eruptions
Effect of volcanic emissions on clouds during the 2008 and 2018 Kilauea degassing events (2021)

Abstract. Volcanic eruptions in otherwise clean environments are natural experiments wherein the effects of aerosol emissions on clouds and climate can be partitioned from meteorological variability and anthropogenic activities. In this work, we combined satellite retrievals, reanalysis products, and atmospheric modeling to analyze the mechanisms of aerosolcloud interactions during two degassing events at the Kilauea volcano in 2008 and 2018. The eruptive nature of the 2008 and 2018 degassing events was distinct from long-term volcanic activity for Kilauea. Although previous studies assessed the modulation of cloud properties from the 2008 event, this is the first time such an analysis has been reported for the 2018 event and that multiple degassing events have been analyzed and compared at this location. Both events resulted in significant changes in cloud effective radius and cloud droplet number concentration that were decoupled from local meteorology and in line with an enhanced cloud albedo. However, it is likely that the effects of volcanic emissions on liquid water path and cloud fraction were largely offset by meteorological variability. Comparison of cloud anomalies between the two events suggested a threshold response of aerosolcloud interactions to overcome meteorological effects, largely controlled by aerosol loading. In both events, the ingestion of aerosols within convective parcels enhanced the detrainment of condensate in the upper troposphere, resulting in deeper clouds than observed under pristine conditions. Accounting for ice nucleation on ash particles led to enhanced ice crystal concentrations at cirrus levels and a slight decrease in ice water content, improving the correlation of the model results with the satellite retrievals. Overall, aerosol loading, plume characteristics, and meteorology contributed to changes in cloud properties during the Kilauea degassing events.

Research areas: Volcanic Eruptions
Lidar ratios of stratospheric volcanic ash and sulfate aerosols retrieved from CALIOP measurements (2017)

Abstract. We apply a two-way transmittance constraint to nighttime CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) observations of volcanic aerosol layers to retrieve estimates of the particulate lidar ratio (Sp) at 532 nm. This technique is applied to three volcanic eruption case studies that were found to have injected aerosols directly into the stratosphere. Numerous lidar observations permitted characterization of the optical and geometric properties of the volcanic aerosol layers over a time period of 12 weeks. For the volcanic ash-rich layers produced by the Puyehue-Cordon Caulle eruption (June 2011), we obtain mean and median particulate lidar ratios of 69  13 sr and 67 sr, respectively. For the sulfate-rich aerosol layers produced by Kasatochi (August 2008) and Sarychev Peak (June 2009), the means of the retrieved lidar ratios were 66  19 sr (median 60 sr) and 63  14 sr (median 59 sr), respectively. The 532 nm layer-integrated particulate depolarization ratios (p) observed for the Puyehue layers (p = 0.33  0.03) were much larger than those found for the volcanic aerosol layers produced by the Kasatochi (p = 0.09  0.03) and Sarychev (p = 0.05  0.04) eruptions. However, for the Sarychev layers we observe an exponential decay (e-folding time of 3.6 days) in p with time from 0.27 to 0.03. Similar decreases in the layer-integrated attenuated colour ratios with time were observed for the Sarychev case. In general, the Puyehue layers exhibited larger colour ratios ( = 0.53  0.07) than what was observed for the Kasatochi ( = 0.35  0.07) and Sarychev ( = 0.32  0.07) layers, indicating that the Puyehue layers were generally composed of larger particles. These observations are particularly relevant to the new stratospheric aerosol subtyping classification scheme, which has been incorporated into version 4 of the level 2 CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) data products.

Research areas: Volcanic Eruptions
Remotely sensed deformation and thermal anomalies at Mount Pagan, Mariana Islands (2019)

Volcanic islands in remote settings are challenging to study with ground-based instrumentation; nevertheless it is important to define normal background activity at these volcanoes because they pose threats to air and sea traffic. A combination of remote sensing methods is critical to adequately characterize volcanic activity, and in this study we present space-based observations of both thermal anomalies and surface deformation at Pagan Island in the Mariana Island Arc. Mt. Pagan produced a large eruption (>0.1 km3) in 1981, and recent smaller eruptions (>0.001 km3) in 2011 and 2012 that triggered volcanic ash advisories. In this study we examine available Interferometric Synthetic Aperture Radar (InSAR) from Envisat and ALOS between October 2004 and June 2010 for precursory deformation leading up to the most recent eruptions. Although we do not observe evidence for shallow magma reservoir inflation, we do observe a zone of subsidence of up to -3 cm/yr located on the northern flank likely caused by continuing scoria compaction of 1981 eruptive deposits. CosmoSkyMed InSAR measurements spanning the October 2012 eruption also shows deposit subsidence, but no detectable co-eruptive deflation. We also present remotely-sensed thermal time series from the MODIS and ASTER instruments spanning over a decade. There are two distinct locations of anomalous surface temperatures on the island, which correlate with previously documented, fumarolically active vents at South Pagan and Mt. Pagan. Ultimately, we did not find thermal or deformation precursors for recent eruptive activity, plausibly because the volcano had an open conduit and persistent degassing during this time period. We compare and contrast the efficacy of various sensor types currently available to characterize transient dynamics at small and remote volcanic islands such as Pagan.

Research areas: Volcanic Eruptions
A pulse of mid-Pleistocene rift volcanism in Ethiopia at the dawn of modern humans (2016)

The Ethiopian Rift Valley hosts the longest record of human co-existence with volcanoes on Earth, however, current understanding of the magnitude and timing of large explosive eruptions in this region is poor. Detailed records of volcanism are essential for interpreting the palaeoenvironments occupied by our hominin ancestors; and also for evaluating the volcanic hazards posed to the 10 million people currently living within this active rift zone. Here we use new geochronological evidence to suggest that a 200 km-long segment of rift experienced a major pulse of explosive volcanic activity between 320 and 170 ka. During this period, at least four distinct volcanic centres underwent large-volume (>10 km3) caldera-forming eruptions, and eruptive fluxes were elevated five times above the average eruption rate for the past 700 ka. We propose that such pulses of episodic silicic volcanism would have drastically remodelled landscapes and ecosystems occupied by early hominin populations.

Research areas: Volcanic Eruptions
Out of the blue: Volcanic SO2 emissions during the 2021-2022 eruptions (2022)

Most volcanism on Earth is submarine, but volcanic gas emissions by submarine eruptions are rarely observed and hence largely unquantified. On 15 January 2022 a submarine eruption of Hunga Tonga-Hunga Haapai (HTHH) volcano (Tonga) generated an explosion of historic magnitude, and was preceded by 1 month of Surtseyan eruptive activity and two precursory explosive eruptions. We present an analysis of ultraviolet (UV) satellite measurements of volcanic sulfur dioxide (SO
              2
              ) between December 2021 and the climactic 15 January 2022 eruption, comprising an unprecedented record of Surtseyan eruptive emissions. UV measurements from the Ozone Monitoring Instrument (OMI) on NASAs Aura satellite, the Ozone Mapping and Profiler Suite (OMPS) on Suomi-NPP, the Tropospheric Monitoring Instrument (TROPOMI) on ESAs Sentinel-5P, and the Earth Polychromatic Imaging Camera (EPIC) aboard the Deep Space Climate Observatory (DSCOVR) are combined to yield a consistent multi-sensor record of eruptive degassing. We estimate SO
              2
              emissions during the eruptions key phases: the initial 19 December 2021 eruption (0.01 Tg SO
              2
              ); continuous SO
              2
              emissions from 20 December 2021early January 2022 (0.12 Tg SO
              2
              ); the 13 January 2022 stratospheric eruption (0.06 Tg SO
              2
              ); and the paroxysmal 15 January 2022 eruption (0.40.5 Tg SO
              2
              ); yielding a total SO
              2
              emission of 0.60.7 Tg SO
              2
              for the eruptive episode. We interpret the vigorous SO
              2
              emissions observed prior to the January 2022 eruptions, which were significantly higher than measured in the 2009 and 2014 HTHH eruptions, as strong evidence for a rejuvenated magmatic system. High cadence DSCOVR/EPIC SO
              2
              imagery permits the first UV-based analysis of umbrella cloud spreading and volume flux in the 13 January 2022 eruption, and also tracks early dispersion of the stratospheric SO
              2
              cloud injected on January 15. The 0.40.5 Tg SO
              2
              discharged by the paroxysmal 15 January 2022 HTHH eruption is low relative to other eruptions of similar magnitude, and a review of other submarine eruptions in the satellite era indicates that modest SO
              2
              yields may be characteristic of submarine volcanism, with the emissions and atmospheric impacts likely dominated by water vapor. The origin of the low SO
              2
              loading awaits further investigation but scrubbing of SO
              2
              in the water-rich eruption plumes and rapid conversion to sulfate aerosol are plausible, given the exceptional water emission by the 15 January 2022 HTHH eruption.

Research areas: Volcanic Eruptions
U–Th whole rock data and high spatial resolution U–Th disequilibrium and U–Pb zircon ages of Mt. Erciyes and Mt. Hasan Quaternary stratovolcanic … (2020)

Thirty-eight lava and pyroclastic samples were collected from Mt. Erciyes and Mt. Hasan, the two largest stratovolcanic complexes of the Central Anatolian Volcanic Province in Turkey. More than 1000 zircon crystals were dated by Secondary Ion Mass Spectrometry (SIMS) applying UTh disequilibrium and UPb methods. Model ages were calculated from zircon 230Th238U232Th isotopic compositions in combination with UTh whole rock data of digested lava samples generated by Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). Middle and Late Pleistocene ages dominate the dataset, but are complemented by both older (predominantly Early Pleistocene) and younger (Holocene) ages. UTh disequilibrium and UPb zircon data provide maximum eruption ages that can be further specified by (UTh)/He geochronology (zircon double dating). Additionally, these data are important to constrain the longevity and size of magmatic systems, and their potential for reactivation leading to potentially hazardous eruptions.

Research areas: Volcanic Eruptions
Digital Elevation Model resolution: Effects on the chronometry-oriented morphological analysis of monogenetic scoria cones in the Sierra Chichinautzin, central … (2021)

Morphological characterization of monogenetic cones provides essential information on different genetic, evolutionary, and hazard-related features of dispersive volcanism. Specifically, it may be used to measure the degree of erosional shape alteration of scoria cones, and from there, to estimate the age of individual volcanoes in extensive volcanic fields and the hazard implications of the cones' age distribution. Here we compare diverse morphometric parameters, some resulting from the elevation profiles analyses, and a novel one obtained from a shape characterization of elevation contours using Elliptical Fourier Descriptors, of 19 radiometrically-dated monogenetic scoria cones in the Sierra Chichinautzin Volcanic Field in Central Mexico. The parameters were calculated from two independent Digital Elevation Models with different resolutions: the 12 m resolution TanDEM-X SAR database, and a 5 m resolution airborne LIDAR DEM. From the analysis of the available information on the volcanic cones in the age range 1.6 to 222 ka, we conclude that the age-relevant morphometric parameters calculated from the TanDEM-X satellite DEM render alike values and perform equally well as the LIDAR airborne DEM for the morpho-chronological characterization of scoria cones, expanding the role of digital satellite elevation data to the study of detailed features of distributed volcanism at a global level.

Research areas: Volcanic Eruptions
A global space-based stratospheric aerosol climatology: 1979–2016 (2018)

Abstract. We describe the construction of a continuous 38-year record of stratospheric aerosol optical properties. The Global Space-based Stratospheric Aerosol Climatology, or GloSSAC, provided the input data to the construction of the Climate Model Intercomparison Project stratospheric aerosol forcing data set (19792014) and we have extended it through 2016 following an identical process. GloSSAC focuses on the Stratospheric Aerosol and Gas Experiment (SAGE) series of instruments through mid-2005, and on the Optical Spectrograph and InfraRed Imager System (OSIRIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data thereafter. We also use data from other space instruments and from ground-based, air, and balloon borne instruments to fill in key gaps in the data set. The end result is a global and gap-free data set focused on aerosol extinction coefficient at 525 and 1020 nm and other parameters on an as available basis. For the primary data sets, we developed a new method for filling the post-Pinatubo eruption data gap for 19911993 based on data from the Cryogenic Limb Array Etalon Spectrometer. In addition, we developed a new method for populating wintertime high latitudes during the SAGE period employing a latitude-equivalent latitude conversion process that greatly improves the depiction of aerosol at high latitudes compared to earlier similar efforts. We report data in the troposphere only when and where it is available. This is primarily during the SAGE II period except for the most enhanced part of the Pinatubo period. It is likely that the upper troposphere during Pinatubo was greatly enhanced over non-volcanic periods and that domain remains substantially under-characterized. We note that aerosol levels during the OSIRIS/CALIPSO period in the lower stratosphere at mid- and high latitudes is routinely higher than what we observed during the SAGE II period. While this period had nearly continuous low-level volcanic activity, it is possible that the enhancement in part reflects deficiencies in the data set. We also expended substantial effort to quality assess the data set and the product is by far the best we have produced. GloSSAC version 1.0 is available in netCDF format at the NASA Atmospheric Data Center at https://eosweb.larc.nasa.gov/. GloSSAC users should cite this paper and the data set DOI (https://doi.org/10.5067/GloSSAC-L3-V1.0).

Research areas: Volcanic Eruptions
Incorporation of volcanic SO2 emissions in the Hemispheric CMAQ (H-CMAQ) version 5.2 modeling system and assessing their impacts on sulfate aerosol … (2021)

Abstract. The state-of-the-science Community Multiscale Air Quality (CMAQ) Modeling System has recently been extended for hemispheric-scale modeling applications (referred to as H-CMAQ). In this study, satellite-constrained estimation of the degassing SO2 emissions from 50 volcanoes over the Northern Hemisphere is incorporated into H-CMAQ, and their impact on tropospheric sulfate aerosol (SO42-) levels is assessed for 2010. The volcanic degassing improves predictions of observations from the Acid Deposition Monitoring Network in East Asia (EANET), the United States Clean Air Status and Trends Network (CASTNET), and the United States Integrated Monitoring of Protected Visual Environments (IMPROVE). Over Asia, the increased SO42- concentrations were seen to correspond to the locations of volcanoes, especially over Japan and Indonesia. Over the USA, the largest impacts that occurred over the central Pacific were caused by including the Hawaiian Kilauea volcano, while the impacts on the continental USA were limited to the western portion during summertime. The emissions of the Soufriere Hills volcano located on the island of Montserrat in the Caribbean Sea affected the southeastern USA during the winter season. The analysis at specific sites in Hawaii and Florida also confirmed improvements in regional performance for modeled SO42- by including volcanoes SO2 emissions. At the edge of the western USA, monthly averaged SO42- enhancements greater than 0.1 g m3 were noted within the boundary layer (defined as surface to 750 hPa) during JuneSeptember. Investigating the change on SO42- concentration throughout the free troposphere revealed that although the considered volcanic SO2 emissions occurred at or below the middle of free troposphere (500 hPa), compared to the simulation without the volcanic source, SO42- enhancements of more than 10 % were detected up to the top of the free troposphere (250 hPa). Our model simulations and comparisons with measurements across the Northern Hemisphere indicate that the degassing volcanic SO2 emissions are an important source and should be considered in air quality model simulations assessing background SO42- levels and their source attribution.

Research areas: Volcanic Eruptions
Strong constraints on aerosolcloud interactions from volcanic eruptions (2017)

Aerosols have a potentially large effect on climate, particularly through their interactions with clouds, but the magnitude of this effect is highly uncertain. Large volcanic eruptions produce sulfur dioxide, which in turn produces aerosols; these eruptions thus represent a natural experiment through which to quantify aerosolcloud interactions. Here we show that the massive 20142015 fissure eruption in Holuhraun, Iceland, reduced the size of liquid cloud dropletsconsistent with expectationsbut had no discernible effect on other cloud properties. The reduction in droplet size led to cloud brightening and global-mean radiative forcing of around 0.2 watts per square metre for September to October 2014. Changes in cloud amount or cloud liquid water path, however, were undetectable, indicating that these indirect effects, and cloud systems in general, are well buffered against aerosol changes. This result will reduce uncertainties in future climate projections, because we are now able to reject results from climate models with an excessive liquid-water-path response.

Research areas: Volcanic Eruptions