Major Eruptions Research Articles

Tibetan Peat Records Global Major Explosive Volcanic Eruptions in the Holocene

AbstractMajor explosive volcanic eruptions were important triggers of abrupt climate changes during the Holocene and crucial sources of Hg to the atmosphere, yet there remains limited understanding regarding the long‐range transportation of this volcanic Hg and its imprint in natural archives. Here, we present a reconstruction of Holocene global volcanism based on the anomalies in Hg concentrations, accumulation fluxes, and Hg/C ratios in three high‐resolution peat profiles spanning Eurasia. Our reconstruction reveals that the two Tibetan peat profiles recorded 33 major explosive volcanic eruptions (with 11 eruptions being synchronously detected), which correspond with a French Pyrenees peat record and sulfate anomalies in polar ice cores. Additionally, the major explosive volcanic eruptions recorded in the TP peat profiles coincided with abrupt decreases in solar irradiance during the Holocene, suggesting these eruptions might have had a greater global climate impact. Our results suggest the atmospheric transport of volcanic Hg within the Northern Hemisphere and underscore the significant role played by major explosive volcanic eruptions in precipitating abrupt global climate and environmental changes during the Holocene. This study has implications for deciphering the configuration of volcanic eruption seasons, locations, and magnitudes during the Holocene and aligning the chronology of peat deposits with ice cores.

Evolution of eruption rate between two caldera-forming eruptions in the Jemez Mountains volcanic field, New Mexico, USA

Rhyolites that erupted between the Otowi and Tshirege members of the Bandelier Tuff, known as the Valle Toledo Member, were investigated in the Jemez Mountains volcanic field to infer changes in eruptive rate and flux between two caldera-forming eruptions. Our analysis combines high-precision 40Ar/39Ar single-crystal laser-fusion dating of sanidine, matrix glass compositions and mineralogy of pumice, depositional textures, and volumetric estimates of erupted rhyolites to present a revised Valle Toledo Member eruptive chronology that integrates our observations with those of previous studies. With the improved temporal resolution of our high-precision eruption ages (median 2σ uncertainty of ±2.9 ka), the updated Valle Toledo Member eruption chronology consists of at least 42 temporally or mineralogically distinct eruptions that we group into four periods of time based on eruption rate. Within the first 8.1 ± 5.1 kyr (~1605–1597 ka) that followed the Otowi caldera-forming eruption at 1605.4 ± 2.3 ka, six eruptions are recognized. This suggests an average recurrence interval on the order of 1.4 ± 0.9 kyr. Twenty-seven eruptions occurred during the next 194.4 ± 5.1 kyr (from ~1597–1403 ka) and the average recurrence interval increased to 7.2 ± 0.2 kyr. Following this second period of slower eruption rate, a previously unrecognized eruption hiatus of up to 162.4 ± 3.1 kyr occurred from 1402.9 ± 2.3 ka to 1240.5 ± 2.1 ka. Resumption of volcanic activity is characterized by a series of at least nine volcanic eruptions during the next 8.6 ± 2.5 kyr, culminating in the eruption of the 400 km3 Tshirege Member of the Bandelier Tuff and formation of Valles caldera at 1231.9 ± 1.3 ka. This last phase of pre-caldera activity has the shortest observed average recurrence interval (1.0 ± 0.3 kyr) and greatest eruptive flux (≥ 0.4 ± 0.2 km3/kyr) that occurred between the two caldera-forming eruptions. We interpret the shifts in eruption rate and flux following the 162.4 ± 3.1 kyr eruption hiatus, in addition to mineralogical changes present in post-hiatus rhyolites, as indicators that the Bandelier system was trending towards another major eruption. The magmatic system may have grown gradually throughout the ca. 162 kyr period of volcanic repose; however, the heightened eruption rate in the ca. 10 kyr before caldera collapse is consistent with relatively rapid growth of the magmatic system before the Tshirege event as previously proposed by other studies. Furthermore, the new dataset is consistent with prior geochronology studies of the region that show the four largest explosive eruptions in the Jemez field were all proceeded by very slow eruptive rates or hiatuses. This demonstrates that sequences of heightened volcanic activity can initiate on rapid geological timescales from states of volcanic quiescence in the Bandelier system.

Temperature and Ozone Response to Different Forcing in the Lower Troposphere and Stratosphere

To evaluate the contributions of different forcings to the temperature and atmospheric composition changes between 1980 and 2020, we exploited the chemistry-climate model (CCM) SOCOLv3. The study examined ozone content and atmospheric temperature response to (1) ozone-depleting substances; (2) greenhouse gas concentrations, ocean surface temperature, and sea ice coverage; (3) solar irradiance; and (4) stratospheric aerosol loading and, separately, (5) greenhouse gas concentrations, (6) ocean surface temperature and sea ice coverage, and (7) NOx surface emissions. To evaluate the impacts of specific factors, we performed model runs driven by each factor (1–7) variability as well as a reference experiment that accounted for the influence of all factors simultaneously. We identified the relative contribution of different factors to the evolution of the temperature and ozone content of the lower troposphere and stratosphere from 1980 to 2020. The model results were in good agreement with the reanalyses (MERRA2 and ERA5). We showed that stratospheric ozone depletion before the Montreal Protocol introduction and partial recovery after that were chiefly driven by ODS. Stratospheric aerosol from major volcanic eruptions caused only short-term (up to 5 years) ozone decline. Increased greenhouse gas emissions dominate the ongoing long-term stratospheric cooling as well as tropospheric and surface warming. Solar irradiance contributed to short-term fluctuations but had a minimal long-term impact. Furthermore, our analysis of the solar signal in the tropical stratosphere underscores the complex interplay of solar radiation with volcanic, oceanic, and atmospheric factors, revealing significant altitudinal distributions of temperature and ozone responses to solar activity. Our findings advocate further innovative methodologies to take into account the nonlinearity of the atmospheric processes.

X‐Raying Neutral Density Disturbances in the Mesosphere and Lower Thermosphere Induced by the 2022 Hunga‐Tonga Volcano Eruption‐Explosion

AbstractWe present X‐ray observations of the upper atmospheric density disturbance caused by the explosive eruption of the Hunga Tonga‐Hunga Ha'apai (HTHH) volcano on 15 January 2022. From 14 January to 16 January, the Chinese X‐ray astronomy satellite, Insight‐HXMT, was observing the supernova remnant Cassiopeia A. The X‐ray data obtained during Earth's atmospheric occultations allowed us to measure neutral densities in the altitude range of 90–150 km. The density profiles above 110 km altitude obtained before the major eruption are in reasonable agreement with expectations by both GAIA and NRLMSIS 2.0 models. In contrast, after the HTHH eruption, a severe density depletion was found up to 1,000 km away from the epicenter, and a relatively weak depletion extending up to km for over 8 hr after the eruption. In addition, density profiles showed wavy structures with a typical length scale of either 20 km (vertical) or 1,000 km (horizontal). This may be caused by Lamb waves or gravity waves triggered by the volcanic eruption.

Volcanic tuff as a World Heritage Georesource, a Case Study of Tokaj Wine Region UNESCO Cultural Landscape

Volcanic tephra and pyroclastic rocks are common georesources worldwide. Volcanic eruptions produce these materials, and the freshly deposited volcaniclastic sediments undergo variable diagenesis and possible hydrothermal alteration. The rhyolitic pyroclastic rocks of the Carpathian Basin were formed as a result of major silicic volcanism during the Miocene and are exposed in several volcanic regions. The use of these stones depends on their physical properties, such as hardness, colour, and transportability, especially in masonry and ornamental design. The study site, the Tokaj Wine Region (TWR) Historic Cultural Landscape is a UNESCO site located in NE Hungary, which was inscribed on the World Heritage List in 2002. The silicic pyroclastic rocks, here we also referred to them as rhyolite tuffs, are significant geological resources in the UNESCO cultural heritage designation. The pyroclastic formations cover an area of about 100 km2 and were deposited by three major explosive eruptions (13.1–11.5 Ma). The local varieties are defined by primary volcanological features and secondary (diagenetic, hydrothermal) effects. The stone was extracted from more than 40 open pit quarries dating from the Middle Ages. The wine cellars and dry-built terrace walls are important cultural features of the volcanic tuff use. The geoconservation value of the rhyolite tuff is well illustrated by the exposed special geological features, which represent important sites of volcanic formations. However, only one site has been declared a nature conservation area. Several historic quarries are currently abandoned, and there are many problems due to the lack of their restoration. The most common problems are the instability of quarry walls, illegal dumping, pollution, and dense vegetation covering the geological values. The volcanic tuff has a great potential as a georesource (quarries, cellars, and terrace walls) adding value to World Heritage Site, but special efforts are needed to demonstrate its potential for geoconservation, geotourism, and geo-education.

Geology, Archaeology, and Historical Studies of the Late 16th Century Plinian Eruption of Raung Volcano: A Potential Case for Disaster Geotourism in Ijen UNESCO Global Geopark, East Java, Indonesia

The enigmatic major eruption in the late 16th century, believed to have originated from Raung, the most active stratovolcano in the Ijen UNESCO Global Geopark in East Java, Indonesia, has ignited significant debate among researchers and historians due to its profound impact on the region. This research aims to substantiate Raung as the likely source of the major eruption by integrating geological, archaeological, and historical data. This study synthesizes current findings and explores ongoing debates surrounding historical volcanic activities. Eruption parameters suggest that the late 16th century eruption exhibited a Plinian type, characterized by an explosive eruption column reaching the stratosphere, widespread pumiceous tephra fallout, and pyroclastic density current (PDC). Stratigraphic succession reveals that the eruption occurred in five phases, with deposits from 10 eruptive units. These deposits are mainly concentrated on the northwestern flank of Raung. Archaeological findings, historical records, and local legends converge to pinpoint the occurrence of this catastrophic event in the late 16th century. These diverse sources estimate that the eruption resulted in approximately 10,000 casualties, marking it as one of the most significant volcanic disasters in the past 500 years. The implications of this eruption extend beyond historical documentation, providing a critical case study for advancing disaster mitigation strategies through geotourism in the geopark area. Moreover, the eruption record outcrops identified in this study can be proposed as potential new geosites within the Ijen UNESCO Global Geopark, enhancing its educational and touristic value. We propose the Jebung Kidul, Alas Sumur, and Batu Sappar sites as potential disaster-based geosites, considering that these sites record the eruption process and preserve archaeological structures. This addition would not only commemorate the historical event but also promote awareness and preparedness for future volcanic activities in the region.

Dynamical downscaling and data assimilation for a cold-air outbreak in the European Alps during the Year Without a Summer of 1816

Abstract. The “Year Without a Summer” in 1816 was characterized by extraordinarily cold and wet periods in central Europe, and it was associated with severe crop failures, famine, and socio-economic disruptions. From a modern perspective, and beyond its tragic consequences, the summer of 1816 represents a rare opportunity to analyze the adverse weather (and its impacts) after a major volcanic eruption. However, given the distant past, obtaining the high-resolution data needed for such studies is a challenge. In our approach, we use dynamical downscaling, in combination with 3D variational data assimilation of early instrumental observations, for assessing a cold-air outbreak in early June 1816. We find that the cold spell is well represented in the coarse-resolution 20th Century Reanalysis product which is used for initializing the regional Weather Research and Forecasting Model. Our downscaling simulations (including a 19th century land use scheme) reproduce and explain meteorological processes well at regional to local scales, such as a foehn wind situation over the Alps with much lower temperatures on its northern side. Simulated weather variables, such as cloud cover or rainy days, are simulated in good agreement with (eye) observations and (independent) measurements, with small differences between the simulations with and without data assimilation. However, validations with partly independent station data show that simulations with assimilated pressure and temperature measurements are closer to the observations, e.g., regarding temperatures during the coldest night, for which snowfall as low as the Swiss Plateau was reported, followed by a rapid pressure increase thereafter. General improvements from data assimilation are also evident in simple quantitative analyses of temperature and pressure. In turn, data assimilation requires careful selection, preprocessing, and bias-adjustment of the underlying observations. Our findings underline the great value of digitizing efforts of early instrumental data and provide novel opportunities to learn from extreme weather and climate events as far back as 200 years or more.

Magma recharge at Manam volcano, Papua New Guinea, identified through thermal and SO2 satellite remote sensing of open-vent emissions

Manam is one of the most frequently active volcanoes in Papua New Guinea and is a top contributor to global volcanic volatile emissions due to its persistent open-vent degassing. Here, we present a multi-year time series (2018–2021) of thermal and SO2 emissions for Manam from satellite remote sensing, which we interpret in the context of open-vent feedback between magma supply, reservoir pressure, and outgassing. We classify the time series into four phases based on the varying SO2 flux and observe a transient, yet substantial, increase in time-averaged SO2 flux from background levels of ~ 0.6 to ~ 4.72 kt day−1 between March and July 2019. We also identify a transition from temporally coupled to decoupled gas and thermal emissions during this period which we explain in the context of a magma recharge event that supplied new, volatile-rich magma to the shallow plumbing system beneath Manam. We infer that the arrival of this recharge magma triggered the series of eruptions between August 2018 and March 2019. These explosive events collectively removed 0.18 km3 of degassed residual magma and signalled the onset of a renewed period of unrest that ultimately culminated in a major eruption on 28 June 2019. We quantify the magnitude of “excess” degassing at Manam after the removal of the inferred residual magma. SO2 emissions reveal that ~ 0.18 km3 of magma was supplied, but only ~ 0.08 km3 was erupted between April 2019 and December 2021. We highlight how multi-parameter remote sensing observations over months to years enable the interpretation of open-vent processes that may be missed by short-duration campaign measurements.

Tree-ring anomalies as time markers for ice-core chronologies, with special reference to 5281 BCE as the possible date of the Kikai volcanic event

The synchronization of Greenland and Antarctica ice core data with tree-ring data, other proxies, and direct observations of natural processes and events is important to understand past climatic variation and environmental change. One of the methods that is used to correct the dating of ice layers is to match volcanic eruption footprints in ice cores with tree rings, manifested as sulphate spikes and anomalous rings, respectively. In this study, we inventoried the occurrence of tree-ring anatomical anomalies and extremes in ring width during three 200-year periods. These periods included three of the eight largest Holocene volcanic eruptions, each with a Volcanic Explosivity Index (VEI) of 7. The initial period spanned from 6560 to 6360 BCE and included the eruption of Ilyinsky Volcano in Kamchatka. The second period was from 5780 to 5580 BCE, during which Mount Mazama Volcano in North America erupted. The third period was from 5380 to 5180 BCE when the Kikai Volcano in the Japanese Islands erupted. Throughout the first two periods, no substantial tree-ring anomalies were observed suggesting the absence of any significant climate consequences of a major volcanic eruption. However, in the 5380–5180 BCE period, a clear sharp decline in tree growth and an exceptionally high frequency of tree-ring anomalies were identified in 5281 BCE and the subsequent 5 years. We propose that the exceptionally narrow light rings in these 6 years are indicative of the climatic impact resulting from the Kikai volcanic eruption. We suggest utilising the year 5281 BCE as the reference year for synchronising the Greenland and Antarctica ice core chronologies. In the case that our assumption is correct, this would imply the necessity to adjust the time of the event to an earlier date compared to the dates indicated by the existing ice core chronologies of the GICC05 (Greenland Ice Core Chronology 2005), adjusted according to Kobashi (2017), and WD2014 used for creating HolVol 1.0 (Holocene ice-core volcanic eruption catalogue from 9500 BCE - 1900 CE) by 67 and 54 years, respectively, for the period around 5300 BCE. A verification of our assumption could be conducted by examining the nearby Miyake event, a spike in cosmogenic radiocarbon, of 5258 BCE. Ice core layers displaying potential signs of this event should be approximately 25 years later than the markers of the Kikai volcanic eruption.

Decadal prediction centers prepare for a major volcanic eruption

Abstract The World Meteorological Organization’s Lead Centre for Annual-to-Decadal Climate prediction issues operational forecasts annually as guidance for regional climate centers, climate outlook forums and national meteorological and hydrological services. The occurrence of a large volcanic eruption such as that of Mount Pinatubo in 1991, however, would invalidate these forecasts and prompt producers to modify their predictions. To assist and prepare decadal prediction centers for this eventuality, the Volcanic Response activities under the World Climate Research Programme’s Stratosphere-troposphere Processes And their Role in Climate (SPARC) and the Decadal Climate Prediction Project (DCPP) organized a community exercise to respond to a hypothetical large eruption occurring in April 2022. As part of this exercise, the Easy Volcanic Aerosol forcing generator was used to provide stratospheric sulfate aerosol optical properties customized to the configurations of individual decadal prediction models. Participating centers then reran forecasts for 2022-2026 from their original initialization dates, and in most cases also from just before the eruption at the beginning of April 2022, according to two candidate response protocols. This article describes various aspects of this SPARC/DCPP Volcanic Response Readiness Exercise (VolRes-RE), including the hypothesized volcanic event, the modified forecasts under the two protocols from the eight contributing centers, the lessons learned during the coordination and execution of this exercise, and the recommendations to the decadal prediction community for the response to an actual eruption.

A treatment of the all-clear problem for solar energetic particle events and subsequent decision making

We discuss the relatively overlooked problem of All Clear in Solar Energetic Particle (SEP) event prediction. These proton and heavier ion events are injected in major solar eruptions, propagate directionally into the heliosphere at relativistic speeds and threaten equipment and personnel at low-Earth orbit and beyond. SEPs are rare to extreme events associated with solar flares and coronal mass ejections (CMEs), with one SEP event detected in-situ every several hundreds of flares and CMEs observed remotely. This abysmal overall association improves drastically to below 1:2 for fast (i.e., shock-fronted) and halo (i.e., propagating mainly along the Sun–Earth line) CMEs. All Clear implies an assessment of tolerable conditions within a preset prediction window. Relying on one of the most comprehensive data sets for SEP events, we implement a methodology that provides an All Clear for events of NOAA severity S1 and above (S1+) and identify the minimal eruption attributes (flare size and CME speed) that could give rise to such SEP events from source locations in the Sun. The results correspond to and reflect settings of minimum complexity, giving rise to different attributes for different longitudinal zones in the earthward solar hemisphere. This work presents proof of concept; complexity can be increased at will for more demanding All Clear definitions, subject only to sufficient statistics due to the scarcity of the phenomenon. At this point, feedback is desired from stakeholders on what fits their definition of All Clear (we expect different definitions from different operators), so that to define the precise settings on which to run this and similar exercises.

Presenting a Long-Term, Reprocessed Dataset of Global Sea Surface Temperature Produced Using the OSTIA System

Over the past few decades, the oceans have stored the majority of the excess heat in the climate system resulting from anthropogenic emissions. An accurate, long-term sea surface temperature (SST) dataset is essential for monitoring and researching the changes to the global oceans. A variety of SST datasets have been produced by various institutes over the years, and here, we present a new SST data record produced originally within the Copernicus Marine Environment Monitoring Service (which is therefore named CMEMS v2.0) and assess: (1) its accuracy compared to independent observations; (2) how it compares with the previous version (named CMEMS v1.2); and (3) its performance during two major volcanic eruptions. By comparing both versions of the CMEMS datasets using independent in situ observations, we show that both datasets are within the target accuracy of 0.1 K, but that CMEMS v2.0 is closer to the ground truth. The uncertainty fields generated by the two analyses were also compared, and CMEMS v2.0 was found to provide a more accurate estimate of its own uncertainties. Frequency and vector analysis of the SST fields determined that CMEMS v2.0 feature resolution and horizontal gradients were also superior, indicating that it resolved oceanic features with greater clarity. The behavior of the two analyses during two volcanic eruption events (Mt. Pinatubo and El Chichón) was examined. A comparison with the HadSST4 gridded in situ dataset suggested a cool bias in the CMEMS v2.0 dataset versus the v1.2 dataset following the Pinatubo eruption, although a comparison with sparser buoy-only observations yielded less clear results. No clear impact of the El Chichón eruption (which was a smaller event than Mt. Pinatubo) on CMEMS v2.0 was found. Overall, with the exception of a few specific and extreme events early in the time series, CMEMS v2.0 possesses high accuracy, resolution, and stability and is recommended to users.

Magma storage conditions of Lascar andesites, central volcanic zone, Chile

Abstract. Lascar volcano, located in northern Chile, is among the most active volcanoes of the Andean Central Volcanic Zone (CVZ). Its activity culminated in the last major explosive eruption in April 1993. Lascar andesites which erupted in April 1993 have a phase assemblage composed of plagioclase, clinopyroxene, orthopyroxene, Fe–Ti oxides, and rhyolitic glass. To better constrain storage conditions and mechanisms of magmatic differentiation for andesitic magmas in a thick continental crust, crystallization experiments were performed in internally heated pressure vessels at 300 and 500 MPa, in the temperature (T) range of 900–1050 °C, at various water activities (aH2O) and oxygen fugacities (logfO2 between QFM+1.5 and QFM+3.3 at aH2O =1; QFM is quartz–fayalite–magnetite oxygen buffer). The comparison of experimental products with natural phase assemblages, phase compositions, and whole-rock compositions was used to estimate magma storage conditions and to reconstruct the magma plumbing system. We estimate that Lascar two-pyroxene andesitic magmas were stored at 975±25 °C, 300±50 MPa, and logfO2 of QFM+1.5±0.5, under H2O-undersaturated conditions with 2.5 wt % to 4.5 wt % H2O in the melt. The geochemical characteristics of the entire suite of Lascar volcanics indicates that a fractionating magmatic system located at a depth of 10–13 km is periodically replenished with less evolved magma. Some eruptive stages were dominated by volcanic products resulting most probably from the mixing of a mafic andesitic magma with a felsic component, whereas compositional variations in other eruptive stages are better explained by crystal fractionation processes. The relative importance of these two mechanisms (mixing vs. crystal fractionation) may be related to the amount and frequency of magma recharge in the reservoir.

Decoding Capua’s roof terracotta: A multi-analytical study of the Fondo Patturelli sanctuary and Alveo Marotta furnace (6th century BCE – 1st century BCE)

The main focus of this study was to examine 25 samples of archaeological ceramic materials currently preserved in the Archaeological Museum of the Ancient Capua and Mitreo investigated in the framework of an international project. These samples primarily consist of architectural terracotta from the Fondo Patturelli extra-urban sanctuary, as well as architectural terracotta, pottery and waste material from the nearby Alveo Marotta furnace.To investigate these artifacts, a multi-analytical mineralogical-petrographic approach was performed. Thin section observations revealed that almost all samples exhibit a coarse-grained paste. The fragments were categorized into three petrographic groups based on the type and quantity of temper, which is mostly composed of volcanic grains. They include lithics and juvenile fragments (obsidians and pumices) ascribed to the products of the major Campanian eruptions as detected via FESEM-EDS. Bulk chemical analyses (WD-XRF) show that almost all samples form a homogeneous group made with Ca-rich clayey raw materials, also including three wastes of tiles from the Alveo Marotta. By contrast, other two wastes from Alveo Marotta were produced with Ca-poor clay suggesting the use of a different raw material.From a technological point of view the samples are characterized by a thermal range that varies from 750 to 900 °C, notably different between the earlier and later production periods, with the former fired at lower temperatures.

Andesite magma genesis, conduit dynamics and variable decompression from shallow reservoirs drive contrasting PDC events at Volcán de Colima, Mexico

Volcán de Colima, one of the Earth's most active and hazardous andesitic stratovolcanoes, experienced its last major explosive eruption on July 2015 with two distinct events. The July-10 event comprised the collapse of a large summit dome, forming block-and-ash flow deposits of dense dome lava clasts. The July-11 event produced pyroclastic density currents (PDCs) that flowed to maximum 10.5 km-distance from the crater, burned the vegetation, and formed valley and overbank deposits of up to 30 vol% vesicular scoria clasts. Whereas the July-10 event fits well within the last 20 years' typical activity of Volcán de Colima, the July-11 PDCs were unprecedented. We present a close examination of the July-11 deposits via combined field, microtextural, and chemical analyses, including electron microscopy and X-ray microtomography. Results show that andesite magma (58–59 wt% SiO2) at 1021 °C and having 2 wt% H2O degassed and crystallized (102–105 mm−3 vesicles and 102–103 mm−3 microlite number densities) while ascending to the surface from ∼2 km-depth reservoirs, driven by decompression rates of 0.4–1.7 MPa s−1. These variable rates reflected heterogenous andesite magma rheology produced by different stages of melt genesis, mobility, stalling, crystallization and vesiculation. Prior to experiencing fragmentation, the andesite magma mingled with rhyolite melts produced from partial melting of silicic mush stored at depths from ∼2 to 5 km. Magmas fragmented at maximum strain rates of 10−3 s−1, powering the July-11 energetic (106–107 kg s−1) and pulsating PDCs that released 102–103 m3 s−1 on surface. The rapid <20 h transition from the July-10 to the July-11 events suggests only hours timescales from dome collapse to magma decompression and explosive eruption.

Validating a microphysical prognostic stratospheric aerosol implementation in E3SMv2 using observations after the Mount Pinatubo eruption

Abstract. This paper describes the addition of a stratospheric prognostic aerosol (SPA) capability – developed with the goal of accurately simulating sulfate aerosol formation and evolution in the stratosphere – in the Department of Energy (DOE) Energy Exascale Earth System Model, version 2 (E3SMv2). The implementation includes changes to the four-mode Modal Aerosol Module microphysics in the stratosphere to allow for larger particle growth and more accurate stratospheric aerosol lifetime following the Pinatubo eruption. E3SMv2-SPA reasonably reproduces stratospheric aerosol lifetime, burden, aerosol optical depth, and top-of-atmosphere flux when compared to remote sensing observations. E3SMv2-SPA also has close agreement with the interactive chemistry–climate model CESM2-WACCM (Community Earth System Model version 2–Whole Atmosphere Community Climate Model) – which has a more complete chemical treatment – and the observationally constrained, prescribed volcanic aerosol treatment in E3SMv2. Global stratospheric aerosol size distributions identify the nucleation and growth of sulfate aerosol from volcanically injected SO2 from both major and minor volcanic eruptions from 1991 to 1993. The modeled aerosol effective radius is consistently lower than satellite and in situ measurements (max differences of ∼ 30 %). Comparisons with in situ size distribution samples indicate that this simulated underestimation in both E3SMv2-SPA and CESM2-WACCM is due to overly small accumulation and coarse-mode aerosols 6–18 months post-eruption, with E3SMv2-SPA simulating ∼ 50 % of the coarse-mode geometric mean diameters of observations 11 months post-eruption. Effective radii from the models and observations are used to calculate offline scattering and absorption efficiencies to explore the implications of smaller simulated aerosol size for the Pinatubo climate impacts. Scattering efficiencies at wavelengths of peak solar irradiance (∼ 0.5 µm) are 10 %–80 % higher for daily samples in models relative to observations through 1993, suggesting higher diffuse radiation at the surface and a larger cooling effect in the models due to the smaller simulated aerosol; absorption efficiencies at the peak wavelengths of outgoing terrestrial radiation (∼ 10 µm) are 15 %–40 % lower for daily samples in models relative to observations, suggesting an underestimation in stratospheric heating in the models due to the smaller simulated aerosol. These potential biases are based on aerosol size alone and do not take into account differences in the aerosol number. The overall agreement of E3SMv2-SPA with observations and its similar performance to the well-validated CESM2-WACCM makes E3SMv2-SPA a viable alternative to simulating climate impacts from stratospheric sulfate aerosols.

Supersharp Images Reveal Scars of Major Eruption on Io

Supersharp Images Reveal Scars of Major Eruption on Io

How Volcanic Aerosols Globally Inhibit Precipitation

AbstractVolcanic aerosols reduce global mean precipitation in the years after major eruptions, yet the mechanisms that produce this response have not been rigorously identified. Volcanic aerosols alter the atmosphere's energy balance, with precipitation changes being one pathway by which the atmosphere acts to return toward equilibrium. By examining the atmosphere's energy budget in climate model simulations using radiative kernels, we explain the global precipitation reduction as largely a consequence of Earth's surface cooling in response to volcanic aerosols reflecting incoming sunlight. These aerosols also directly add energy to the atmosphere by absorbing outgoing longwave radiation, which is a major cause of precipitation decline in the first post‐eruption year. We additionally identify factors limiting the post‐eruption precipitation decline, and provide evidence that our results are robust across climate models.

Geology, chronology, and temporal evolution of basaltic to dacitic magma system in Raung volcano, East Java, Indonesia

Raung volcano, located within the Ijen UNESCO Global Geopark in East Java, poses a significant risk of volcanic hazard for nearby residents and visitors. Our study provides a framework to understand Raung long-term behavior and potential hazards by examining its stratigraphy, petrology, and temporal magma evolution. The erupted products of Raung vary from lava flow, pyroclastic density current (ignimbrite and block and ash flow), scoria fall, and pumice fall. Radiocarbon dating of charcoal samples within pyroclastic deposits and weathered sediments beneath tephra fall layers yield the age of 840 ± 30 BP to 370 ± 30 BP. It provides an important chronological marker that confirms the past VEI-4 to VEI-5 eruption around 1200 to 1600 CE. Petrological and geochemical data reveal that Raung magma composition ranges from basalt to dacite (48–64 wt% SiO2) and can be classified into two distinct magma types. Type 1 magma has med-K series, low Rb/Nb, and no Eu anomaly. Type 2 magma has high-K series, high Rb/Nb, and negative Eu anomaly. Evidence of disequilibrium features (e.g., reverse zoning, sieve texture, resorption texture, orthopyroxene mantled by clinopyroxene) and mingling texture, along with geochemical features, indicate magma mixing and many episodes of mafic magma replenishment. While the current volcanic activity is dominated by andesitic Strombolian eruption, the characteristics of Raung eruptive products suggest that past major Plinian eruptions (VEI 4–5) had occurred in both andesitic and dacitic magmatic systems, with greater VEI associated with dacitic composition. The study of Raung temporal evolution documented various eruptive behaviors related to its wide range of magma composition, thus providing an essential database for hazard assessment and mitigation.

The Recovery and Re-Calibration of a 13-Month Aerosol Extinction Profiles Dataset from Searchlight Observations from New Mexico, after the 1963 Agung Eruption

The recovery and re-calibration of a dataset of vertical aerosol extinction profiles of the 1963/64 stratospheric aerosol layer measured by a searchlight at 32° N in New Mexico, US, is reported. The recovered dataset consists of 105 aerosol extinction profiles at 550 nm that cover the period from December 1963 to December 1964. It is a unique record of the portion of the aerosol cloud from the March 1963 Agung volcanic eruption that was transported into the Northern Hemisphere subtropics. The data-recovery methodology involved re-digitizing the 105 original aerosol extinction profiles from individual Figures within a research report, followed by the re-calibration. It involves inverting the original equation used to compute the aerosol extinction profile to retrieve the corresponding normalized detector response profile. The re-calibration of the original aerosol extinction profiles used Rayleigh extinction profiles calculated from local soundings. Rayleigh and aerosol slant transmission corrections are applied using the MODTRAN code in transmission mode. Also, a best-estimate aerosol phase function was calculated from observations and applied to the entire column. The tropospheric aerosol phase function from an AERONET station in the vicinity of the searchlight location was applied between 2.76 to 11.7 km. The stratospheric phase function, applied for a 12.2 to 35.2 km altitude range, is calculated from particle-size distributions measured by a high-altitude aircraft in the vicinity of the searchlight in early 1964. The original error estimate was updated considering unaccounted errors. Both the re-calibrated aerosol extinction profiles and the re-calibrated stratospheric aerosol optical depth magnitudes showed higher magnitudes than the original aerosol extinction profiles and the original stratospheric aerosol optical depth, respectively. However, the magnitudes of the re-calibrated variables show a reasonable agreement with other contemporary observations. The re-calibrated stratospheric aerosol optical depth demonstrated its consistency with the tropics-to-pole decreasing trend, associated with the major volcanic eruption stratospheric aerosol pattern when compared to the time-coincident stratospheric aerosol optical depth lidar observations at Lexington at 42° N.