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1
Crowley, T. J., and M. B. Unterman. "Technical details concerning development of a 1200-yr proxy index for global volcanism." Earth System Science Data Discussions 5, no. 1 (January 26, 2012): 1–28. http://dx.doi.org/10.5194/essdd-5-1-2012.
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Abstract. This technical report describes details of developing a volcano forcing reconstruction (Crowley et al., 2008) for climate models that is based primarily on sulphate records in Antarctic and Greenland ice cores. The chronology of eruptions is considered accurate to within 1 yr for the interval AD 1104–2000 and 2 yr for AD 800–1103. The reconstruction involves: (1) calibration against satellite aerosol optical depth (AOD) estimates of the 1991 Pinatubo/Hudson eruptions; (2) partial validation against independent lunar estimates of AOD and global sulphate emissions; (3) partial assessment of uncertainties in AOD estimates; (4) assessment of possible tropical "false positives" in ice core reconstructions due to simultaneous occurrence of mid/high-latitude eruptions in each hemisphere; (5) identification of a new category of eruptions, termed "unipolar" tropical eruptions, in which the eruption plume penetrates mainly to polar regions in only the hemisphere of its eruption; (6) use of different growth curves for high- and low-latitude eruptions; (7) specification of 2/3 power shortwave scaling for eruptions larger than the 1991 Pinatubo eruption; and (8) compensatory introduction of an estimate of effective particle size that affects lifetime and scattering properties of stratospheric aerosols.
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Crowley, T. J., and M. B. Unterman. "Technical details concerning development of a 1200 yr proxy index for global volcanism." Earth System Science Data 5, no. 1 (May 23, 2013): 187–97. http://dx.doi.org/10.5194/essd-5-187-2013.
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Abstract. This report describes details of developing a volcano forcing reconstruction (Crowley et al., 2008) for climate models that is based primarily on sulphate records in Antarctic and Greenland ice cores. The chronology of eruptions is considered accurate to within 1 yr for the interval AD 1104–2000 and about 2 yr for AD 800–1103. The reconstruction involves (1) calibration against satellite aerosol optical depth (AOD) estimates of the 1991 Pinatubo/Hudson eruptions; (2) partial validation against independent lunar estimates of AOD and global sulphate emissions; (3) partial assessment of uncertainties in AOD estimates; (4) assessment of possible tropical "false positives" in ice core reconstructions due to simultaneous occurrence of mid/high-latitude eruptions in each hemisphere; (5) identification of a new category of eruptions, termed "unipolar" tropical eruptions, in which the eruption plume penetrates mainly to polar regions in only the hemisphere of its eruption; (6) use of different growth curves for high- and low-latitude eruptions; (7) specification of 2/3 power shortwave scaling for eruptions larger than the 1991 Pinatubo eruption; (8) introduction of an estimate of effective particle size that affects lifetime and scattering properties of stratospheric aerosols; and (9) utilization of bimonthly-resolution electrical conductivity measurements to estimate the eruption date of the 1258/1259 eruption as 1257.7±0.2. The data, and a high-temporal resolution reconstruction for climate models, are available at: http://hurricane.ncdc.noaa.gov/pls/paleox/f?p=519:1:::::P1_STUDY_ID:14168.
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Nakamura, Yoichi, Kazuyoshi Fukushima, Xinghai Jin, Motoo Ukawa Teruko Sato, and Yayoi Hotta. "Mitigation Systems by Hazard Maps, Mitigation Plans, and Risk Analyses Regarding Volcanic Disasters in Japan." Journal of Disaster Research 3, no. 4 (August 1, 2008): 297–304. http://dx.doi.org/10.20965/jdr.2008.p0297.
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More than 60 volcanic hazard maps have been published on 38 of Japan’s 108 active volcanoes. Two maps were published before 1990, 17 after the 1991 eruptions of Unzen, and 19 after the 2000 eruptions of Usuzan and Miyakejima. Large eruptions greatly increase concern over volcanic hazards. The earlier academic maps themselves have changed from being specialist-oriented to being designed to be more easily understood with volcanic terms clearly explained. This is especially true of revised maps. The 1961 Disaster Countermeasures Basic Act directs that local disaster management plans be promoted by local governments, but only 5 of the local governments in the 25 prefectures neighboring on active volcanoes have set up established specific volcano-oriented antidisaster programs. Others mention volcanic disaster measures in the context of general or storm and flood disaster measures, and another six make no mention of particular measures for volcanic disasters. This lack of concern is somewhat understandably related to budget policies, but real-time hazard maps with probability tree algorithms for forecasting volcanic events are needed to manage potential volcanic disasters effectively. For this purpose, volcanic disaster measures with volcanic risk, or threat analyses assessments must be completed, but no local governments have yet conducted assessments of volcanic risk analyses. Whatever and however complex the reasons, local governments should, cooperating with volcanologists and supported by local residents, take action before an eruption next occurs.
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Webster, Helen N., Benjamin J. Devenish, Larry G. Mastin, David J. Thomson, and Alexa R. Van Eaton. "Operational Modelling of Umbrella Cloud Growth in a Lagrangian Volcanic Ash Transport and Dispersion Model." Atmosphere 11, no. 2 (February 13, 2020): 200. http://dx.doi.org/10.3390/atmos11020200.
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Large explosive eruptions can result in the formation of an umbrella cloud which rapidly expands, spreading ash out radially from the volcano. The lateral spread by the intrusive gravity current dominates the transport of the ash cloud. Hence, to accurately forecast the transport of ash from large eruptions, lateral spread of umbrella clouds needs to be represented within volcanic ash transport and dispersion models. Here, we describe an umbrella cloud parameterisation which has been implemented into an operational Lagrangian model and consider how it may be used during an eruption when information concerning the eruption is limited and model runtime is key. We examine different relations for the volume flow rate into the umbrella, and the rate of spreading within the cloud. The scheme is validated against historic eruptions of differing scales (Pinatubo 1991, Kelud 2014, Calbuco 2015 and Eyjafjallajökull 2010) by comparing model predictions with satellite observations. Reasonable predictions of umbrella cloud spread are achieved using an estimated volume flow rate from the empirical equation by Bursik et al. and the observed eruption height. We show how model predictions can be refined during an ongoing eruption as further information and observations become available.
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Zanchettin, D., O. Bothe, C. Timmreck, J. Bader, A. Beitsch, H. F. Graf, D. Notz, and J. H. Jungclaus. "Inter-hemispheric asymmetry in the sea-ice response to volcanic forcing simulated by MPI-ESM (COSMOS-Mill)." Earth System Dynamics 5, no. 1 (June 25, 2014): 223–42. http://dx.doi.org/10.5194/esd-5-223-2014.
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Abstract. The decadal evolution of Arctic and Antarctic sea ice following strong volcanic eruptions is investigated in four climate simulation ensembles performed with the COSMOS-Mill version of the Max Planck Institute Earth System Model. The ensembles differ in the magnitude of the imposed volcanic perturbations, with sizes representative of historical tropical eruptions (1991 Pinatubo and 1815 Tambora) and of tropical and extra-tropical "supervolcano" eruptions. A post-eruption Arctic sea-ice expansion is robustly detected in all ensembles, while Antarctic sea ice responds only to supervolcano eruptions, undergoing an initial short-lived expansion and a subsequent prolonged contraction phase. Strong volcanic forcing therefore emerges as a potential source of inter-hemispheric interannual-to-decadal climate variability, although the inter-hemispheric signature is weak in the case of eruptions comparable to historical eruptions. The post-eruption inter-hemispheric decadal asymmetry in sea ice is interpreted as a consequence mainly of the different exposure of Arctic and Antarctic regional climates to induced meridional heat transport changes and of dominating local feedbacks that set in within the Antarctic region. Supervolcano experiments help to clarify differences in simulated hemispheric internal dynamics related to imposed negative net radiative imbalances, including the relative importance of the thermal and dynamical components of the sea-ice response. Supervolcano experiments could therefore serve the assessment of climate models' behavior under strong external forcing conditions and, consequently, favor advancements in our understanding of simulated sea-ice dynamics.
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Fujiwara, M., T. Hibino, S. K. Mehta, L. Gray, D. Mitchell, and J. Anstey. "Global temperature response to the major volcanic eruptions in multiple reanalysis datasets." Atmospheric Chemistry and Physics Discussions 15, no. 9 (May 6, 2015): 13315–46. http://dx.doi.org/10.5194/acpd-15-13315-2015.
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Abstract. Global temperature response to the eruptions of Mount Agung in 1963, El Chichón in 1982 and Mount Pinatubo in 1991 is investigated using nine reanalysis datasets (JRA-55, MERRA, ERA-Interim, NCEP-CFSR, JRA-25, ERA-40, NCEP-1, NCEP-2, and 20CR). Multiple linear regression is applied to the zonal and monthly mean time series of temperature for two periods, 1979–2009 (for eight reanalysis datasets) and 1958–2001 (for four reanalysis datasets), by considering explanatory factors of seasonal harmonics, linear trends, Quasi-Biennial Oscillation, solar cycle, and El Niño Southern Oscillation. The residuals are used to define the volcanic signals for the three eruptions separately. In response to the Mount Pinatubo eruption, most reanalysis datasets show strong warming signals (up to 2–3 K for one-year average) in the tropical lower stratosphere and weak cooling signals (down to −1 K) in the subtropical upper troposphere. For the El Chichón eruption, warming signals in the tropical lower stratosphere are somewhat smaller than those for the Mount Pinatubo eruption. The response to the Mount Agung eruption is asymmetric about the equator with strong warming in the Southern Hemisphere midlatitude upper troposphere to lower stratosphere. The response to three other smaller-scale eruptions in the 1960s and 1970s is also investigated. Comparison of the results from several different reanalysis datasets confirms the atmospheric temperature response to these major eruptions qualitatively, but also shows quantitative differences even among the most recent reanalysis datasets.
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Toohey, M., K. Krüger, U. Niemeier, and C. Timmreck. "The influence of eruption season on the global aerosol evolution and radiative impact of tropical volcanic eruptions." Atmospheric Chemistry and Physics Discussions 11, no. 8 (August 8, 2011): 22443–81. http://dx.doi.org/10.5194/acpd-11-22443-2011.
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Abstract. Simulations of tropical volcanic eruptions using a general circulation model with coupled aerosol microphysics are used to assess the influence of season of eruption on the aerosol evolution and radiative impacts at the Earth's surface. This analysis is presented for eruptions with SO2 injection magnitudes of 17 and 700 Tg, the former consistent with estimates of the 1991 Mt. Pinatubo eruption, the later a near-"super eruption". For each eruption magnitude, simulations are performed with eruptions at 15° N, at four equally spaced times of year, and sensitivity to eruption season is quantified as the difference between the maximum and minimum cumulative anomalies. Eruption season has a significant influence on aerosol optical depth (AOD) and clear-sky shortwave (SW) radiative flux anomalies for both eruption magnitudes. The sensitivity to eruption season for both fields is generally weak in the tropics, but increases in the mid- and high latitudes, reaching maximum values of ~80 %. Global mean AOD and clear-sky SW anomalies show sensitivity to eruption season on the order of 15–20 %, which results from differences in aerosol effective radius for the different eruption seasons. Smallest aerosol size and largest cumulative impact result from a January eruption for the Pinatubo-magnitude, and from a July eruption for the near-super eruption. In contrast to AOD and clear-sky SW anomalies, all-sky SW anomalies are found to be insensitive to season of eruption for the Pinatubo-magnitude eruption experiment, due to the reflection of solar radiation by clouds in the mid- to high latitudes. However, differences in all-sky SW anomalies between eruptions in different seasons are significant for the larger eruption magnitude, and the ~15 % sensitivity to eruption season of the global mean all-sky SW anomalies is comparable to the sensitivity of global mean AOD and clear-sky SW anomalies. Our estimates of sensitivity to eruption season are larger than previously reported estimates: implications regarding volcanic AOD timeseries reconstructions and their use in climate models are discussed.
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Laakso, A., H. Kokkola, A. I. Partanen, U. Niemeier, C. Timmreck, K. E. J. Lehtinen, H. Hakkarainen, and H. Korhonen. "Radiative and climate impacts of a large volcanic eruption during stratospheric sulfur geoengineering." Atmospheric Chemistry and Physics Discussions 15, no. 15 (August 12, 2015): 21837–81. http://dx.doi.org/10.5194/acpd-15-21837-2015.
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Abstract. Both explosive volcanic eruptions, which emit sulfur dioxide into the stratosphere, and stratospheric geoengineering via sulfur injections can potentially cool the climate by increasing the amount of scattering particles in the atmosphere. Here we employ a global aerosol-climate model and an earth system model to study the radiative and climate impacts of an erupting volcano during solar radiation management (SRM). According to our simulations, the radiative impacts of an eruption and SRM are not additive: in the simulated case of concurrent eruption and SRM, the peak increase in global forcing is about 40 % lower compared to a corresponding eruption into a clean background atmosphere. In addition, the recovery of the stratospheric sulfate burden and forcing was significantly faster in the concurrent case since the sulfate particles grew larger and thus sedimented faster from the stratosphere. In our simulation where we assumed that SRM would be stopped immediately after a volcano eruption, stopping SRM decreased the overall stratospheric aerosol load. For the same reasons, a volcanic eruption during SRM lead to only about 1/3 of the peak global ensemble-mean cooling compared to an eruption under unperturbed atmospheric conditions. Furthermore, the global cooling signal was seen only for 12 months after the eruption in the former scenario compared to over 40 months in the latter. In terms of the global precipitation rate, we obtain a 36 % smaller decrease in the first year after the eruption and again a clearly faster recovery in the concurrent eruption and SRM scenario. We also found that an explosive eruption could lead to significantly different regional climate responses depending on whether it takes place during geoengineering or into an unperturbed background atmosphere. Our results imply that observations from previous large eruptions, such as Mt Pinatubo in 1991, are not directly applicable when estimating the potential consequences of a volcanic eruption during stratospheric geoengineering.
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Zanchettin, D., O. Bothe, C. Timmreck, J. Bader, A. Beitsch, H. F. Graf, D. Notz, and J. H. Jungclaus. "Inter-hemispheric asymmetry in the sea-ice response to volcanic forcing simulated by MPI-ESM (COSMOS-Mill)." Earth System Dynamics Discussions 5, no. 1 (February 3, 2014): 121–68. http://dx.doi.org/10.5194/esdd-5-121-2014.
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Abstract. The decadal evolution of Arctic and Antarctic sea ice following strong volcanic eruptions is investigated in four climate simulation ensembles performed with the COSMOS-Mill version of the Max Planck Institute-Earth System Model. The ensembles differ in the magnitude of the imposed volcanic perturbations, with sizes representative of historical tropical eruptions (1991 Pinatubo and 1815 Tambora) and of tropical and extra-tropical "supervolcano" eruptions. A post-eruption Arctic sea-ice expansion is robustly detected in all ensembles, while Antarctic sea ice responds only to "supervolcano" eruptions, undergoing an initial short-lived expansion and a subsequent prolonged contraction phase. Strong volcanic forcing therefore emerges as a potential source of inter-hemispheric interannual-to-decadal climate variability, although the inter-hemispheric signature is weak in the case of historical-size eruptions. The post-eruption inter-hemispheric decadal asymmetry in sea ice is interpreted as a consequence mainly of different exposure of Arctic and Antarctic regional climates to induced meridional heat transport changes and of dominating local feedbacks that set in within the Antarctic region. "Supervolcano" experiments help clarifying differences in simulated hemispheric internal dynamics related to imposed negative net radiative imbalances, including the relative importance of the thermal and dynamical components of the sea-ice response. "Supervolcano" experiments could therefore serve the assessment of climate models' behavior under strong external forcing conditions and, consequently, favor advancements in our understanding of simulated sea-ice dynamics.
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Xu, Sheng, Hideo Hoshizumi, Kozo Uto, and Stewart P. H. T. Freeman. "Radiocarbon Dating of Fugendake Volcano in Unzen, SW Japan." Radiocarbon 55, no. 3 (2013): 1850–61. http://dx.doi.org/10.1017/s0033822200048761.
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This article presents new radiocarbon ages for the lavas, pyroclastic flow, and lahar deposits that originated from the Fugendake and Mayuyama volcanoes of the Younger Unzen Volcano, SW Japan. Nine charcoal samples were collected from the lavas and pyroclastic flow deposits, and 17 soil samples from the underlying volcanic-related products. This data set, together with previously published ages (thermoluminescence, K-Ar, fission track, and 14C), yielded new information about the timing of Late Pleistocene eruptions and an improved understanding of the evolution of the Fugendake and Mayuyama volcanoes. Fugendake Volcano started to build within the scar of Myokendake around 29 cal ka BP, and its eruption products spread over the flank of Myokendake. The remarkable eruptions of Fugendake Volcano included the lava and pyroclastic flow deposits around 22, 17, 12, and 4.5 cal ka BP. Subsequent historical eruptions occurred in AD 1663, 1792, and 1991–1995. Developed on the eastern extension of Fugendake Volcano, Mayuyama Volcano was active during the building stage of Fugendake at 4.5 cal ka BP. This study also identified a pumice eruption at ∼10 ka and 2 volcanic-related lahar deposits around 1.6 and 0.7 ka, which need to be addressed in future research.
11
Toohey, M., K. Krüger, U. Niemeier, and C. Timmreck. "The influence of eruption season on the global aerosol evolution and radiative impact of tropical volcanic eruptions." Atmospheric Chemistry and Physics 11, no. 23 (December 9, 2011): 12351–67. http://dx.doi.org/10.5194/acp-11-12351-2011.
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Abstract. Simulations of tropical volcanic eruptions using a general circulation model with coupled aerosol microphysics are used to assess the influence of season of eruption on the aerosol evolution and radiative impacts at the Earth's surface. This analysis is presented for eruptions with SO2 injection magnitudes of 17 and 700 Tg, the former consistent with estimates of the 1991 Mt. Pinatubo eruption, the later a near-"super eruption". For each eruption magnitude, simulations are performed with eruptions at 15° N, at four equally spaced times of year. Sensitivity to eruption season of aerosol optical depth (AOD), clear-sky and all-sky shortwave (SW) radiative flux is quantified by first integrating each field for four years after the eruption, then calculating for each cumulative field the absolute or percent difference between the maximum and minimum response from the four eruption seasons. Eruption season has a significant influence on AOD and clear-sky SW radiative flux anomalies for both eruption magnitudes. The sensitivity to eruption season for both fields is generally weak in the tropics, but increases in the mid- and high latitudes, reaching maximum values of ~75 %. Global mean AOD and clear-sky SW anomalies show sensitivity to eruption season on the order of 15–20 %, which results from differences in aerosol effective radius for the different eruption seasons. Smallest aerosol size and largest cumulative impact result from a January eruption for Pinatubo-magnitude eruption, and from a July eruption for the near-super eruption. In contrast to AOD and clear-sky SW anomalies, all-sky SW anomalies are found to be insensitive to season of eruption for the Pinatubo-magnitude eruption experiment, due to the reflection of solar radiation by clouds in the mid- to high latitudes. However, differences in all-sky SW anomalies between eruptions in different seasons are significant for the larger eruption magnitude, and the ~15 % sensitivity to eruption season of the global mean all-sky SW anomalies is comparable to the sensitivity of global mean AOD and clear-sky SW anomalies. Our estimates of sensitivity to eruption season are larger than previously reported estimates: implications regarding volcanic AOD timeseries reconstructions and their use in climate models are discussed.
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Mastin, Larry G., and Alexa R. Van Eaton. "Comparing Simulations of Umbrella-Cloud Growth and Ash Transport with Observations from Pinatubo, Kelud, and Calbuco Volcanoes." Atmosphere 11, no. 10 (September 27, 2020): 1038. http://dx.doi.org/10.3390/atmos11101038.
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The largest explosive volcanic eruptions produce umbrella clouds that drive ash radially outward, enlarging the area that impacts aviation and ground-based communities. Models must consider the effects of umbrella spreading when forecasting hazards from these eruptions. In this paper we test a version of the advection–dispersion model Ash3d that considers umbrella spreading by comparing its simulations with observations from three well-documented umbrella-forming eruptions: (1) the 15 June 1991 eruption of Pinatubo (Philippines); (2) the 13 February 2014 eruption of Kelud (Indonesia); and (3) phase 2 of the 22–23 April 2015 eruption of Calbuco (Chile). In volume, these eruptions ranged from several cubic kilometers dense-rock equivalent (DRE) for Pinatubo to about one tenth for Calbuco. In mass eruption rate (MER), they ranged from 108–109 kg s−1 at Pinatubo to 9–16 × 106 kg s−1 at Calbuco. For each case we ran simulations that considered umbrella growth and ones that did not. All umbrella-cloud simulations produced a cloud whose area was within ~25% of the observed cloud by the end of the eruption. By the eruption end, the simulated areas of the Pinatubo, Kelud, and Calbuco clouds were 851, 53.2, and 100 × 103 km2 respectively. These areas were 2.2, 2.2, and 1.5 times the areas calculated in simulations that ignored umbrella growth. For Pinatubo and Kelud, the umbrella simulations provided better agreement with the observed cloud area than the non-umbrella simulations. Each of these simulations extended 24 h from the eruption start. After the eruption ended, the difference in cloud area (umbrella minus non-umbrella) at Pinatubo persisted for many hours; at Kelud it diminished and became negative after 14 h and at Calbuco it became negative after ~23 h. The negative differences were inferred to result from the fact that non-umbrella simulations distributed ash over a wider vertical extent in the plume, and that wind shear spread the cloud out in multiple directions. Thus, for some smaller eruptions, wind shear can produce a larger cloud than might be produced by umbrella spreading alone.
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Churakova (Sidorova), Olga V., Marina V. Fonti, Matthias Saurer, Sébastien Guillet, Christophe Corona, Patrick Fonti, Vladimir S. Myglan, et al. "Siberian tree-ring and stable isotope proxies as indicators of temperature and moisture changes after major stratospheric volcanic eruptions." Climate of the Past 15, no. 2 (April 5, 2019): 685–700. http://dx.doi.org/10.5194/cp-15-685-2019.
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Abstract. Stratospheric volcanic eruptions have far-reaching impacts on global climate and society. Tree rings can provide valuable climatic information on these impacts across different spatial and temporal scales. To detect temperature and hydroclimatic changes after strong stratospheric Common Era (CE) volcanic eruptions for the last 1500 years (535 CE unknown, 540 CE unknown, 1257 CE Samalas, 1640 CE Parker, 1815 CE Tambora, and 1991 CE Pinatubo), we measured and analyzed tree-ring width (TRW), maximum latewood density (MXD), cell wall thickness (CWT), and δ13C and δ18O in tree-ring cellulose chronologies of climate-sensitive larch trees from three different Siberian regions (northeastern Yakutia – YAK, eastern Taimyr – TAY, and Russian Altai – ALT). All tree-ring proxies proved to encode a significant and specific climatic signal of the growing season. Our findings suggest that TRW, MXD, and CWT show strong negative summer air temperature anomalies in 536, 541–542, and 1258–1259 at all studied regions. Based on δ13C, 536 was extremely humid at YAK, as was 537–538 in TAY. No extreme hydroclimatic anomalies occurred in Siberia after the volcanic eruptions in 1640, 1815, and 1991, except for 1817 at ALT. The signal stored in δ18O indicated significantly lower summer sunshine duration in 542 and 1258–1259 at YAK and 536 at ALT. Our results show that trees growing at YAK and ALT mainly responded the first year after the eruptions, whereas at TAY, the growth response occurred after 2 years. The fact that differences exist in climate responses to volcanic eruptions – both in space and time – underlines the added value of a multiple tree-ring proxy assessment. As such, the various indicators used clearly help to provide a more realistic picture of the impact of volcanic eruption on past climate dynamics, which is fundamental for an improved understanding of climate dynamics, but also for the validation of global climate models.
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Tejedor, Ernesto, Nathan J. Steiger, Jason E. Smerdon, Roberto Serrano-Notivoli, and Mathias Vuille. "Global hydroclimatic response to tropical volcanic eruptions over the last millennium." Proceedings of the National Academy of Sciences 118, no. 12 (March 8, 2021): e2019145118. http://dx.doi.org/10.1073/pnas.2019145118.
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Large tropical volcanic eruptions can affect the climate of many regions on Earth, yet it is uncertain how the largest eruptions over the past millennium may have altered Earth’s hydroclimate. Here, we analyze the global hydroclimatic response to all the tropical volcanic eruptions over the past millennium that were larger than the Mount Pinatubo eruption of 1991. Using the Paleo Hydrodynamics Data Assimilation product (PHYDA), we find that these large volcanic eruptions tended to produce dry conditions over tropical Africa, Central Asia and the Middle East and wet conditions over much of Oceania and the South American monsoon region. These anomalies are statistically significant, and they persisted for more than a decade in some regions. The persistence of the anomalies is associated with southward shifts in the Intertropical Convergence Zone and sea surface temperature changes in the Pacific and Atlantic oceans. We compare the PHYDA results with the stand-alone model response of the Community Earth System Model (CESM)-Last Millennium Ensemble. We find that the proxy-constrained PHYDA estimates are larger and more persistent than the responses simulated by CESM. Understanding which of these estimates is more realistic is critical for accurately characterizing the hydroclimate risks of future volcanic eruptions.
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Maeno, Fukashi, Setsuya Nakada, Mitsuhiro Yoshimoto, Taketo Shimano, Natsumi Hokanishi, Akhmad Zaennudin, and Masato Iguchi. "Eruption Pattern and a Long-Term Magma Discharge Rate over the Past 100 Years at Kelud Volcano, Indonesia." Journal of Disaster Research 14, no. 1 (February 1, 2019): 27–39. http://dx.doi.org/10.20965/jdr.2019.p0027.
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Kelud Volcano is among the most active volcanoes in Indonesia, with repeated explosive eruptions throughout its history. Here, we reconstructed the relationship between the repose period and the cumulative volume of erupted material over the past 100 years and estimated the long-term magma discharge rate and future eruptive potential and hazards. Tephra data and eruption sequences described in historical documents were used to estimate the volume and mass discharge rate. The volumes of the 1901, 1919, 1951, 1966, 1990, and 2014 eruptions were estimated as 51–296 × 106m3. The mass discharge rates were estimated to be on the order of 107kg/s for the 1919, 1951, and 2014 eruptions and the order of 106kg/s for the 1966 and 1990 eruptions. Based on a linear relationship between the repose period and cumulative erupted mass, the long-term mass discharge rate was estimated as ∼ 1.5 × 1010kg/year, explaining the features of the larger eruptions (1919, 1951, and 2014) but not those of the smaller eruptions (1966 and 1990). This estimate is relatively high compared to other typical basaltic-andesitic subduction-zone volcanoes. This result provides important insights into the evolution of magmatic systems and prediction of future eruptions at Kelud Volcano.
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Manville, V., D. Johnston, S. Stammers, and B. Scott. "Comparative preparedness in New Zealand and the Philippines for response to, and recovery from, volcanic eruptions." Bulletin of the New Zealand Society for Earthquake Engineering 33, no. 4 (December 31, 2000): 445–76. http://dx.doi.org/10.5459/bnzsee.33.4.445-476.
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New Zealand and the Philippines are two of the most tectonically and volcanically active regions in the world, due to their setting as large island chains on the convergent margin of the Pacific Plate. The Philippines has experienced numerous volcanic disasters over the past 400 years with the loss of over 7000 lives and considerable damage to infrastructure. The 1991 eruption of Mount Pinatubo, after 500 years of dormancy, was the largest volcanic eruption globally in the last 50 years, with serious socio-economic consequences for the Philippines. The 1995-6 eruptions of New Zealand's Mount Ruapehu, were the most serious volcanic activity experienced in the country over the last 50 years, but occurred at a frequently active volcano for which monitoring, hazard assessment, and response systems were already in place. Although the eruptions differ in size by two orders of magnitude, they illustrate how volcanic activity impacts infrastructure and society at different levels of economic development and vulnerability. Two of New Zealand's volcanic centres, Taupo and Okataina, have the potential to generate eruptions of a similar, or even greater, scale than Pinatubo. Therefore, lessons learnt from the Philippine experience will be of vital importance in planning for the mitigation of future volcanic disasters in New Zealand.
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Aramaki, Shigeo. "Hazardouc volcanic eruptions in Japan." Episodes 14, no. 3 (September 1, 1991): 264–68. http://dx.doi.org/10.18814/epiiugs/1991/v14i3/012.
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Cole-Dai, Jihong, and Ellen Mosley-Thompson. "The Pinatubo eruption in South Pole snow and its potential value to ice-core paleovolcanic records." Annals of Glaciology 29 (1999): 99–105. http://dx.doi.org/10.3189/172756499781821319.
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AbstractSnow samples collected in the 1996 austral summer at South Pole show that sulfate concentrations in snow and, by inference, sulfur aerosol concentrations in the Antarctic atmosphere were elevated from the end of 1991 to mid-1994 over a stable, non-volcanic background. The new data support earlier findings that the June 1991 Pinatubo eruption and the Hudson eruption in the same year deposited volcanic sulfate and tephra in South Pole snow, and provide strong evidence of the global distribution of volcanic materials from the Pinatubo eruption. In this study, snow samples were taken in six snow pits spatially distributed around the South Pole station in order to evaluate the local spatial variability of volcanic signals due to glaciological variables such as snow-accumulation rates and snow redistribution by wind after initial deposition. The results indicate that Pinatubo sulfate flux varies by as much as 20% throughout a 400 km2area centered around the South Pole station. This glaciological variability probably represents the likely range of volcanic signals due to variations in snow deposition and post-depositional changes.The Pinatubo eruption provides an unprecedented opportunity to estimate aerosol mass loadings by explosive volcanic eruptions found in Antarctic ice cores via a quantitative relationship between aerosol mass loadings and sulfate flux in Antarctic snow. Here the satellite-estimated Pinatubo SO2emission and the measured volcanic sulfate flux in snow, with an assumed linearly quantitative relationship, are used to calculate SO2loadings for several well-known volcanic eruptions in the past 300 years covered by a shallow (42 m) South Pole firn core drilled in 1996. The errors for the calculated mass loadings are estimated by means of the glaciological variability associated with Pinatubo volcanic flux.
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Barnes, Elizabeth A., Susan Solomon, and Lorenzo M. Polvani. "Robust Wind and Precipitation Responses to the Mount Pinatubo Eruption, as Simulated in the CMIP5 Models." Journal of Climate 29, no. 13 (June 14, 2016): 4763–78. http://dx.doi.org/10.1175/jcli-d-15-0658.1.
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Abstract The volcanic eruption of Mount Pinatubo in June 1991 is the largest terrestrial eruption since the beginning of the satellite era. Here, the monthly evolution of atmospheric temperature, zonal winds, and precipitation following the eruption in 14 CMIP5 models is analyzed and strong and robust stratospheric and tropospheric circulation responses are demonstrated in both hemispheres, with tropospheric anomalies maximizing in November 1991. The simulated Southern Hemisphere circulation response projects strongly onto the positive phase of the southern annular mode (SAM), while the Northern Hemisphere exhibits robust North Atlantic and North Pacific responses that differ significantly from that of the typical northern annular mode (NAM) pattern. In contrast, observations show a negative SAM following the eruption, and internal variability must be considered along with forced responses. Indeed, evidence is presented that the observed El Niño climate state during and after this eruption may oppose the eruption-forced positive SAM response, based on the El Niño–Southern Oscillation (ENSO) state and SAM response across the models. The results demonstrate that Pinatubo-like eruptions should be expected to force circulation anomalies across the globe and highlight that great care must be taken in diagnosing the forced response as it may not fall into typical seasonal averages or be guaranteed to project onto typical climate modes.
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Laakso, A., H. Kokkola, A. I. Partanen, U. Niemeier, C. Timmreck, K. E. J. Lehtinen, H. Hakkarainen, and H. Korhonen. "Radiative and climate impacts of a large volcanic eruption during stratospheric sulfur geoengineering." Atmospheric Chemistry and Physics 16, no. 1 (January 18, 2016): 305–23. http://dx.doi.org/10.5194/acp-16-305-2016.
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Abstract. Both explosive volcanic eruptions, which emit sulfur dioxide into the stratosphere, and stratospheric geoengineering via sulfur injections can potentially cool the climate by increasing the amount of scattering particles in the atmosphere. Here we employ a global aerosol-climate model and an Earth system model to study the radiative and climate changes occurring after an erupting volcano during solar radiation management (SRM). According to our simulations the radiative impacts of the eruption and SRM are not additive and the radiative effects and climate changes occurring after the eruption depend strongly on whether SRM is continued or suspended after the eruption. In the former case, the peak burden of the additional stratospheric sulfate as well as changes in global mean precipitation are fairly similar regardless of whether the eruption takes place in a SRM or non-SRM world. However, the maximum increase in the global mean radiative forcing caused by the eruption is approximately 21 % lower compared to a case when the eruption occurs in an unperturbed atmosphere. In addition, the recovery of the stratospheric sulfur burden and radiative forcing is significantly faster after the eruption, because the eruption during the SRM leads to a smaller number and larger sulfate particles compared to the eruption in a non-SRM world. On the other hand, if SRM is suspended immediately after the eruption, the peak increase in global forcing caused by the eruption is about 32 % lower compared to a corresponding eruption into a clean background atmosphere. In this simulation, only about one-third of the global ensemble-mean cooling occurs after the eruption, compared to that occurring after an eruption under unperturbed atmospheric conditions. Furthermore, the global cooling signal is seen only for the 12 months after the eruption in the former scenario compared to over 40 months in the latter. In terms of global precipitation rate, we obtain a 36 % smaller decrease in the first year after the eruption and again a clearly faster recovery in the concurrent eruption and SRM scenario, which is suspended after the eruption. We also found that an explosive eruption could lead to significantly different regional climate responses depending on whether it takes place during geoengineering or into an unperturbed background atmosphere. Our results imply that observations from previous large eruptions, such as Mount Pinatubo in 1991, are not directly applicable when estimating the potential consequences of a volcanic eruption during stratospheric geoengineering.
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Timmreck, Claudia, Graham W. Mann, Valentina Aquila, Rene Hommel, Lindsay A. Lee, Anja Schmidt, Christoph Brühl, et al. "The Interactive Stratospheric Aerosol Model Intercomparison Project (ISA-MIP): motivation and experimental design." Geoscientific Model Development 11, no. 7 (July 5, 2018): 2581–608. http://dx.doi.org/10.5194/gmd-11-2581-2018.
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Abstract. The Stratospheric Sulfur and its Role in Climate (SSiRC) Interactive Stratospheric Aerosol Model Intercomparison Project (ISA-MIP) explores uncertainties in the processes that connect volcanic emission of sulfur gas species and the radiative forcing associated with the resulting enhancement of the stratospheric aerosol layer. The central aim of ISA-MIP is to constrain and improve interactive stratospheric aerosol models and reduce uncertainties in the stratospheric aerosol forcing by comparing results of standardized model experiments with a range of observations. In this paper we present four co-ordinated inter-model experiments designed to investigate key processes which influence the formation and temporal development of stratospheric aerosol in different time periods of the observational record. The Background (BG) experiment will focus on microphysics and transport processes under volcanically quiescent conditions, when the stratospheric aerosol is controlled by the transport of aerosols and their precursors from the troposphere to the stratosphere. The Transient Aerosol Record (TAR) experiment will explore the role of small- to moderate-magnitude volcanic eruptions, anthropogenic sulfur emissions, and transport processes over the period 1998–2012 and their role in the warming hiatus. Two further experiments will investigate the stratospheric sulfate aerosol evolution after major volcanic eruptions. The Historical Eruptions SO2 Emission Assessment (HErSEA) experiment will focus on the uncertainty in the initial emission of recent large-magnitude volcanic eruptions, while the Pinatubo Emulation in Multiple models (PoEMS) experiment will provide a comprehensive uncertainty analysis of the radiative forcing from the 1991 Mt Pinatubo eruption.
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Toohey, Matthew, Bjorn Stevens, Hauke Schmidt, and Claudia Timmreck. "Easy Volcanic Aerosol (EVA v1.0): an idealized forcing generator for climate simulations." Geoscientific Model Development 9, no. 11 (November 11, 2016): 4049–70. http://dx.doi.org/10.5194/gmd-9-4049-2016.
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Abstract. Stratospheric sulfate aerosols from volcanic eruptions have a significant impact on the Earth's climate. To include the effects of volcanic eruptions in climate model simulations, the Easy Volcanic Aerosol (EVA) forcing generator provides stratospheric aerosol optical properties as a function of time, latitude, height, and wavelength for a given input list of volcanic eruption attributes. EVA is based on a parameterized three-box model of stratospheric transport and simple scaling relationships used to derive mid-visible (550 nm) aerosol optical depth and aerosol effective radius from stratospheric sulfate mass. Precalculated look-up tables computed from Mie theory are used to produce wavelength-dependent aerosol extinction, single scattering albedo, and scattering asymmetry factor values. The structural form of EVA and the tuning of its parameters are chosen to produce best agreement with the satellite-based reconstruction of stratospheric aerosol properties following the 1991 Pinatubo eruption, and with prior millennial-timescale forcing reconstructions, including the 1815 eruption of Tambora. EVA can be used to produce volcanic forcing for climate models which is based on recent observations and physical understanding but internally self-consistent over any timescale of choice. In addition, EVA is constructed so as to allow for easy modification of different aspects of aerosol properties, in order to be used in model experiments to help advance understanding of what aspects of the volcanic aerosol are important for the climate system.
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Pitari, G., and E. Mancini. "Short-term climatic impact of the 1991 volcanic eruption of Mt. Pinatubo and effects on atmospheric tracers." Natural Hazards and Earth System Sciences 2, no. 1/2 (June 30, 2002): 91–108. http://dx.doi.org/10.5194/nhess-2-91-2002.
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Abstract. Large explosive volcanic eruptions are capable of injecting considerable amounts of particles and sulphur gases (mostly sulphur dioxide) above the tropopause, causing increases in the stratospheric aerosol optical depth that may be even larger than one order of magnitude. The e-folding particle lifetime in the stratosphere is much longer than in the troposphere (one year versus a few days) so that climatic perturbations in a timeframe of a few years are produced after major volcanic eruptions. A climate-chemistry coupled model is used here to study the dynamical effects of the radiative forcing due to stratospheric aerosols formed after the June, 1991 cataclysmic eruption of Mt. Pinatubo in the Philippines. It is shown that the dynamical perturbation is twofold: (a) the stratospheric mean meridional circulation is affected by local aerosol radiative heating (mostly located in the tropical lower stratosphere); (b) the planetary wave propagation in the mid- to high-latitude lower stratosphere is altered as a consequence of decreasing atmospheric stability due to the climatic perturbation. Dynamical results of the climate model are compared with available observations; a discussion is made regarding the similarities with the dynamical regime of the easterly phase of the equatorial quasi-biennial oscillation. Major findings of this study are: (a) radiatively forced changes in the stratospheric circulation during the first two years after the eruption may, to a large extent, explain the observed trend decline of long-lived greenhouse gases (CH4 and N2O, in particular); (b) the dynamical perturbation helps explain why simple photochemical studies of the ozone trends during 1991–1993 generally fail in reproducing the satellite observed feature consisting of a 2% additional global ozone depletion during 1993 with respect to 1992. In both cases we conclude that an increase in the mid- to high-latitude downward flux at the tropopause is the key factor for explaining the behaviour of these atmospheric tracers during 1991/92.
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Fujiwara, M., T. Hibino, S. K. Mehta, L. Gray, D. Mitchell, and J. Anstey. "Global temperature response to the major volcanic eruptions in multiple reanalysis data sets." Atmospheric Chemistry and Physics 15, no. 23 (December 9, 2015): 13507–18. http://dx.doi.org/10.5194/acp-15-13507-2015.
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Abstract. The global temperature responses to the eruptions of Mount Agung in 1963, El Chichón in 1982, and Mount Pinatubo in 1991 are investigated using nine currently available reanalysis data sets (JRA-55, MERRA, ERA-Interim, NCEP-CFSR, JRA-25, ERA-40, NCEP-1, NCEP-2, and 20CR). Multiple linear regression is applied to the zonal and monthly mean time series of temperature for two periods, 1979–2009 (for eight reanalysis data sets) and 1958–2001 (for four reanalysis data sets), by considering explanatory factors of seasonal harmonics, linear trends, Quasi-Biennial Oscillation, solar cycle, and El Niño Southern Oscillation. The residuals are used to define the volcanic signals for the three eruptions separately, and common and different responses among the older and newer reanalysis data sets are highlighted for each eruption. In response to the Mount Pinatubo eruption, most reanalysis data sets show strong warming signals (up to 2–3 K for 1-year average) in the tropical lower stratosphere and weak cooling signals (down to −1 K) in the subtropical upper troposphere. For the El Chichón eruption, warming signals in the tropical lower stratosphere are somewhat smaller than those for the Mount Pinatubo eruption. The response to the Mount Agung eruption is asymmetric about the equator with strong warming in the Southern Hemisphere midlatitude upper troposphere to lower stratosphere. Comparison of the results from several different reanalysis data sets confirms the atmospheric temperature response to these major eruptions qualitatively, but also shows quantitative differences even among the most recent reanalysis data sets. The consistencies and differences among different reanalysis data sets provide a measure of the confidence and uncertainty in our current understanding of the volcanic response. The results of this intercomparison study may be useful for validation of climate model responses to volcanic forcing and for assessing proposed geoengineering by stratospheric aerosol injection, as well as to link studies using only a single reanalysis data set to other studies using a different reanalysis data set.
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Pallister, John S., Richard P. Hoblitt, and Agnes G. Reyes. "A basalt trigger for the 1991 eruptions of Pinatubo volcano?" Nature 356, no. 6368 (April 1992): 426–28. http://dx.doi.org/10.1038/356426a0.
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Rothenberg, D., N. Mahowald, K. Lindsay, S. C. Doney, J. K. Moore, and P. Thornton. "Volcano impacts on climate and biogeochemistry in a coupled carbon–climate model." Earth System Dynamics 3, no. 2 (October 19, 2012): 121–36. http://dx.doi.org/10.5194/esd-3-121-2012.
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Abstract. Volcanic eruptions induce a dynamical response in the climate system characterized by short-term global reductions in both surface temperature and precipitation, as well as a response in biogeochemistry. The available observations of these responses to volcanic eruptions, such as to Pinatubo, provide a valuable method to compare against model simulations. Here, the Community Climate System Model Version 3 (CCSM3) reproduces the physical climate response to volcanic eruptions in a realistic way, as compared to direct observations from the 1991 eruption of Mount Pinatubo. The model's biogeochemical response to eruptions is smaller in magnitude than observed, but because of the lack of observations, it is not clear why or where the modeled carbon response is not strong enough. Comparison to other models suggests that this model response is much weaker over tropical land; however, the precipitation response in other models is not accurate, suggesting that other models could be getting the right response for the wrong reason. The underestimated carbon response in the model compared to observations could also be due to the ash and lava input of biogeochemically important species to the ocean, which are not included in the simulation. A statistically significant reduction in the simulated carbon dioxide growth rate is seen at the 90% level in the average of 12 large eruptions over the period 1870–2000, and the net uptake of carbon is primarily concentrated in the tropics, with large spatial variability. In addition, a method for computing the volcanic response in model output without using a control ensemble is tested against a traditional methodology using two separate ensembles of runs; the method is found to produce similar results in the global average. These results suggest that not only is simulating volcanoes a good test of coupled carbon–climate models, but also that this test can be performed without a control simulation in cases where it is not practical to run separate ensembles with and without volcanic eruptions.
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Rothenberg, D., N. Mahowald, K. Lindsay, S. C. Doney, J. K. Moore, and P. Thornton. "Volcano impacts on climate and biogeochemistry in a coupled carbon-climate model." Earth System Dynamics Discussions 3, no. 1 (April 18, 2012): 279–323. http://dx.doi.org/10.5194/esdd-3-279-2012.
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Abstract. Volcanic eruptions induce a dynamical response in the climate system characterized by short-term, global reductions in both surface temperature and precipitation, as well as a response in biogeochemistry. The available observations of these responses to volcanic eruptions, such as to Pinatubo, provide a valuable method to compare against model simulations. Here, the Community Climate System Model Version 3 (CCSM3) reproduces the physical climate response to volcanic eruptions in a realistic way, as compared to direct observations from the 1991 eruption of Mount Pinatubo. The model biogeochemical response to eruptions is smaller in magnitude than observed, but because of the lack observations, it is not clear why or where the modeled carbon response is not strong enough. Comparison to other models suggests that this model response is much weaker in the tropical land; however the precipitation response in other models is not accurate, suggesting that other models could be getting the right response for the wrong reason. The underestimated carbon response in the model compared to observations could also be due to the ash and lava input of biogeochemical important species to the ocean, which are not included in the simulation. A statistically significant reduction in the simulated carbon dioxide growth rate is seen at the 90% level in the average of 12 large eruptions over the period 1870–2000, and the net uptake of carbon is primarily concentrated in the tropics with large spatial variability. In addition, a method for computing the volcanic response in model output without using a control ensemble is tested against a traditional methodology using two separate ensembles of runs; the method is found to produce similar results. These results suggest that not only is simulating volcanoes a good test of coupled carbon-climate models, but also that this test can be performed without a control simulation in cases where it is not practical to run separate ensembles with and without volcanic eruptions.
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Löffler, M., S. Brinkop, and P. Jöckel. "Impact of major volcanic eruptions on stratospheric water vapour." Atmospheric Chemistry and Physics Discussions 15, no. 23 (December 8, 2015): 34407–37. http://dx.doi.org/10.5194/acpd-15-34407-2015.
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Abstract. Volcanic eruptions can have significant impact on the earth's weather and climate system. Besides the subsequent tropospheric changes also the stratosphere is influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry-climate model simulations. This study is based on two simulations with specified dynamics of the EMAC model, performed within the Earth System Chemistry integrated Modelling (ESCiMo) project, of which only one includes the volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour after the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as important sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on the tropospheric water vapour and ENSO are evident.
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De Angelis, M., J. Simões, H. Bonnaveira, J. D. Taupin, and R. J. Delmas. "Volcanic eruptions recorded in the Illimani ice core (Bolivia): 1918–1998 and Tambora periods." Atmospheric Chemistry and Physics 3, no. 5 (October 16, 2003): 1725–41. http://dx.doi.org/10.5194/acp-3-1725-2003.
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Abstract. Acid layers of volcanic origin detected in polar snow and ice layers are commonly used to document past volcanic activity on a global scale or, conversely, to date polar ice cores. Although most cataclysmic eruptions of the last two centuries (Pinatubo, El Chichon, Agung, Krakatoa, Cosiguina, Tambora, etc.) occurred in the tropics, cold tropical glaciers have not been used for the reconstruction of past volcanism. The glaciochemical study of a 137 m ice core drilled in 1999 close to the summit of Nevado Illimani (Eastern Bolivian Andes, 16°37' S, 67°46' W, 6350 m asl) demonstrates, for the first time, that such eruptions are recorded by both their tropospheric and stratospheric deposits. An 80-year ice sequence (1918-1998) and the Tambora years have been analyzed in detail. In several cases, ash, chloride and fluoride were also detected. The ice records of the Pinatubo (1991), Agung (1963) and Tambora (1815) eruptions are discussed in detail. The potential impact of less important regional eruptions is discussed.
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Gerwing, Elena, Matthias Hort, Jörn Behrens, and Bärbel Langmann. "An adaptive semi-Lagrangian advection model for transport of volcanic emissions in the atmosphere." Natural Hazards and Earth System Sciences 18, no. 5 (June 1, 2018): 1517–34. http://dx.doi.org/10.5194/nhess-18-1517-2018.
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Abstract. The dispersion of volcanic emissions in the Earth atmosphere is of interest for climate research, air traffic control and human wellbeing. Current volcanic emission dispersion models rely on fixed-grid structures that often are not able to resolve the fine filamented structure of volcanic emissions being transported in the atmosphere. Here we extend an existing adaptive semi-Lagrangian advection model for volcanic emissions including the sedimentation of volcanic ash. The advection of volcanic emissions is driven by a precalculated wind field. For evaluation of the model, the explosive eruption of Mount Pinatubo in June 1991 is chosen, which was one of the largest eruptions in the 20th century. We compare our simulations of the climactic eruption on 15 June 1991 to satellite data of the Pinatubo ash cloud and evaluate different sets of input parameters. We could reproduce the general advection of the Pinatubo ash cloud and, owing to the adaptive mesh, simulations could be performed at a high local resolution while minimizing computational cost. Differences to the observed ash cloud are attributed to uncertainties in the input parameters and the course of Typhoon Yunya, which is probably not completely resolved in the wind data used to drive the model. The best results were achieved for simulations with multiple ash particle sizes.
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Fujiwara, Masatomo, Patrick Martineau, and Jonathon S. Wright. "Surface temperature response to the major volcanic eruptions in multiple reanalysis data sets." Atmospheric Chemistry and Physics 20, no. 1 (January 10, 2020): 345–74. http://dx.doi.org/10.5194/acp-20-345-2020.
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Abstract. The global response of air temperature at 2 m above the surface to the eruptions of Mount Agung in March 1963, El Chichón in April 1982, and Mount Pinatubo in June 1991 is investigated using 11 global atmospheric reanalysis data sets (JRA-55, JRA-25, MERRA-2, MERRA, ERA-Interim, ERA-40, CFSR, NCEP-NCAR R-1, 20CR version 2c, ERA-20C, and CERA-20C). Multiple linear regression (MLR) is applied to the monthly mean time series of temperature for two periods – 1980–2010 (for 10 reanalyses) and 1958–2001 (for 6 reanalyses) – by considering explanatory factors of seasonal harmonics, linear trends, quasi-biennial oscillation (QBO), solar cycle, tropical sea surface temperature (SST) variations in the Pacific, Indian, and Atlantic Oceans, and Arctic SST variations. Empirical orthogonal function (EOF) analysis is applied to these climatic indices to obtain a set of orthogonal indices to be used for the MLR. The residuals of the MLR are used to define the volcanic signals for the three eruptions separately. First, area-averaged time series of the residuals are investigated and compared with the results from previous studies. Then, the geographical distribution of the response during the peak cooling period after each eruption is investigated. In general, different reanalyses show similar geographical patterns of the response, but with the largest differences in the polar regions. The Pinatubo response shows the largest average cooling in the 60∘ N–60∘ S region among the three eruptions, with a peak cooling of 0.10–0.15 K. The El Chichón response shows slightly larger cooling in the NH than in the Southern Hemisphere (SH), while the Agung response shows larger cooling in the SH. These hemispheric differences are consistent with the distribution of stratospheric aerosol optical depth after these eruptions; however, the peak cooling after these two eruptions is comparable in magnitude to unexplained cooling events in other periods without volcanic influence. Other methods in which the MLR model is used with different sets of indices are also tested, and it is found that careful treatment of tropical SST variability is necessary to evaluate the surface response to volcanic eruptions in observations and reanalyses.
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Armitage, P. J., M. Livio, and J. E. Pringle. "Dynamo Driven Accretion Discs and Dwarf Nova Eruptions." International Astronomical Union Colloquium 158 (1996): 107–8. http://dx.doi.org/10.1017/s0252921100038355.
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A magnetic dynamo whose crucial ingredient is the Balbus-Hawley instability (Balbus & Hawley 1991) is a promising candidate for generating accretion disc viscosity. Both semi-quantitative analyses (Tout & Pringle 1992) and simulations (e.g. Brandenberg et al. 1995) suggest that such dynamos can operate in a disc environment. Here we aim to apply simple dynamo ideas to models of dwarf novae, and in particular investigate how dynamo driven discs can produce different values for α in quiescence and in outburst.
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Staunton-Sykes, John, Thomas J. Aubry, Youngsub M. Shin, James Weber, Lauren R. Marshall, Nathan Luke Abraham, Alex Archibald, and Anja Schmidt. "Co-emission of volcanic sulfur and halogens amplifies volcanic effective radiative forcing." Atmospheric Chemistry and Physics 21, no. 11 (June 14, 2021): 9009–29. http://dx.doi.org/10.5194/acp-21-9009-2021.
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Abstract. The evolution of volcanic sulfur and the resulting radiative forcing following explosive volcanic eruptions is well understood. Petrological evidence suggests that significant amounts of halogens may be co-emitted alongside sulfur in some explosive volcanic eruptions, and satellite evidence indicates that detectable amounts of these halogens may reach the stratosphere. In this study, we utilise an aerosol–chemistry–climate model to simulate stratospheric volcanic eruption emission scenarios of two sizes, both with and without co-emission of volcanic halogens, in order to understand how co-emitted halogens may alter the life cycle of volcanic sulfur, stratospheric chemistry, and the resulting radiative forcing. We simulate a large (10 Tg of SO2) and very large (56 Tg of SO2) sulfur-only eruption scenario and a corresponding large (10 Tg SO2, 1.5 Tg HCl, 0.0086 Tg HBr) and very large (56 Tg SO2, 15 Tg HCl, 0.086 Tg HBr) co-emission eruption scenario. The eruption scenarios simulated in this work are hypothetical, but they are comparable to Volcanic Explosivity Index (VEI) 6 (e.g. 1991 Mt Pinatubo) and VEI 7 (e.g. 1257 Mt Samalas) eruptions, representing 1-in-50–100-year and 1-in-500–1000-year events, respectively, with plausible amounts of co-emitted halogens based on satellite observations and volcanic plume modelling. We show that co-emission of volcanic halogens and sulfur into the stratosphere increases the volcanic effective radiative forcing (ERF) by 24 % and 30 % in large and very large co-emission scenarios compared to sulfur-only emission. This is caused by an increase in both the forcing from volcanic aerosol–radiation interactions (ERFari) and composition of the stratosphere (ERFclear,clean). Volcanic halogens catalyse the destruction of stratospheric ozone, which results in significant stratospheric cooling, offsetting the aerosol heating simulated in sulfur-only scenarios and resulting in net stratospheric cooling. The ozone-induced stratospheric cooling prevents aerosol self-lofting and keeps the volcanic aerosol lower in the stratosphere with a shorter lifetime. This results in reduced growth by condensation and coagulation and a smaller peak global-mean effective radius compared to sulfur-only simulations. The smaller effective radius found in both co-emission scenarios is closer to the peak scattering efficiency radius of sulfate aerosol, and thus co-emission of halogens results in larger peak global-mean ERFari (6 % and 8 %). Co-emission of volcanic halogens results in significant stratospheric ozone, methane, and water vapour reductions, resulting in significant increases in peak global-mean ERFclear,clean (> 100 %), predominantly due to ozone loss. The dramatic global-mean ozone depletion simulated in large (22 %) and very large (57 %) co-emission scenarios would result in very high levels of UV exposure on the Earth's surface, with important implications for society and the biosphere. This work shows for the first time that co-emission of plausible amounts of volcanic halogens can amplify the volcanic ERF in simulations of explosive eruptions. It highlights the need to include volcanic halogen emissions when simulating the climate impacts of past or future eruptions, as well as the necessity to maintain space-borne observations of stratospheric compounds to better constrain the stratospheric injection estimates of volcanic eruptions.
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De Angelis, M., J. Simões, H. Bonnaveira, J. D. Taupin, and R. J. Delmas. "Volcanic eruptions recorded in the Illimani ice core (Bolivia): 1918–1998 and Tambora periods." Atmospheric Chemistry and Physics Discussions 3, no. 3 (May 15, 2003): 2427–63. http://dx.doi.org/10.5194/acpd-3-2427-2003.
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Abstract. Acid layers of volcanic origin detected in polar snow and ice layers are commonly used to document past volcanic activity on a global scale or, conversely, to date polar ice cores. Although most cataclysmic eruptions of the last two centuries (Pinatubo, El Chichon, Agung, Krakatoa, Cosiguina, Tambora, etc.) occurred in the tropics, cold tropical glaciers have not been used for the reconstruction of past volcanism. The glaciochemical study of a 137 m ice core drilled in 1999 close to the summit of Nevado Illimani (Eastern Bolivian Andes, 16°37' S, 67°46' W, 6350 m a.s.l.) demonstrates, for the first time, that such eruptions are recorded by both their tropospheric and stratospheric deposits. An 80-year ice sequence (1918–1998) and the Tambora years have been analyzed in detail. In several cases, ash, chloride and fluoride were also detected. The ice records of the Pinatubo (1991), Agung (1963) and Tambora (1815) eruptions are discussed in detail. Less important eruptions located in the Andes are also recorded and may also disturb background aerosol composition on a regional scale.
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De Ragone, Argelia H. C., Amalia N. F. De Manzano, Ana G. Elias, and Marta Z. De Artigas. "Ionospheric effects of volcanic eruptions." Geofísica Internacional 43, no. 2 (April 1, 2004): 187–92. http://dx.doi.org/10.22201/igeof.00167169p.2004.43.2.169.
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Se han realizado numerosos estudios sobre los efectos ionosféricos de la erupción volcánica del Monte Pinatubo de junio de 1991. Basados en intervalos de 1 minuto de sondaje realizado en estaciones ubicadas al norte del volcán, se han detectado perturbaciones ionosféricas caracterizadas por trenes de onda cuasi-periódicas. Las ondas ionosféricas fueron atribuidas a ondas gravitatorias generadas por la fuerte erupción volcánica del Monte Pinatubo y sus características fueron determinadas. En el presente trabajo se busca detectar perturbaciones ionosféricas causadas por erupciones volcánicas en América, basados en datos horarios de la frecuencia crítica de la capa F2 (foF2) y la altura virtual de la capa F (h’F). El estudio fue realizado para periodos de nivel de actividad magnética tranquila. Ninguna de las erupciones aquí analizadas alcanza la intensidad del Pinatubo. Sin embargo, un decrecimiento de foF2 y de su amplitud de variación y un aumento de h’F en relación con sus valores durante el día previo y el posterior al de la erupción fueron detectados en algunos casos. En otros, la perturbación fue detectada solamente en uno de los parámetros analizados. La ausencia de perturbaciones en registros horarios podría deberse a la falta de coincidencia de los máximos apartamientos de los valores respecto a una situación de normalidad con el momento del registro de los parámetros ionosféricos. La observación de los efectos está directamente relacionada con la intensidad de la erupción.
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Bluth, Gregg J. S., Scott D. Doiron, Charles C. Schnetzler, Arlin J. Krueger, and Louis S. Walter. "Global tracking of the SO2clouds from the June, 1991 Mount Pinatubo eruptions." Geophysical Research Letters 19, no. 2 (January 24, 1992): 151–54. http://dx.doi.org/10.1029/91gl02792.
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Lynch, James S. "Mount Pinatubo—Explosive Volcanic Eruptions." Weather and Forecasting 6, no. 4 (December 1991): 576–80. http://dx.doi.org/10.1175/1520-0434(1991)006<0576:mpve>2.0.co;2.
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Bousquet, Jean-Claude, and Gianni Lanzafame. "Nouvelle interpretation des fractures des eruptions laterales de l'Etna; consequences pour son cadre tectonique." Bulletin de la Société Géologique de France 172, no. 4 (July 1, 2001): 455–67. http://dx.doi.org/10.2113/172.4.455.
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Abstract Mt Etna is cut by numerous fractures (fissures and faults) of very different origin and orientation. They have been used to define the activity and the tectonic setting of the volcano. After a discussion of the proposed tectonic models for Etna, an examination of the fractures, which are linked to the high flank eruptions, was carried out based on the geological and geophysical studies of the recent eruptions (1983, 1989, 1991-93). All of these surface breaks are of strictly volcanic origin; they open and advance very slowly, in relation to the propagation of the dyke, as well as its width and depth from the volcano surface. If the dyke summit is not too far from the surface (about 200-300 m), fissures and normal faults, arranged in a graben, appear. When the dyke intersects the slope of the volcano, a flank eruption follows. Therefore, these fractures do not have a tectonic or volcano-tectonic origin: they do not cut the entire volcanic edifice, and thus cannot be used to define the rift-zones nor to characterise the tectonic regime controlling the functioning of Etna. They give information on the dyke orientation on the slopes of the volcanic edifice and cannot be used as significative markers of extension [Frazzetta and Villari, 1981; Kieffer 1983a and b; Monaco et al., 1997]. The simultaneous opening of radial fractures, according to various azimuths, is frequent and clearly indicates that, in these cases, the regional stress field is not implicated. But high on Etna, the concentration of flank eruptions, on the eastern side, and the orientation change of the fractures (fig. 6), when they travel away from the summit, have been repeatedly indicated. The repetition of flank eruptions and the azimuth changes can be explained, simply, by the closeness of the Valle del Bove [Murray, 1994], which induces a decrease of the confinement pressure. The dyke emplacements of the summit eruptions cause an eastward displacement of the higher part of Etna. Marine geophysical data indicate that this volcano is, however, not the site of a large scale lateral spreading to the Ionian sea. Consequently, an eastward detachment is present only on the superior part of the volcano (figs. 1B and 7C). In fact, an up to 100 m high and oversteepened east-facing scarp, between the towns of Vena and Presa, extends towards the south for some kilometers [Lanzafame et al., 2000]. It is made up of volcanic rocks affected by strong brecciation. Inverse faults are found in front of the scarp. The base of this one is found at the level of the pre-Etnean clays, which would have helped the displacement of the volcanics. The studies on the tectonic setting in which Etna is located has called the attention of numerous researchers. From the earliest studies, the presence of numerous normal faults has supported the idea that this volcano, as many others, is active in an extensional regime. The most recent geological and geophysical data show a more complex situation. Deep under Etna (more than 10 km), a compressive field (sigma 1 N-S) is present according to focal mechanisms [Cardaci et al.; 1990; Ferrucci et al., 1993; Cocina et al., 1997]. More superficially, instead, extension is usual. The importance of the weight of the volcanic edifice, in the spatial (horizontal and vertical) modification of the compressive stress field, must still be clarified. It is very clear, in any case, that Etna cannot be explained by an extensional regime or kinematics in extension [Monaco et al., 1997] using normal faults, which form during the flank eruptions.
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Iwi, Alan M., Leon Hermanson, Keith Haines, and Rowan T. Sutton. "Mechanisms Linking Volcanic Aerosols to the Atlantic Meridional Overturning Circulation." Journal of Climate 25, no. 8 (April 10, 2012): 3039–51. http://dx.doi.org/10.1175/2011jcli4067.1.
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Abstract This study examines the sensitivity of the climate system to volcanic aerosol forcing in the third climate configuration of the Met Office Unified Model (HadCM3). The main test case was based on the 1880s when there were several volcanic eruptions, the well-known Krakatau being the largest. These eruptions increased atmospheric aerosol concentrations and induced a period of global cooling surface temperatures. In this study, an ensemble of HadCM3 has been integrated with the standard set of radiative forcings and aerosols from the Intergovernmental Panel on Climate Change Fourth Assessment Report simulations, from 1860 to present. A second ensemble removes the volcanic aerosols from 1880 to 1899. The all-forcings ensemble shows an attributable 1.2-Sv (1 Sv ≡ 106 m3 s−1) increase in the Atlantic meridional overturning circulation (AMOC) at 45°N—with a 0.04-PW increase in meridional heat transport at 40°N and increased northern Atlantic SSTs—starting around 1894, approximately 11 years after the first eruption, and lasting a further 10 years at least. The mechanisms responsible are traced to the Arctic, with suppression of the global water cycle (high-latitude precipitation), which leads to an increase in upper-level Arctic and Greenland Sea salinities. This then leads to increased convection in the Greenland–Iceland–Norwegian (GIN) Seas, enhanced Denmark Strait overflows, and AMOC changes with density anomalies traceable southward along the western Atlantic boundary. The authors investigate whether a similar response to the Pinatubo eruption in 1991 could still be ongoing, but do not find strong evidence.
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Chai, Jing, Fei Liu, Chen Xing, Bin Wang, Chaochao Gao, Jian Liu, and Deliang Chen. "A robust equatorial Pacific westerly response to tropical volcanism in multiple models." Climate Dynamics 55, no. 11-12 (September 9, 2020): 3413–29. http://dx.doi.org/10.1007/s00382-020-05453-6.
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Abstract After each of the 1963 Agung, 1982 El Chichón, and 1991 Pinatubo eruptions, an El Niño was observed. The increased likelihood of an El Niño after a tropical eruption has also been found in long-term reconstructed proxy data. Through examining simulations over the last millennium by 11 different models, we show that a tropical volcano eruption can robustly excite a western-to-central equatorial Pacific (WCEP) westerly anomaly at 850 hPa in eight out of the 11 models; such a westerly anomaly is favorable for El Niño development. Under the volcanic forcing, there are significant extratropical continent surface cooling and tropical drying with negative precipitation anomalies over the South–South East Asia (SSEA), West African monsoon, and Intertropical Convergence Zone (ITCZ) regions. This common precipitation suppression response occurs in most of the models. Sensitivity experiments show that a WCEP westerly anomaly can be excited by the tropical land cooling, especially the SSEA cooling induced precipitation suppression rather than by the extratropical land surface cooling. Theoretical results show that a WCEP westerly anomaly is excited due to a Gill response to reduced precipitation over the SSEA and West African monsoon regions; and the SSEA contributes more than the West African monsoon does. The ITCZ weakening, however, excites an easterly wind anomaly. The models with more sensitive convective feedback tend to simulate an El Niño more easily, while a failed simulation of an El Niño after a robust westerly anomaly in some models calls for further studies on these models’ delayed responses to radiative forcing induced by volcano eruptions.
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Flaathen, Therese K., and Sigurdur R. Gislason. "The effect of volcanic eruptions on the chemistry of surface waters: The 1991 and 2000 eruptions of Mt. Hekla, Iceland." Journal of Volcanology and Geothermal Research 164, no. 4 (August 2007): 293–316. http://dx.doi.org/10.1016/j.jvolgeores.2007.05.014.
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Poberaj, C. Schnadt, J. Staehelin, and D. Brunner. "Missing Stratospheric Ozone Decrease at Southern Hemisphere Middle Latitudes after Mt. Pinatubo: A Dynamical Perspective." Journal of the Atmospheric Sciences 68, no. 9 (September 1, 2011): 1922–45. http://dx.doi.org/10.1175/jas-d-10-05004.1.
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Abstract Although large total ozone decreases occurred in the Northern Hemisphere extratropics in the years after the volcanic eruption of Mt. Pinatubo that are generally attributed to the eruption, comparable decreases did not emerge in the Southern Hemisphere. To study this missing decrease, a multiple linear regression was applied to the Chemical and Dynamical Influences on Decadal Ozone Change (CANDIDOZ) Assimilated Three-Dimensional Ozone (CATO) dataset including the solar cycle, the quasi-biennial oscillation (QBO), the effect of volcanic eruptions, the lower stratospheric (LS) Eliassen–Palm (EP) flux to describe the Brewer–Dobson circulation, and stratospheric chlorine increase as explanatory variables. Volcanically induced chemical ozone depletion was overcompensated by the QBO and by a pronounced EP flux anomaly. Using NCEP–NCAR reanalysis data, it is found that the anomalous EP flux was caused by several significant stratospheric wave events (SWEs) from September–November 1991 through 1992 that, together with aerosol heating, led to a significantly enhanced Brewer–Dobson circulation and more ozone transport from the tropics to the extratropics. The onset of the volcanic ozone loss was shifted into 1992 and the strength of the signal was reduced. Most SWEs can be traced back to the troposphere and a significant fraction was associated with atmospheric blocking patterns preceding the SWEs. In 1991/92, the southern annular mode was in a negative phase and El Niño–Southern Oscillation in a warm phase. It is suggested that this constellation favored a flow preconditioning toward quasi-stationary features including blocking, which was significantly enhanced in 1991/92. During June–August 1992, blocking occurred preferably over the southeastern Pacific, pointing to a major ENSO influence on LS wave activity.
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de Vries, Tjalling W., and Florence van Hunsel. "Adverse drug reactions of systemic antihistamines in children in the Netherlands." Archives of Disease in Childhood 101, no. 10 (April 18, 2016): 968–70. http://dx.doi.org/10.1136/archdischild-2015-310315.
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BackgroundAntihistamines are used for the treatment of allergic rhinitis, allergic conjunctivitis, chronic spontaneous urticaria and atopic eczema.ObjectiveTo study the reports of adverse drug reactions (ADRs) in children using antihistamines to provide prescribers with an overview of the possible toxicity.DesignWe studied ADRs in children reported to the Netherlands Pharmacovigilance Centre Lareb in the years 1991–2014, assessed the Naranjo score and, when possible, computed the reporting OR.ResultsSerious ADRs included one death (malignant neuroleptic syndrome), cardiac arrhythmia (one case) and convulsions (three cases). Skin eruptions, headache and somnolence were the most frequently reported ADRs. Aggression and agitation were also reported.ConclusionsToxicity can occur with second-generation antihistamines. The main toxicity relates to skin eruptions and central nervous system problems.
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Thomas, M. A., C. Timmreck, M. A. Giorgetta, H. F. Graf, and G. Stenchikov. "Simulation of the climate impact of Mt. Pinatubo eruption using ECHAM5 – Part 1: Sensitivity to the modes of atmospheric circulation and boundary conditions." Atmospheric Chemistry and Physics Discussions 8, no. 3 (May 22, 2008): 9209–38. http://dx.doi.org/10.5194/acpd-8-9209-2008.
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Abstract. Large volcanic eruptions and their subsequent climate responses are relatively short-lived perturbations to the climate system. They provide an excellent opportunity to understand the response of the climate system to a global radiative forcing and to assess the ability of our climate models to simulate such large perturbations. The eruption of Mt. Pinatubo in Philippines in June 1991 was one of the strongest volcanic eruptions in the 20th century and this well observed eruption can serve as an important case study to understand the subsequent weather and climate changes. In this paper, the most comprehensive simulations to date of the climate impact of Mt. Pinatubo eruption are carried out with prescribed volcanic aerosols including observed SSTs, QBO and volcanically induced ozone anomalies. This is also the first attempt to include all the known factors for the simulation of such an experiment. Here, the climate response is evaluated under different boundary conditions including one at a time, thereby, investigating the radiative and dynamical responses to individual and combined forcings by observed SSTs, QBO and volcanic effects. Two ensembles of ten members each, for unperturbed and volcanically perturbed conditions were carried out using the middle atmosphere configuration of ECHAM5 model. Our results show that the pure aerosol response in lower stratospheric temperature is insensitive to the boundary conditions in the tropics and does not show some observed features which results from the boundary conditions. To simulate realistically the lower stratospheric temperature response, one must include all the known factors. The pure QBO and ocean responses are simulated consistent with earlier studies. The dynamical response manifested as the winter warming pattern is not simulated in the ensemble mean of the experiments. Our analysis also shows that the response to El Niño conditions is very strong in the model and that it partially masks the effects due to volcanic forcing.
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Mullineaux, L. S., S. W. Mills, N. Le Bris, S. E. Beaulieu, S. M. Sievert, and L. N. Dykman. "Prolonged recovery time after eruptive disturbance of a deep-sea hydrothermal vent community." Proceedings of the Royal Society B: Biological Sciences 287, no. 1941 (December 23, 2020): 20202070. http://dx.doi.org/10.1098/rspb.2020.2070.
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Deep-sea hydrothermal vents are associated with seafloor tectonic and magmatic activity, and the communities living there are subject to disturbance. Eruptions can be frequent and catastrophic, raising questions about how these communities persist and maintain regional biodiversity. Prior studies of frequently disturbed vents have led to suggestions that faunal recovery can occur within 2–4 years. We use an unprecedented long-term (11-year) series of colonization data following a catastrophic 2006 seafloor eruption on the East Pacific Rise to show that faunal successional changes continue beyond a decade following the disturbance. Species composition at nine months post-eruption was conspicuously different than the pre-eruption ‘baseline' state, which had been characterized in 1998 (85 months after disturbance by the previous 1991 eruption). By 96 months post-eruption, species composition was approaching the pre-eruption state, but continued to change up through to the end of our measurements at 135 months, indicating that the ‘baseline' state was not a climax community. The strong variation observed in species composition across environmental gradients and successional stages highlights the importance of long-term, distributed sampling in order to understand the consequences of disturbance for maintenance of a diverse regional species pool. This perspective is critical for characterizing the resilience of vent species to both natural disturbance and human impacts such as deep-sea mining.
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Löffler, Michael, Sabine Brinkop, and Patrick Jöckel. "Impact of major volcanic eruptions on stratospheric water vapour." Atmospheric Chemistry and Physics 16, no. 10 (May 30, 2016): 6547–62. http://dx.doi.org/10.5194/acp-16-6547-2016.
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Abstract. Volcanic eruptions can have a significant impact on the Earth's weather and climate system. Besides the subsequent tropospheric changes, the stratosphere is also influenced by large eruptions. Here changes in stratospheric water vapour after the two major volcanic eruptions of El Chichón in Mexico in 1982 and Mount Pinatubo on the Philippines in 1991 are investigated with chemistry–climate model simulations. This study is based on two simulations with specified dynamics of the European Centre for Medium-Range Weather Forecasts Hamburg – Modular Earth Submodel System (ECHAM/MESSy) Atmospheric Chemistry (EMAC) model, performed within the Earth System Chemistry integrated Modelling (ESCiMo) project, of which only one includes the long-wave volcanic forcing through prescribed aerosol optical properties. The results show a significant increase in stratospheric water vapour induced by the eruptions, resulting from increased heating rates and the subsequent changes in stratospheric and tropopause temperatures in the tropics. The tropical vertical advection and the South Asian summer monsoon are identified as sources for the additional water vapour in the stratosphere. Additionally, volcanic influences on tropospheric water vapour and El Niño–Southern Oscillation (ENSO) are evident, if the long-wave forcing is strong enough. Our results are corroborated by additional sensitivity simulations of the Mount Pinatubo period with reduced nudging and reduced volcanic aerosol extinction.
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Toohey, M., K. Krüger, M. Bittner, C. Timmreck, and H. Schmidt. "The impact of volcanic aerosol on the Northern Hemisphere stratospheric polar vortex: mechanisms and sensitivity to forcing structure." Atmospheric Chemistry and Physics 14, no. 23 (December 9, 2014): 13063–79. http://dx.doi.org/10.5194/acp-14-13063-2014.
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Abstract. Observations and simple theoretical arguments suggest that the Northern Hemisphere (NH) stratospheric polar vortex is stronger in winters following major volcanic eruptions. However, recent studies show that climate models forced by prescribed volcanic aerosol fields fail to reproduce this effect. We investigate the impact of volcanic aerosol forcing on stratospheric dynamics, including the strength of the NH polar vortex, in ensemble simulations with the Max Planck Institute Earth System Model. The model is forced by four different prescribed forcing sets representing the radiative properties of stratospheric aerosol following the 1991 eruption of Mt. Pinatubo: two forcing sets are based on observations, and are commonly used in climate model simulations, and two forcing sets are constructed based on coupled aerosol–climate model simulations. For all forcings, we find that simulated temperature and zonal wind anomalies in the NH high latitudes are not directly impacted by anomalous volcanic aerosol heating. Instead, high-latitude effects result from enhancements in stratospheric residual circulation, which in turn result, at least in part, from enhanced stratospheric wave activity. High-latitude effects are therefore much less robust than would be expected if they were the direct result of aerosol heating. Both observation-based forcing sets result in insignificant changes in vortex strength. For the model-based forcing sets, the vortex response is found to be sensitive to the structure of the forcing, with one forcing set leading to significant strengthening of the polar vortex in rough agreement with observation-based expectations. Differences in the dynamical response to the forcing sets imply that reproducing the polar vortex responses to past eruptions, or predicting the response to future eruptions, depends on accurate representation of the space–time structure of the volcanic aerosol forcing.
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Oppenheimer, Clive. "Climatic, environmental and human consequences of the largest known historic eruption: Tambora volcano (Indonesia) 1815." Progress in Physical Geography: Earth and Environment 27, no. 2 (June 2003): 230–59. http://dx.doi.org/10.1191/0309133303pp379ra.
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The 1815 eruption of Tambora volcano (Sumbawa island, Indonesia) expelled around 140 gt of magma (equivalent to ≈50 km3 of dense rock), making it the largest known historic eruption. More than 95% by mass of the ejecta was erupted as pyroclastic flows, but 40% by mass of the material in these flows ended up as ash fallout from the ‘phoenix’ clouds that lofted above the flows during their emplacement. Although they made only a minor contribution to the total magnitude of the eruption, the short-lived plinian explosions that preceded the climactic eruption and caldera collapse were powerful, propelling plumes up to 43 km altitude. Over 71 000 people died during, or in the aftermath of, the eruption, on Sumbawa and the neigh-bouring island of Lombok. The eruption injected ≈60 mt of sulfur into the stratosphere, six times more than was released by the 1991 Pinatubo eruption. This formed a global sulfate aerosol veil in the stratosphere, which resulted in pronounced climate perturbations. Anomalously cold weather hit the northeastern USA, maritime provinces of Canada, and Europe the following year. 1816 came to be known as the ‘Year without a summer’ in these regions. Crop failures were widespread and the eruption has been implicated in accelerated emigration from New England, and widespread outbreaks of epidemic typhus. These events provide important insights into the volcanic forcing of climate, and the global risk of future eruptions on this scale.
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Kratzmann, David J., Steven N. Carey, Julie Fero, Roberto A. Scasso, and Jose-Antonio Naranjo. "Simulations of tephra dispersal from the 1991 explosive eruptions of Hudson volcano, Chile." Journal of Volcanology and Geothermal Research 190, no. 3-4 (February 2010): 337–52. http://dx.doi.org/10.1016/j.jvolgeores.2009.11.021.
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Cheng, Kang, and Yinn-Nien Huang. "Ionospheric disturbances observed during the period of Mount Pinatubo eruptions in June 1991." Journal of Geophysical Research 97, A11 (1992): 16995. http://dx.doi.org/10.1029/92ja01462.
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