Monitoring volcanoes in Mexico

Mexico has at least 46 volcanic centers (including monogenetic volcanic fields) that are considered active or potentially active. Due to the federal governance of the country, the Centro Nacional de Prevención de Desastres (CENAPRED) is the entity responsible for monitoring natural hazards. Individual Mexican states also monitor active volcanoes within their territoryand through local universities. Specific observatories exist for Colima, Citlaltépetl (Pico de Orizaba), San Martín Tuxtla, El Chichón, and Tacaná volcanoes, which are considered among the volcanoes with the highest hazard potential in the country. Details on instrumentation, data acquisition, hazard management, information dissemination and outreach are given for each volcano and observatory. The creation of a National Volcanological Service, based at CENAPRED and in full cooperation with local university-based observatories, would help consolidate all monitoring data and official information on active volcanoes at a single institution, procure and distribute resources, and allocate those resources according to the relative risk posed by the different volcanoes. México tiene al menos 46 centros volcánicos que podrían considerarse activos o potencialmente activos (incluyendo campos volcánicos monogenéticos). Debido al carácter federal del país, el Centro Nacional de Prevención de Desastres (CENAPRED) es la entidad responsable de monitorear los fenómenos naturales. Individualmente, algunos estados mexicanos también monitorean los volcanes activos dentro de su territorio, a través de las universidades locales, por lo que existen observatorios específicos para Colima, Citlaltépetl (Pico de Orizaba), San Martín Tuxtla, El Chichón y Tacaná; todos estos considerados entre los volcanes de mayor riesgo relativo del país. Se proporcionan detalles sobre instrumentación, adquisición de datos, gestión de riesgos y difusión y divulgación de información para cada volcán y observatorio. La creación de un Servicio Vulcanológico Nacional, con sede en CENAPRED, y en cooperación plena con los observatorios universitarios locales, ayudaría a concentrar todos los datos de monitoreo e información oficial sobre los volcanes activos en una sola institución, así como a adquirir y asignar recursos, de acuerdo con el riesgo relativo que representan los diferentes volcanes.

Evaluating the simulated radiative forcings, aerosol properties, and stratospheric warmings from the 1963 Mt Agung, 1982 El Chichón, and 1991 Mt Pinatubo volcanic aerosol clouds

Accurately quantifying volcanic impacts on climate is a key requirement for robust attribution of anthropogenic climate change. Here we use the Unified Model – United Kingdom Chemistry and Aerosol (UM-UKCA) composition–climate model to simulate the global dispersion of the volcanic aerosol clouds from the three largest eruptions of the 20th century: 1963 Mt Agung, 1982 El Chichón, and 1991 Mt Pinatubo. The model has interactive stratospheric chemistry and aerosol microphysics, with coupled aerosol–radiation interactions for realistic composition–dynamics feedbacks. Our simulations align with the design of the Interactive Stratospheric Aerosol Model Intercomparison (ISA-MIP) “Historical Eruption SO2 Emissions Assessment”. For each eruption, we perform three-member ensemble model experiments for upper, mid-point, and lower estimates of SO2 emission, each re-initialised from a control run to approximately match the observed transition in the phase of the quasi-biennial oscillation (QBO) in the 6 months after the eruptions. With this experimental design, we assess how each eruption's emitted SO2 translates into a tropical reservoir of volcanic aerosol and analyse the subsequent dispersion to mid-latitudes. We compare the simulations to the volcanic forcing datasets (e.g. Space-based Stratospheric Aerosol Climatology (GloSSAC); Sato et al., 1993, and Ammann et al., 2003) that are used in historical integrations for the two most recent Coupled Model Intercomparison Project (CMIP) assessments. For Pinatubo and El Chichón, we assess the vertical extent of the simulated volcanic clouds by comparing modelled extinction to the Stratospheric Aerosol and Gas Experiment (SAGE-II) v7.0 satellite measurements and to 1964–1965 Northern Hemisphere ground-based lidar measurements for Agung. As an independent test for the simulated volcanic forcing after Pinatubo, we also compare simulated shortwave (SW) and longwave (LW) top-of-the-atmosphere radiative forcings to the flux anomalies measured by the Earth Radiation Budget Experiment (ERBE) satellite instrument. For the Pinatubo simulations, an injection of 10 to 14 Tg SO2 gives the best match to the High Resolution Infrared Sounder (HIRS) satellite-derived global stratospheric sulfur burden, with good agreement also with SAGE-II mid-visible and near-infra-red extinction measurements. This 10–14 Tg range of emission also generates a heating of the tropical stratosphere that is consistent with the temperature anomaly present in the ERA-Interim reanalysis. For El Chichón, the simulations with 5 and 7 Tg SO2 emission give best agreement with the observations. However, these simulations predict a much deeper volcanic cloud than represented in the GloSSAC dataset, which is largely based on an interpolation between Stratospheric Aerosol Measurements (SAM-II) satellite and aircraft measurements. In contrast, these simulations show much better agreement during the SAGE-II period after October 1984. For 1963 Agung, the 9 Tg simulation compares best to the forcing datasets with the model capturing the lidar-observed signature of the altitude of peak extinction descending from 20 km in 1964 to 16 km in 1965. Overall, our results indicate that the downward adjustment to SO2 emission found to be required by several interactive modelling studies when simulating Pinatubo is also needed when simulating the Agung and El Chichón aerosol clouds. This strengthens the hypothesis that interactive stratospheric aerosol models may be missing an important removal or re-distribution process (e.g. effects of co-emitted ash) which changes how the tropical reservoir of volcanic aerosol evolves in the initial months after an eruption. Our model comparisons also identify potentially important inhomogeneities in the CMIP6 dataset for all three eruption periods that are hard to reconcile with variations predicted in the interactive stratospheric aerosol simulations. We also highlight large differences between the CMIP5 and CMIP6 volcanic aerosol datasets for the Agung and El Chichón periods. Future research should aim to reduce this uncertainty by reconciling the datasets with additional stratospheric aerosol observations.

Characterization of Thermophilic Microorganisms in the Geothermal Water Flow of El Chichón Volcano Crater Lake

This study reports for the first time the isolation, identification and characterization of lipase-producing thermophilic strain from the geothermal water of the El Chichón volcano crater lake. Two strains were identified by 16S rRNA sequencing as Geobacillus jurassicus CHI2 and Geobacillus stearothermophilus CHI1. Results showed that G. jurassicus CHI2 is Gram-positive, able to ferment maltose, fructose and sucrose and to hydrolyze starch and casein; while G. stearothermophilus CHI1 showed to be Gram-variable, able to ferment maltose and fructose and to hydrolyze starch. Colonies of both strains presented irregular shape, umbilicated elevation of gummy texture and cells presented flagellar movement to survive in fluids with high temperature and mass gradients due to complex phenomena of heat and mass transfer present in the geothermal fluids. Lipase production for G. stearothermophilus CHI1 was also evaluated. It was found that this strain possesses a growth associated with extracellular lipase production with a high activity of 143 U/mL at 8.3 h of incubation time, superior to the activities reported for other microorganisms of genus Geobacillus; for this reason, it can be said that the thermal flow of the El Chichón volcano crater lake can be a useful source of lipase-producing thermophilic bacteria.

Evaluating the simulated radiative forcings, aerosol properties and stratospheric warmings from the 1963 Agung, 1982 El Chichón and 1991 Mt Pinatubo volcanic aerosol clouds

Accurate quantification of the effects of volcanic eruptions on climate is a key requirement for better attribution of anthropogenic climate change. Here we use the UM-UKCA composition-climate model to simulate the atmospheric evolution of the volcanic aerosol clouds from the three largest eruptions of the 20th century: 1963 Agung, 1982 El Chichón and 1991 Pinatubo. The model has interactive stratospheric chemistry and aerosol microphysics, with coupled aerosol–radiation interactions for realistic composition-dynamics feedbacks. Our simulations align with the design of the Interactive Stratospheric Aerosol Model Intercomparison (ISA-MIP) Historical Eruption SO2 Emissions Assessment. For each eruption, we perform 3-member ensemble model experiments with upper, mid-point and lower estimates for SO2 emission, each initialised to a meteorological state to match the observed phase of the quasi-biennial oscillation (QBO) at the times of the eruptions. We assess how each eruption's emitted SO2 evolves into a tropical reservoir of volcanic aerosol and analyse the subsequent dispersion to mid-latitudes. We compare the simulations to the three volcanic forcing datasets used in historical integrations for the two most recent Coupled Model Intercomparison Project (CMIP) assessments: the Global Space-based Stratospheric Aerosol Climatology (GloSSAC) for CMIP6, and the Sato et al. (1993) and Ammann et al. (2003) datasets used in CMIP5. We also assess the vertical extent of the volcanic aerosol clouds by comparing simulated extinction to Stratospheric Aerosol and Gas Experiment II (SAGE-II) v7.0 satellite aerosol data (1985–1995) for Pinatubo and El Chichón, and to 1964–65 northern hemisphere ground-based lidar measurements for Agung. As an independent test for the simulated volcanic forcing after Pinatubo, we also compare to the shortwave (SW) and longwave (LW) Top-of-the-Atmosphere flux anomalies measured by the Earth Radiation Budget Experiment (ERBE) satellite instrument. For the Pinatubo simulations, an injection of 10 to 14 Tg SO2 gives the best match to the High Resolution Infrared Sounder (HIRS) satellite-derived global stratospheric sulphur burden, with good agreement also to SAGE-II mid-visible and near-infrared extinction measurements. This 10–14 Tg range of emission also generates a heating of the tropical stratosphere that is comparable with the temperature anomaly seen in the ERA-Interim reanalyses. For El Chichón the simulations with 5 Tg and 7 Tg SO2 emission give best agreement with the observations. However, these runs predict a much deeper volcanic cloud than present in the CMIP6 data, with much higher aerosol extinction than the GloSSAC data up to October 1984, but better agreement during the later SAGE-II period. For 1963 Agung, the 9 Tg simulation compares best to the forcing datasets with the model capturing the lidar-observed signature of peak extinction descending from 20 km in 1964 to 16 km in 1965. Overall, our results indicate that the downward adjustment to previous SO2 emission estimates for Pinatubo as suggested by several interactive modelling studies is also needed for the Agung and El Chichón aerosol clouds. This strengthens the hypothesis that interactive stratospheric aerosol models may be missing an important removal or redistribution process (e.g. effects of co-emitted ash) which changes how the tropical reservoir of volcanic aerosol evolves in the initial months after an eruption. Our analysis identifies potentially important inhomogeneities in the CMIP6 dataset for all three periods that are hard to reconcile with variations predicted by the interactive stratospheric aerosol model. We also highlight large differences between the CMIP5 and CMIP6 volcanic aerosol datasets for the Agung and El Chichón periods. Future research should aim to reduce this uncertainty by reconciling the datasets with additional stratospheric aerosol observations.

Surface temperature response to the major volcanic eruptions in multiple reanalysis data sets

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.

Surface temperature response to the major volcanic eruptions in multiple reanalysis data sets

The global response of air temperature at 2 metre 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 six 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, latitudinally 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 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.