Stratospheric residence time and the lifetime of volcanic aerosol

2021 ◽  
Author(s):  
Matthew Toohey ◽  
Yue Jia ◽  
Susann Tegetmeier
Keyword(s):  
Residence Time ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Volcanic Aerosol ◽  
Aerosol Forcing ◽  
Radiative Impact ◽  
The Common ◽  
The Impact ◽  
The Relationship ◽  
Common Era

<p>The cumulative radiative impact of major volcanic eruptions depends strongly on the length of time volcanic sulfate aerosol remains in the stratosphere. Observations of aerosol from recent eruptions have been used to suggest that residence time depends on the latitude of the volcanic eruption, with tropical eruptions producing aerosol loading that persists longer than that from extratropical eruptions. However, the limited number of eruptions observed make it difficult to disentangle the roles of latitude and injection height in controlling aerosol lifetime. Here we use satellite observations and model experiments to explore the relationship between eruption latitude, injection height and resulting residence time of stratospheric aerosol. We find that contrary to earlier interpretations of observations, the residence time of aerosol from major tropical eruptions like Pinatubo (1991) is on the order of 24 months. Model results suggest that the residence time is greatly sensitive to the height of the sulfur injection, especially within the lowest few kilometers of the stratosphere. As injection heights and latitudes are unknown for the majority of eruptions over the common era, we estimate the impact of this uncertainty on volcanic aerosol forcing reconstructions. </p>

Model comparison of volcanic aerosol forcing and climate impact of tropical and extratropical eruptions

2021 ◽  
Author(s):  
Zhihong Zhuo ◽  
Herman Fuglestvedt ◽  
Matthew Toohey ◽  
Michael J. Mills ◽  
Kirstin Krüger
Keyword(s):  
Large Scale ◽  
Model Comparison ◽  
Climate Model ◽  
Volcanic Eruptions ◽  
Climate Impact ◽  
Stratospheric Aerosol ◽  
Volcanic Aerosol ◽  
Surface Cooling ◽  
Aerosol Forcing ◽  
Central American Volcanic Arc

<p>Major volcanic eruptions increase sulfate aerosols in the stratosphere. This causes a large-scale dimming effect with significant surface cooling and stratosphere warming. However, the climate impact differs for tropical and extratropical eruptions, and depends on the eruption season and height, and volcanic volatiles injections. In order to study different volcanic aerosol forcing and their climate impact, we perform simulations based on the fully coupled Community Earth System Model version 2 (CESM2) with the version 6 of the Whole Atmosphere Community Climate Model (WACCM6) with prognostic stratospheric aerosol and chemistry. In this study, explosive eruptions at 14.6 N and 63.6 N in January and July injecting 17 MT and 200 MT SO<sub>2</sub> at 24 km with and without halogens are simulated, in line with Central American Volcanic Arc and Icelandic volcanic eruptions. Simulated changes in the stratospheric sulfate and halogen burdens, and related impacts on aerosol optical depth, radiation, ozone and surface climate are analyzed. These simulated volcanic eruption cases will be compared with simulations based on the aerosol-climate model MAECHAM5-HAM.</p>

scholarly journals Quantifying CanESM5 and EAMv1 sensitivities to volcanic forcing for the CMIP6 historical experiment

2020 ◽  
Author(s):  
Landon A. Rieger ◽  
Jason N. S. Cole ◽  
John C. Fyfe ◽  
Stephen Po-Chedley ◽  
Philip J. Cameron-Smith ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Earth System Model ◽  
System Model ◽  
Global Ocean ◽  
Earth System ◽  
Model Version ◽  
Aerosol Forcing ◽  
The Impact

Abstract. Large volcanic eruptions reaching the stratosphere have caused marked perturbations to the global climate including cooling at the Earth's surface, changes in large-scale circulation and precipitation patterns and marked temporary reductions in global ocean heat content. Many studies have investigated these effects using climate models, however uncertainties remain in the modelled response to these eruptions. This is due in part to the diversity of forcing datasets that are used to prescribe the distribution of stratospheric aerosols resulting from these volcanic eruptions, as well as uncertainties in optical property derivations from these datasets. To reduce these uncertainties in the Coupled Model Intercomparison Project 6 (CMIP6) a combined stratospheric aerosol dataset, the Global Space-based Stratospheric Aerosol Climatology, GloSSAC, was constructed. Along with information from ice-cores and sun photometers, GloSSAC was used to generate aerosol distributions, characteristics and optical properties and construct a consistent stratospheric aerosol forcing dataset for models participating in CMIP6. This version 3 of the stratospheric aerosol forcing has been endorsed for use in all contributing CMIP6 simulations. Recent updates to the underlying GloSSAC from version 1 to version 1.1 affected the 1991 to 1994 period and necessitated an update to the stratospheric aerosol forcing from version 3 to version 4. As version 3 remains the official CMIP6 input, quantification of the impact on radiative forcing and climate is both relevant and timely for interpreting results from experiments such as the CMIP6 historical simulations. This study uses the Canadian Earth System Model version 5 (CanESM5) to estimate the difference in instantaneous radiative forcing in simulated post-Pinatubo climate response when using version 4 instead of version 3. Differences in temperature, precipitation, and radiative forcings are generally found to be small compared to internal variability. To further elucidate sensitivities that are representative of the CMIP6 model suite, additional simulations are performed using the Energy Exascale Earth System Model (E3SM) Atmosphere Model version 1 (EAMv1), which also indicates that the impact of the update to GloSSAC version 4 on climate are relatively minor. An exception to this is differences in temperature anomalies in the stratosphere, which can be as large as 3 °C following the eruption of Mt. Pinatubo.

scholarly journals Quantifying CanESM5 and EAMv1 sensitivities to Mt. Pinatubo volcanic forcing for the CMIP6 historical experiment

2020 ◽  
Vol 13 (10) ◽  
pp. 4831-4843 ◽  
Author(s):  
Landon A. Rieger ◽  
Jason N. S. Cole ◽  
John C. Fyfe ◽  
Stephen Po-Chedley ◽  
Philip J. Cameron-Smith ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Earth System Model ◽  
System Model ◽  
Global Ocean ◽  
Earth System ◽  
Model Version ◽  
Aerosol Forcing ◽  
The Impact

Abstract. Large volcanic eruptions reaching the stratosphere have caused marked perturbations to the global climate including cooling at the Earth's surface, changes in large-scale circulation and precipitation patterns and marked temporary reductions in global ocean heat content. Many studies have investigated these effects using climate models; however, uncertainties remain in the modelled response to these eruptions. This is due in part to the diversity of forcing datasets that are used to prescribe the distribution of stratospheric aerosols resulting from these volcanic eruptions, as well as uncertainties in optical property derivations from these datasets. To improve this situation for the sixth phase of the Coupled Model Intercomparison Project (CMIP6), a two-step process was undertaken. First, a combined stratospheric aerosol dataset, the Global Space-based Stratospheric Aerosol Climatology (GloSSAC; 1979–2016), was constructed. Next, GloSSAC, along with information from ice cores and Sun photometers, was used to generate aerosol distributions, characteristics and optical properties to construct a more consistent stratospheric aerosol forcing dataset for models participating in CMIP6. This “version 3” of the stratospheric aerosol forcing has been endorsed for use in all contributing CMIP6 simulations. Recent updates to the underlying GloSSAC from version 1 to version 1.1 affected the 1991–1994 period and necessitated an update to the stratospheric aerosol forcing from version 3 to version 4. As version 3 remains the official CMIP6 input, quantification of the impact on radiative forcing and climate is both relevant and timely for interpreting results from experiments such as the CMIP6 historical simulations. This study uses two models, the Canadian Earth System Model version 5 (CanESM5) and the Energy Exascale Earth System Model (E3SM) Atmosphere Model version 1 (EAMv1), to estimate the difference in instantaneous radiative forcing in simulated post-Pinatubo climate response when using version 4 instead of version 3. Differences in temperature, precipitation and radiative forcings are generally found to be small compared to internal variability. An exception to this is differences in monthly temperature anomalies near 24 km altitude in the tropics, which can be as large as 3 ∘C following the eruption of Mt. Pinatubo.

Dependency in Africa: Stages of African Political Economy

1983 ◽  
Vol 9 (2) ◽  
pp. 229-247 ◽  
Author(s):  
Amechi Okolo
Keyword(s):  
Political Economy ◽  
International System ◽  
Raw Material ◽  
The West ◽  
Cheap Labour ◽  
History Of ◽  
The Common ◽  
First Contact ◽  
The Impact ◽  
The Relationship

This paper traces the history of the relationship between Africa and the West since their first contact brought about by the outward thrust of the West, under the impetus of rising capitalism, in search of cheap labour and cheap raw material for its industries and expanding markets for its industrial products, both of which could be better ensured through domination and exploitation. The paper identifies five successive stages that African political economy has passed through under the impact of this relationship, each phase qualitatively different from the other but all having the common characteristic of domination-dependence syndrome, and each phase having been dictated by the dynamics of capitalism in different eras and by the dominant forces in the changing international system. Its finding is that the way to the latest stage, the dependency phase, was paved by the progressive proletarianization of the African peoples and the maintenance of an international peonage system. It ends by indicating the direction in which Africa can make a beginning to break out of dependency and achieve liberation.

scholarly journals Effect of volcanic aerosol on stratospheric NO<sub>2</sub> and N<sub>2</sub>O<sub>5</sub> from 2002–2014 as measured by Odin-OSIRIS and Envisat-MIPAS

2016 ◽  
Author(s):  
Cristen Adams ◽  
Adam E. Bourassa ◽  
Chris A. McLinden ◽  
Chris E. Sioris ◽  
Thomas von Clarmann ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
Pearson Correlation ◽  
Michelson Interferometer ◽  
Correlation Coefficients ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Volcanic Aerosol ◽  
Quasi Biennial Oscillation ◽  
El Chichón ◽  
El Chichon

Abstract. Following the large volcanic eruptions of Pinatubo in 1991 and El Chichón in 1982, decreases in stratospheric NO2 associated with enhanced aerosol were observed. The Optical Spectrograph and InfraRed Imaging Spectrometer (OSIRIS) likewise measured widespread enhancements of stratospheric aerosol following seven volcanic eruptions between 2002 and 2014, although the magnitudes of these eruptions were all much smaller than the Pinatubo and El Chichón eruptions. In order to isolate and quantify the relationship between volcanic aerosol and NO2, NO2 anomalies were calculated using measurements from OSIRIS and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS). In the tropics, variability due to the quasi-biennial oscillation was subtracted from the timeseries. OSIRIS profile measurements indicate that the strongest relationships between NO2 and volcanic aerosol extinction were for the layer ~ 3–7 km above the tropopause, where OSIRIS stratospheric NO2 partial columns for ~ 3–7 km above the tropopause were found to be smaller than baseline levels during these aerosol enhancements by up to ~ 60 % with typical Pearson correlation coefficients of R ~ −0.7. MIPAS also observed decreases in NO2 partial columns during periods of affected by volcanic aerosol, with percent differences of up to ~ 25 %. An even stronger relationship was observed between OSIRIS aerosol optical depth and MIPAS N2O5 partial columns, with R ~ −0.9, although no link with MIPAS HNO3 was observed. The variation of OSIRIS NO2 with increasing aerosol was found to be quantitatively consistent with simulations from a photochemical box model in terms of both magnitude and degree of non-linearity.

scholarly journals Research on Mediating Mechanisms and the Impact on Food Provision Services in Poor Areas from the Perspective of Stakeholders

2021 ◽  
Vol 18 (19) ◽  
pp. 10510
Author(s):  
Tianwei Geng ◽  
Hai Chen ◽  
Di Liu ◽  
Qinqin Shi ◽  
Hang Zhang
Keyword(s):  
Ecosystem Service ◽  
Behavioral Responses ◽  
The Loess Plateau ◽  
Trade Offs ◽  
Different Types ◽  
Mediating Mechanisms ◽  
The Common ◽  
Food Provision ◽  
The Impact ◽  
The Relationship

Exploring and analyzing the common demands and behavioral responses of different stakeholders is important for revealing the mediating mechanisms of ecosystem service (ES) and realizing the management and sustainable supply of ES. This study took Mizhi County, a poverty-stricken area on the Loess Plateau in China, as an example. First, the main stakeholders, common demands, and behavioral responses in the food provision services were identified. Second, the relationship among stakeholders was analyzed. Finally, this study summarized three types of mediating mechanisms of food provision services and analyzed the influence of the different types of mediating mechanisms. The main conclusions are as follows: (1) Five main stakeholders in the study area were identified: government, farmers, enterprises, cooperatives, and middlemen. (2) Increasing farmers’ income is the common demand of most stakeholders in the study area, and this common demand has different effects on the behavioral responses of different stakeholders. (3) There are three types of mediating mechanisms in the study area: government + farmers mediating corn and mutton, government + enterprises mediating millet, and government + cooperatives mediating apples. On this basis, the effects of the different types of mediating mechanisms on variations in food yield, and trade-offs and synergies in typical townships, were analyzed.

scholarly journals Increment in the volcanic unrest and number of eruptions after the 2012 large earthquakes sequence in Central America

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gino González ◽  
Eisuke Fujita ◽  
Bunichiro Shibazaki ◽  
Takumi Hayashida ◽  
Giovanni Chiodini ◽  
...  
Keyword(s):  
Central America ◽  
Seismic Waves ◽  
Dynamic Stress ◽  
Reaction Times ◽  
Volcanic Eruptions ◽  
Large Magnitude ◽  
Tectonic Earthquakes ◽  
The Impact ◽  
The Relationship ◽  
Large Earthquakes

AbstractUnderstanding the relationship cause/effect between tectonic earthquakes and volcanic eruptions is a striking topic in Earth Sciences. Volcanoes erupt with variable reaction times as a consequence of the impact of seismic waves (i.e. dynamic stress) and changes in the stress field (i.e. static stress). In 2012, three large (Mw ≥ 7.3) subduction earthquakes struck Central America within a period of 10 weeks; subsequently, some volcanoes in the region erupted a few days after, while others took months or even years to erupt. Here, we show that these three earthquakes contributed to the increase in the number of volcanic eruptions during the 7 years that followed these seismic events. We found that only those volcanoes that were already in a critical state of unrest eventually erupted, which indicates that the earthquakes only prompted the eruptions. Therefore, we recommend the permanent monitoring of active volcanoes to reveal which are more susceptible to culminate into eruption in the aftermath of the next large-magnitude earthquake hits a region.

scholarly journals A new Geoengineering Model Intercomparison Project (GeoMIP) experiment designed for climate and chemistry models

2014 ◽  
Vol 7 (4) ◽  
pp. 5447-5464 ◽  
Author(s):  
S. Tilmes ◽  
M. J. Mills ◽  
U. Niemeier ◽  
H. Schmidt ◽  
A. Robock ◽  
...  
Keyword(s):  
Model Comparison ◽  
Stratospheric Aerosol ◽  
Atmospheric Composition ◽  
Model Intercomparison ◽  
Data Set ◽  
Aerosol Forcing ◽  
Input Dataset ◽  
Intercomparison Project ◽  
Total Burden ◽  
The Impact

Abstract. A new Geoengineering Model Intercomparison Project (GeoMIP) experiment "G4 specified stratospheric aerosols" (short name: G4SSA) is proposed to investigate the impact of stratospheric aerosol geoengineering on atmospheric composition, climate, and the environment. In contrast to the earlier G4 GeoMIP experiment, which requires an emission of sulphur dioxide (SO2) into the model, a prescribed aerosol forcing file is provided to the community, to be consistently applied to future model experiments between 2020 and 2100. This stratospheric aerosol distribution, with a total burden of about 2 Tg S has been derived using the ECHAM5-HAM microphysical model, based on a continuous annual tropical emission of 8 Tg SO2 year−1. A ramp-up of geoengineering in 2020 and a ramp-down in 2070 over a period of two years are included in the distribution, while a background aerosol burden should be used for the last 3 decades of the experiment. The performance of this experiment using climate and chemistry models in a multi-model comparison framework will allow us to better understand the significance of the impact of geoengineering and the abrupt termination after 50 years on climate and composition of the atmosphere in a changing environment. The zonal and monthly mean stratospheric aerosol input dataset is available at https://www2.acd.ucar.edu/gcm/geomip-g4-specified-stratospheric-aerosol-data-set.

Can a replacing sponsor benefit?

2019 ◽  
Vol 53 (12) ◽  
pp. 2481-2500 ◽  
Author(s):  
François Anthony Carrillat ◽  
Reinhard Grohs
Keyword(s):  
Behavioral Intentions ◽  
Underlying Mechanism ◽  
Randomized Experiments ◽  
Altruistic Motive ◽  
Content Type ◽  
Consumer Responses ◽  
Sponsorship Effectiveness ◽  
The Common ◽  
The Impact ◽  
The Relationship

Purpose This paper aims to examine the common situation where the sponsor of an event is replaced and the impact of this situation on consumers’ behavioral intentions toward the new sponsor. Design/methodology/approach An original conceptual framework was developed to account for consumers’ reactions toward a new sponsor in the context of a sponsorship change, depending on whether the former and new sponsors are competitors, the duration of the relationship between the former sponsor and the event (tenure length), and the level of congruence between the new and the former sponsor and the event. This framework, based on consumer motive attributions, was tested by means of three completely randomized experiments. Findings The results of the first experiment show that if the former and new sponsors are competitors, consumers’ behavioral intentions toward the new sponsor are more positive if the former sponsor’s tenure duration was short. When the former and the new sponsors are not competitors, the former sponsor’s tenure duration does not impact behavioral intentions. The second experiment demonstrates that consumers’ altruistic motive attributions are the underlying mechanism that explains these effects. Finally, the third experiment identifies a boundary condition, that is, these effects occur only if the new and the former sponsor are congruent with the sponsored property. Research limitations/implications This research has not considered the situation where the former and new sponsors have different levels of congruence with the event (e.g. when the former sponsor is congruent but the new sponsor is incongruent with the event) and has examined only sponsorship tenure durations of one versus 15 years. Practical implications Sponsorship managers learn that replacing a sponsor that was supporting the event for a short rather than a long period of time is more beneficial, but only if replacing a competitor that is congruent with the sponsored property. The reason is that such a replacement triggers more altruistic motive attributions compared with contexts where the former sponsor is not a competitor or incongruent with the sponsored property. Suggestions of sponsorship activation strategies known to increase perceptions of altruism are provided to enhance sponsorship effectiveness for new sponsors. Originality/value This study is the first to look at how consumer responses to a new sponsor vary depending on the former sponsor’s tenure length, competitor status and event congruency.

scholarly journals The Interactive Stratospheric Aerosol Model Intercomparison Project (ISA-MIP): motivation and experimental design

2018 ◽  
Vol 11 (7) ◽  
pp. 2581-2608 ◽  
Author(s):  
Claudia Timmreck ◽  
Graham W. Mann ◽  
Valentina Aquila ◽  
Rene Hommel ◽  
Lindsay A. Lee ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Volcanic Eruptions ◽  
Stratospheric Aerosol ◽  
Transport Processes ◽  
Aerosol Layer ◽  
Model Intercomparison ◽  
Aerosol Model ◽  
Model Experiments ◽  
Aerosol Forcing ◽  
Intercomparison Project

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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