scholarly journals Simulation of ash clouds after a Laacher See-type eruption

2021 ◽  
Author(s):  
Ulrike Niemeier ◽  
Felix Riede ◽  
Claudia Timmreck
Keyword(s):  
Explosive Volcanism ◽  
Stratospheric Aerosol ◽  
Radiative Heating ◽  
The Arctic ◽  
Current Evidence ◽  
Aerosol Model ◽  
Model Experiments ◽  
North East ◽  
Volcanic Cloud ◽  
The Impact

<p>The large explosive eruption of the Laacher See volcano c. 12,900 yrs BP marked the end of explosive volcanism in the East Eifel volcanic zone (Germany). We have reviewed the current evidence for the impact of the Laacher See Eruption (LSE) on the immediate and wider environment as recorded in a range of proxies with a series of interactive stratospheric aerosol model experiments. Recent studies about the climate impact of NH extratropical eruptions and new insights about the dating of the LSE warrant a return to this cataclysmic eruption and its potential influence on Northern Hemisphere climate. Rather detailed reconstructions of its eruption dynamics have been proposed. The eruption might have lasted several weeks or even months, most likely with an initial (~10h) intense early phase resulting in deposits over north-east Germany and the Baltic Sea, and a slightly later and weaker phase leaving deposits south of the volcano towards the Alps.</p><p>Our interactive stratospheric aerosol model experiments are based on a reference LSE experiment with emission estimates of 20 Tg of sulfur dioxide (SO<sub>2</sub>) and 200 Tg of fine-ash, across two eruptive phases in May and June. Additional sensitivity experiments reflect the estimated range of uncertainty of the injection rate and altitude and, assess how the solar-absorptive heating from the 150 Tg of sub-micron ash emitted in the first eruptive phase changed the LSE cloud’s dispersion. Our simulations reveal that the heating of the ash likely played an important role in the transport of ash and sulfate. Depending on the altitude of the injection, our simulated volcanic cloud begins to rotate shortly after the eruption. This meso-cyclone, as well as the additional radiative heating of the fine ash then changes the dispersion of the cloud to be more southerly compared to dispersal estimated without fine-ash heating. Sulfate transport is similarly impacted by the heating of the ash, resulting in a stronger transport to low-latitudes, later arrival of the volcanic cloud in the Arctic regions and a longer lifetime compared to cases without injection of fine ash.</p>

scholarly journals Simulation of ash clouds after a Laacher See-type eruption

2021 ◽  
Vol 17 (2) ◽  
pp. 633-652
Author(s):  
Ulrike Niemeier ◽  
Felix Riede ◽  
Claudia Timmreck
Keyword(s):  
Ice Cores ◽  
Stratospheric Aerosol ◽  
Radiative Heating ◽  
The Arctic ◽  
Transport Pathways ◽  
Aerosol Model ◽  
Volcanic Clouds ◽  
Volcanic Cloud ◽  
The Impact ◽  
Ash Cloud

Abstract. Dated to approximately 13 000 years ago, the Laacher See (East Eifel volcanic zone) eruption was one of the largest midlatitude Northern Hemisphere volcanic events of the Late Pleistocene. This eruptive event not only impacted local environments and human communities but probably also affected Northern Hemispheric climate. To better understand the impact of a Laacher See-type eruption on NH circulation and climate, we have simulated the evolution of its fine ash and sulfur cloud with an interactive stratospheric aerosol model. Our experiments are based around a central estimate for the Laacher See aerosol cloud of 15 Tg of sulfur dioxide (SO2) and 150 Tg of fine ash, across the main eruptive phases in May and a smaller one in June with 5 Tg SO2 and 50 Tg of fine ash. Additional sensitivity experiments reflect the estimated range of uncertainty of the injection rate and altitude and assess how the solar-absorptive heating from the fine ash emitted in the first eruptive phase changed the volcanic clouds' dispersion. The chosen eruption dates were determined by the stratospheric wind fields to reflect the empirically observed ash lobes as derived from geological, paleoecological and archeological evidence linked directly to the prehistoric Laacher See eruption. Whilst our simulations are based on present-day conditions, and we do not seek to replicate the climate conditions that prevailed 13 000 years ago, we consider our experimental design to be a reasonable approximation of the transport pathways in the midlatitude stratosphere at this time of year. Our simulations suggest that the heating of the ash plays an important role for the transport of ash and sulfate. Depending on the altitude of the injection, the simulated volcanic cloud begins to rotate 1 to 3 d after the eruption. This mesocyclone, as well as the additional radiative heating of the fine ash, then changes the dispersion of the cloud itself to be more southward compared to dispersal estimated without fine ash heating. This ash-cloud-generated southerly migration process may at least partially explain why, as yet, no Laacher See tephra has been found in Greenland ice cores. Sulfate transport is similarly impacted by the heating of the ash, resulting in stronger transport to low latitudes, later arrival of the volcanic cloud in the Arctic regions and a longer lifetime compared to cases without injection of fine ash. Our study offers new insights into the dispersion of volcanic clouds in midlatitudes and addresses a likely behavior of the ash cloud of the Laacher See eruption that darkened European skies at the end of the Pleistocene. In turn, this study can also serve as significant input for scenarios that consider the risks associated with re-awakened volcanism in the Eifel.

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.

scholarly journals The impact of model grid zooming on tracer transport in the 1999/2000 Arctic polar vortex

2003 ◽  
Vol 3 (5) ◽  
pp. 1833-1847 ◽  
Author(s):  
M. M. P. van den Broek ◽  
M. K. van Aalst ◽  
A. Bregman ◽  
M. Krol ◽  
J. Lelieveld ◽  
...  
Keyword(s):  
Transport Model ◽  
Potential Temperature ◽  
Polar Vortex ◽  
Vertical Gradient ◽  
The Arctic ◽  
Strong Mixing ◽  
Tropical Region ◽  
Tracer Transport ◽  
Model Experiments ◽  
The Impact

Abstract. We have used a 3D chemistry transport model to evaluate the transport of HF and CH4 in the stratosphere during the Arctic winter of 1999/2000. Several model experiments were carried out with the use of a zoom algorithm to investigate the effect of different horizontal resolutions. Balloon-borne and satellite-borne observations of HF and CH4 were used to test the model. In addition, air mass descent rates within the polar vortex were calculated and compared to observations. Outside the vortex the model results agree well with the observations, but inside the vortex the model underestimates the observed vertical gradient in HF and CH4, even when the highest available resolution (1º x 1º) is applied. The calculated diabatic descent rates agree with observations above potential temperature levels of 450 K. These model results suggest that too strong mixing through the vortex edge could be a plausible cause for the model discrepancies, associated with the calculated mass fluxes, although other reasons are also discussed. Based on our model experiments we conclude that a global 6º x 9º resolution is too coarse to represent the polar vortex, whereas the higher resolutions, 3º x 2º and 1º x 1º, yield similar results, even with a 6º x 9º resolution in the tropical region.

scholarly journals Improvement of stratospheric aerosol extinction retrieval from OMPS/LP using a new aerosol model

2018 ◽  
Vol 11 (12) ◽  
pp. 6495-6509 ◽  
Author(s):  
Zhong Chen ◽  
Pawan K. Bhartia ◽  
Robert Loughman ◽  
Peter Colarco ◽  
Matthew DeLand
Keyword(s):  
Size Distribution ◽  
Gamma Function ◽  
Spectral Dependence ◽  
Stratospheric Aerosol ◽  
Cumulative Distribution ◽  
Aerosol Size Distribution ◽  
Retrieval Algorithm ◽  
Aerosol Extinction ◽  
Aerosol Model ◽  
The Impact

Abstract. The Ozone Mapping and Profiler Suite Limb Profiler (OMPS/LP) has been flying on the Suomi National Polar-orbiting Partnership (S-NPP) satellite since October 2011. It is designed to produce ozone and aerosol vertical profiles at ∼2 km vertical resolution over the entire sunlit globe. Aerosol extinction profiles are computed with Mie theory using radiances measured at 675 nm. The operational Version 1.0 (V1.0) aerosol extinction retrieval algorithm assumes a bimodal lognormal aerosol size distribution (ASD) whose parameters were derived by combining an in situ measurement of aerosol microphysics with the Stratospheric Aerosol and Gas Experiment (SAGE II) aerosol extinction climatology. Internal analysis indicates that this bimodal lognormal ASD does not sufficiently explain the spectral dependence of LP-measured radiances. In this paper we describe the derivation of an improved aerosol size distribution, designated Version 1.5 (V1.5), for the LP retrieval algorithm. The new ASD uses a gamma function distribution that is derived from Community Aerosol and Radiation Model for Atmospheres (CARMA)-calculated results. A cumulative distribution fit derived from the gamma function ASD gives better agreement with CARMA results at small particle radii than bimodal or unimodal functions. The new ASD also explains the spectral dependence of LP-measured radiances better than the V1.0 ASD. We find that the impact of our choice of ASD on the retrieved extinctions varies strongly with the underlying reflectivity of the scene. Initial comparisons with collocated extinction profiles retrieved at 676 nm from the SAGE III instrument on the International Space Station (ISS) show a significant improvement in agreement for the LP V1.5 retrievals. Zonal mean extinction profiles agree to within 10  % between 19 and 29 km, and regression fits of collocated samples show improved correlation and reduced scatter compared to the V1.0 product. This improved agreement will motivate development of more sophisticated ASDs from CARMA results that incorporate latitude, altitude and seasonal variations in aerosol properties.

Impact of Clouds on Broadband Radiation Profiles in the Summer Arctic Measured by a Tethered Balloon During MOSAiC: First Results

2021 ◽  
Author(s):  
Michael Lonardi ◽  
Christian Pilz ◽  
Ulrike Egerer ◽  
André Ehrlich ◽  
Matthew D. Shupe ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Radiative Forcing ◽  
Arctic Sea Ice ◽  
Radiative Heating ◽  
The Arctic ◽  
Radiative Energy ◽  
Tethered Balloon ◽  
Local Cooling ◽  
Airborne Measurements ◽  
The Impact

<p>Arctic boundary layer clouds play an important role in the Arctic amplification due to their impact on the radiative energy budget, e. g., local cooling at cloud top which strongly affects boundary-layer dynamics. High resolution in-situ data characterizing the irradiance profile in clouds over the Arctic sea ice are rare due to the accessibility of this region, the challenges posed by icing and the limited resolution of airborne measurements.</p><p>The tethered balloon system BELUGA (Balloon-bornE moduLar Utility for profilinG the lower Atmosphere) was deployed from the ice camp of the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC) in July 2020. BELUGA consists of a 90 m³ helium-filled tethered balloon with maximum flight altitude of 1500 m and an adaptable scientific payload to characterize radiation, cloud, aerosol and turbulence properties which was specifically developed for Arctic tethered balloon operations.</p><p>Here a first analysis of vertical profiles of upwards and downwards solar and terrestrial irradiances in cloudy and cloud-free conditions is presented. Profiles of radiative heating were calculated and compared for different cloud covers. The case studies were evaluated by radiative transfer simulations  to quantify the impact of different cloud and atmospheric properties on the heating rate profiles. In combination with surface-based measurements, the cloud radiative forcing in the summer Arctic was assessed.</p>

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

2018 ◽  
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 sulphur 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 4 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 sulphur emissions and transport processes over the period 1998–2012 and their role in the warming hiatus. Two further experiments will investigate the stratospheric sulphate 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.

scholarly journals Improvement of stratospheric aerosol extinction retrieval from OMPS/LP using a new aerosol model

2018 ◽  
Author(s):  
Zhong Chen ◽  
Pawan K. Bhartia ◽  
Robert Loughman ◽  
Peter Colarco ◽  
Matthew DeLand
Keyword(s):  
Size Distribution ◽  
Gamma Function ◽  
Spectral Dependence ◽  
Stratospheric Aerosol ◽  
Cumulative Distribution ◽  
Aerosol Size Distribution ◽  
Retrieval Algorithm ◽  
Aerosol Extinction ◽  
Aerosol Model ◽  
The Impact

Abstract. The Ozone Mapping and Profiler Suite Limb Profiler (OMPS/LP) has been flying on the Suomi NPP satellite since October 2011. It is designed to produce ozone and aerosol vertical profiles at ~2 km vertical resolution over the entire sunlit globe. Aerosol extinction profiles are computed with Mie theory using radiances measured at 675 nm. The operational Version 1.0 (V1.0) aerosol extinction retrieval algorithm assumes a bimodal lognormal aerosol size distribution (ASD) whose parameters were derived by combining an in situ measurement of aerosol microphysics with the SAGE II aerosol extinction climatology. Internal analysis indicates that this bimodal lognormal ASD does not sufficiently explain the spectral dependence of LP measured radiances. In this paper we describe the derivation of an improved aerosol size distribution, designated Version 1.5 (V1.5), for the LP retrieval algorithm. The new ASD uses a gamma function distribution that is derived from Community Aerosol and Radiation Model for Atmospheres (CARMA) calculated results. A cumulative distribution fit derived from the gamma function ASD gives better agreement with CARMA results at small particle radii than bimodal or unimodal functions. The new ASD also explains the spectral dependence of LP measured radiances better than the V1.0 ASD. We find that the impact of our choice of ASD on the retrieved extinctions varies strongly with the underlying reflectivity of the scene. Initial comparisons with co-located extinction profiles retrieved at 676 nm from the SAGE III/ISS instrument show a significant improvement in agreement for the LP V1.5 retrievals. Zonal mean extinction profiles agree to within 10 % between 19–29 km, and regression fits of collocated samples show improved correlation and reduced scatter compared to the V1.0 product. This improved agreement will motivate development of more sophisticated ASDs from CARMA results that incorporate latitude, altitude, and seasonal variations in aerosol properties.

scholarly journals Simulation of ash clouds after a Laacher See-type eruption

2020 ◽  
Author(s):  
Ulrike Niemeier ◽  
Felix Riede ◽  
Claudia Timmreck
Keyword(s):  
Late Pleistocene ◽  
Ice Cores ◽  
Meteorological Conditions ◽  
Radiative Heating ◽  
The Arctic ◽  
Wind Fields ◽  
Volcanic Cloud ◽  
Set Up ◽  
Laacher See Tephra ◽  
Ash Cloud

Abstract. Dated to ca. 13,000 years ago, the Laacher See (East Eifel Volcanic Zone) eruption was one of the largest mid-latitude Northern Hemisphere volcanic events of the Late Pleistocene. This eruptive event not only impacted local environments and human communities but also NH climate. We have simulated the evolution of the fine ash and sulfur cloud of an LSE-type eruption under present-day meteorological conditions that mirror the empirically known ash transport distribution as derived from geological, palaeo-ecological and archaeological evidence linked directly to the Late Pleistocene eruption of the Laacher See volcano. This evidence has informed our experimental set-up and we simulated corresponding eruptions of different injection altitudes (30, 60 and, 100 hPa) with varying emission strengths of sulfur and fine ash (1.5, 15, 100 Tg SO2) and at different days in spring. The chosen eruption dates were determined by the stratospheric wind fields to reflect the empirically observed ash lobes. While it proved difficult to replicate the meteorological conditions that likely prevailed 13,000 years ago, our novel simulations suggest that the heating of the ash plays a crucial role for the transport of ash and sulfate. Depending on the altitude of the injection, the volcanic cloud begins to rotate one to three days after the eruption. The rotation, as well as the additional radiative heating of the fine ash, adds a southerly component to the transport vectors. This ash cloud-generated southerly migration process may at least partially explain why, as yet, no Laacher See tephra has been found in Greenlandic ice-cores. Sulfate transport, too, is impacted by the heating of the ash, resulting in a stronger transport to low-latitudes, later arrival of the volcanic cloud in the Arctic regions and, a longer lifetime. Our models throw new light on the likely behaviour of the ash cloud that darkened European skies at the end of the Pleistocene, and serve as significant input for scenarios that consider the risks associated with re-awakened volcanism in the Eifel.

scholarly journals The impact of model grid zooming on tracer transport in the 1999/2000 Arctic polar vortex

2003 ◽  
Vol 3 (3) ◽  
pp. 2261-2284
Author(s):  
M. M. P. van den Broek ◽  
M. K. van Aalst ◽  
A. Bregman ◽  
M. Krol ◽  
J. Lelieveld ◽  
...  
Keyword(s):  
Transport Model ◽  
Potential Temperature ◽  
Polar Vortex ◽  
Vertical Gradient ◽  
The Arctic ◽  
Strong Mixing ◽  
Tropical Region ◽  
Tracer Transport ◽  
Model Experiments ◽  
The Impact

Abstract. We have used a 3D chemistry transport model to evaluate the transport of HF and CH4 in the stratosphere during the Arctic winter of 1999/2000. Several model experiments were carried out with the use of a zoom algorithm to investigate the effect of different horizontal resolutions. Balloon-borne and satellite-borne observations of HF and CH4 were used to test the model. In addition, air mass descent rates within the polar vortex were calculated and compared to observations. Outside the vortex the model results agree well with the observations, but inside the vortex the model underestimates the observed vertical gradient in HF and CH4, even when the highest available resolution (1°×1°) is applied. The calculated diabatic descent rates agree with observations above potential temperature levels of 450 K. These model results suggest that too strong mixing through the vortex edge could be a plausible cause for the model discrepancies, associated with the calculated mass fluxes, although other reasons are also discussed. Based on our model experiments we conclude that a global 6°×9° resolution is too coarse to represent the polar vortex, whereas the higher resolutions, 3°×2° and 1°×1°, yield similar results, even with a 6°×9° resolution in the tropical region.

Consideration of Geopolitical Challenges within the Analysis of Geoenvironmental Risks for Oil and Gas Development of the Russian Arctic

2019 ◽  
Vol 16 (6) ◽  
pp. 50-59
Author(s):  
O. P. Trubitsina ◽  
V. N. Bashkin
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Optimal Operation ◽  
The Arctic ◽  
Stage Model ◽  
Oil And Gas Development ◽  
Gas Industry ◽  
The Impact ◽  
Further Development ◽  
Geopolitical Risks

The article is devoted to the consideration of geopolitical challenges for the analysis of geoenvironmental risks (GERs) in the hydrocarbon development of the Arctic territory. Geopolitical risks (GPRs), like GERs, can be transformed into opposite external environment factors of oil and gas industry facilities in the form of additional opportunities or threats, which the authors identify in detail for each type of risk. This is necessary for further development of methodological base of expert methods for GER management in the context of the implementational proposed two-stage model of the GER analysis taking to account GPR for the improvement of effectiveness making decisions to ensure optimal operation of the facility oil and gas industry and minimize the impact on the environment in the geopolitical conditions of the Arctic.The authors declare no conflict of interest

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