Schlagwort: stratosphere

Peer-reviewed Publications

Yue, Chao; et al. (2021): Insensitivity of mass loss of Icelandic Vatnajökull ice cap to solar geoengineering

Yue, Chao; Schmidt, Louise Steffensen; Zhao, Liyun; Wolovick, Michael; Moore, John C. (2021): Insensitivity of mass loss of Icelandic Vatnajökull ice cap to solar geoengineering. [in review]. In The Cryosphere Discuss. [preprint]. DOI: 10.5194/tc-2021-318.

„Geoengineering by stratospheric aerosol injection (SAI) may reduce the mass loss from Vatnajökull ice cap (VIC), Iceland, by slowing surface temperature rise, despite relative increases in ocean heat flux brought by the Atlantic Meridional Circulation (AMOC). Although surface mass balance (SMB) is affected by the local climate, the sea level contribution is also dependent on ice dynamics. We use the Parallel Ice Sheet Model (PISM) to estimate the VIC mass balance under the CMIP5 (Coupled Model Intercomparison Project Phase 5) RCP4.5, 8.5 and GeoMIP (Geoengineering Model Intercomparison Project) G4 SAI scenarios during the period 1982–2089. The G4 scenario is based on the RCP4.5, but with additional 5 Tg yr−1 of SO2 injection to the lower stratosphere. By 2089, G4 reduces VIC mass loss from 16 % lost under RCP4.5, to 12 %. Ice dynamics are important for ice cap loss rates, increasing mass loss for RCP4.5 and G4 by 1/4 to 1/3 compared with excluding ice dynamics, but making no difference to mass loss difference under the scenarios. We find that VIC dynamics are remarkably insensitive to climate forcing partly because of AMOC compensation to SMB and low rates of iceberg calving making ocean forcing close to negligible. But the exceptionally high geothermal heat flow under parts of the ice cap which produces correspondingly high basal melt rates means that surface forcing changes are relatively less important than for glaciers with lower geothermal heat flow.“

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Peer-reviewed Publications

Tilmes, S.; et al. (2021): Sensitivity of total column ozone to stratospheric sulfur injection strategies

Tilmes, S.; Richter, J. H.; Kravitz, B.; MacMartin, D. G.; Glanville, A. S.; Visioni, D. et al. (2021): Sensitivity of total column ozone to stratospheric sulfur injection strategies. In Geophysical Research Letters. DOI: 10.1029/2021GL094058.

„We explore the impact of different stratospheric sulfur injection strategies to counter greenhouse gas induced warming on total column ozone (TCO), including high and low altitude injections at four latitudes, equatorial injections, and using a configuration with higher vertical resolution, based on a state-of-the-art Earth system model. The experiments maintain global surface temperatures at 2020 conditions, while following the unmitigated future scenario. Within the first ten years of the injection, we find an abrupt deepening of the Antarctic ozone hole by 8–20% and changes up to urn:x-wiley:00948276:media:grl63028:grl63028-math-00015% for other regions and seasons. The ozone hole recovery is delayed by urn:x-wiley:00948276:media:grl63028:grl63028-math-000225 to over 55 years, with the fastest recovery for low-altitude injections and slowest for equatorial injections. Mid to high-latitude TCO increases by urn:x-wiley:00948276:media:grl63028:grl63028-math-000315% in Northern Hemisphere winter and spring between 2010–2019 and 2080–2089 due to both increasing greenhouse gases and increasing sulfur injections. Implications for ecosystems need to be investigated.“

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Video

Video: CNBC: Why Bill Gates Is Funding Solar Geoengineering Research

„Fires burning across the Amazon rainforest have renewed the debate about solutions to climate change. Bill Gates is backing the first high-altitude experiment of one radical approach called solar geoengineering. It’s meant to mimic the effects of a giant volcanic eruption. Thousands of planes would fly at high altitudes, spraying millions of tons of particles around the planet to create a massive chemical cloud that would cool the surface. […] The technology is not far from being ready and it’s affordable, but it could cause massive changes in regional weather patterns and eradicate blue sky. […]Watch the video to learn how it would work and hear the debate around the ethics and efficacy of solar geoengineering.“

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Peer-reviewed Publications

Zhang, Yan; et al. (2021): Data from: How large is the design space for stratospheric aerosol geoengineering?

Zhang, Yan; MacMartin, Douglas G.; Visioni, Daniele; Kravitz, Ben (2021): Data from: How large is the design space for stratospheric aerosol geoengineering?

„Data in support of research: Stratospheric aerosol injection (SAI), as a possible supplement to emission reduction, has the potential to reduce some of the risks associated with climate change. Adding aerosols to the lower stratosphere results in global cooling. However, different choices for the aerosol injection latitude(s) and season(s) have been shown to lead to significant differences in regional surface climate, introducing a design aspect to SAI. Past research has shown that there are at least three independent degrees of freedom (DOF) that can be used to simultaneously manage three different climate goals. Knowing how many more DOFs there are, and thus how many independent climate goals can be simultaneously managed, is essential to understanding fundamental limits of how well SAI might compensate for anthropogenic climate change, and evaluating any underlying trade-offs between different climate goals. Here we quantify the number of meaningfully-independent DOFs of the SAI design space.“

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Peer-reviewed Publications

Visioni, Daniele; et al. (2021): Reduced poleward transport due to stratospheric heating under geoengineering

Visioni, Daniele; Simpson, Isla Ruth; MacMartin, Douglas G.; Richter, Jadwiga H.; Kravitz, Ben; Lee, Walker (2021): Reduced poleward transport due to stratospheric heating under geoengineering. DOI: 10.1002/essoar.10503509.1.

„Simulating the complex aerosol microphysical processes in a comprehensive Earth System Model can be very computationally intensive and therefore many models utilize a modal approach, where aerosol size distributions are represented by observations-derived lognormal functions. This approach has been shown to yield satisfactory results in a large array of applications, but there may be cases where the simplification in this approach may produce some shortcomings. In this work we show specific conditions under which the current approximations used in modal approaches might yield some incorrect answers. Using results from the Community Earth System Model v1 (CESM1) Geoengineering Large Ensemble (GLENS) project, we analyze the effects in the troposphere of a continuous increasing load of sulfate aerosols in the stratosphere, with the aim of counteracting the surface warming produced by non-mitigated increasing greenhouse gases concentration between 2020–2100.“

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Peer-reviewed Publications

Yue, Chao; et al. (2021): Vatnajökull mass loss under solar geoengineering due to the North Atlantic meridional overturning circulation

Yue, Chao; Schmidt, Louise Steffensen; Zhao, Liyun; Wolovick, Michael; Moore, John C. (2021): Vatnajökull mass loss under solar geoengineering due to the North Atlantic meridional overturning circulation. In Earth’s Future. DOI: 10.1029/2021EF002052.

„The objective of solar geoengineering by stratospheric aerosol injection (SAI) is to lower global temperatures, but it may also have adverse side-effects. Iceland is situated close to the overturning regions of the Atlantic Meridional Overturning Circulation (AMOC) that warms the North Atlantic area. Hence this may be one region where reduced irradiance by SAI may not be successful in reducing impacts from greenhouse gas warming. We examine this proposition by estimating how the Icelandic Vatnajökull ice cap (VIC) surface mass balance (SMB) and surface runoff changes in response to greenhouse gas and solar geoengineering scenarios over the period 1982-2089.“

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Peer-reviewed Publications

Huynh, Han N.; McNeill, V. Faye (2021): Heterogeneous Reactivity of HCl on CaCO 3 Aerosols at Stratospheric Temperature

Huynh, Han N.; McNeill, V. Faye (2021): Heterogeneous Reactivity of HCl on CaCO 3 Aerosols at Stratospheric Temperature. In ACS Earth Space Chem. DOI: 10.1021/acsearthspacechem.1c00151.

„We studied the kinetics of HCl uptake on airborne CaCO3 aerosols at stratospheric temperature, 207 ± 3 K, by performing experiments under dry conditions using an aerosol flow tube coupled with a custom-built quadrupole chemical ionization mass spectrometer (CIMS) for HCl detection.“

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Peer-reviewed Publications

Weisenstein, Debra K.; et al. (2021): A Model Intercomparison of Stratospheric Solar Geoengineering by Accumulation-Mode Sulfate Aerosols

Weisenstein, Debra K.; Visioni, Daniele; Franke, Henning; Niemeier, Ulrike; Vattioni, Sandro; Chiodo, Gabriel et al. (2021): A Model Intercomparison of Stratospheric Solar Geoengineering by Accumulation-Mode Sulfate Aerosols. Preprint. In Atmospheric Chemistry and Physics. DOI: 10.5194/acp-2021-569.

„The intercomparison explores how the injection of new accumulation-mode particles changes the large-scale particle size distribution and thus the overall radiative and dynamical response to sulfate aerosol injection.“

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