A two‐dimensional model of sulfur species and aerosols

Weisenstein, Debra K.; Yue, Glenn K.; Ko, Malcolm K. W.; Sze, Nien Dak; Rodríguez, José M.; Scott, Courtney J.

doi:10.1029/97jd00901

Cited by 175 publications

(173 citation statements)

References 71 publications

Supporting

Mentioning

163

Contrasting

Order By: Relevance

“…We use the AER 2-D chemical transport−aerosol model (26)(27)(28), as modified to include both liquid sulfate particles and solid particles along with their interactions (2). The model uses a sectional representation of aerosol size distributions, with 40 logarithmically spaced bins for sulfate particles and eight bins for solid particles.…”

Section: Methodsmentioning

confidence: 99%

Stratospheric solar geoengineering without ozone loss

Keith

Weisenstein

Dykema

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

123

127

View full text Add to dashboard Cite

Injecting sulfate aerosol into the stratosphere, the most frequently analyzed proposal for solar geoengineering, may reduce some climate risks, but it would also entail new risks, including ozone loss and heating of the lower tropical stratosphere, which, in turn, would increase water vapor concentration causing additional ozone loss and surface warming. We propose a method for stratospheric aerosol climate modification that uses a solid aerosol composed of alkaline metal salts that will convert hydrogen halides and nitric and sulfuric acids into stable salts to enable stratospheric geoengineering while reducing or reversing ozone depletion. Rather than minimizing reactive effects by reducing surface area using high refractive index materials, this method tailors the chemical reactivity. Specifically, we calculate that injection of calcite (CaCO3) aerosol particles might reduce net radiative forcing while simultaneously increasing column ozone toward its preanthropogenic baseline. A radiative forcing of −1 W⋅m−2, for example, might be achieved with a simultaneous 3.8% increase in column ozone using 2.1 Tg⋅y−1 of 275-nm radius calcite aerosol. Moreover, the radiative heating of the lower stratosphere would be roughly 10-fold less than if that same radiative forcing had been produced using sulfate aerosol. Although solar geoengineering cannot substitute for emissions cuts, it may supplement them by reducing some of the risks of climate change. Further research on this and similar methods could lead to reductions in risks and improved efficacy of solar geoengineering methods.

show abstract

Section: Methodsmentioning

confidence: 99%

Stratospheric solar geoengineering without ozone loss

Keith

Weisenstein

Dykema

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

123

127

View full text Add to dashboard Cite

show abstract

“…Here, we have extended the scheme to also include a stratospheric aerosol precursor chemistry scheme (Weisenstein et al, 1997) with updates to reaction rates from Sander et al (2006), see Table 1. The added chemistry includes the steady background source of SO 2 from OCS, which principally maintains the stratospheric aerosol during volcanically quiescent periods (e.g.…”

Section: Stratospheric Chemistry Extended To Include the Sulfur Cyclementioning

confidence: 99%

“…However, sizeresolved stratospheric aerosol modules which include microphysical processes such as new particle formation, coagulation and condensation have also been developed. The first Pinatubo aerosol microphysics simulations were carried out in 2-D models (Bekki and Pyle, 1994;Weisenstein et al, 1997) with single-moment sectional schemes where mass in numerous size bins is transported. More recently, several 3-D general circulation models (GCMs) with aerosol microphysics schemes have also been developed, to predict sedimentation and changes in radiative properties in conjunction with an evolving stratospheric particle size distribution (e.g.…”

mentioning

confidence: 99%

Aerosol microphysics simulations of the Mt.~Pinatubo eruption with the UM-UKCA composition-climate model

et al. 2014

View full text Add to dashboard Cite

Abstract. We use a stratosphere-troposphere compositionclimate model with interactive sulfur chemistry and aerosol microphysics, to investigate the effect of the 1991 Mount Pinatubo eruption on stratospheric aerosol properties. Satellite measurements indicate that shortly after the eruption, between 14 and 23 Tg of SO 2 (7 to 11.5 Tg of sulfur) was present in the tropical stratosphere. Best estimates of the peak global stratospheric aerosol burden are in the range 19 to 26 Tg, or 3.7 to 6.7 Tg of sulfur assuming a composition of between 59 and 77 % H 2 SO 4 . In light of this large uncertainty range, we performed two main simulations with 10 and 20 Tg of SO 2 injected into the tropical lower stratosphere. Simulated stratospheric aerosol properties through the 1991 to 1995 period are compared against a range of available satellite and in situ measurements. Stratospheric aerosol optical depth (sAOD) and effective radius from both simulations show good qualitative agreement with the observations, with the timing of peak sAOD and decay timescale matching well with the observations in the tropics and mid-latitudes. However, injecting 20 Tg gives a factor of 2 too high stratospheric aerosol mass burden compared to the satellite data, with consequent strong high biases in simulated sAOD and surface area density, with the 10 Tg injection in much better agreement. Our model cannot explain the large fraction of the injected sulfur that the satellite-derived SO 2 and aerosol burdens indicate was removed within the first few months after the eruption. We suggest that either there is an additional alternative loss pathway for the SO 2 not included in our model (e.g. via accommodation into ash or ice in the volcanic cloud) or that a larger proportion of the injected sulfur was removed via cross-tropopause transport than in our simulations.We also critically evaluate the simulated evolution of the particle size distribution, comparing in detail to balloonborne optical particle counter (OPC) measurements from Laramie, Wyoming, USA (41 • N). Overall, the model captures remarkably well the complex variations in particle concentration profiles across the different OPC size channels. However, for the 19 to 27 km injection height-range used here, both runs have a modest high bias in the lowermost stratosphere for the finest particles (radii less than 250 nm), and the decay timescale is longer in the model for these particles, with a much later return to background conditions. Also, Published by Copernicus Publications on behalf of the European Geosciences Union. S. S. Dhomse et al.: Simulation of Pinatubo aerosol in a CCMwhereas the 10 Tg run compared best to the satellite measurements, a significant low bias is apparent in the coarser size channels in the volcanically perturbed lower stratosphere. Overall, our results suggest that, with appropriate calibration, aerosol microphysics models are capable of capturing the observed variation in particle size distribution in the stratosphere across both volcanically perturbed and quiescen...

show abstract

“…be simplified. The aerosol distribution in aerosol modules is described in most cases using the bulk approach (Liao and Seinfeld, 2005;Liu et al, 2005;Reddy et al, 2005;, modal approach (Ghan et al, 2001;Wilson et al, 2001;Herzog et al, 2004;Vignati et al, 2004;Lauer et al, 2005;Stier et al, 2005), and sectional approach (Weisenstein et al, 1997;Jacobson, 2001;Timmreck, 2001;Rodriguez and Dabdub, 2004;Spracklen et al, 2005;Hommel, 2008;Kokkola et al, 2008). In the bulk approach, only the aerosol mass is prognostic.…”

Section: Introductionmentioning

confidence: 99%

Aerosol microphysics modules in the framework of the ECHAM5 climate model – intercomparison under stratospheric conditions

et al. 2009

View full text Add to dashboard Cite

Abstract. In this manuscript, we present an intercomparison of three different aerosol microphysics modules that are implemented in the climate model ECHAM5. The comparison was done between the modal aerosol microphysics module M7, which is currently the default aerosol microphysical core in ECHAM5, and two sectional aerosol microphysics modules SALSA, and SAM2. The detailed aerosol microphysical model MAIA was used as a reference to evaluate the results of the aerosol microphysics modules with respect to sulphate aerosol.The ability of the modules to describe the development of the aerosol size distribution was tested in a zero dimensional framework. We evaluated the strengths and weaknesses of different approaches under different types of stratospheric conditions. Also, we present an improved method for the time integration in M7 and study how the setup of the modal aerosol modules affects the evolution of the aerosol size distribution.Intercomparison simulations were carried out with varying SO 2 concentrations from background conditions to extreme values arising from stratospheric injections by large volcanic eruptions. Under background conditions, all microphysics modules were in good agreement describing the shape of the aerosol size distribution, but the scatter between the model results increased with increasing SO 2 concentrations. In particular in the volcanic case the setups of the aerosol modules have to be adapted in order to dependably capture the evoluCorrespondence to: H. Kokkola (harri.kokkola@fmi.fi) tion of the aerosol size distribution, and to perform in global model simulations.In summary, this intercomparison serves as a review of the different aerosol microphysics modules which are currently available for the climate model ECHAM5.

show abstract

A two‐dimensional model of sulfur species and aerosols

Cited by 175 publications

References 71 publications

Stratospheric solar geoengineering without ozone loss

Stratospheric solar geoengineering without ozone loss

Aerosol microphysics simulations of the Mt.~Pinatubo eruption with the UM-UKCA composition-climate model

Aerosol microphysics modules in the framework of the ECHAM5 climate model – intercomparison under stratospheric conditions

Contact Info

Product

Resources

About