scholarly journals North Atlantic Oscillation response in GeoMIP experiments G6solar and G6sulfur: why detailed modelling is needed for understanding regional implications of solar radiation management

2020 ◽  
Author(s):  
Andy Jones ◽  
Jim M. Haywood ◽  
Anthony C. Jones ◽  
Simone Tilmes ◽  
Ben Kravitz ◽  
...  
Keyword(s):  
Solar Radiation ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Winter Season ◽  
Solar Radiation Management ◽  
Positive Anomaly ◽  
Continental Scale ◽  
Detailed Modelling ◽  
Radiation Management ◽  
The Impact

Abstract. The realisation of the difficulty of limiting global mean temperatures to within 1.5 °C or 2.0 °C above pre-industrial levels stipulated by the 21st Conference of Parties in Paris has led to increased interest in solar radiation management (SRM) techniques. Proposed SRM schemes aim to increase planetary albedo to reflect more sunlight back to space and induce a cooling that acts to partially offset global warming. Under the auspices of the Geoengineering Model Intercomparion Project, we have performed model experiments whereby global temperature under the high forcing SSP5–8.5 scenario is reduced to follow that of the medium forcing SSP2–4.5 scenario. Two different mechanisms to achieve this are employed, the first via a reduction in the solar constant (experiment G6solar) and the second via modelling injections of sulfur dioxide (experiment G6sulfur) which forms sulfate aerosol in the stratosphere. Results from two state-of-the-art coupled Earth system models both show an impact on the North Atlantic Oscillation (NAO) in G6sulfur but not in G6solar. Both models show a persistent positive anomaly in the NAO during the Northern Hemisphere winter season in G6sulfur, suggesting an increase in zonal flow and an increase in North Atlantic storm track activity impacting the Eurasian continent leading to regional warming. These findings are broadly consistent with previous findings on the impact of stratospheric volcanic aerosol on the NAO and emphasise that detailed modelling of geoengineering processes is required if accurate impacts of SRM impacts are to be simulated. Differences remain between the two models in predicting regional changes over the continental USA and Africa, suggesting that more models need to perform such simulations before attempting to draw any conclusions regarding potential continental-scale climate change under SRM.

scholarly journals North Atlantic Oscillation response in GeoMIP experiments G6solar and G6sulfur: why detailed modelling is needed for understanding regional implications of solar radiation management

2021 ◽  
Vol 21 (2) ◽  
pp. 1287-1304
Author(s):  
Andy Jones ◽  
Jim M. Haywood ◽  
Anthony C. Jones ◽  
Simone Tilmes ◽  
Ben Kravitz ◽  
...  
Keyword(s):  
Solar Radiation ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Winter Season ◽  
Storm Track ◽  
Solar Radiation Management ◽  
Positive Anomaly ◽  
Continental Scale ◽  
Detailed Modelling ◽  
Radiation Management

Abstract. The realization of the difficulty of limiting global-mean temperatures to within 1.5 or 2.0 ∘C above pre-industrial levels stipulated by the 21st Conference of Parties in Paris has led to increased interest in solar radiation management (SRM) techniques. Proposed SRM schemes aim to increase planetary albedo to reflect more sunlight back to space and induce a cooling that acts to partially offset global warming. Under the auspices of the Geoengineering Model Intercomparison Project, we have performed model experiments whereby global temperature under the high-forcing SSP5-8.5 scenario is reduced to follow that of the medium-forcing SSP2-4.5 scenario. Two different mechanisms to achieve this are employed: the first via a reduction in the solar constant (experiment G6solar) and the second via modelling injections of sulfur dioxide (experiment G6sulfur) which forms sulfate aerosol in the stratosphere. Results from two state-of-the-art coupled Earth system models (UKESM1 and CESM2-WACCM6) both show an impact on the North Atlantic Oscillation (NAO) in G6sulfur but not in G6solar. Both models show a persistent positive anomaly in the NAO during the Northern Hemisphere winter season in G6sulfur, suggesting an increase in zonal flow and an increase in North Atlantic storm track activity impacting the Eurasian continent and leading to high-latitude warming over Europe and Asia. These results are broadly consistent with previous findings which show similar impacts from stratospheric volcanic aerosol on the NAO and emphasize that detailed modelling of geoengineering processes is required if accurate impacts of SRM effects are to be simulated. Differences remain between the two models in predicting regional changes over the continental USA and Africa, suggesting that more models need to perform such simulations before attempting to draw any conclusions regarding potential continental-scale climate change under SRM.

scholarly journals Heterogeneous reaction of N<sub>2</sub>O<sub>5</sub> with airborne TiO<sub>2</sub> particles and its implication for stratospheric particle injection

2014 ◽  
Vol 14 (4) ◽  
pp. 4421-4456 ◽  
Author(s):  
M. J. Tang ◽  
P. J. Telford ◽  
F. D. Pope ◽  
L. Rkiouak ◽  
N. L. Abraham ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Climate Model ◽  
Heterogeneous Reaction ◽  
High Refractive Index ◽  
Heterogeneous Reactions ◽  
Solar Radiation Management ◽  
Particle Injection ◽  
Stratospheric Chemistry ◽  
Radiation Management ◽  
The Impact

Abstract. Injection of aerosol particles (or their precursors) into the stratosphere to scatter solar radiation back into space, has been suggested as a solar-radiation management scheme for the mitigation of global warming. TiO2 has recently been highlighted as a possible candidate particle because of its high refractive index, but its impact on stratospheric chemistry via heterogeneous reactions is as yet unknown. In this work the heterogeneous reaction of airborne sub-micrometre TiO2 particles with N2O5 has been investigated for the first time, at room temperature and different relative humidities (RH), using an atmospheric pressure aerosol flow tube. The uptake coefficient of N2O5 onto TiO2, γ(N2O5), was determined to be ∼ 1.0 × 10−3 at low RH, increasing to ∼ 3 × 10−3 at 60% RH. The uptake of N2O5 onto TiO2 is then included in the UKCA chemistry climate model to assess the impact of this reaction on stratospheric chemistry. While the impact of TiO2 on the scattering of solar radiation is chosen to be similar to the aerosol from the Mt. Pinatubo eruption, the impact of TiO2 injection on stratospheric N2O5 is much smaller.

Spatial differences in the impact of the North Atlantic Oscillation on the flow of rivers in Europe

2011 ◽  
Vol 42 (1) ◽  
pp. 30-39 ◽  
Author(s):  
Dariusz Wrzesiński ◽  
Rafał Paluszkiewicz
Keyword(s):  
North Atlantic Oscillation ◽  
North Atlantic ◽  
Winter Season ◽  
Winter Period ◽  
The North ◽  
The North Atlantic ◽  
Positive Correlations ◽  
The North Atlantic Oscillation ◽  
River Profiles ◽  
The Impact

The article presents regional differences in the impact that the North Atlantic Oscillation (NAO) exerts on the flow of European rivers. The impact is determined by temporal variations in the strength of relations expressed by coefficients of correlation between monthly or seasonal NAO indices and discharges recorded at 510 river profiles. The results of the correlation analysis were arranged using Ward’s method of hierarchical grouping. The classification of river profiles thus obtained made it possible to distinguish seven regions differing in the nature of the dependence between streamflow and the intensity of the NAO. The most statistically significant positive correlations are displayed by the rivers of Fennoscandia, Denmark and the northwest part of the British Isles in the winter period, while the most significant negative correlations (also in winter) are recorded for streams of the Mediterranean Basin, western France and the southeast of England. In the southeast part of the Baltic Sea drainage basin, significant positive correlations of streamflow with the NAO indices can be observed in the winter season and negative correlations are observed in spring.

scholarly journals Heterogeneous reaction of N<sub>2</sub>O<sub>5</sub> with airborne TiO<sub>2</sub> particles and its implication for stratospheric particle injection

2014 ◽  
Vol 14 (12) ◽  
pp. 6035-6048 ◽  
Author(s):  
M. J. Tang ◽  
P. J. Telford ◽  
F. D. Pope ◽  
L. Rkiouak ◽  
N. L. Abraham ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Climate Model ◽  
Heterogeneous Reaction ◽  
High Refractive Index ◽  
Heterogeneous Reactions ◽  
Solar Radiation Management ◽  
Particle Injection ◽  
Stratospheric Chemistry ◽  
Radiation Management ◽  
The Impact

Abstract. Injection of aerosol particles (or their precursors) into the stratosphere to scatter solar radiation back into space has been suggested as a solar-radiation management scheme for the mitigation of global warming. TiO2 has recently been highlighted as a possible candidate particle because of its high refractive index, but its impact on stratospheric chemistry via heterogeneous reactions is as yet unknown. In this work the heterogeneous reaction of airborne sub-micrometre TiO2 particles with N2O5 has been investigated for the first time, at room temperature and different relative humidities (RH), using an atmospheric pressure aerosol flow tube. The uptake coefficient of N2O5 onto TiO2, γ(N2O5), was determined to be ~1.0 × 10−3 at low RH, increasing to ~3 × 10−3 at 60% RH. The uptake of N2O5 onto TiO2 is then included in the UKCA chemistry–climate model to assess the impact of this reaction on stratospheric chemistry. While the impact of TiO2 on the scattering of solar radiation is chosen to be similar to the aerosol from the Mt Pinatubo eruption, the impact of TiO2 injection on stratospheric N2O5 is much smaller.

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