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RESEARCH PAPERSEckert, C., Hernandez-Jaramillo, D. C., Medcraft, C., Harrison, D. P., & Kelaher, B. P. (2024). Drone-Based Measurement of the Size Distribution and Concentration of Marine Aerosols above the Great Barrier Reef. Drones, 8(7), 292. Abstract Marine aerosol particles can act as cloud condensation nuclei and influence the atmospheric boundary layer by scattering solar radiation. The interaction of ocean waves and coral reefs may affect the distribution and size of marine aerosol particles. Measuring this effect has proven challenging. Here, we tested the hypothesis that the distribution and size of marine aerosol particles would vary over three distinct zones (i.e., coral lagoon, surf break, and open water) near One Tree Island in the Great Barrier Reef, which is approximately 85 km off the east coast of Australia. We used a modified DJI Agras T30 drone fitted with a miniaturised scanning electrical mobility sizer and advanced mixing condensation particle counter to collect data on aerosol size distribution between 30 and 300 nm at 20 m above the water surface. We conducted 30 flights over ten days during the Austral summer/autumn of 2023. The fitted bimodal lognormal curves indicate that the number concentrations for aerosols below 85 nm diameter are more than 16% higher over the lagoon than over open water. The average mean mode diameters remained constant across the different zones, indicating no significant influence of breaking waves on the detected aerosol size modes. The most influential explanatory variable for aerosol size distribution was the difference between air temperature and the underlying sea surface, explaining around 40% of the variability. Salinity also exhibited a significant influence, explaining around 12% of the measured variability in the number concentration of aerosols throughout the campaign. A calculated wind stress magnitude did not reveal significant variation in the measured marine aerosol concentrations. Overall, our drone-based aerosol measurements near the water surface effectively characterise the dynamics of background marine aerosols around One Tree Island Reef, illustrating the value of drone-based systems for providing size-dependent aerosol information in difficult-to-access and environmentally sensitive areas.
Ryan, R. G., Toms-Hardman, L., Smirnov, A., Harrison, D., & Schofield, R. (2024). Measurement report: Aerosol vertical profiling over the Southern Great Barrier Reef using lidar and MAX-DOAS measurements. EGUsphere, 2024, 1-20. Abstract Aerosol vertical profile measurements were made using multi-axis differential optical absorption spectroscopy (MAX-DOAS) and mini-Micropulse LiDAR (MPL) at One Tree Island in the Southern Great Barrier Reef from February to April 2023. This is an understudied location in terms of atmospheric aerosols and chemistry but is growing in importance as multiple research streams examine the influence of aerosols on radiation over the Great Barrier Reef. Solar radiation management proposals require regional-scale aerosol modelling, which is evaluated against aerosol extinction and optical depth measurements, necessitating a thorough understanding of measurements of these quantities. MPL aerosol retrieval showed extinction-to-backscatter ratios (0.031 on average) and depolarization ratios (0.015 on average) consistent with clean, unpolluted Southern hemispheric marine aerosol. The maximum depolarization ratio tended to be above the layer of maximum MPL backscatter, which is attributed to dried sea-salt layers above the boundary layer. MAX-DOAS and MPL extinction profiles show aerosol layers extending beyond 2 km altitude in the middle of the day, but predominantly below 1 km at other times. We also compared aerosol optical depth measurements from integrating the MAX-DOAS and MPL extinction profiles, with observations from a hand-held Microtops sun photometer. Mean aerosol optical depth (AOD) values across the campaign compare well, being 0.083 ± 0.002 for the Microtops, 0.090 ± 0.032 for the MAX-DOAS and 0.104 ± 0.028 for the MPL. However, AOD observations at a given time, and the AOD diurnal cycle, often varied between instruments. This likely indicates strong horizontal inhomogeneity in aerosol in this environment, a factor which makes it challenging to accurately compare AOD estimates from different viewing geometries, but which is important for future aerosol modelling studies in this region to consider.
Määttänen, A., Lameille, T., Kloeck, C., Boucher, O., & Ravetta, F. (2024). Uncertainties and confidence in stratospheric aerosol injection modelling: a systematic literature review. Oxford Open Climate Change, kgae007. Abstract Model projections performed to evaluate the efficacy and impacts of solar geoengineering interventions, such as Stratospheric Aerosol Injection (SAI), include multiple sources of uncertainty, namely scenario, model, and natural variability uncertainty. It is well accepted that a quantitative uncertainty assessment related to SAI modelling is required to provide robust and policy-relevant information on SAI. This study investigates how and to what extent articles using a climate modelling approach on SAI quantify and communicate uncertainty sources. We conducted a systematic literature review of a sample of 60 peer-reviewed articles in order to (a) analyse whether uncertainties were addressed, and if yes, which methods were used to characterize uncertainties, and (b) study how the articles communicated assumptions and limits that contribute to the estimation of confidence in the used models and the resulting projections. We present statistics on the uncertainty quantification methods used in the articles and we discuss the vocabulary employed for conveying these uncertainties and model confidence. In the studied article sample, the attention paid to uncertainty estimations in the SAI literature increased with time, and overall, uncertainties were treated using a variety of methods. Model confidence was not always explicitly communicated as the models used are already tested in the literature and their strengths and weaknesses are known to the community although this is often implicit. Our results show that it is currently difficult to perform global, quantitative assessments of uncertainty related to SAI research, in line with recent review reports on solar geoengineering.
Bolsen, T., Palm, R., & Kingsland, J. T. (2024). How scientific and partisan media shape support for research on stratospheric aerosol injection. Environmental Politics, 1-22. Abstract Stratospheric aerosol injection (SAI) is a controversial technique that has been suggested as a means of temporarily halting global warming. A study conducted on 441 individuals in the US in November 2023 investigated the impact of three video presentations either promoting or opposing research on SAI. Two of the videos were presented by scientific experts either promoting or opposing further research into this technology. The third was politicized, featuring Tucker Carlson on Fox News, and arguing that SAI would endanger Americans. We found that all three of the video presentations had a strong influence on general support for or against research, and that the politicized presentation not only reduced support for research but also reduced trust in science and technology to provide solutions to problems facing humanity. The findings suggest the strong impact of messaging on public opinion about research into SAI as a climate change intervention strategy.
Irfan, M., Musarat, M. A., Ayub, S., & Alaloul, W. S. (2024). Stratospheric aerosol injection for controlling greenhouse gas emission. In Advances and Technology Development in Greenhouse Gases: Emission, Capture and Conversion (pp. 455-473). Elsevier. Abstract An artificial method of injecting sulfate aerosols into the stratosphere to reduce greenhouse gas emissions (GHGs) is called stratospheric aerosol injection (SAI). By releasing sulfates into the atmosphere, volcanic eruptions naturally disperse sunlight and lower the temperature of the Earth’s surface. This technique attempts to replicate that process. SAI has drawn interest as a possible geoengineering technique to mitigate the effects of climate change. It does, however, present important ethical, technical, and environmental issues that need to be properly resolved before deployment is ever discussed. Regional climate alteration, ozone layer depletion, disruption of precipitation patterns, and negative health consequences on humans are among the possible dangers linked to solar radiation exposure. Concerns about consent, equity, governance frameworks, and unexpected repercussions are all included in the category of ethical considerations. Moreover, there are unknowns about the best injection heights and aerosol volume needed for efficient cooling while reducing additional hazards. To make informed judgments in the future regarding the sustainability and practicality of using SAI as a tool to reduce greenhouse gas emissions, it is imperative to have a thorough grasp of these intricate concerns. Therefore, the current chapter will analyze the concept of SAI and its anticipated benefits and challenges.
WEB POSTS Solar Geoengineering Updates5 days ago · 1 like · Andrew Lockley
PODCASTSExtra-tropical cyclones - Reboita | Reviewer 2 does geoengineering | Extra-tropical cyclones - Reboita Reviewer 2 does geoengineering 44:20 |
"How does SAI affect extra-tropical cyclones? Michelle Simões Reboita explains during a tight interview slot, but @geoengineering1 fails to understand (it takes him at least an hour to understand ANYTHING). Paper: Response of the Southern Hemisphere extratropical cyclone climatology to climate intervention with stratospheric aerosol injection. https://iopscience.iop.org/article/10.1088/2752-5295/ad519e/meta"
"Our guest is Gwynne Dyer, an author, columnist, broadcaster and lecturer on international affairs. In this episode, we discuss the key messages from his new book Intervention Earth: Life-Saving Ideas from the World’s Climate Engineers, based on extensive interviews with the world’s top climate scientists. We discuss his insights from these interviews on the state of our climate, and address controversies and concerns over carbon dioxide removal (CDR) and solar radiation management (SRM)."
YOUTUBE VIDEOSCloud-brightening experiment halted on San Francisco Bay | KPIX | CBS NEWS BAY AREA “Climate experiments, such as using sea salt particles to test potential cloud brightening, will continue to be funded. Anne Makovec and Molly McCrea report.”
Sci-Fi or Reality? Talking Tomorrow’s Climate Tech | The Aspen Institute “It sounds like sci-fi: Scientists are beaming solar energy from space, subbing seaweed for plastic and brightening clouds to reflect sunlight to lower temperatures in a warming world. In this series of short talks, innovators working at the cutting edge of climate tech share recent breakthroughs in the field.”
UPCOMING EVENTSSolar Geoengineering Events Calendar GUIDELINES:Sync selected events to your default calendar in these simple steps:1) Click on the event you want to sync.2) Tap the menu icon (three vertical lines) at the top left.3) Choose 'Share.'4) Pick your default calendar.5) Save the event.Sync the entire Teamup Calendar to your default calendar with these simple steps:1) Tap the menu icon (three vertical lines) at the top right.2) Choose 'Preferences.'3) Click 'iCalendar Feeds.'4) Copy the URL shown for 'Solar Geoengineering Events / SRM Deadlines.'’5) Paste the URL into your default calendar settings (Open Google Calendar in your web browser if you are using Gcal).6) Click 'Subscribe' or 'Add Calendar.'
You can directly sync all Solar Geoengineering events to your default calendars by pressing the link below:Sync SG Events to your Default Calendar
DEADLINESSRM Sessions at AGU2024:
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