Stratospheric aerosol, volcanic eruptions and climate

平流层气溶胶对地球气候有重大影响，有时甚至是剧烈影响。平流层气溶胶位于地球表面上方约15-30公里处，由微小的液体和固体颗粒组成，它们在穿过大气层时散射和吸收辐射。平流层浮质数量的突然增加-例如由于大型火山爆发将硫注入平流层-导致到达地表的太阳辐射强度下降，全球变冷。事实上，在前工业时代，大规模火山爆发造成的平流层气溶胶扰动是全球气候逐年变化的最重要原因。因此，准确重建平流层气溶胶的历史对于解释过去气候变率的记录和测试气候模型至关重要，这些模型是估计气候敏感性和未来气候变化的基础。我的研究项目旨在促进对平流层气溶胶及其对地球气候影响的了解。该研究计划将提高对控制平流层气溶胶生命周期的过程的理解。它还将根据对大气与气溶胶的物理和辐射特性之间联系的新的基本认识，对平流层气溶胶辐射作用力进行新的改进重建。最后，该研究计划将提高对平流层气溶胶在过去气候变化中的作用及其对未来气候的潜在影响的理解。这些研究目标将通过开发和使用气溶胶、大气和气候的数值模型来实现，这些模型从简单的理想化模型到全面的耦合模型。模型开发将以现有的气溶胶观测为指导，包括卫星和地面仪器的检索以及极地冰芯和树木年轮的代用记录。该项目将产生广泛的科学影响，其研究结果将有助于从根本上了解大气和气溶胶过程以及过去气候变异的原因，并对气候预测和气候变化政策产生影响。该项目的结果将与一些正在进行的国际活动以及政府间气候变化专门委员会今后的评估报告有关。该项目将支持加拿大气候建模能力的进步，有助于测试和开发加拿大用于预测未来气候和严重气溶胶事件（包括野火和火山爆发）影响的建模工具。

Stratospheric aerosol has a significant--and occasionally drastic--impact on Earth's climate. Sitting roughly 15-30 km above the Earth's surface, stratospheric aerosol consists of tiny liquid and solid particles, which scatter and absorb radiation as it passes through the atmosphere. Sudden increases in the amount of stratospheric aerosol--for example due to the injection of sulfur to the stratosphere by large volcanic eruptions--lead to decreases in the intensity of solar radiation reaching the surface and global cooling. In fact, in the pre-industrial era, stratospheric aerosol perturbations produced by large volcanic eruptions were the most important cause of year-to-year global climate variability. Accurate reconstructions of the history of stratospheric aerosol are therefore essential to interpret records of past climate variability and test climate models, which underpin estimates of climate sensitivity and future climate change. My research program aims to advance understanding of stratospheric aerosol and its impacts on Earth's climate. The research program will improve understanding of processes that control the lifecycle of stratospheric aerosol. It will also produce new, improved reconstructions of stratospheric aerosol radiative forcing, building upon new fundamental understanding of the links between the atmosphere and the physical and radiative properties of aerosols. Finally, the research program will improve understanding of the role of stratospheric aerosol in past climate variations, and its potential impacts on future climate. These research objectives will be realized through the development and use of numerical models of aerosols, the atmosphere and climate ranging from simple idealized models to comprehensive coupled models. Model development will be guided by available aerosol observations, including retrievals from satellite- and ground-based instruments, as well as proxy records from polar ice cores and tree rings. The project will have a broad scientific impact, with findings relevant to fundamental understanding of atmospheric and aerosol processes and the causes of past climate variability, with implications for climate prediction and climate change policy. Results from the project will be relevant to a number of ongoing international activities, and to future Assessment Reports from the Intergovernmental Panel on Climate Change. The project will support advancement of Canadian climate modeling capabilities, contributing to the testing and development of modeling tools used in Canada to predict future climate and the effects of severe aerosol events including wildfires and volcanic eruptions.