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Hello everyone. My name is Shohei Hattori from Nanjing University. I have been in China for only two years, so I am not yet proficient in speaking Chinese. Please allow me to present in English today. Thank you for inviting me to this opportunity. Although our time is short, I hope you will learn about the research I am planning. Today, I will talk about four main points. Additional information can be found in the application form and at the end of the PPT slides, so please refer to those as well. First, I will talk about my research capabilities through my past achievements. I am originally from Tokyo, Japan. I received my Ph.D. from the Tokyo Institute of Technology in 2012. After a three-month postdoctoral fellowship, I became an Assistant Professor. After nine years of teaching experience, I started working at Nanjing University in 2022, where I obtained HWYQ to advance my research. My research focuses on environmental geochemistry, including atmospheric and biogeochemical studies. I specialize in stable isotopes, particularly using mass-independent fractionation to study Δ17O anomalies in atmospheric chemical reactions. My work includes studies on atmospheric sulfur cycles and nitrogen cycles in the atmosphere and biosphere, including the polar regions. I am working interdisciplinary overlapping three different academic fields geochemistry, glaciology, and atmospheric chemistry with unique isotope techniques and indicators. Here are some of my key research achievements. I have published many papers in high-level journals, but one of the most significant is my 2021 Science Advances paper. This study revealed changes in atmospheric sulfate formation processes since the 1980s through isotope analysis. The study has been cited in review papers in international journals on atmospheric chemistry, geochemistry, and physical chemistry, highlighting its impact. Since moving to Nanjing in 2022, I have continued to conduct high-level research, publishing papers with new research members in journals such as Nature Geoscience. In addition to publishing papers, I have received many awards. My research spans multiple fields, including geochemistry, glaciology, and atmospheric chemistry, which has led to receiving awards from three different academic societies. In 2022, I received the Environmental Sustainability Research Award from the ASAHI-related organization, and this year, I received the Emerging Investigator Award from the International Association of Geochemistry. I have also given invited lectures at many conferences and worked to connect the geochemistry societies of China and Japan as a member of the International Liaison Committee of the Japan Geochemical Society, fostering deeper collaboration between the two countries. Here, I show the research grants I have received. In Japan, I secured numerous research grants, and in China, I have begun obtaining competitive grants like HWYQ. Now in my third year in China, I am proposing a new research project with the support I have received. Next, I will explain the significance of my research plan. The background of this research involves the impact of human activities on climate change, air quality, and polar aerosols. As recently highlighted in a paper published in Nature Climate Change, climate change due to aerosols in polar regions is a critical factor, yet many uncertainties remain. Specifically, there is little information on atmospheric chemical reactions involving aerosol formation and historical changes in atmospheric oxidants. Using the triple oxygen isotope signature, or Δ17O values, I have reconstructed atmospheric chemical reactions from observations. For example, this is done by analyzing the Δ17O values of sulfate to reconstruct the historical changes in atmospheric oxidation processes. The use of ice cores is unique in this approach, as they preserve past aerosols directly, making it possible to trace back the chemical reactions that aerosols like sulfate, nitrate, and MSA underwent. One scientific issue we address is the atmospheric chemical changes caused by fluctuations in human activities. This is critical due to the issue of chemical feedback mechanisms. For example, the comparison of anthropogenic nitrate concentrations in ice cores with NOx emissions since the pre-industrial era shows a slow decrease in nitrate despite the reduction of NOx emissions since the 1980s. Similar observations have been made for sulfate, suggesting feedback mechanisms in the atmosphere that reduce the effectiveness of emission controls. To address this, we plan to analyze Δ17O values to identify these chemical feedback mechanisms and develop an accurate atmospheric chemistry model that incorporates these mechanisms, ultimately aiding in predicting future air pollution and climate change. Human activities also significantly affect natural aerosols and cloud formation, yet their actual impact is poorly understood. The oxidation process of biogenic DMS to sulfate and MSA is complex and crucial for understanding aerosol-cloud interactions in polar regions. Our study aims to be the first in the world to apply Δ17O to MSA analysis. MSA, derived from biogenic DMS, has shown changes in concentration since the industrial revolution and recent pollution reductions. We aim to elucidate the mechanisms behind these changes and accurately reflect these complex atmospheric chemical processes in models. To undertake this research, several challenges need to be addressed. These include the lack of analytical methods, appropriate ice cores, and verification methods for chemical processes in models. However, this research leverages new analytical methods using Orbitrap-MS, the highly reliable SE-Dome ice core for atmospheric aerosol deposition reconstruction, and the development of our own isotope-inclusive atmospheric chemistry model. This approach will not only reconstruct past aerosol dynamics but also build accurate atmospheric chemistry models to predict future aerosol dynamics and climate impacts. Next, I will discuss the details of the research. This research aims to reconstruct the formation processes of sulfate, nitrate, and MSA aerosols using Δ17O isotope data from the SE-Dome II ice core. By updating our model to accurately reflect these reconstructions and considering chemical feedback mechanisms, we will build a high-precision model. This model, incorporating future human activity scenarios, will analyze climate change and air quality up to 2050 and 2100, proposing solutions to environmental problems. The innovative points of this research are shown here. We will use unique Δ17O isotope indicators and new analytical methods to analyze previously unused samples. Moreover, we will conduct modeling to not only reconstruct past conditions but also update the model for future predictions and propose solutions. Finally, let me discuss the feasibility of the research. This research is highly feasible, as it is based on my recent achievements. The innovative points have been well-prepared, allowing us to start immediately upon approval. Nanjing University and the State Key Laboratory provide a robust platform for this research. ICIER, established in 2019, has the world’s best isotope analysis equipment, making it one of the few institutions capable of conducting the analyses proposed in this research. With these platforms, the research foundation is well-prepared. This is our research team. I have secured three Ph.D. students to collaborate with me at Nanjing University, with the potential for more. We will conduct sample and model work internationally, leveraging over a decade of strong collaborative research. Additionally, a French ice core researcher has expressed interest in joining us as a postdoctoral fellow. This international collaboration between China, Japan, and the US, along with new members from Nanjing University and France, promises excellent research advancement through new interactions. With this preparation, I am here today to discuss our new research. Thank you for your attention.