Collaborative Research: Understanding Emission Sources and Sinks of Nitrous Acid in North American Forests

合作研究：了解北美森林亚硝酸的排放源和汇

• 批准号: 2243202
• 负责人: Jonathan Raff
• 金额: $ 89.26万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2243202&HistoricalAwards=false
• 关键词: Collaborative; Research; Understanding; Emission; Sources

This project focuses on land-atmosphere interactions and the mechanisms by which nitrous acid (HONO) and other nitrogen oxides emitted from soils influence the oxidizing capacity of the atmosphere. The experimental plans include the use of growth chambers under controlled conditions combined with field data to study the uptake of HONO onto leaves from a range of tree species that dominate major forested regions across North America. Since HONO is not well represented in chemical transport models, improvements in understanding HONO sources and sinks are expected to have important implications for improving air quality models and for determining the lifetime of some greenhouse gases, such as methane, in the atmosphere.This effort combines expertise in atmospheric chemistry, microbial ecology, and modeling with unique analytical capabilities for measuring HONO soil emissions. The central hypothesis of this proposal is that variations in below-canopy hydrogen oxide radical (HOx) cycling and ozone levels in forested regions are driven by the variability of soil emissions of HONO (SHONO) and nitrogen oxide (NO) (SNO), that depend on season, edaphic properties, aboveground vegetation surfaces, and belowground nitrogen cycling that is mediated by microbe-plant interactions. Preliminary data show that high SNO has a significant impact on below canopy HOx in a forested environment, that NOy (the sum of reactive nitrogen oxides) fluxes are linked to forest composition, and that spatial variability in NOy fluxes can be mapped across the continental U.S. using forest inventory plots. The objectives of the research are to: (1) Establish geospatial trends in SHONO across U.S. forests; (2) Carry out field campaigns to measure SHONO in mixed deciduous forests; and (3) Quantify uptake of HONO by leaf and soil surfaces.The project will support a full-time postdoctoral researcher and a graduate student who will receive training in state-of-the science analytical and modeling methods. Undergraduate students will be directly involved in the research as part of Indiana University’s Groups Summer Research Experience Program, which gives entering first-year students research experience and skills to excel in STEM majors.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目重点研究陆地与大气的相互作用以及土壤排放的亚硝酸（HONO）和其他氮氧化物影响大气氧化能力的机制，实验计划包括在受控条件下使用生长室并结合现场数据来研究。研究北美主要森林地区的一系列树种叶子对 HONO 的吸收，由于 HONO 在化学运输模型中没有得到很好的体现，因此对 HONO 源和汇的了解预计将具有重要意义。这项工作将大气化学、微生物生态学和建模方面的专业知识与测量 HONO 土壤排放的独特分析能力相结合。该提案的主要内容是，森林地区树冠下氧化氢自由基（HOx）循环和臭氧水平的变化是由HONO（SHONO）和氮氧化物（NO）（SNO）土壤排放的变化驱动的，即取决于季节、土壤特性、地上植被表面以及由微生物与植物相互作用介导的地下氮循环。初步数据表明，高 SNO 对森林环境中冠层下方的 HOx（即 NOy）（反应性总和）有显着影响。氮氧化物）通量与森林组成相关，并且可以使用森林清查图来绘制美国大陆的 NOy 通量的空间变异性。该研究的目标是： (1) 确定美国森林中 SHONO 的地理空间趋势；(2) 开展实地活动，测量混合落叶林中的 SHONO；(3) 量化树叶和土壤表面对 HONO 的吸收。该项目将支持全职博士后作为印第安纳大学团体夏季研究体验计划的一部分，将接受最新科学分析和建模方法培训的研究员和研究生将直接参与研究。一年级学生在 STEM 专业中取得优异成绩的研究经验和技能。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。