Collaborative Research: Isotopic Fingerprinting of Nitrous Oxide Emissions from the United States Corn Belt

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。这项研究的目的是通过结合同位素指纹、高塔观测和区域尺度的反向模拟来增加对美国玉米带一氧化二氮排放来源和动态的了解。一氧化二氮是一种寿命较长的痕量气体，会导致气候变暖和平流层臭氧的破坏。农业地区是大气中一氧化二氮的主要来源，但这些地区排放的一氧化二氮的大小和途径存在很大的不确定性。该项目将提供关于一氧化二氮源动态的新知识，这对于设计有效的战略以减少来自不同农业景观的一氧化二氮排放至关重要。该研究项目的目标是：(1)建立密集的野外活动，以量化农业土壤、自然土壤和典型的玉米带农业排水网络中氧化亚氮(N2O)排放的代表性同位素特征；(2)对N2O同位素进行高频、高精度(185米)观测，并结合大气传输模型来表征区域尺度上N2O排放的同位素组成；以及(3)使用双示踪逆向模拟方法，利用浓度和同位素约束将N2O排放划分为农业土壤的直接排放以及N淋溶和挥发过程产生的间接排放。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). The goal of this research is to increase the understanding of the sources and dynamics of nitrous oxide emissions from the US Corn Belt through a combination of isotopic fingerprinting, tall tower observations, and regional-scale inverse modeling. Nitrous oxide is a long-lived trace gas that contributes to climate warming and the destruction of stratospheric ozone. Agricultural regions are a major source of nitrous oxide to the atmosphere, but large uncertainties exist in the magnitude and pathways of their emissions from these regions. This project will provide new knowledge about nitrous oxide source dynamics that will be critical to designing effective strategies for mitigating nitrous oxide emissions from heterogeneous agricultural landscapes. The objectives of this research project are to: (1) Establish intensive field campaigns to quantify representative isotopic signatures for nitrous oxide (N2O) emissions from agricultural soils, natural soils, and agricultural drainage networks typical of the Corn Belt; (2) Make high-frequency, high-precision tall tower (185 m) observations of N2O isotopocules that will be used in combination with atmospheric transport modeling to characterize the isotopic composition of N2O emissions at the regional scale; and (3) Use a dual-tracer inverse modeling approach that leverages concentration and isotopic constraints to partition N2O emissions into direct emissions from agricultural soils as well as indirect emissions arising from N leaching and volatilization processes.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.