Sources of nitrous oxide, an important greenhouse gas, over the central United States

Scot Miller, Harvard University

Photo of Scot Miller

Nitrous oxide (N2O) is the third-largest long-lived greenhouse gas in terms of radiative forcing, but knowledge of N2O sources over the United States is highly uncertain. We present top-down constraints on the magnitude, spatial distribution, and seasonality of N2O emissions over the central United States. We pair data from aircraft measurements and tall towers in 2004 and 2008 with a high-resolution back-trajectory model known as STILT. Our results indicate a seasonal cycle and magnitude of emissions lacking in existing inventories. The spatial distribution of sources closely mirrors data on fertilizer application with particularly large N2O sources over the U.S. Corn Belt.

Abstract Author(s): Scot Miller, Eric Kort, Adam Hirsch, Ed Dlugokencky, Arlyn Andrews, Xiaofen Xu, Hanqin Tian, Anna Michalak, and Steve Wofsy