NOAA: Reactive Nitrogen Biogeochemical Cycle in the GFDL Earth System Model

Executive Summary

Both Aneja and Schlesinger have pursued a productive career in studies of biogeochemistry, focusing on atmospheric (Aneja) and soils (Schlesinger). Aneja has examined the sources and transformations of reactive nitrogen gases in the atmosphere, at scales from the local (farm fields) to regional (e.g., the southeastern United States) to continental (e.g., India). Currently he is examining how to use satellite remote sensing to inform regional models of the sources, concentrations, and transport of ammonia in the atmosphere. His recent work has alerted global modelers and policy makers of the importance of agricultural activities as a source of ammonia, nitric oxide, and nitrous oxide. And, of course, increasing agricultural intensification to feed a growing human population will make these processes all the more critical in models of future global condition. Moreover, working with the US Environmental Protection Agency, he is modeling the fundamental biogeochemcal processes in agricultural soils. This development could add to comparing and contrasting such processes as ascertained by the current development in the GFDL-NOAA Earth System Model.

Schlesinger has devoted his career to the study of soils as an arena for biogeochemical cycling, and the role of processes in global biogeochemical cycles (Schlesinger and Bernhardt 2013). For nitrogen, his past assessments include a budget for the emission of ammonia to the global atmosphere, an accounting of the fate of nitrogen applied to the land surface, and a global estimate of the uptake of nitrous oxide by soils, where it is apparently transformed by soil bacteria to dinitrogen gas. He has also evaluated the net effect of fertilizer practices on carbon sequestration in agricultural systems. For the proposed project, he will compile and synthesize the flux of nitrogen species in agricultural and natural ecosystems as needed by the modeling team.

Aneja and Schlesinger see themselves as providing one major data compilation to the modeling, synthesis, and integration team. Aneja will also provide (at no cost to the project) a graduate student to assist Aneja and Schlesinger in the successful completion of the project. For us to be more integrated with the Science Team of the project, we request a visit to NOAA-GFDL for technical and scientific discussions all three years by travel funds provided by the project.3