Improving Nitrogen Predictions by Updating Tropospheric Kinetics (INPUT-K)

University Of Florida, Gainesville FL

Investigators

Abstract

The objective of this research is to provide alternative estimates of reaction rate coefficients using statistical methods to improve model predictions of atmospheric nitrogen chemistry. This is a demonstration project that will make direct use of field observations to guide further investment in laboratory experiments and reveal mechanisms that can lead to modeling biases. The independent estimates of reaction rates provided by this project will provide an important constraint on estimating the health and climate impacts of reactive nitrogen chemistry. This project aims to improve model simulations of reactive nitrogen by achieving the following objectives: (1) Apply a previously successful inference modeling framework to a more recent observational campaign (such as the NSF-supported DC3 campaign) where nitrogen imbalances in 3-D models have been shown; (2) Constrain rate coefficients and product stoichiometry in climate relevant environments using likelihood calculations based on reduced model ensembles and observational datasets; and (3) Replace stochastic physical transport with mechanistic transport using an ensemble of simulated air parcel trajectories that are representative of post-convection transport. Together, stochastic modeling, mechanistic chemistry, and high quality observations will be used to supplement laboratory studies and identify reactions for subsequent laboratory investigation.