“Toward a meteorological early warning system for reducing the transport and deposition of nitrogen in Rocky Mountain National Park”

Schumacher, Russ; Piña, Aaron; Paulus, Matt

The transport and deposition of fixed nitrogen into Rocky Mountain National Park (RMNP) can lead to alterations to fragile ecosystems in the alpine environment. Past research (e.g., Baron and Denning 1993; Malm et al. 2009; Benedict et al. 2013) has found that the sources of nitrogen to RMNP are varied, including both regions west (i.e., originating in the western U.S.) and east of the park. In particular, periods of easterly (upslope) flow can, under certain conditions, transport ammonia/ammonium from agricultural sources along the Front Range and eastern Colorado into the park. The purpose of this project was to analyze the meteorological conditions associated with these high-deposition time periods, as a step toward providing improved forecasts and alerts for these conditions. This research has informed the development of a pilot “early warning system” (EWS) for nitrogen deposition in RMNP, which gives agricultural producers in eastern Colorado the option to alter management practices that lead to volatilization of ammonia. This report summarizes the overall results of the project. It begins with an overview of when deposition most frequently occurs in RMNP, and then addresses the typical weather conditions responsible for high deposition. Then, we discuss the configuration of a relatively simple atmospheric modeling framework for identifying periods that will be favorable for the transport and deposition and nitrogen from eastern Colorado toward the park. Finally, we present the results obtained thus far from this system, how it is used in the context of the EWS, and methods for enhancing it in the future.