Prediction system for nitrogen deposition in Rocky Mountain National Park
For the early warning system, 5 runs of WRF-ARW v3.3.1 with varied physical parameterizations and initial conditions were used. From each run, 6-hour forward trajectories were release from 32 points in close-proximity to 4 municipalities in eastern Colorado. Multivariate kernel density estimation then utilized the endpoints of the 6-hour trajectories to detect high concentrations of advected “particles” released from the Fort Collins, Greeley, Fort Morgan, and Limon vicinities. Because some days with issued warnings did not end with high deposition in RMNP, a metric of success for this early warning system was when an issued warning verified with high concentrations of NH4+ in RMNP based on reports from the National Atmospheric Deposition Program's National Trend Network (NADP/NTN).