The accuracy of trajectories during ANATEX calculated using dynamic model analyses versus rawinsonde observations

Abstract

Aircraft tracer measurements all made within 300 km of the release sites during the Across North America Tracer Experiment (ANATEX) provided 30 separate trials to evaluate the error of back-trajectory calculations. The trajectory calculations used dynamic-model-output meteorological data from the NOAA prognostic Nested Grid Model (NGM) and from comparable gridded meteorological fields from 4-day rawinsonde or 2-day rawinsonde observations. Over all trials, no significant difference was discernable in trajectory accuracy using the different meteorological input data; absolute trajectory error ranged from 20% to 30% of the travel distance. The primary conclusion is that the NGM-generated meteorological data can be an adequate substitute for rawinsonde data in trajectory calculations. -from Author