Air parcel trajectories in the lower stratosphere using winds from the SKYHI general circulation model

摘要

The development of the 3-D particle trajectory code for use with the 'SKYHI' model winds was completed. One issue that had to be faced was the reduction of the GCM wind 'data' that were used to advect the trace particles. The data were available at the full GCM resolution (1 deg lat. x 1.2 deg long.) every 12 hrs. Small-scale motions were aliased and we found it necessary to take 3 deg averages to remove erratic motion of the particles. The code was used in numerical experiments with many (10-30 thousand) particles in order to document transport in the GCM. The first series of experiments completed comprised an investigation of transport in and near the polar vortices. One of the major intentions of the planned research was investigation of stratosphere-troposphere exchange and, in particular, of the fate of pollutants emitted by supersonic aircraft. Experiments designed to explore this issue, however, revealed apparent deficiencies in the model transport that were not resolved when the project was completed. The model developed in this project (which, despite the deficiencies noted above, is still useful for investigation of the processes, if not the rates, of stratospheric transport) is being applied for more general investigations in the course of other, NASA-funded, research.