FSU - SONEX

Product Description

All products on the following pages were calculated from analysis data assembled by The European Centre for Medium-Range Weather Forecasts. The data set has a 1 degree by 1 degree horizontal resolution, 31 sigma level vertical resolution and was supplied at 6 hourly intervals throughout the SONEX period. The data sets closest to the time of the actual flights were used for product generation. The threshold for determination of the tropopause was taken to be 3.5 PVU. Five day backward trajectories were calculated using a kinematic model, i.e., employing the u, v, and w wind components from the ECMWF analyses. A cubic spline procedure was used to vertically interpolate the gridded data from the 31 initial levels to 201 levels at 5-hPa intervals between 1025 and 25 hPa. Linear interpolation provided values within these 5-hPa intervals and at the parcel's precise horizontal locations. Linear interpolation also was used to temporally interpolate at 5-min time steps. Additional details about the trajectory model, along with a comparison between kinematic and isentropic trajectories, are given in Fuelberg et al., [J. Geophys. Res., 101, 23927-23939 1996]. Digital trajectory data can be accessed through FSU's anonymous FTP site given below. Special thanks to Peter van Velthoven of KNMI (Royal Netherlands Meteorological Institute) for his generosity in the supply of the ECMWF data.

For quicker downloading, all plots may be accessed through FSU's anonymous FTP site at bertha.met.fsu.edu . All files are contained in /pub/outgoing/sonex/. Potential vorticity along flight paths also available via ftp.