On August 1st, 2001 the South Pole Meteorology Department officially switched to a GPS-based atmospheric sounding system.  The equipment now in use by the department consist of Vaisala RS-80 GPS radiosondes and a Vaisala Marwin reciever.  This replaces the former system that utlized A.I.R. Inc. model 5A radiosondes and an A.I.R. Inc radiotheodolite tracking antenna and receiver. The department continues to utilize the software developed by A.I.R. Inc to process the raw upper air data, though this is viewed as a temporary measure.  

**IMPORTANT - UPDATED 12/5/01**
The grid wind directions produced by this system are currently incorrect.  Due to the location of the station at 90 degrees South latitude, wind directions are calculated using the prime meridian as north, the dateline as south, etc.  The Vaisala system described above appears to be displaying a "mirroring" effect based off the grid East-West line.  As a result, winds directions along that line seem to be accurate, but as the flight travels to grid north or south of that line, direction is calculated incorrectly, maximizing error at 180 degrees off the correct direction when the flight tracks due north or south.  As soon as the problem is corrected this notice file will be updated.  Please contact the South Pole Meteorology Department at met@spole.gov with any questions.