WXP version 5
User's Guide

Upper Air Data Conversion

The upper air data conversion program called uacvt reformats and collates the data into a compact form. The upper air data is broadcast twice a day (observed at 0000 GMT and 1200 GMT) with special soundings taken at 0600 and 1800 GMT. Upper air data for a station is sent in up to 8 parts:

The conversion process performed on these various reports takes two steps. The first step is to parse consecutive hourly data files for the occurrence of upper air data, since these data are generally captured over a two to four hour period. Once the appropriate upper air data is found (either a TTAA, TTBB, TTCC, TTDD, PAA, PPBB, PPCC or PPDD report) within one of the files, it is decoded and placed into a structured array for all reporting stations. Significant levels are then sorted and duplicate levels removed. This gives three arrays of data for a particular station. The first contains all the mandatory levels to 10 millibars plus the tropopause and maximum wind level. The second contains all the significant level information and the third contains the significant wind levels. The three arrays for each station are saved in a single file in either ASCII WXP or netCDF format with the file name representing the hour of the report.


Last updated June 3, 1998