The operator entered 960.2 for the surface pressure in both the log and
the system. The first reading from the sonde is 950.9. Examination of
the absolutely raw data shows that the sonde pressure before launch was
952.3. The THWAPS reading was 964.2. From the raw data it appears that
either the system was not reset before this sounding or that a second
sonde was started without resetting the system. The sonde pressure
may be low in absolute terms or the operator may have mis-entered the
actual sonde reading. In either case the absolute altitude will be wrong
in this sounding and the ascent rates will be incorrect for the first
30 seconds. |