| Issues in
Maintaining the Current Radiosonde Systems |
|
| The mechanical portions of the ground-based
system were installed in the 1950's and certain electronic components were
implemented in the early 1980's. More than 90% of the system parts are
currently obsolete, making the system more difficult to maintain. The
numerous integrated circuit chips used throughout the system are particularly
difficult to replace. Due to the age of the equipment, failures have
increased and will become routine if the system is not replaced. The
number of parts repaired has risen by more than 100% in the past five years
(see chart below). |
 |
| The supply of parts necessary to maintain the
outdated IBM PC/XT computer is only sufficient to last two years, and the
software must be rewritten before use on a newer computer. |
 |
| At some stations, additional ground equipment
(transponders) provide special tracking of the radiosondes when they are
carried over the horizon in high-wind situations. This transponder
equipment uses vacuum tubes which are no longer available. In 1990, 33
stations had transponder units. Currently, only two stations have the
equipment still functioning. As a result high-altitude wind data are lost
and the placement of the jet stream in upper level analyses can be in error.
These occasional errors degrade numerical prediction models and also
degrade the application of the data for aviation users projecting aircraft fuel
usage. |
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