To meet the continuing requirement of a broad
base of users for atmospheric sounding data, the NWS will replace its entire
current network of radiosonde systems with a modern design to:
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Maintain or increase system availability and
data accuracy |
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Reduce the use of radio-frequency spectrum |
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Require less operator interaction and
maintenance |
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Provide a complete high-resolution data set to
users |
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Provide a balloon inflation and launch shelter
capable of controlled balloon launches for use at NWS facilities that have
space limitations |
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Provide consistent and accurate measurement of
surface weather parameters at the point of balloon release |
The NWS must
implement and operate an economical and efficient upper air observing system
over the next 20 to 25 years to continue meeting the data availability
requirements of weather forecasters and climate researchers. The new system
must make efficient use of allocated radio frequencies in order to coexist with
other users in the same or nearby spectrum band. The system must operate as
much as possible in an automated mode, yet allow operator intervention when
appropriate.
The current radiosonde system provides for the
distribution to users of only a small portion of the data collected. These data
sets do not contain sufficient detail to fully meet the needs of today’s
numerical prediction models. The replacement system will distribute
high-resolution data sets and give users access to the full set of observed
data collected by the system. The newer generations of numerical prediction
models are now able to apply this high- resolution data. The data sets will
include both processed and unprocessed data. The processed data will meet user
requirements for the highest quality data (corrected for solar radiation
effects on sensors). Unprocessed values will be provided for climate
researchers, who require the capability to reprocess old data using newer
algorithms to maintain data continuity.
The modernization and restructuring of the NWS has
relocated many facilities. Construction of large balloon inflation buildings
supporting the current antenna system are impractical in certain cases. Balloon
launches from these current structures are performed manually by the observer,
who carries the balloon to a suitable launch point to avoid having the
radiosonde crash into the launch shelter. Smaller balloon inflation shelters
can be used to provide the capability to automatically release the balloon,
saving observer time and requiring less obstruction-free real estate
surrounding the release site. These new shelters will be used on a case by case
basis at locations lacking suitable conventional inflation buildings. Rooftop
installation of these shelters will be possible in cases of extreme land
restrictions and urban environments.
Radiosonde soundings require the accurate determination of
surface weather parameters (temperature, humidity, pressure, and wind) to
successfully process the data from the complete sounding. Surface data are used
in the calculation of the height of the radiosonde (using pressure measurements
from the surface and radiosonde). Small errors in surface pressure, for
example, can lead to large height errors later in the sounding. Most NWS
automated surface observing equipment (Automated Surface Observing System) is
positioned more than a quarter mile from the balloon release point, and is not
representative of the upper air site environment. A dedicated suite of
instruments will be deployed for consistent measurement of surface weather data
supporting the radiosonde operation. |
