Radiosonde Temperature Sensor Benefits from Stronger Structure
Small sensor packages called radiosondes (or “sondes”) are used to transmit atmospheric information from weather balloons as they rise through the air. Vaisala, the supplier of sondes used at all the ACRF sites, has introduced an improved temperature sensor for the RS92 sonde, the latest version of their sonde technology. The sensor’s old protective boom frame has been replaced with a strong quartz fiber material that is integrated into the sensor’s structure. This reinforced framework offers the following benefits:
- Five times better mechanical strength without losing responsiveness and accuracy
- Very small solar radiation absorption
- Less prone to damage during flight preparation and ascension
- Improved air flow to the sensor due to removal of the boom frame.
Though the use of quartz fiber increases the thermal mass of the sensor, removal of the old boom structure improves heat transfer from the ambient air. This results in a net decrease of thermal mass on the sensor to maintain the needed response time. It also compensates for the slightly increased radiation absorption, so no correction technique is needed. Because of the reinforced structure, the new sensor is especially useful if sondes are tethered together and launched simultaneously.
To track data quality during the short transition period to the RS92 sondes with the reinforced framework, the different sondes can be traced by serial number. If the four last digits are between 3000 and 5999, the sonde is manufactured with the fiber-reinforced temperature sensor. Instrument mentors are developing software that will merge the sonde’s raw pre-launch data with the data collected by the Surface Temperature and Humidity Reference System at SGP. When completed, the merged streams will be submitted as a new ARM data product to help assess the accuracy of the radiosonde data.
