Instructions to Prepare a Rigging for Comparison Sounding PR210147EN-A
Succesfull Radiosonde Intercomparisons The key purpose of the Intercomparisons between the radiosonde models is to understand their different behavior in the operational use To be successful in this target, it is important to ensure that the test setup does not introduce phenomenon that are not real in the operational use The purpose of this document is to give guidance to achieve the goal with Vaisala radiosondes.
Recommendations for Rig Setup The optimum ventilation of the radiosondes in comparison rig is eventual for gaining the high quality comparison data For the optimum ventilation, ensure that the ascent rate of the rig setup is at least 5 m/s in average and utilize the nozzle lift recommendation as given in slide 4, but remember also to adjust according to local weather conditions For the optimum ventilation, allow also movement of the radiosonde when attached to the rod, do not tape directly to the rod
Recommended Rigging The radiosonde shall be hanged with at least 80 cm long string The unwinder string length can vary but minimum shall be 30 m, 60 m is recommended For safety reasons the parachute shall always be used Total payload of the rig setup is about 950 g Page 4 © Vaisala 2014-03-12 PR210147EN-A
Nozzle Lift Recommendation and Estimated Bursting Altitude Vaisala Radiosonde Comparison Rigging (~950 g) Balloon Weight (g) 1200 1500 2000 3000 Nozzle Lift (g)* 2400 2700 2800 3100 * Nozzle lift in good weather conditions, need to be adjusted according to local weather conditions.
Detailed Information on Rigging The detailed instructions for radiosonde rigging and sounding preparations are given in Vaisala Guide to Sounding Preparations Technical Reference M211367EN The Technical Reference is available on request from your Vaisala contact or can be found from MW41 user documentation folder The recommendations are in line with WMO- No 8’s proposing ascent rates of 300 to 400 m min-1 (5.0 to 6.
