A High-Resolution Continuous Pressure Sensor Modification for Radiosondes

Abstract

This paper describes how continuous pressure measurements may be obtained by making a relatively simple modification to any standard or clock-switched radiosonde which can be flown on a rising or floating balloon. The continuous pressure device is composed of an aneroid sensor which controls the frequency of a subcarrier oscillator. Frequency modulation of the radiosonde transmitting tube is used instead of amplitude modulation. The receiver for this system utilizes the standard GMD-1B ground tracker with a special demodulator, the standard TMQ-5 recorder, and a frequency counter with printer. Each pressure sensor is calibrated for frequency vs. pressure; precision of reading the pressure is to 1 mb as currently used, but readings to 0.1 mb are easily obtainable. Pressure data from three superpressure balloon flights are presented to show the detail obtained by the instrument with this modification. This modified instrument provides the research meteorologist with a new inexpensive research tool.