A new tethersonde system for remote measurement of wind and temperature

An economical tethersonde system was developed for use in the light-to-moderate wind conditions typically accompanying nocturnal inversions to obtain vertical profiles of wind velocity and temperature at heights in excess of 300 m. Minimal capital investment and operational expenditure were achieved with the use of a spherical balloon, the development of a simple and reliable thermistor temperature sensor, and the development of algorithms to obtain quantitative estimates of wind velocity from the measured position of the balloon and from the known aerodynamic drag properties of both the balloon and the tether. With the length and suspension geometry of the tether line known, an approximation is applied to accommodate its nonlinearity; the position vector of the balloon and instrument package can then be determined by a single theodolite fix. The vertical component of the position vector so determined corresponds to the geometric height of the sensor, while the horizontal component is directly related to wind velocity. Heights and horizontal wind velocities estimated by these methods compare well with direct independent measurements.