Controlling Inherent Uncertainties in Double Theodolite Measurements

Abstract

This note examines the uncertainty inherent in calculations of wind speed, wind direction, temperature lapse rate and balloon height as determined by double theodolite-pibal/minisonde techniques. It is found that short observation intervals intended to provide good spatial resolution can lead to balloon position uncertainties so large as to make the derived data quite unreliable. The same problem occurs with short baselines or inadequate angle resolution. A double-theodolite field program is recommended which maintains the best possible spatial resolution consistent with acceptable levels of confidence in the measurements.