We present here an extensive study of the accuracy of the determination of the PWV from antenna measurements and in the determination of the pathlength variations (and thus phase variations). The study focussed on the effects of instrument measurement effects and software issues. We have also investigated the effect of the water vapour scale height and the presence of water vapour layers in the determination of the path delay. After correcting the software for the instrumental effects and applying empirically determined corrections to the path delay estimates we reached a good agreement between observed path delay variations and the inferred path delay variations determined from the PWV measurements.
View a pdf version of ALMA Memo #451.
Last modified: 2003-04-10