Atmospheric VLBI: A method to validate long time series of water vapour content

Övrigt konferensbidrag, 2009

We assess the possibility to validate time series of the atmospheric integrated water vapour (IWV) from GPS observations using geodetic VLBI at the Onsala Space Observatory in Sweden. An overall motivation is to determine the relation—and its uncertainties— between trends in the IWV with trends in the ground temperature. We find that the frequency of VLBI experiments is too low in order to validate estimated linear trends using data acquired over a ten year period. On the other hand, the VLBI method provides an accuracy of the same order, compared to using GPS or nearby radiosonde launches for validation of the IWV on an absolute scale. Further assessments using other, as well as larger, data sets are called for.