SPATIAL INTERPOLATION OF THE ATMOSPHERIC WATER-VAPOR CONTENT BETWEEN SITES IN A GROUND-BASED GPS NETWORK

We have studied three methods of spatially interpolating GPS-estimated wet delay time series. Five months of data from three sites in the Sw edish continuously operating GPS network were used for interpolation t o a fourth site. Different geometries were used, resulting in interpol ation distances of 40-120 km. To assess the quality of the interpolati ons we compared the obtained time series with estimated wet delay from a GPS station and with radiosonde data. A method based on the theory of atmospheric turbulence showed the lowest errors when compared to bo th the GPS estimates and the radiosonde data. The rms errors using thi s method are typically 1 cm.