Comparisons of GPS‐derived precipitable water vapors with radiosonde observations in Japan

摘要: We investigated the accuracy and features of precipitable water vapor (PWV) obtained from Japanese Global Positioning System (GPS) network. compared PWVs estimated Geographical Survey Institute (GSI) routine geodetic analysis using Bernese software with those derived nearest 10 radiosonde stations over islands. The comparisons for a half year showed that agreement GPS-derived PWV was 3.7 mm in terms rms difference, standard deviation 2.6 mean bias −2.7 mm, which is less precise than central North America. This may reflect high temporal spatial variability islands, causing differences between if GPS launch are not colocated. also found systematic biases PWV. absolute value at 1200 UT systematically larger 0000 UT. Their difference reached as much 2 mm. Moreover, tended to increase increased. confirmed there were similar our GIPSY resolution. fact indicates depend neither on nor resolution estimation. analyzed data collected Tsukuba station years possibility attributed ocean tidal loading seasonal variation mapping function both taken into account GIPSY. These results suggest importance implementing them accurate estimates