[SGD02-P08] A study to measure PWV and wave height over the ocean by kinematic PPP procedure with MADOCA Real-time Orbits
Keywords:GNSS, Precipitable Water Vapor, Wave height
One antenna was set on the mast (MAST) while another antenna was set on the upper deck (DECK). The GNSS analysis was conducted using the Precise Point Positioning procedure with a real-time GNSS orbit. A quality control (QC) procedure based on the amount of Zenith Tropospheric Delay (ZTD) time variation was proposed. After the QC was applied, the retrieved PWVs were compared to 77 radiosonde observations. The PWVs of MAST agreed with the radiosonde observations with a 1.7 mm root mean square (RMS) difference, a −0.7 mm bias, and 3.6% rejection rate, while that of DECK showed a 3.2 mm, −0.8 mm, and 15.7%. The larger RMS and higher rejection rate of DECK implies a stronger multi-path effect on the deck. We also, compared vertical antenna displacement with those obtained by WM-2 wave height meter. Because the location of the two instruments are different, phase of vertical displacement is different, but cycle were close each other.
The differences in the GNSS PWV versus radiosonde observations were compared to the atmospheric delay, the estimated altitude of the GNSS antenna, the vessel’s moving speed, the wind speed, and the wave height. The atmospheric delay and GNSS antenna altitude showed moderate correlation with the differences. The results suggest the kinematic PPP’s potential for not only practical water vapor monitoring but also wave height measurement over oceans worldwide. At the same time, from the growing negative biases with the PWV value and with estimated antenna altitude, it could be inferred that the difficulty grows in separating the signal delay from the vertical coordinate under high humidity conditions.