Comparison of precipitable water over Hawaii using AVHRR-based split-window techniques, GPS and radiosondes

Precipitable water vapour (PWV) was estimated over Lihue, Kauai, from AVHRR data using split-window techniques. The predicted values using the satellite sensor data were compared to precipitable water vapour amounts obtained from radiosondes and corrected GPS measurements. Compared to the corrected GPS precipitable water, the Dalu and RV satellite methods had rms errors of 7.3 and 3.8 mm, respectively. Typical values of PWV over Hawaii are approximately 27.5 mm, suggesting errors of about 14% in values estimated using the satellite split window technique near Hawaii.