Development of a New Vertical Water Vapor Model for GNSS Water Vapor Tomography

One of the main challenges Global Navigation Satellite System (GNSS) tomography is in solving ill-conditioned system equations. Vertical constraint models are typically used solution procedure and play an important role quality GNSS tomography, addition to helping resolve ill-posed problems In this study, based on a water vapor (WV) parameter, namely IRPWV, new vertical model with six sets coefficients for different WV states was developed tested throughout 2019 Hong Kong region four tomographic schemes, which were carried out traditional using three types scale height parameters. Experimental results numerically compared against their corresponding radiosonde-derived values. Compared tests that model, our showed that, first, daily relative error density (WVD) less than 30%, can lead at least 10% 49% improvement average lower layers (below 3 km, except ground surface) upper (about 5–10 km), respectively. Second, skill score monthly root-mean-square (RMSE) layered WVD above 10 accounted about 83%, 87%, 64%. Third, annual biases WVD, significantly decreased by 1.1–1.5 g/m3 2–3 1 where all schemes maximal bias value. Finally, RMSE 0.6–3 km) improved 13–42% 5–47%, Overall, performed better accuracy results, model.