We first present a novel method of monitoring the UHI intensity using GNSS data. We overcomes two major challenges in the algorithm development. The first challenge is the determination of the GNSS tomographic top grid height, and the second challenge is the estimation of temperature from wet refractivity. The result shows that the proposed algorithm can achieve an accuracy of 1.2 K at a 95 % confidence level.

The lack of collocated meteorological data at GNSS stations makes it difficult to take full advantage of GNSS observations for weather studies. This research demonstrates the potentials of retrieving accurate PWV from GNSS using adjacent synoptic data and generating high-quality PWV maps from the GNSS network for weather prediction in near-real time. Results also demonstrate that it's possible to reveal the moisture advection, transportation and convergence during heavy rainfalls using PWV maps.

This paper proposes an optimal tropospheric tomography approach with the support of an auxiliary area, which has the ability to use the signals crossing out from the top boundary of the tomographic area. Additionally, the top height of the tomography body is determined based on the average water vapour distribution derived from the COSMIC data. The compared result reveals the superiority of the proposed method when compared to the conventional method.

We proposed a new method to determine the scale height of water vapor, which will improve the quality of vertical constraints. Then, the smoothing factor in the horizontal constraint was determined based on ERA-Interim products. The evaluation results show that the water vapor density quality obtained by the optimized technique is 13.8 % better below 3.8 km and 8.1 % better above 3.8 km than that obtained by the traditional technique.

This study focused on the extraction of the atmospheric excess phases using the non-difference processing strategy. The COSMIC POD processing is used to accurately determine the position and velocity of the centre of mass of the satellite and the receiver offset based on PANDA software. Finally, the bending angle, refractive and dry temperature profiles are taken from AEP using ROPP software.