Inter-technique validation of tropospheric slant total delays

Abstract

Abstract. An extensive validation of line-of-sight tropospheric Slant Total Delays (STD) from Global Navigation Satellite Systems (GNSS), ray-tracing in Numerical Weather Prediction Models (NWM) fields and microwave Water Vapour Radiometer (WVR) is presented. Ten GNSS reference stations and almost two months of data from 2013, including severe weather events, entered the comparison. Seven institutions delivered their STDs based on GNSS observations processed using five software and eleven strategies. STDs from NWM ray-tracing came from three institutions using three different NWM models. Results show generally a very good mutual agreement among all solutions from all the techniques. The mean bias (over all stations) between the GNSS solution selected as reference, which did not use post-fit residuals in STDs, and all other GNSS solutions without post-fit residuals is −0.6 mm for STDs scaled in the zenith direction, and the corresponding mean standard deviation is 3.7 mm. Standard deviations of comparisons between GNSS a NWM ray-tracing solutions are typically 10 mm ± 2 mm (scaled in the zenith direction), depending on the NWM model and the particular station considered. When comparing GNSS versus WVR STDs, standard deviations reached 12 mm ± 2 mm, as scaled in zenith direction. Moreover, the influence of adding raw GNSS post-fit residuals, as well as residuals screened out of systematic effects, to STDs was studied. It was found that adding raw post-fit residuals always led to lower quality of GNSS STDs while the situation was not that straightforward after the post-fit residuals cleaning.

Monitoring and prediction of hurricane tracks using GPS tropospheric products

“…Liou and Huang (2000) and Sapucci et al (2016) reported a sharp increase in GPS-IWV prior to a rainfall event. In addition, recent studies have investigated the accuracy of GPS tropospheric products by identifying factors that affect the quality of GPS processing (Kačmařík et al 2017;Klos et al 2018, Ejigu et al 2019. Furthermore, in areas where a dense network of GPS stations is available, it is possible to produce optimal GPS-IWV distribution maps to investigate spatiotemporal changes in water vapor.…”

TOMOREF Operator for Assimilation of GNSS Tomography Wet Refractivity Fields in WRF DA System

“…The second step of the quality control process was based on the values of wet refractivity vertical gradients. The reference values of the gradients were calculated using the ALADIN‐CZ model (Kacmarík et al, 2017). These values, together with the mean and standard deviation, are presented in Figure 1.…”

“…The reference values of the gradients were calculated using the ALADIN-CZ model (Kacmarík et al, 2017). These values, together with the mean and standard deviation, are presented in Figure 1.…”

Tracking Hurricanes Using GPS Atmospheric Precipitable Water Vapor Field

“…Thus, the use of GPS tropospheric products for regional severe storm prediction is a current research topic and an application that the geodetic community wishes to promote within the meteorological groups. Besides, recent studies have investigated the accuracy of GPS tropospheric products by identifying factors that affect their quality when GPS data are processed (Kačmařík et al 2017;Klos et al 2018;Ejigu et al 2018).…”