Abstract
A new concept is proposed for estimating the zenith wet delay (ZWD) and atmospheric weighted average temperature by inputting the temperature, total pressure, and specific humidity from surface weather data. In addition, a new ZWD integral method is described for highly accurate calculation of the ZWD from radiosonde observation. To evaluate the advantages of the new discrete integral formula, we utilized the 8-year radiosonde profiles of 85 stations in China from 2010 to 2017 to validate the accuracy of the radiosonde-derived ZWD. The results showed that the mean accuracy of the ZWD derived from radiosonde data was 4.28 mm. Next, the new ZWD model was assessed using two sets of reference values derived from radiosonde data and GNSS precise point positioning in China. The results confirm that the new development improved the accuracy of the estimation of the tropospheric wet delay from the surface meteorological data. The performance of this new model can be seen as an important step toward accurately correcting the tropospheric delay in Global Navigation Satellite System (GNSS) real-time navigation and positioning. It can also be used in GNSS meteorology for weather forecasting and climate research.
Highlights
The propagation delay induced in signals from the Global Navigation Satellite System (GNSS) through the neutral atmosphere is a major error source in GNSS real-time navigation and positioning [1]
Many studies have confirmed that the zenith hydrostatic delay (ZHD) can be well estimated with an accuracy of a few millimeters by using surface meteorological data based on the Saastamoinen ZHD model [7,8,9,10]
The results show that the performances of these models still have large inaccuracies in some areas, so it is necessary to establish a new model to compensate for the poor zenith wet delay (ZWD) estimation accuracy [7]
Summary
The propagation delay induced in signals from the Global Navigation Satellite System (GNSS) through the neutral atmosphere is a major error source in GNSS real-time navigation and positioning [1]. Many studies have confirmed that the zenith hydrostatic delay (ZHD) can be well estimated with an accuracy of a few millimeters by using surface meteorological data based on the Saastamoinen ZHD model [7,8,9,10]. Since the 1970s, many ZWD models have been proposed to derive the ZWD from surface meteorology observations [3,11,12,13,14,15,16,17] The performances of these empirical ZWD models have been comprehensively and systematically investigated in specific regions or globally using benchmark values derived from radiosonde data or products of the European Center for Medium-Range Weather Forecasts [7,18]. The performance of the new ZWD model with respect to radiosonde data and in GNSS PPP is discussed in the fourth section. Conclusions and final remarks are given in the last section
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