PyROEX: a python-based open-source software toolkit for GNSS radio occultation data preprocessing in ROEX format

Abstract Currently, GNSS radio occultation (RO) detection technology has been successfully implemented in satellite missions, including CHAMP, GRACE, COSMIC, Metop, the FengYun-3 series, et al., and has been operationally integrated into numerical weather prediction systems. Despite its technical maturity, the lack of standardized observation-independent exchange format remains a significant challenge for effective data exchange and unified processing of occultation data. To address this limitation, the National Space Science Center (NSSC) of the Chinese Academy of Sciences has proposed and developed the GNSS Radio Occultation Observation Independent Exchange Format (ROEX), aiming to improve data sharing and enhance the application of RO technology in atmospheric sounding and weather forecasting. Based on this, this paper develops a python-based open-source software tool for ROEX file preprocessing, named PyROEX. The software is a graphical user interface (GUI) tool which provides functions for file observation monitoring, observation scientific combination, data integrity checking, and file cutting. Users can freely select the observation they wish to view or combine, and analyze the file quality through plotted graphs. This paper introduces the ROEX format and the functional modules of PyROEX, as well as the analysis results of its operation. It is expected that this software will contribute to the widespread adoption of the ROEX format, thereby reducing the economic costs, time costs, and personnel costs associated with data exchange, communication, and software development caused by inconsistent data formats, and accelerate the operational application of GNSS occultation products.