Statistical Validation of GNSS Radio Occultation data over Egypt | ||||
| Advances in Basic and Applied Sciences | ||||
| Article 3, Volume 2, Issue 1, January 2024, Page 29-45 PDF (1.61 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/abas.2024.223245.1024 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
hala Eldosoky gomaa  1; Ashraf mousa2; Mohamed Yousef3; Ayman Mahrous3
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| 1physics department, faculty of science, Helwan University | ||||
| 2National Research Institute of Astronomy and Geophysics (NRIAG) | ||||
| 3Space Weather Monitoring Centre (SWMC), Faculty of Science, Helwan University | ||||
| Abstract | ||||
| Radiosonde (RS) measurements of the upper atmosphere have long been the principal source of data, with measurements spanning more than 60 years . RS have limited number of stations on Egypt. Thus, it has poor spatial and temporal resolution, and This negatively affects meteorological research, atmospheric observation, and weather forecasting studies over Egypt. It is needed to find an additional technique characterized by the length of the available time series as well as with the high vertical resolution. Global Positioning System Radio Occultation (GPS RO) is the satellite technique received by a low-Earth orbiting satellites to profile the Earth's atmosphere with high vertical resolution and global coverage. This technique has been found to enhance weather forecasting and climate monitoring. In this study, the GPS RO temperature and vapor pressure profiles of COSMIC satellite mission over Egypt from 2007 to 2019 have been validated with those of the available six Radiosonde stations (RS). GPS RO and RS profiles collocated by matching the position and the time, The horizontal distance between the chosen RS stations and the GPS RO event is within 150 km and the time window was 3 hours. The comparison was performed only on the standard pressure level. The main objective of this paper is to check the accuracy of the GPS RO at different elevations. For this aim the differences between RS and GPS RO were sorted according to pressure level in to 4 groups. It is found from the results that GPS RO profiles agree well with RS data. The mean temperature bias for all stations equal (0.22) with standard deviation (1.83). On the other hand, mean vapor pressure bias equal (-0.02) with standard deviation (0.12). According to pressure level sorting, the change of temperature mean bias and standard deviation are increasing with the pressure level decreasing. | ||||
| Keywords | ||||
| GPS radio occultation; Radiosonde; Water vapor distribution | ||||
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