New methods and strategies for electrons density profiles retrieval from radio occultation for the Brazilian region

• Grant number: 22/00276-5
• Support type: Scholarships abroad - Research Internship - Post-doctor
• Effective date (Start): November 01, 2022
• Effective date (End): October 31, 2023
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geodesy
• Principal researcher: Daniele Barroca Marra Alves
• Grantee: Gabriel Oliveira Jerez
• Supervisor abroad: Manuel Hernandez-Pajares
• Home Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil
• Research place: Universitat Politècnica de Catalunya (UPC), Spain
• Associated to the scholarship: 21/05285-0 - New strategies for retrieving profiles from GNSS radio occultation data considering the Brazilian atmosphere, BP.PD

Abstract

Global Navigation Satellite System (GNSS) radio occultation (RO) enables investigations of the Earth's atmosphere. From GNSS satellites to the receivers onboard Low Earth Orbiting (LEO) satellites, the propagated signals are influenced by the atmosphere in different ways. This makes it possible to calculate the refractivity, which provides information on the composition of the atmosphere, such as electron density profiles. Due to the distribution homogeneity, information from RO is especially important when considering scenarios such as the Brazilian atmosphere. Due to its location, in the equatorial region, Brazil has a complex and dynamic ionosphere. In the RO technique, the Abel inversion is commonly used for profiles retrieval, with the assumption of spherically symmetric atmosphere. The technique performance is degraded due to this assumption, mainly in cases such as the retrieval of electron density profiles in regions with high horizontal gradients. To overcome this issue, some alternative methods have emerged, such as the use of additional ionospheric information to take into account its horizontal variability. However, when regions with high horizontal gradients are considered, this is still a challenging topic. In addition, the processing strategies adopted consider global characteristics, due to the coverage of the technique. In this context, this project aims to investigate and develop new retrieval methods and strategies for ionospheric profiles from RO, considering the Brazilian region. With this project, it is expected that more realistic products will be obtained. From those products, ionospheric models which use RO data, may benefit from the inclusion of more accurate profiles.