Tropospheric and Ionospheric Modeling Using GNSS Time Series in Volcanic Eruptions (La Palma, 2021) Barba Ceballos, Paola Jiménez Morales, Vanesa Inmaculada Troposphere Ionosphere ZTD TEC GNSS system Volcanic eruptions La Palma Island Funded by the “INICIA-INV” grant from the “Own Plan 2021–2022” from the University of Cádiz. The signal coming from the artificial satellites of the GNSS system suffers various effects that considerably decrease the precision in solving the positioning problem. To mathematically model these effects, the atmosphere is divided into two main parts, the troposphere and the ionosphere. The troposphere can only be modelled, while the ionospheric effect can be modeled or eliminated depending on the geodetic sophistication of the receivers used. In this way, information is obtained about both layers of the atmosphere. For tropospheric modeling, the parameters of total zenithal delay (ZTD) or precipitable water vapor (PVW) will be taken, and for the ionosphere the total electron content (TEC) will be taken. In this work, statistical and analytical techniques will be applied with the R software; for example, ARMA, ARIMA models, least squares methods, wavelet functions, Kalman techniques, and CATS analysis. With this, the anomalies that occurred in the values of the ZTD and TEC in the case of the 2021 eruption of the Cumbre Vieja volcano on the island of La Palma. 2023-11-06T09:04:59Z 2023-11-06T09:04:59Z 2023-07-04 journal article Barba, P.; Ramírez-Zelaya, J.; Jiménez, V.; Rosado, B.; Jaramillo, E.; Moreno, M.; Berrocoso, M. Tropospheric and Ionospheric Modeling Using GNSS Time Series in Volcanic Eruptions (La Palma, 2021). Eng. Proc. 2023, 39, 47. [https://doi.org/10.3390/engproc2023039047] https://hdl.handle.net/10481/85464 10.3390/engproc2023039047 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional MDPI