%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES
%A Albino, F.
%A Gremion, S.
%A Pinel, Virginie
%A Bouygues, P.
%A Peltier, A.
%A Beauducel, F.
%A Froger, J. L.
%A Santoso, A. B.
%T Benefits of GNSS local observations compared to global weather-based models for InSAR tropospheric corrections over tropical volcanoes : case studies of Piton de la Fournaise and Merapi
%D 2025
%L fdi:010093359
%G ENG
%J Journal of Geophysical Research : Solid Earth
%@ 2169-9313
%K REUNION ; INDONESIE ; JAVA ; LA FOURNAISE ; MERAPI
%M ISI:001457319900001
%N 4
%P e2024JB028898 [28 ]
%R 10.1029/2024jb028898
%U https://www.documentation.ird.fr/hor/fdi:010093359
%> https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2025-05/010093359.pdf
%V 130
%W Horizon (IRD)
%X From repeat-pass interferometry, tropospheric signals often prevent the detection of ground deformation signals. In recent years, tropospheric corrections derived from global weather-based models have been implemented in several InSAR processing chains. In this study, we evaluate the performance of two weather-based models (ERA5 and GACOS) on two tropical volcanoes: Piton de la Fournaise and Merapi. For Piton de la Fournaise, the reduction of the tropospheric noise is efficient for similar to 30% and similar to 60% of the data sets for GACOS and ERA5, respectively. For Merapi, the performance reaches similar to 40% for GACOS and similar to 50% for ERA5. Although GNSS local stations provide real-time information about tropospheric delays, their potential for improving InSAR corrections on active volcanoes is under-exploited. Here, we produce local GNSS-based tropospheric corrections and compare their performance to global weather-based models. For Piton de la Fournaise, the gain of performance with similar to 34 GNSS stations is about 25% compared to ERA5 models. GNSS-based corrections increase the signal-to-noise ratio in InSAR time series allowing the detection of ground displacements between July and December 2021. For Merapi, GNSS-based models with only 5 stations spatially distributed at different elevations are as efficient as ERA5 models. GNSS-based corrections induce a decrease in the noise level from values >1-0.5 cm in a period of quiescence. Here, we show that GNSS-based models are an efficient alternative to global weather-based models for instrumented volcanoes. The proposed approach paves the way toward near real-time InSAR monitoring of volcanic unrest and other processes (landslides, groundwater extraction).
%$ 021 ; 020 ; 066