Ionospheric Corrections for Satellite Altimetry ? Impact on Global Mean Sea Level Trends

Atmospheric delay corrections for satellite altimetry measurements are essential deriving highly accurate sea surface heights and reliable global mean level (GMSL) trend estimates. A commonly used method to correct ionospheric path delays the usage of GNSS-based Global Ionospheric Maps (GIM). The different orbit GNSS altimeter satellites require an adaption GIM account free electrons in Earth plasmasphere. This study shows that widely scaling approach based on International Reference Ionosphere (IRI) is not able accurately scale models. impact neglecting plasmaspheric part atmosphere strongly correlates with solar activity about 11 years. manifests itself as errors GMSL. For Jason period (2002–2021) a error 0.17 mm/year can be shown, which even larger smaller periods (e.g., 1.0 Jason-1 lifetime). application additional constant factor 0.886 reduce differences below 0.05 mm/year.