ALTIS: a new tool for processing along-track altimetry data
Event: 2019 Ocean Surface Topography Science Team Meeting
Session: Others (poster only)
Presentation type: Type Poster
Analysis of along-track information contained in radar altimetry GDR could present some difficulties when dealing with long-term records over wide region. The new ALtimetry TIme Series (ALTIS) software offers new opportunities to end-users for processing along-track altimetry data. This software operates in two modes. One with a Graphical User Interface (GUI) which could be mostly used for the definition of altimetry vitual stations over inland water bodies taht requires a very specific processing composed of a refined selection of valid data for estimating water levels and eventually the correction of hooking effect. Inheriting from the Multi-mission Altimetry Processing Software (MAPS), it offers the possibility to end-users to define their own virtual stations using the altimetry data contained in the Geophysical Data Records (GDRs) for the most recent nadir-looking altimetry misisons (i.e., Envisat, Jason-1, Jason-2, and Saral). Once achieved a coarse selection of the altimetry measurements present in the sudy area, altimetry heights are computed using the geophysical and environmental corrections for different type of surface (rivers and small lakes, great lakes, ocean, and coastal areas). A graphical user interface allows to visualize not only the altimetry heights derived from the different retracked ranges available for each mission (e.g., Ocean, Ice-1, Ice-2, Sea Ice, MLE-3) inside the study area, but also any corrections used and other parameters (e.g., backscattering coefficients) that can be useful for selecting the valid altimeter heights. Correction of the hooking effects can be performed on the selected or a part of the selected data at any cycle. The selection of the valid data can be saved at any time and reloaded. Time-series of altimeter heights are then computed based on the user’s selection of the valid data and can be exported. The second mode allows the reconditionning of the altimetry data using the normalized tracks defined at CTOH. These normalized tracks were defined to order the altimetry data using an along-track grid allowing aneasier handling of the altimetry data especially for the statistical analysis. This software will be soon available on the CTOH website: htpp://ctoh.legos.obs-mip.fr.