AlTiS Software for generating Time-Series of Water Levels from Radar Altimetry Data
Résumé
Satellite radar altimetry can be used to determine water level height of continental water bodies, if used with appropriate processing that depends on the size and geometrical configuration of the targets. AlTiS (Altimetry Time Series) is software designed to visualize and process radar altimetry data with the goal of generating time series data of radar altimetry data over water bodies of different sizes such as river, lakes and wetlands. Even if its major goal is the creation of time-series of water levels derived from the altimetry range, it can also be used to generate time series of any other altimetry parameters (e.g., corrections applied to the range, backscattering coefficients, or brightness temperatures).
Through a Graphical User Interface (GUI), without any skills in data processing, the user can handle altimetry data in order to:
• Display several parameters of altimetry data like surface height, altimetric range, atmospheric corrections (ionosphere and wet and dry troposphere path delay corrections) and also to display some characteristic parameters of the waveform like the backscatter coefficient, and peakiness.
• Graphically select altimetric measurements to remove outliers and easily done owing to Landsat background image.
• Generate water height time series from the valid altimetry data previously selected
• Export the time series into various files format as CSV and HydroWeb
AlTiS accepts CTOH altimetry products (Level 2 GDR supplied by the CTOH). CTOH GDR data have been specifically conditioned to optimize the data size by making a geographical selection and includes the right altimetry parameters for hydrological studies.
AlTiS can process several altimetric data products from followed missions : Jason-1/2/3, ERS-2, ENVISAT, SARAL, Sentinel-3A/B, and soon, Sentinel-6/Jason-CS and the nadir altimeter onboard SWOT. They are supplied for free through a web request form on the CTOH website (http://ctoh.legos.obs-mip.fr/applications/land_surfaces/altimetric_data/altis).
AlTiS is mainly employed for hydrological applications and can be used for training courses on radar altimetry at bachelor or master levels. It is also a very convenient tool to analyse the radar altimetry data contained in the GDR over any type of land surfaces.
AlTiS is a software developed by CTOH as part of its activities as a National Observation Service. AlTiS is a free software and it is released as an open source under the CeCill License. Altis is working under python3 environment and tested for GNU/Linux, Windows 10/11.
AlTiS is available on GitLab : https://gitlab.com/ctoh/altis
Origine : Fichiers produits par l'(les) auteur(s)
Licence : CC BY - Paternité
Licence : CC BY - Paternité