“For the past 30 years, the OSR SO area has benefited from an exceptional coverage in terms of satellite acquisitions in different spectral domains (optical, thermal, passive microwave, radar), allowing to document the state and evolution of surfaces regularly and over large areas”.
Time series of optical and thermal data
- LANDSAT
LANDSAT satellites have been providing 30-meter resolution data for 30 years. Since then, these data have been acquired regularly over all earth surfaces with a 16-day ground coverage cycle. Although their image frequency (note Susan: je n’ai trouvé le terme repetitivity ou repetitiveness que dans des traductions de sites .fr, et pas dans des publications internationales) and resolution are now somewhat insufficient, the LANDSAT 4,5,7 and 8 satellites are very useful to prepare Sentinel-2 data exploitation over large areas.
For this reason, the thematic pole on continental surfaces THEIA has decided to allow users to access LANDSAT data acquired over France since 2009.
To access LANDSAT surface reflectance images (Level 2A) processed by the THEIA data and services center: click here.
- SPOT AND FORMASAT-2
SPOT and FORMOSAT-2 data concerning the OSR area (see here) (note Susan: lien hypertexte à définir) are available since 1992 and 2006 respectively. The Kalideos OSR MiPy database gives access to the following data:
i. images from Spot 1 to Spot 5 satellites, gathering 10-years archive data from the same family of sensors, which is ideal for the analysis of landscape evolution in the southwest of Toulouse
ii. Formosat-2 optical satellite images, allowing us to zoom in on a part of this region to study more specific topics of interest.
- SENTINEL
The ESA Sentinel-2 mission, recently launched as part of the European Union’s Copernicus program, consists of two satellites, Sentinel-2A and Sentinel-2B: the first was launched in June 2015 and the second in March 2017.
Each of these satellites allows an observation of all land surfaces every 5 days, at 10-m resolution, in 13 spectral bands ranging from visible to mid-infared.
These data are freely accessible here.
For more information on space missions, visit the MultiTemp blog!
Radar data time series
Radar data provide images whatever the meteorological conditions (night, cloud cover).
Since 2004 and 2008, ENVISAT and TERRASAR-X data are acquired frequently over the OSR South West study area. In addition, as part of the MCM’10 experiment, RADARSAT2 and ALOS data have also been acquired in various configurations (resolutions, polarizations…).