The colocation consist in relating together data from various sources (in-situ or satellite sensors, numerical models), according to space and time criteria, which means :
- retrieving n-uplets of the closer (in space and time) single observations from two (or more) sources ( minimal level)
- or collecting all almost simultaneous observations from several sources over a given geographical area ( total level)
These products are specially intended for the following studies :
- calibration/validation or inter-comparison of sensors
- monitoring the quality and possibly drift of sensors
- estimating the relations between various geophysical parameters (each retrieved from a different source)
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monitoring geophysical features or events over specific areas and time periods (from various sensors)
Many colocation products, coupling satellite, in-situ (TAO, TOGA, ...buoy networks) and models (ECMWF) observations are now generated and distributed at CERSAT.
What is colocation?
The colocation consists in grouping measurements close in space and time from various sensors (or other data sources like numerical model outputs). Two measurements are said to be close if they are below a given distance and time difference. These colocation criteria are set according to each sensor geometry as well as each satellite orbital parameters; For each colocated measurement, a selection of parameters from each source data product (associated to a sensor) is provided.
Applications of colocation are numerous :
- calibrating new sensors
- monitoring sensor quality
- getting the most complete near-instantaneous glance at a geophysical phenomenon
- exhibiting cross-correlations between various geophysical parameters
Refer also to the Applications section which exhibits some results and studies grounded on the colocated datasets generated at CERSAT.
