SIRTA-ReOBS is a project whose goal is to synthetize, analyze, homogeneize, all SIRTA observations hourly averaged in a single NetCDF file.
It has been developped in order to study regional climate variability, for the particular case of Paris area.

Actually, when interested in the regional climate scales that involve both the influence of large-scale atmospheric circulation and local processes, it is necessary to use a dataset suitable for these scales. But the exercise is complex because it involves all the system parameters and all spatial and temporal scales. Also the small magnitude of the signals that we are looking for, and connections between processes at local scales and anomalies at climate scale, add to this complexity. It is therefore necessary to use a dataset dedicated to these climate issues: multi-year, with good time resolution (hourly), multi-parameters without calibration problem.

To make its data easily usable, the SIRTA [Haeffelin et al., 2005] provides an important work on their homogenization, quality control, averaging... The goal of SIRTA-ReOBS project is to write in a single netcdf file all variables hourly averaged from 2003 to now, their description, quality control indices, their spatial and temporal variability.

SIRTA-ReOBS is relevant to answer the question of the variability observed in the Paris region at the decadal scale because:

  • The oldest observations date back to 2003 and therefore have a strong statistical value in addition to the multi-annual coverage
  • The time resolution also allows to address the daily cycle scale
  • Multi-parameter approach allows rising to the level of processes
  • The coupling of in situ, passive, and active remote sensing measurement, provides the most possible resolved atmospheric column at all time scales mentioned above

This approach is consistent with different international initiatives such as the COPERNICUS Climate Change Service (C3S) European project. It is also discussed in the framework of ACTRIS European project, and it has been identified as recommendation #12 by the WCRP climate symposium 2014.