Comparison of TRACIS campaign data with data from radiosonde, IPRAL Lidar and ERA5

The study of atmospheric composition is a major priority for improving the understanding of future climate models; therefore, it is essential to analyze in detail the variations of certain key variables, particularly water vapor, which strongly influences meteorological phenomena and plays a major role in radiative forcing. During my doctoral project, my research focused on studying the variability of water vapor using radiosoundings, an instrumental method for obtaining precise and high-quality measurements down to the UT/LS zone, by improving the quality of measurements through instrumentation. In addition to internal tests aimed at obtaining higher-quality measurements, setting up observation campaigns is a top priority in order to validate the performance of the sondes under real-world conditions, identify seasonal biases, and thus be able to make various corrections if necessary. Therefore, the TRACIS (Tropospheric Research Campaign on Air Moisture Content by Ipral at SIRTA) comparison campaign, in which I participated and which took place at the SIRTA site (Atmospheric Remote Sensing Research Instrumental Site) [48.71331°N, 2.20901°E] from May 12 to June 12, 2025, made it possible to assess the consistency of the data between the different sondes, while comparing these datasets with auxiliary sources such as ground-based observations and satellite measurements. This multi-source approach notably includes measurements from the IPRAL LiDAR, as well as fields from the ERA5 reanalysis model, thus strengthening the comparison, identifying potential systematic biases, and improving the overall interpretation of the results. Preliminary analyses focus on comparisons between the combined working measurement standard (CWS; mean RH M10/RS41) and other convergent datasets (M20, ERA5, and IPRAL LiDAR), allowing an evaluation of the representativeness and consistency of the different observation sources.