Sensitivity study on the use of Argo data for the validation of altimeter products in the Mediterranean Sea
Event: 2015 Ocean Surface Topography Science Team Meeting
Session: Science III: Large scale and global change ocean processes: the ocean's role in climate
Presentation type: Type Poster
Contribution: PDF file
In this work, performed in the frame of the E-AIMS FP7 European project, we review the method of comparison between SLA and DHA in the Mediterranean Sea (regional scale) in order to validate altimeter sea level measurements with an increased confidence. Namely, we focus on the sensitivity of specific SLA gridded products provided by AVISO in the Mediterranean Sea to the reference depth (400 or 900 dbars) selected in the computation of the Argo dynamic height as an integration of the Argo T/S profiles (Coriolis-GDAC dataset) through the water column. As a previous step to the comparison, the dynamic height anomalies were referenced to a synthetic climatology (400 or 900 m). Finally, to perform the comparison of both datasets, altimeter grids and synthetic climatologies were spatially and temporally interpolated at the position and time of each in-situ Argo profile by a mapping method based on an optimal interpolation scheme. Then, statistics and coherence analyses were carried out between altimetry and the in-situ Argo reference. The analysis was conducted in both the entire Mediterranean Sea and different sub-regions of the basin in order to (1) check biases in the altimetry validation to different reference depths of Argo DHA and (2) investigate the impacts of a given reference depth of integration on the regional and sub-regional Argo sampling and on the comparison with altimeter data. Preliminary results show that correlations between altimeter product and Argo data using 400 m as reference level are slightly higher than those obtained using a 900 m reference level. On the other hand, the standard deviation of the difference between both datasets exhibits the opposite behaviour with higher mean values in the later.