Assessment of the impact of TS assimilation from ARGO floats in the Mediterranean Sea

[摘要] In this paper, the impact of assimilating Temperature (T) and Salinity (S)profiles from Argo floats in the Mediterranean Sea is quantitativelyinvestigated using the Observing System Simulation Experiments (OSSE)approach. The impact of varying the number of floats and their launchpositions is considered, using numerical simulations with a MOM model and areduced-order multivariate Optimal Interpolation scheme (SOFA) forassimilation. Realistic float coverage and launch positions used during thefirst MFSTEP phase are considered, as well as "ideal" density coveragethat can be envisioned for the future, corresponding to a double coveragewith respect to MFSTEP and with floats released along the VOS tracks. Themost effective float trajectories are identified, showing that frontalregions play a major role, and that it is crucial to maintain a sufficientcoverage of them. In addition to this, a comparison is also performedbetween the results obtained from MEDARGO floats in ideal conditions andresults from "ideal" profiles taken at fixed points along the VOS tracks,as for the XBT data. For consistency the coverage considered is double theactual XBT coverage during MFSTEP, resulting in a threefold increase in thenumber of profiles compared to the MEDARGO experiment. The maximum errorreduction is of approximately 10%, suggesting that spatially coarserprofiles from floats can be more efficient since they follow flow features.

[学科分类] 海洋学与技术