Implementation of position assimilation for ARGO floats in a realistic Mediterranean Sea OPA model and twin experiment testing

[摘要] In this paper, a Lagrangian assimilation method is presented and implementedin a realistic OPA OGCM with the goal of providing an assessment of theassimilation of realistic Argo float position data. We focus on anapplication in the Mediterranean Sea, where in the framework of the MFSTEPproject an array of Argo floats have been deployed with parking depth at 350m and sampling interval of 5 days. In order to quantitatively test themethod, the "twin experiment" approach is followed and synthetictrajectories are considered. The method is first tested using "perfect"data, i.e. without shear drift errors and with relatively high coverage.Results show that the assimilation is effective, correcting the velocityfield at the parking depth, as well as the velocity profiles and thegeostrophically adjusted mass field. We then consider the impact ofrealistic datasets, which are spatially sparse and characterized by sheardrift errors. Such data provide a limited global correction of the modelstate, but they efficiently act on the location, intensity and shape of thedescribed mesoscale structures of the intermediate circulation.

[学科分类] 海洋学与技术