Two schemes on assimilation with Argo data obatined from the west Pacific

The Ocean Variational Analysis System(OVALS) assimilation system designed by the institute of Atmospheric Physics,Chinese Academy of Sciences and nudging method were used to assimilate the Argo grid data with the resolution of 1°x1° and Argo profile data into Princeton Ocean Model(POM)numerical model,respectively. The assimilation of Argo grid data in 2006 indicated that the 3D variation data assimilation improved the simulation results of temperature,reducing about 1.0℃ in root mean square error of either horizontal or vertical distribution except for SST. Furthermore,the grid data assimilation evolved over time,which was better in March and April than that in January and February. In comparison with independent OGCM for the Earth Simulator(OFES) data,the data assimilation only partially enhanced the accuracy of simulated temperature pattern due to an inherent large difference between OFES data and Argo grid data that were used during the data assimilation. The nudging method was applied to assimilate the Argo profile data into POM numerical model in the summer of 2006. The process of nudging was very rapid,which completed within about half day assuming the relaxation coefficient was 0.5. The nudging assimilation also manifested that the temperature structure even far from the Argo profiles could be rapidly influenced,and the remote impact could remain several days.