LAUSR

Underwater gliders can provide real-time and spatially flexible temperature/salinity (T/S) observations for improving the marine forecast by data assimilation. By conducting Observing System Simulation Experiments (OSSEs), this study aims to investigate the effect of assimilating glider-observed T/S profiles regarding the horizontal resolution of glider deployment and assimilation frequency, as well as the combination of assimilating satellite-derived sea level anomaly (SLA), on the forecast skill for an extreme warm eddy in the Northwestern South China Sea (SCS) in 2010. The results of OSSEs show that assimilating either glider-observed T/S profiles or satellite-derived SLA is able to improve the forecast skill, and assimilating both of them gains the largest improvement. Under the premise of a full coverage of the eddy, it is found that the higher horizontal resolution of glider deployment is, the better forecast skill will be obtained. Meanwhile, the assimilation of the glider-observed T/S profiles with a 12-h interval achieves the best forecast skill among the intervals of 4 h, 8 h, 12 h, and 24 h. These results provide valuable reference for the deployment of underwater gliders as well as the assimilation strategy of glider observations for improving the real-time marine forecast in the Northwestern SCS in the future.