[A-OS21] Global ocean observation networks: Current status, results, re-assessments, and future perspectives

[AOS21-P01] UN Ocean Decade Project "SynObs" and Observing System Experiments for assesing the impact of Argo salinity drift

*Yosuke Fujii¹ (1.Meteorological Research Institute, Japan Meteorological Agency)

Keywords:UN Ocean Decade, Observing System Experiment, Ocean Prediction System, Argo Float, Data Assimilation, Observing System Design

“Synergistic Observing Network for Ocean Prediction” (SynObs) is proposed by OceanPredict Observing System Evaluation Task Team (OSEval TT) as a common comprehensive UN Ocean Decade Project to the three UN Decade Programmes, ForeSea, CoastPredict, and Observing System Co-Design. SynObs will seek to extract maximum benefit from combining of various observation platforms’ measurements, typically satellite and in situ observation data, or combinations of coastal and open ocean platforms for ocean/coastal predictions. SynObs aims to identify the optimal combination of the different ocean observation platforms through observing system design and evaluation, and to develop assimilation methods which can enable drawing synergistic effects from these combinations. Targets of SynObs include open-ocean, such as global, tropical, mid-latitude, arctic and subarctic oceans, as well as coastal-sea, and biogeochemical observing systems. SynObs plans to have an international Symposium on the ocean observation impacts in ocean and coupled predictions in Tsukuba, Japan, this November.

As one of the activities for SynObs, OSEval TT is currently conducting multi-system observing system experiments (OSEs) for the abrupt salinity drift (ASD) of Argo floats. Several ocean prediction centers, including JMA, ECMWF, and CSIRO, participate in the activity. In the JMA’s OSE result, artificial increase of global salt content due to ASD is mostly suppressed by substituting the real-time Argo data assimilated into the model with their delayed-mode equivalent, but the ASD effect is not sufficiently suppressed by just applying the gray list provided by the Argo Global Data Assembly Center (GDAC) to the real-time data.