An OOPC/WCRP-CLIVAR joint session was successfully organised online on 22 April 2021 during the OOPC-24, in order to further strengthen the interaction between OOPC and WCRP/CLIVAR. There were around 20 people attending the session. M. Ravichandran (CLIVAR SSG), Regina Rodrigues and Greg Foltz (CLIVAR ARP), Roxy Mathew Koll and Juliet Hermes (CLIVAR/IOC-GOOS IORP), Sophie Cravatte (CLIVAR PRP) and Jose Santos and Jing Li (ICPO) from CLIVAR side attended the session.

The session consisted of five invited talks, including a brief introduction to OOPC, by Sabrina Speich, co-chair of OOPC and former co-chair of ARP; Tropical Atlantic Observing System (TAOS) Review, by Regina Rodrigues from ARP; Indian Ocean Observing System (IndOOS), by Roxy Mathew Koll from IORP; Tropic Pacific Observing System 2020 (TPOS2020), by Weidong Yu, co-chair of OOPC and former co-chair of IORP; and an introduction on the CLIVAR-GOOS workshop on ocean observation, also by Weidong Yu. The CLIVAR’s role on pilot and process studies, as well as the best practice and scientific design of ocean observing system are highly appraised by OOPC co-chairs. Some common issues facing by the regional observing systems in different basins have been identified, such as the difficulty in accessing the Exclusive Economic Zone (EEZ) and coastal areas; the piracy and vandalism of buoys; and how to better link in situ observations with satellite missions, new technologies, and etc. While, other featured practices were also highlighted, such as the IndOOS Resource Forum (IRF) for mobilizing resources from Indian Ocean rim countries and international funding agencies to support IndOOS; the officially signed MoU among France, US and Brazil to maintain the sustainable funding support to PIRATA; and the routine process for TPOS assessment, and etc.

During the discussion, participants were excited to have the cross-basin discussion, and thought it would be necessary to be continued, for which the planned CLIVAR-GOOS workshop on ocean observation can really fit into. Due to the COVID-19 pandemics, the workshop is now postponed to 2022 with series of informing seminars being planned in 2021. Meanwhile, the OOPC webinar series on boundary observing system will start on 4 May 2021, aiming to bring the observational and modelling groups together to support the boundary measurement.

Another session dedicating to the updates on different tasks within OOPC (BSTT, Air-Sea fluxes, Indicators, etc.) will be organised soon, and representatives from CLIVAR will be invited.