Participants of PRP-12 in Busan, 21 October, 2017

The 12^th session of CLIVAR Pacific Region Panel (PRP) was held on 21 October 2017 at Busan, Rep of Korea. This session was held back to back with the ENSO complexity workshop organized by ICCP (IBS Climate Center for Climate Physics), Pusan National University.

Given the breath of topics relevant to the Pacific sector and the limited time available, the PRP prioritized two high-priority topics for panel discussion: (1) the decadal and multi-decadal variability in the tropical Pacific in connection with the paleo-community, including decadal ENSO modulation and inter-basin relationship, and (2) drafting a recommendation letter to TPOS2020 implementation plan.

It was recognized by the panel that the tropical Pacific also experienced strong decadal trends that the current generation of models seems unable to capture. The full range of these decadal modulations, their driving mechanisms and the ability of current models to capture them are currently unknown. Given the tremendous impacts of the tropical Pacific variability worldwide, the PRP acknowledges that there is an urgent need to address and overcome these issues through the combined analysis of instrumental and paleo ENSO records and model simulations. This led the panel to propose the following action items for the following year:

1. CLIVAR recommendations on TPOS2020 design: Despite the sizeable efforts of TPOS2020 committee towards the design of a tropical Pacific Ocean observing system that meet the scientific challenges of the next decades in many aspects, the proposed decommissioning of many mooring sites of the original TAO/TRITON array is of serious concern to the PRP. In conjunction with ENSO RF, PRP has written a letter that will be circulated to other relevant CLIVAR panels and SSG for endorsement, before sending this letter to TPOS2020 steering group. Along the same lines, unlocking the full potential of the paleo-space require the climate community to include these isotopic measurements within the frame of the current TPOS2020 design. Towards that goal, the PRP panel is also planning to write a letter to TPOS2020 steering group to include these aspects in the redesign of the current tropical Pacific moored array.
2. PRP involvement in TPOS2020 2018 workshop: TPOS2020 is considering to organize a workshop gathering observationalists and modellers to identify the physical processes that will be most important to improve in models over the next decade in order to better understand the tropical Pacific variability, and what observational sampling strategies might be best to depict these processes through sustained monitoring. Given the above concerns, the PRP will try to get actively involved in this workshop to convey these important messages.
3. ENSO conference in 2018 in Guayaquil and proposed workshop: the 4^th international conference on ENSO in a warmer climate will be held in October 2018 in Guayaquil (Ecuador). Three PRP members are already part of the scientific committee of this conference. Given the focus of the PRP activities in the next couple of years, PRP plans to strongly contribute to this conference and to have its next PRP meeting right after it. PRP is also planning to have a small workshop to discuss the range of ENSO decadal variability simulated by long coupled runs (> 1000 years) that will be analysed in the coming year as part of the PRP activities. 
4. Review paper on trans-basins connection in the tropics: A large body of literature recently discussed the potential decadal feedbacks between the Atlantic and Indian Ocean and the tropical Pacific that may have contributed to the recent Pacific cooling trend. In this context, PRP members are planning to contribute to a paper reviewing the connections existing between the three tropical basins across a wide range of timescales. A small workshop gathering the lead authors will be held in China or Australia at the beginning of 2018 to initiate the drafting of this review.
5. ENSO summer school: The PRP will get involved in the organisation of summer school on ENSO to be held in July 2019 in Urbino (Italy). This school should gather ~20 students and last for 10 days. It will also involve members from the ENSO RF.

The meeting venue was coordinated by ICCP, to which the organizer would like to express thanks for supporting the CLIVAR events.