Towards a Tropical Pacific Observing System for 2020 and Beyond.

The international TPOS 2020 Project arose out of a review workshop in January 2014, following challenges sustaining TAO-TRITON array in 2012, with the aim of rethinking the tropical Pacific arrays in light of new scientific understanding and new ocean technology since its original design in the 1980s-90s.

Observing and understanding ENSO remains a fundamental motivation, extending to biogeochemical phenomena, to processes on smaller scales that rectify into the low frequency, and, to the interaction of the coupled boundary layers of the upper ocean and lower atmosphere. Our primary customers remain the operational prediction centers and we will design an array to support research into physical processes, especially those not well represented in current-generation models.

Current-generation forecast systems (data assimilation and the model physics) do not make effective-enough use of observations, thus the modeling centers are well-represented in the TPOS 2020 structure and our sampling is targeted to where the forecasts systems need guidance for improvement

While we advocate evolution of the present arrays, the long climate records built up at mooring sites, repeated ship surveys, and island stations are fundamental to detecting and diagnosing both natural climate variability and detecting climate change signatures.

Task teams have been established in specific topic areas. These will report in mid-2016, when a plan for the revised arrays will be presented to the agencies and governments, for completion of the evolution by 2020.This presentation will discuss the motivation, guiding principles, and potential changes of direction for the tropical Pacific observing system.