2nd TPDV Working Group Meeting

The Tropical Pacific Decadal Variability Working Group (TPDV WG), coordinated by the Pacific Region Panel, organised its 2nd telecon on 28 June 2021. Twenty TPDV WG members participated in the telecon.

During the meeting, a thematic talk on ‘Wind stress forcing and low-frequency variability of the Pacific Subtropical Cells (STCs)’ was given by Dr. Giorgio Graffino, a TPDV WG member from the National Centre for Atmospheric Science, and Department of Meteorology, University of Reading, UK, highlighting the following two topics: 1) Influence of wind forcing in different latitude bands on the STC transport and equatorial SSTs and 2) Magnitude of STC transport and relationship between transport convergence and tropical SST anomalies  in the CMIP5 and CMIP6 models relative to a set of ocean reanalyses. During the following discussion, potential areas for future studies have been identified, including: 1) Elucidate why anomalous wind stress forcing in subtropical regions is more effective in forcing STC variability and what the origin of this anomalous wind forcing is; 2) Assess whether realistic changes in subtropical wind stresses can result in significant equatorial SST changes; 3) Consider whether anomalous heat fluxes could also alter the STC strength; and 4) Perform more in-depth analyses of climate models (e.g., examine the three-dimensional representation of the STCs in the models, and the processes responsible for the STCs’ impact on equatorial SST anomalies), in order to understand inter-model differences and achieve a more in-depth assessment of the STC’s role in Tropical Pacific, and basin-wide, variability.

The next TPDV WG telecon is scheduled for 28 July 2021.