The 8^th conference call of the CLIVAR ENSO conceptual models working group was held on September 8^th, 2021 and lasted about 1h45 with 16 members of the working group and guests present. 

The first talk was given by Dr. Xiang-Hui Fang on an extension of the recharge oscillator to a 3-box model that can account for ENSO diversity and represent the one-way influence of low frequency Walker Cell changes on ENSO. The following discussion underlined the need for not only deriving the model parameters empirically from observations, but also better underlining the physical processes. The conceptual model reproduces many desirable features of ENSO, including the skewness of the Central Pacific (CP) and Eastern Pacific (EP) events, but seems to fail to reproduce the quite different spectra of those two ENSO flavours. This conceptual model nonetheless provides a promising way to investigate the global change impact on ENSO through its effect on the Walker Cell intensity. 

The second talk was given by Soong-Ki Kim (abstract below) using two different conceptual models of ENSO to discuss its response to global warming and interdecadal mean state changes. One of the points was that the vertical oceanic structure (thermocline depth and vertical temperature gradient) plays a strong role in modulating the ENSO properties. It was suggested that the apparent lack of relation between the thermocline depth and ENSO changes in CMIP5 could be related to different regime parameters in the models and observations.

The working group will meet again through videoconference in November 2021 and January 2022. The working group will also hopefully meet face-to-face after the OSM2022 meeting in Hawaii back-to-back with a CLIVAR Pacific Region Panel meeting, where a tutorial on ENSO conceptual models and an ENSO session for 2022 Ocean Sciences Meeting (OSM) will be organised by some members (deadline for abstract submission to 2022 OSM is 29th September).