Diagnostic Method for Atmosphere–Ocean Coupling Over Tropical Oceans at the Sub‐Seasonal Timescale

Abstract This study introduces a novel diagnostic method to assess tropical atmosphere‐ocean coupling, using a two‐dimensional plane defined by the 90‐day high‐pass‐filtered sea surface temperature (SST) and column water vapor (CWV). The method was applied to reanalysis data and high‐resolution coupled atmosphere‐ocean simulation data. In the Indo–Pacific warm pool region, the phase relationship between SST and CWV remained consistent across both reanalysis and simulation data sets. However, differences in the temporal evolution of these variables were observed in the central Pacific region. The heat budget analysis results indicate that the differences between the two data sets in the central Pacific are related to variations in the effects of atmospheric disturbances on SST. This study demonstrates the potential of our novel diagnostic method for evaluating atmosphere–ocean coupling in climate models.