North Pacific Model Biases Influence Kuroshio Extension Atmospheric Circulation Patterns

Abstract The Kuroshio Extension (KE) system significantly impacts decadal North Pacific climate variability by modulating downstream atmospheric circulation patterns. Using satellite‐derived and reanalysis products, and simulations from the High Resolution Model Intercomparison Project within the Coupled Model Intercomparison Project Phase 6, we evaluate how well coupled models reproduce KE atmospheric circulation patterns and their mechanisms. Observational KE regression patterns show that warm sea surface temperature (SST) anomalies over the Kuroshio‐Oyashio Extension (KOE) enhance local surface evaporation and lower‐tropospheric diabatic heating, accompanied by downstream cyclonic circulation anomalies over the North Pacific. In coupled models, a stronger latent heat flux response is linked to better simulation of these mechanisms and circulation patterns, whereas models with cold SST biases over the KOE region systematically underperform. Increasing resolution does not consistently alleviate these biases, reflecting structural issues across models that may obscure the potential benefits of higher resolution.