Structure of the Pacific Walker Circulation Depicted by the Reanalysis and CMIP6

The Pacific Walker circulation (PWC) is one of the most important components large-scale tropical atmospheric circulations. PWC and its influences have been studied extensively by numerical models reanalysis. newly released ERA5 NCEP2 are widely used reanalysis datasets serve as benchmarks for evaluation model simulations. If results these differ significantly, this could lead to a bias in projected long-term climate knowledge. For better understanding future change, it necessary evaluate productions. As result, we compared structures between from month seasonal time scales. We zonal mass streamfunction (ZMS) over equatorial indicate strength PWC. PWC’s average monthly or cycle peaks around July. From February June, shows higher intensity, whereas greater intensity July December. center generally stronger wider than ERA5. ERA5, however, revealed that west edge (zero line ZMS western Pacific) had moved 10 degrees westward comparison NCEP2. In addition, mean state CMIP6 models; vertical multi-model ensemble (MME) similar those reanalyses structure but weaker two datasets. broader CMIP6, boundary 7 17 farther NCEP2, respectively. This study suggests that, when using structural changes edge, extreme caution should be exercised.