TCs’ contribution on summertime subtropical ISOs and submonthly wave patterns over the western North Pacific

A TC-removed technique was applied to global analyses to study the impact of TCs on the summertime subtropical ISO propagating over the western North Pacific (WNP). The TC-removed ISO pattern showed a westward shift from the area between Taiwan and Japan to the northern South China Sea. The monsoon trough thus weakened after TCs were removed from the circulation fields. Furthermore, the interaction between the ISO and submonthly wave patterns also showed weaker signals after TC removal. However, the activity over the South China Sea remained considerable strong because fewer TCs passed through this area. Therefore, the ISO and submonthly wave patterns retained considerable intensity over the South China Sea. The higher frequency of TC occurrences in the westerly phase results in a more pronounced energy reduction following TC removal compared to the easterly phase. Moreover, synoptic-wave PKE exceeds its submonthly counterpart, and the baroclinic conversion exhibits a north-south orientation, both due to the upstream recurving TCs that redirect their paths toward Japan. These findings reinforce our knowledge of climate variability, thus advancing climate modeling accuracy.This research underscores TCs' substantial impact on atmospheric circulations, highlighting their role in coordinating the submonthly wave patterns, synoptic waves, and ISOs in the WNP. This enhanced knowledge facilitates a more accurate explanation of climate variability. Nevertheless, comprehensive analyses and assessments across the global domain are essential to fully include the broader implications and variability of TC interactions with atmospheric perturbations worldwide.