**4. Conclusions**

Using the ERA-20C monthly reanalysis datasets in summer (June–July–August) from 1900 to 2010 and a variety of global precipitation data, our manuscript studies the multidecadal variations in Rossby wave source over the Tibetan Plateau, the corresponding energy transmission, and its impact on atmospheric circulation pattern over East Asia. The conclusions are summarized as follows:


#### **5. Discussion**

By calculating the components of RWS equation and the three-dimensional T-N wave flux, we analyze the causes of TP-RWS and discuss the influence of TP-RWS on the precipitation and atmospheric circulation pattern in East Asia on an interdecadal timescale. The above conclusions are of great significance for further understanding the variabilities and maintenance mechanisms of Rossby wave sources in the NH summer. Considering that the linear detrending may not fully remove the influence of external forcing, the variations in TP-RWS are also modulated by a variety of external forcing factors. While the tropical cumulus convection and heavy rainfall also play a role in the formation of the steady vortex source and the RWS energy propagation during boreal summer. How the interdecadal variations in sea surface temperature in the three oceans will affect the TP-RWS and how the corresponding physical mechanism is are questions worth studying. We will use numerical models to further explore this issue in future work. Due to the limited space, this paper does not elaborate too much.

**Author Contributions:** Formal analysis, X.S. and Y.D.; data curation, X.S. and Q.L.; writing—original draft preparation, X.S.; writing—review and editing, X.S., Y.D., Q.L. and Y.S.; supervision, Y.D. and Y.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was funded by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA20100304), the Second Tibetan Plateau Scientific Expedition and Research Program of China (2019QZKK0208), the National Key Research and Development Program of China (2022YFE0136000), the National Natural Science Foundation of China (U2242207, 41965005, 41790471), the Natural Science Foundation of Anhui Province of China (2208085UQ08), and the Innovative Development Special Project of China Meteorological Administration (CXFZ2022J039).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The ERA-20C data can be downloaded from the website https://www. ecmwf.int/en/forecasts/datasets/reanalysis-datasets/era-20c (accessed on 1 January 2022). The NCEP-20C data can be downloaded from the website https://www.psl.noaa.gov/data/gridded/ data.20thC\_ReanV3.html (accessed on 1 January 2022).

**Conflicts of Interest:** The authors declare no conflict of interest.
