## 5 Conclusions  
In this study, GNSS, GRACE, and precipitation data were combined to analyze the seasonal deformation of the Sichuan-Yunnan region. The following main conclusions were drawn:  
1. The three data types for Sichuan and Yunnan have significant annual seasonality. The GNSS time series not only has a notable annual cycle but also an evident semi-annual cycle, and thus, the impact of the semi-annual cycle on the horizontal component should not be overlooked. Moreover, there are other shorter and longer periodic signals.
2. A comparative analysis of GNSS and GRACE revealed that the vertical components are largely consistent, but the horizontal components differed considerably. GRACE provides comprehensive observation results for large areas, and has better vertical resolution than horizontal resolution. Regarding the actual observations, GNSS was affected by non-structural factors of large areas, and was easily influenced by the local observation environment.
3. The seasonality of the vertical component of the GNSS three components was strong. The horizontal N component was stronger than the E component, and both were strongly negatively correlated. Seasonal deformation was mainly affected by instantaneous loading deformation and changes in the pore pressure due to precipitation.
4. Regarding seasonal deformation, this study mainly discussed the influence of precipitation. Nevertheless, the GNSS observation stations were also affected by other factors, such as atmospheric pressure load, non-tidal ocean load, thermal expansion effect of bedrock at observation points, and data processing errors, which are also important factors that cause differences between GNSS and GRACE in terms of amplitude and phase.
5. The correction of seasonal deformation of GNSS time series has important theoretical significance and application value for obtaining accurate information of surface movement and accurate use of observation data.
6. Through the integrated application of GNSS and GRACE, it can also effectively monitor the regional land water storage changes or precipitation changes, and make up for the lack of weakness of professional technical means in some research areas.  
Conceptualization, X.L. and H.L.; Investigation, X.L. and H.L.; Writing--original draft, X.L.; project administration, Z.D.; funding acquisition, H.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Spark Program of Earthquake Sciences, grant number XH18068Y.  
Not applicable.  
The Raw GNSS measurements data, surface loading data, GRACE data and precipitation data used in this study can be accessed at [[http://www.eqdsc.com/](http://www.eqdsc.com/)]([http://www.eqdsc.com/](http://www.eqdsc.com/)); [[http://massloading.net](http://massloading.net)]([http://massloading.net](http://massloading.net)); [[https://grace.obs-mip.fr/](https://grace.obs-mip.fr/)]([https://grace.obs-mip.fr/](https://grace.obs-mip.fr/)); [[http://data.cma.cn](http://data.cma.cn)]([http://data.cma.cn](http://data.cma.cn)) and [[http://poles.tpdc.ac.cn/zh-hans/](http://poles.tpdc.ac.cn/zh-hans/)]([http://poles.tpdc.ac.cn/zh-hans/](http://poles.tpdc.ac.cn/zh-hans/)), respectively (all accessed on 27 May 2022).  
We are very grateful for the GNSS data provided by the key project CMONOC, the GRACE equivalent water height data provided by CNES/GRGS, and the precipitation data provided by China Meteorological Science Data Center. This study is supported by the NSFC and some of the figures in the text are drawn by Generic Mapping Tools (GMT) software, which is hereby acknowledged.  
The authors declare no conflict of interest.