## 7 Conclusions  
In this paper, we combined the local drought data and GRACE _TWSC_ data to construct a drought characterization approach, and used this approach to monitor and characterize the drought events in MC from April 2002 to July 2020. _PAI_ was used to verify the drought severity derived from GRACE-DSI. The results show that after the local drought data was calibrated, the total _POD_ of the drought characterization approach increased by 65.69%. We also used the local drought data from 2016 to 2019 to evaluate the _POD_ of the calibrated approach. The results show that the _POD_ reached 98.08%. Finally, by comparing _PAI_, we found that the drought severity determined by the calibrated approach has a certain degree of reliability.  
Our research results have certain reference significance for accurately quantifying drought characteristics, and also help to realize early warning of drought events and provide strong scientific support for relevant government departments to formulate drought resistance and disaster reduction policies.  
Conceptualization, L.C. and Q.L.; methodology, L.C.; software, C.Z.; validation, L.C. and C.Z.; resources, L.L.; data curation, L.C.; writing--original draft preparation, L.C.; writing--review and editing, L.C., X.W. and Q.L.; visualization, L.C.; supervision, Z.L.; funding acquisition, Z.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Key R&D Program of China (Grant No. 2018 YFC1503503), the National Natural Science Foundation of China (Grant No. 41931074, 42061134007), the project funded by the Key Laboratory of Geospace Environment and Geodesy, Ministry of Education, Wuhan University (Grant No. 16-01-04, 18-02-04).  
Not applicable.  
**Data Availability Statement:** GRACE/GRACE-FO RL06 data: [[http://icgem.gfz-potsdam.de/series](http://icgem.gfz-potsdam.de/series)]([http://icgem.gfz-potsdam.de/series](http://icgem.gfz-potsdam.de/series)) (accessed on 16 September 2021); Reconstructed TWSC data: ([[http://data.tpdc.ac.cn](http://data.tpdc.ac.cn)]([http://data.tpdc.ac.cn](http://data.tpdc.ac.cn))); SPEI data: ([[http://spei.csic.es/](http://spei.csic.es/)]([http://spei.csic.es/](http://spei.csic.es/))); SCDSI data: ([[https://crudata.uea.ac.uk/cru/data/drought/](https://crudata.uea.ac.uk/cru/data/drought/)]([https://crudata.uea.ac.uk/cru/data/drought/](https://crudata.uea.ac.uk/cru/data/drought/)) (accessed on 16 September 2021); In-situ drought data: [[http://www.mwr.gov.cn/sj/tigb/zgshzhgb/](http://www.mwr.gov.cn/sj/tigb/zgshzhgb/)]([http://www.mwr.gov.cn/sj/tigb/zgshzhgb/](http://www.mwr.gov.cn/sj/tigb/zgshzhgb/)) (accessed on 16 September 2021); In-situ precipitation data: [[http://data.cma.cn](http://data.cma.cn)]([http://data.cma.cn](http://data.cma.cn)) (accessed on 16 September 2021).  
**Acknowledgments:** We are grateful to the Center of Space Research (CSR) for providing the monthly GRACE gravity field solutions, and to the Goddard Space Flight Center for providing the monthly GLDAS-2.1 data, to the National Tibetan Plateau Data for providing the Dataset of reconstructed terrestrial water storage in China based on precipitation (2002-2019), to the China National Meteorological Science Data Center for providing the monthly precipitation products, to the Climatic Research Unit at university of East Anglia for providing the SCPDSI data, to Vicente-Serrano S.M. and Begueria S for providing the SPEI database and to the China Ministry of Water Resource for providing the Chinese Flood and Drought Yearbooks.  
**Conflicts of Interest:** The authors declare no conflict of interest.