## 5 Conclusions  
We analyzed Landsat satellite images for 1979, 1990, 2000 and 2010, in addition to rain gauge-based daily precipitation observations from January 1979 to December 2010 in Shanghai to investigate the effects of LULC changes on precipitation. The conclusions are summarized as follows.  
1. Precipitation trends show different characteristics in the Ur, OUr and OS region during a period of rapid urbanization. Most Ur regions had an upward trend in terms of annual and extreme precipitation from 1979 to 2010. In comparison, the trends in annual precipitation were downward in most OUr and OS regions. Moreover, we found that the upward trends in extreme precipitation including extreme amount and frequency are distributed throughout the eastern region of the study area. From 1979 to 2010, the areas of most rapid expansion were in the OUr region. The grids with higher change rates of the built-up area are mainly distributed in the OUr region, e.g., within 25 km of the barycenter of the central area. The OS region, far away from the central area, has a relatively lower changing rate.
2. The rapid growth of the built-up area percentage in the OUr is positively correlated with the increase of precipitation. The larger the change of the built-up area percentage, the more pronounced the increase in precipitation over time. In contrast, although the Ur experienced relatively rapid growth of built-up area percentage, there is a negative correlation between precipitation and changes in the built-up area percentage.
3. The quantitative relationship between temperature and the change rates of the built-up indicates that the warming trends in the Ur and OUr region are distinct. The largest increase in the annual mean temperature was observed in the southwest of OUr, where the change rate of the built-up area percentage was highest, which is related to the growth of the built-up area.
4. The data from five rain stations located in coastal areas around Shanghai that have hardly experienced obvious urbanization processes were used for precipitation trend analysis of climate backgrounds. We found that the magnitude of precipitation increased significantly in the Shanghai urban areas, which suggests that urbanization has a profound impact on precipitation at the regional level.  
In summary, we investigated the statistical relationship between urban sprawl and precipitation changes; however, the analysis of the influence mechanism of LULC changes on the regional climate still needs to be further studied. In the future, we will expand the study to include urban agglomerations and attempt to combine climate simulations based on the Weather Research and Forecasting (WRF) model and high-resolution gridded satellite-based precipitation data for further urban agglomeration precipitation analysis.  
**Author Contributions:** [PERSON] carried out the data analysis and wrote the majority of the paper. [PERSON] supported the structure of the paper and revised the paper. [PERSON]. ([PERSON]) is the supervisor of [PERSON] and designed the experiments. [PERSON]. ([PERSON]) contributed many conceptual and practical ideas. [PERSON], [PERSON] and [PERSON] participated in the discussion of the paper. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the Major Program of National Social Science Foundation of China (18 ZDA105); the National Key Research and Development Program of China (2018 YFC1508803); the National Natural Science Foundation of China (41671095 and 41971199); and Shanghai Science and Technology Support Program (19 DZ1201505).  
**Conflicts of Interest:** The authors declare no conflict of interest.