River chemistry aggregate example

Four processed aggregate tables from a two-year observational river-chemistry analysis are provided with a standard-library Python script. The script validates input tables and checksums, recomputes the cross-year similarity of two phase profiles, and performs exact phase-label and constituent-label permutation checks. Two other tables provide selected aggregate numerical summaries. No original four-hour monitoring records, station or section identifiers, coordinates, map assets, or upstream preprocessing pipeline are included. This record supports a bounded aggregate example, not complete reproduction of all analyses. Underlying monitoring source: China National Environmental Monitoring Centre (https://www.cnemc.cn/sssj/).