{
  "rows": 46846,
  "columns": 101,
  "start": "2021-04-23T11:00:00+08:00",
  "end": "2026-08-27T08:00:00+08:00",
  "event_rows": 201,
  "timezone": "Asia/Shanghai, source catalog states Beijing time",
  "qc_codes": {
    "0": "correct",
    "1": "suspect",
    "2": "bad",
    "4": "imputed",
    "8": "missing",
    "9": "not quality-controlled"
  },
  "operations": [
    "9999.9/-9999/-9999.9 to blank in measurement columns",
    "removed group-wise all-missing outer padding only",
    "retained original QC columns; no imputation",
    "outer join by Beijing hourly timestamp and add UTC timestamp"
  ],
  "limitations": [
    "Values/QC both retained; suspect/bad data require explicit subsequent filtering.",
    "FLUX lacks QC columns in original files.",
    "Station is regional background; not source-area precipitation truth."
  ]
}