Nuozhadu: reservoir area vs downstream gauge

Nuozhadu caveat: radar and optical areas differ here mainly because of mixed shoreline pixels (a 1–2 pixel band), and radar agreement with SWOT water height is weak, so month-to-month changes at Nuozhadu should be read with caution.

Water area is a signal, not storage volume. Gauge level also depends on rain and tributaries, so the two lines are context, not cause and effect. Gauge: Chiang Saen monthly mean water level (MRC PMFM public dashboard). Data: Mekong River Commission (MRC). Radar: our processing of Copernicus Sentinel-1.