20206-09-30 ワシントン大学（UW）
Irrigation canals, like this one in Bangladesh, supply vast amounts of water to farmland around the world. A new study from the UW shows that a NASA satellite originally built to monitor oceans and other large bodies of water can also track the ebb and flow of water through hundreds of thousands of kilometers of canals in Asia. Photo: Faisal Hossain
＜関連情報＞
- https://www.washington.edu/news/2026/09/30/nasa-satellite-irrigation-canals-swot-global-agriculture/
- https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2026GL124090
地表水・海洋地形（SWOT）衛星ミッションは、灌漑用水路をどの程度正確に観測できるのか？ How Well Can the Surface Water and Ocean Topography (SWOT) Satellite Mission Observe Irrigation Canals?
Mridul Sharma, Faisal Hossain, Sarath Suresh, Tamlin Pavelsky, Sanchit Minocha, Shahzaib Khan
Geophysical Research Letters Published: 30 September 2026
DOI:https://doi.org/10.1029/2026GL124090
Abstract
The capability of the Surface Water and Ocean Topography (SWOT) satellite for observing irrigation canals has remained relatively unexplored. Here, we assess SWOT observability of irrigation canal networks across 22 Asian countries using a new confidence level (CL) metric. Validation against in situ gauge observations showed that higher CL corresponds to significantly lower water-level retrieval error. Of approximately 795,110 km of canals analyzed, 37.5% (297,799 km) show high confidence, 46.9% (373,035 km) moderate confidence, and 15.6% (124,276 km) low confidence of observability. Observability is highest in the Indus Basin, Indo-Gangetic Plain, Bangladesh delta, North China Plain, and parts of Myanmar, the Philippines, Nepal, and the Mekong delta, and lowest across parts of Central Asia. Our analysis indicates SWOT can meaningfully support irrigation canal water monitoring across much of Asia’s most intensively irrigated regions and around the world.
