Extending Global River Gauge Records Using Satellite Observations

Complete streamflow records are essential for understanding and managing freshwater resources. However, 37% of publicly available global gauge records (N=45,834) are discontinuous (missing ≥ 5% of their data) and 77% of gauge records do not contain data within a month of access. Gauge data availability also tends to decrease during historical periods of social upheaval. Using observations from Landsat and Sentinel-2, we fill in missing records at 2,783 gauge locations worldwide with more than 450,000 daily discharge measurements. This task is accomplished with a river width-based rating curve technique that optimizes measurement location and function (median relative bias=1.9%, median Kling-Gupta efficiency=0.40). The rating curves presented here are capable of providing low-latency discharge information, improving our capabilities for monitoring and managing river resources.