Runoff monitoring in the Lhasa River Basin using passive microwave data

Abstract

Monitoring runoff is critical for water resources management. Remote sensing can be an effective technique to investigate changes in runoff on data-scarce regions. This study used Calibrated Passive Microwave Daily EASE-Grid 2.0 Brightness Temperature Earth System Data Record (CETB) and M/C signal method to simulate runoff in Lhasa River Basin. This satellite-derived runoff was compared with gauge observations and Soil and Water Assessment Tool (SWAT) model simulations. The results show that (1) the well-correlated satellite-derived M/C signals are able to detect the runoff process in the selected river channels. For most gauges, the runoff generated by M/C signals fit well with observation, giving a Pearson correlation coefficient greater than 0.9, Nash-Sutcliffe efficiency coefficient greater than 0.8, and relative error less than 15%; (2) When compared to the SWAT model, the M/C signal method has advantages in flood season runoff simulation. These two simulation methods are nearly equal for the entire runoff process; (3) For runoff simulation influenced by the underlying surface and the shape of the river channel, the M/C signal method is better suited in areas with a low fraction vegetation cover and channels with a typical inverted trapezoid shape. Overall, we conclude that M/C signal method simulation is a valuable source of surface water information and could be used for runoff monitoring in data-scarce areas.

Keywords

• Runoff simulation
• Passive microwave data
• Brightness Temperature Earth System Data Record
• M/C signal method