Assessment of the 2022 Floods in Lower Indus Basin Using Suite of Satellite Sensors and Hydrological Modelling
摘要
Pakistan witnessed one of its most devastating floods during the monsoon of 2022, affecting millions of people and causing significant economic losses. The focus of this study is to analyse the spatial and temporal attributes of the 2022 floods in the lower Indus basin using multi-satellite observations and hydrological modelling. We used observations from satellite sensors including Synthetic Aperture Radar (SAR), passive microwave radiometer, radar altimeters, optical sensors, and gravity measurements to assess the dynamics of flood. SAR images revealed an inundation extent of 14,361 km2 in the lower Indus basin and optical data showed the extent of Lake Manchar swell from 333.76 km2 on 11 August to 512.25 km2 on 26 August 2022. A novel approach to assess flood intensity using brightness temperature observations from a passive microwave radiometer (36.5 GHz) was used to analyse the onset, progression and persistence of inundation. Water level observations from altimeter and water storage change from satellite-based gravity measurements provided additional information to understand the temporal dynamics of flood event. Weather Research and Forecasting-Hydro model simulations revealed a peak discharge of 69,217 m3/s on 26 August 2022 which was ~ 50% higher than the previous year. Model simulated discharge for the Indus River correlated well (R2 = 0.85) with the satellite-observed mean flood index. This paper demonstrates the use of available satellite sensors for effective assessment and modelling of floods, which may prove useful for monitoring and mitigating future flood events.