Astronomy & Space Sciences

Title :

Backscatter analysis using multi temporal, multifrequency and multi polarization SAR data in the context of flooded regions and partially submerged vegetation

Area of research :

Astronomy & Space Sciences

Focus area :

Flood hazard and risk vulnerability analysis, Flood inundation modelling, SAR based assessment of backscattering for inundation mapping urban flooding

Contact info :


Executive Summary :

In recent years the quantity and quality of satellite products available to stakeholders during and after an event has greatly improved. The Sentinel series of satellites is a prime example of this, producing data with high spatial and temporal resolutions that is free to download. The strength of the radar return is dependent on a number of factors, notably surface roughness, dielectric properties, and local topography in relation to the radar look angle. Despite the operational advantages of SAR compared to optical systems, there are challenges in identifying flooded areas. Roughening of the water surface, created by heavy rainfall or wind, can cause backscattering of the radar signal, increasing the possibility of underestimation of inundated areas. Also mixing of flood signature in arid regions especially sand due to low backscatter and therefore leading to overestimation. SAR systems are side looking and, depending on the incidence angle, terrain features can produce radar shadow, overlaying, and foreshadowing. Identification of flooding can also be problematic in areas where other structures protrude the water surface and interact with the radar signal. Therefore, in this project, it is proposed to utilize of multi-temporal,multi-frequency and multi-polarization SAR data in the context of flooded and partially submerged vegetation in different scenarios to assess the backscatter response and also optimize the threshold in case for flood delineation for rapid emergency response.


Shri C.M.Bhatt, Indian Institute of Remote Sensing (IIRS), Dehradun

Organizations involved