Share Email Print
cover

Journal of Applied Remote Sensing

Development of water level estimation algorithms using SARAL/Altika dataset and validation over the Ukai reservoir, India
Author(s): Shard Chander; Debojyoti Ganguly
Format Member Price Non-Member Price
PDF $20.00 $25.00

Paper Abstract

Water level was estimated, using AltiKa radar altimeter onboard the SARAL satellite, over the Ukai reservoir using modified algorithms specifically for inland water bodies. The methodology was based on waveform classification, waveform retracking, and dedicated inland range corrections algorithms. The 40-Hz waveforms were classified based on linear discriminant analysis and Bayesian classifier. Waveforms were retracked using Brown, Ice-2, threshold, and offset center of gravity methods. Retracking algorithms were implemented on full waveform and subwaveforms (only one leading edge) for estimating the improvement in the retrieved range. European Centre for Medium-Range Weather Forecasts (ECMWF) operational, ECMWF re-analysis pressure fields, and global ionosphere maps were used to exactly estimate the range corrections. The microwave and optical images were used for estimating the extent of the water body and altimeter track location. Four global positioning system (GPS) field trips were conducted on same day as the SARAL pass using two dual frequency GPS. One GPS was mounted close to the dam in static mode and the other was used on a moving vehicle within the reservoir in Kinematic mode. In situ gauge dataset was provided by the Ukai dam authority for the time period January 1972 to March 2015. The altimeter retrieved water level results were then validated with the GPS survey and in situ gauge dataset. With good selection of virtual station (waveform classification, back scattering coefficient), Ice-2 retracker and subwaveform retracker both work better with an overall root-mean-square error < 15    cm . The results support that the AltiKa dataset, due to a smaller foot-print and sharp trailing edge of the Ka-band waveform, can be utilized for more accurate water level information over inland water bodies.

Paper Details

Date Published: 24 January 2017
PDF: 15 pages
J. Appl. Remote Sens. 11(1) 016012 doi: 10.1117/1.JRS.11.016012
Published in: Journal of Applied Remote Sensing Volume 11, Issue 1
Show Author Affiliations
Shard Chander, Space Applications Ctr. (India)
Debojyoti Ganguly, Space Applications Ctr. (India)


© SPIE. Terms of Use
Back to Top