Remote Sensing

Monitoring flood in Europe: Optimizing Landsat 8

Flooding in Europe is due to non-stop heavy rainy since the late of May to the beginning of June 2013. In this study we employ NDWI index in order to highlighted water along the river side.

NDWI is Normalized Difference Water Indices. NDWI were computed for each pixel using the equation from Gao, 1996. The equation of NDWI is as follow:

NDWI = (ToA of band 4 – ToA of band 5)/(ToA of band 4+ ToA of band 5)

Algorithm employed in this study:

1. Atm correction (dark object substraction) on DN images

2. DN conversion into ToA (Top of Atmospheric) relfectance

3. NDWI calculation

4. Superimposed “water detected image” on vector map from Yahoo street

5. Employing transparency level on “water detected image”

The study area is Elbe River, part of Elbe drainage basin in Germany. We employ Landsat 8 (path 193/row 23), acquisition date was on June 7, 2013.

Normal river-water situation
Normal river-water situation

It can be seen from the “water detected image” below that small residential along the river side was suffered from the overflow water from the Elbe River.

In the northern part, from Abbendorf to Warnau. While in the northern part to the southern part, from Rabel to Tangermunde are suffered of flood.

Flooding situation along river-side. Water detected is highlighted in light white color. Transparency level is 50%
Flooding situation along river-side. Water detected is highlighted in light white color. Transparency level is 50%
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