Observing of disaster by ALOS

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Calculation of flooded area caused by heavy rain in Pakistan

Northwestern Pakistan in the central Asia has been seriously damaged due to floods caused by heavy rain, which had occurred continuously since end of July 2010. The Japan Aerospace Exploration Agency (JAXA) has performed the follow-up observations continuously to monitor the state of the damage. Flooded areas along the Indus River were calculated from the merged image of before and after the disaster.

Fig. 1 shows merged images assigned band 3, 2 and 1 of AVNIR-2 as the true color composite.

Fig.1: merged images of after the disaster by AVNIR-2 images (Acquisition date: August 20, 2010 - September 30, 2010)

Fig.1: merged images of after the disaster
Acquisition date: August 20, 2010 - September 30, 2010
Sensor: AVNIR-2

Fig. 2: Animated image of before, after the disaster and flooded area along the Indas river basin by AVNIR-2 (Images before, after the disaster and flooded area switch every a second).

Fig.2: Animated image of before, after the disaster and flooded area.
(Images before, after the disaster and flooded area switch every a second).
(Click to View Enlarged Image » before the disaster, after the disaster)

Fig. 2 is animated view of merged images of before, after the disaster and flooded area, and switches every a second. They are assigned band 4, 3 and 2 of AVNIR-2 as the false color composite, therefore vegetation and flood areas can be seen clear in red and light blue or blue colors, respectively. It shows flooded area expand widely along the Indas river basin.

The flooded area could be calculated approximately 24,000 square kilometers from the mosaic image and is 11 times as large as the area of Tokyo.

* Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2):
AVNIR-2 is a visible and near infrared radiometer for observing land and coastal zones.
It provides 10-m spatial-resolution image and 70-km swath on the ground. The pointing angle of AVNIR-2 is +44 and - 44 degrees.

©JAXA EORC