Flood Detection in Changjiang 1998 from Landsat-TM Data
Shinkichi Kishi and Xiangfang Song*, Jiren Li**
*National Research Institute for Earth Science and Disaster Prevention, Tsukuba, Japan
**Ministry of Water Resources, Beijing, China
NIED/STA, Japan and RSTAC/MWR, China have conducted a joint research study on the utilization of remote sensing data during floods in China. This paper outlines the research conducted on flood detection as regards the middle reaches basin of Changjiang in the summer of 1998. NIED provided the spatially mosaic images which made it easier to delineate the flooded areas.
Prior to the detailed analyses of TM data, the mapping of the near-daily extension of flood water was conducted by interpreting multi-temporal pictures from several kinds of satellite.
TM data of the overlapping area of the adjacent landsat paths in nine days during the flood was effectively used to examine the alteration of river water based upon the spectral characteristics of turbidity. Additionally, TM data taken before the flood was also timely used to specify the land cover condition in the area. The results of the study were supported by the examination of the MMR based on the daily discharge data represented by the hydrographs.
As a result, TM data was again practical to grasp the land cover condition in the flooded area and transition of turbidity of flood water. On the other hand, the synthesized observation frequency by several kinds of satellites was not enough in practical use to monitor the daily transition of flooding areas.
Keywords: Flood detection; Remote sensing