H010-0002
POSSIBILITY OF HIGH-FREQUENCY OBSERVATION OF INUNDATION AREA BY SMALL SAR SATELLITES CONSTELLATION
Monday, 7 December 2020
Poster
Natsumi Kitajima1, Rie Seto1, Dai Yamazaki2, Wenchao MA3, Shinjiro Kanae4 and Xudong Zhou5, (1)Tokyo Institute of Technology, Tokyo, Japan, (2)The University of Tokyo, Institute of Industrial Sciences, Tokyo, Japan, (3)University of Tokyo, Bunkyo-ku, Japan, (4)Tokyo Institute of Technology, Department of Civil and Environmental Engineering, Tokyo, Japan, (5)University of Tokyo, Institute of Industrial Science, Bunkyo-ku, Japan
Abstract:
In a disaster management, it is needed to grasp the situation in real-time or semi-real-time, but the it is usually difficult to access affected areas on ground. In such a situation we can take advantage of remote sensing technology, and especially the use of SAR satellites is an effective way to detect inundation areas since it can observe over wide areas even at night or in cloud-cover situations. However, at present observation opportunity by each SAR satellite is limited to twice a day at most. Thanks to the latest technological innovations in miniaturization of SAR satellites, high-frequency observations by a constellation of small SAR satellites could be possible in the near future. Observation capability (the number of satellites, swath and resolution) of a satellite is depending on the purpose of data application. Therefore, in this research, we aim to define a required condition for flood disaster management considering high-frequency observation by SAR satellites at global scale.
Firstly, a constellation of small SAR satellites was designed with Walker Constellation method. In the procedure of the design, parameters of I (inclination of orbit plane to the equator), T (total number of satellites), P (the number of equally spaced orbit planes) and F (relative phase difference between satellites in adjacent planes) were set and the observation frequency in a given condition was calculated for ground check points.
Secondary, we calculated hourly flood depth in CaMa-Flood model, which is designed to simulate the hydrodynamics in continental-scale rivers. As inflow data we used the outputs of Today's Earth, which is land surface and river simulation system. We analyzed the fluctuation of inundation areas for various flood events in each region on the globe and define required conditions for observation of each flood variation.
Combining these two processes, the constellation design was optimized according to the result of the required conditions in each region. For the optimization of constellation design, we need to take into account the difference of flood variation between regions and try to find the optimal setting of parameters I, T, P and F. As a result, we suggest one possible solution of the optimized constellation design for flood disaster management.
