[S-TT39] 合成開口レーダーとその応用

[STT39-04] 海域豪雨シグナルのだいち2号フルポラリメトリーによる高分解能検出

*古屋 正人¹、井手 一斗² (1.北海道大学大学院理学研究院地球惑星科学部門、2.北海道大学理学部地球惑星科学科)

キーワード：だいち2号、合成開口レーダー、豪雨、海上、フルポラリメトリー

Advanced Land Observing Satellite-2 (ALOS-2), launched by JAXA in 2014, carries Phased-Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) that delivers high-spatial-resolution radar images to monitor natural disasters such as earthquakes, volcanic eruptions, floods, and so forth. Besides land areas, PALSAR-2 imageries over oceanic regions have been used to estimate surface winds and sea-ice distributions. However, there are few observation reports of heavy rain episodes over oceanic areas by PALSAR-2, while rain signals would become noise for wind velocity retrieval. Alpers et al (2016) reviewed radar imaging of rain footprints over the ocean but focused mostly on C-band radar images. Here we report two heavy rain episodes over the ocean off south Kyushu imaged by ALOS-2/PALSAR-2 full-polarimetric mode, whose maximum spatial resolution is ~6m.
Figure 1 indicates the amplitude image of the HH-channel acquired on August 11, 2021 with a darker (brighter) area indicating weaker (stronger) scattering amplitude. Comparing Figure 1 with the JMA's rain radar map at the epoch, we confirm that the darker (brighter) area corresponds to higher (lower) rain-rate area. By analyzing other channels, HV, VH, and VV, we aim to map the rain intensity distribution with high-spatial-resolution.