l l l l SAR SAR Ocean Processor

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목차 l l l l 연구 목적 SAR를 이용한 해양 연구 방법 SAR Ocean

목차 l l l l 연구 목적 SAR를 이용한 해양 연구 방법 SAR Ocean Processor (SOP) SOP 프로세서 입출력 Wind: l CMOD 4, CMOD_IFR 2 모델 l Wind Speed Wave: l Inter-Look Cross-Spectra l Wave 파장과 방향 l RADARSAT-1 영상자료의 Wave 결과와 AWS 자료 Current: l Doppler shift estimation 추출 결과 l Doppler shift 속도 벡터 추출 결과 l 예측조류도 결론

SAR를 이용한 해양 연구 방법 Target Methods Wind Wave ( ) Current Wind Retrieval

SAR를 이용한 해양 연구 방법 Target Methods Wind Wave ( ) Current Wind Retrieval Models Wave-SAR Transform Inter-look Cross-Spectra Doppler Shift Dual-Beam ATI Magnitude ○ ○ ○ △ LOS only ○ Direction × (Wind streak) △ 180° ambiguity ○ △ LOS only ○ Spatial Resolution 10 m SAR Resolution 2 km SAR Imagette 10 m SAR resolution Major Limit A priori wind direction required wind + current decomposition New system Values Azimuth cutoff, strongly nonlinear

SAR Ocean Processor (SOP) Raw Data SAR Focusing Az FFT (Imagette) SLC Az FFT,

SAR Ocean Processor (SOP) Raw Data SAR Focusing Az FFT (Imagette) SLC Az FFT, Beam Split, Az i. FFT, Detect Doppler Shift l 1 l 2 l 3 l 4 2 D-FFT (Imagette) Avg Shift Detection L 1 L 3* Surface Velocity L 2 L 4* Cross Spectrum Multi-Look (4 Looks) 2 D FFT (Imagette) Avg Inter-Look Cross Spectra SAR Wave Spectrum Inversion Solve 180° Ambiguity Ocean Wave Spectrum CMOD Wind

SOP 프로세서 입출력 l Language: ANSI-C, Cygwin environment Command-line based l Input: RADARSAT-1 SLC

SOP 프로세서 입출력 l Language: ANSI-C, Cygwin environment Command-line based l Input: RADARSAT-1 SLC (CEOS format) l Output: l l SLC Header Off Multi-look Image (by average) l Wind l l l Wave l l Backscattering Coefficient (Sigma_naught, d. B) CMOD_4 Wind Speed (m/s) CMOD_IFR 2 Wind Speed (m/s) Wave Spectrum Inter-look Cross Spectrum Multi-look image (from inter-look processing) Current l l Doppler Image Doppler Shift Estimation (Vector File) Velocity Estimation (Text File) Velocity Vectors (Vector File)

Wind: CMOD 4, CMOD_IFR 2 모델 l l l The CMOD_4 wind retrieval model:

Wind: CMOD 4, CMOD_IFR 2 모델 l l l The CMOD_4 wind retrieval model: The most commonly used and applied successfully for wind speed retrieval from VVpolarized SAR data The CMOD_IFR 2 wind retrieval model is very similar to the CMOD_4 except the different parameter values. Wind direction is a necessary input parameter for these wind retrieval models. The wind directions could be obtained from wind-induced phenomena that are visible in SAR images or atmospheric model results. Schematic flow chart of wind retrieval from SAR image

Wind Speed l l l RADARSAT-1 standard image data 1999년 11월 15일 제주도 근해

Wind Speed l l l RADARSAT-1 standard image data 1999년 11월 15일 제주도 근해 Nominal incidence angle: 36. 71° Wind direction: 280° (우도 AWS자료 참조) PR: Bragg, Unal, Kirchhoff, Elfouhaily GCP 보정 전 영상

Wave: Inter-Look Cross-Spectra l Inter-look Cross-Spectra l Real part : symmetric l Imaginary part

Wave: Inter-Look Cross-Spectra l Inter-look Cross-Spectra l Real part : symmetric l Imaginary part : antisymmetric l information on the wave propagation direction: positive value of imaginary part l l SAR Spectrum Cross-Spectrum (Amplitude) 180° ambiguity 해결 AWS 기상자료를 참조 l 파랑(너울)의 진행방향 -> imaginary spectrum의 (+) 방향(red part)과 일치함. Cross-Spectrum (real part) Cross-Spectrum (imaginary part) GCP 보정 전 영상자료