MAPPING SHALLOW WATER DEPTH FROM SATELLITE. Title. Ron Abileah. May 1-5, 2006

Transcription

1 MAPPING SHALLOW WATER DEPTH FROM SATELLITE Title Ron Abileah ASPRS Ron Abileah 2006 Annual Conference Reno, May Nevada 5, 2006 May 1-5, 2006

2 Ron Abileah May 5, 2006 Shoaling waves display four depthrelated physical changes 1. Steepening breaking } 2. Wavenumber transformation 3. Refraction kinematics 4. Change in phase velocity Remote sensing bathymetry using ocean waves (WK)

3 Wave spectrum phase Tile Fourier Transform (FT) j S( k, k ) = S ( k, k ) e Ω t x y 0 x y ( k)) t jω( k ) = j( g k tanh( k d) + Ux, U y kx, k y ' Depth Ocean surface current 3

4 WK (Phase Velocity) Depth Estimation Wavenumber spectrum at time t j S( k, k ) = S ( k, k ) e Ω t x y 0 x y ( k)) t jω( k ) = j( g k tanh( k d) + Ux, U y kx, k y ' Depth Ocean surface current Tile from image 1 at t 1 Image 2 at t 2 FT FT S t1 S t 2 Solve for U and d (minimum 2 images) Image n at t n FT S tn 4

5 20 Year History Large array CCD cameras Gotwols and Irani, Optical determination of the phase velocity of short gravity waves, JHU/APL, 1980 Caruthers et al., NORDA Aerial photos Faber, Arete IR video Dugan, Arete AROSS video Abileah Satellite imagery Van Halsema et al. TNO, Netherlands Marine radar Senet et al. GKSS, Germany Marine radar Young, Rosenthal, Ziemer, A three dimensional analysis of marine radar,

6 Caruthers et al

7 20 Year History Large array CCD cameras Gotwols and Irani, Optical determination of the phase velocity of short gravity waves, JHU/APL, 1980 Caruthers et al., NORDA Aerial photos Faber, Arete IR video Dugan, Arete AROSS video Abileah Satellite imagery Van Halsema et al. TNO, Netherlands Marine radar Senet et al. GKSS, Germany Marine radar Young, Rosenthal, Ziemer, A three dimensional analysis of marine radar,

8 Dugan 8

9 Large array CCD cameras Gotwols and Irani, Optical determination of the phase velocity of short gravity waves, JHU/APL, Year History Satellite imagery Caruthers et al., NORDA Aerial photos Faber, Arete IR video Dugan, Arete AROSS video Theory & simulation Test Van Halsema et al. TNO, Netherlands Marine radar Senet et al. GKSS, Germany Marine radar Young, Rosenthal, Ziemer, A three dimensional analysis of marine radar,

10 Satellite image collection Sun 5-15 s etc 5-15 s P3 P2 P s AOI 10

11 IKONOS San Diego Set Footprints Image IDs 11

12 IKONOS San Diego Images SpaceImaging CARTERRA 12

13 San Diego Inlet 13

14 San Diego Inlet Multi-beam ship survey 14

15 WK with 2 images WK depths 128 m tiles, 2 images Fugro multibeam ship survey 15

16 2 vs 4 images 16

17 Comparison to USGS Chart 17

18 Comparison of Satellite-Based Methods Method Type of satellite Depth accuracy Horizontal resolution Est. cost $/km -2 Turbid waters WK Hi Res Pan or Multispectral 5-10% m 50 Yes Photobathymetry Hi Resolution Multispectral 5% but biased 10-30m 50 No Currents interaction Wave refraction SAR 5% 5m 10 Yes SAR 30% 1 km <10 Yes 18

19 Gaps in WK Solutions Wind waves damped by kelp forest (outside figure) No waves Waves blocked by jetty Too deep For 128 m tiles 19

20 Summary WK bathymetry resolution depth accuracy Resolution 10 m accuracy 250 m 4 % 125 m 6 % 50 m 10 % resolution proportional to depth accuracy also depends on number of images Special considerations requires wind waves no solution where waves are blocked or damped out currents, turbidity are not issues 20

21 Extra Slides and Backups 21

22 Current 22

23 WK compared with multibeam 23

24 Reconnaissance Aircraft Photos - Movie 24

25 Phase Velocity Depth (m) Phase velocity vs wavelength and depth

26 Wavelength-Depth-Speed Relationship 20 m 10 m 5 m 2 m 26

27 San Diego Area Depth Contours in m, 10 m increments to 200m 27

28 Multispectral images for photobathymetry 28