Monitoring a Changing Environment with Synthetic Aperture Radar. Alaska Satellite Facility National Park Service Don Atwood

Transcription

1 Monitoring a Changing Environment with Synthetic Aperture Radar Don Atwood Alaska Satellite Facility 1

2 Entering the SAR Age 2

3 SAR Satellites RADARSAT-1 Launched 1995 by CSA 5.6 cm (C-Band) HH Polarization km swath m resolution 24 day Repeat Cycle ERS-2 Launched 1995 by ESA 5.6 cm (C-Band) VV Polarization 100km swath 30m resolution 35 day Repeat Cycle EnviSat Launched 2002 by ESA 5.6 cm (C-Band) HH,HV,VV/HH,HH/HV,VV/HV km swath m resolution 35 day Repeat Cycle 3

4 SAR Satellites ALOS PALSAR Launched 2006 by JAXA 23.6cm (L-Band) Single, Dual, Full Pol km Swath m resolution 46 day Repeat Cycle RADARSAT-2 Launched 2007 by MDA 5.6 cm (C-Band) Single, Dual, Full Pol km swath m resolution 24 day Repeat Cycle TerraSAR-X Launched 2007 by DLR 3.1 cm (X-Band) Single, Dual, Full Pol km swath 1-16 m resolution 11 day Repeat Cycle 4

5 SAR 101 5

6 Synthetic Aperture Radar (SAR) Active, rather than Passive Sensor Data acquisition on 24/7 basis Visibility through darkness, clouds, and smoke Signal sensitive to geomorphology Change detection SAR permits measurement of: Topography (for DEMs) Displacements on the order of cm (in volcanoes and earthquakes) Motion (currents, automobile traffic) 6

7 Radar geometry 7

8 Forming a Synthetic Aperture Pixel constructed from N pulses X Ground Swath Length of Synthetic Aperture Flight Path 8

9 SAR Scattering Mechanisms Surface Scattering 9

10 SAR Attributes Amplitude and Phase 10

11 Coherence 11

12 Radar wavelengths (3.2 cm) (5.7 cm) (23.0 cm) 12

13 Radar Polarization Horizontal Transmit Horizontal Receive HH HV Horizontal Transmit Vertical Receive VV VH Vertical Transmit Vertical Receive Vertical Transmit Horizontal Receive 13

14 Applications 14

15 Urban Change JERS-1 - Oct 1997 ALOS PALSAR - Oct

16 Urban Change ALOS PALSAR (R,B) and JERS (G) with Road Shapefile Overlay 16

17 Volcanic Eruption Detection R, B: July 2007 G: July 2008 Mt. Cleveland 17

18 Coastal Erosion 1955 USGS Map 1:63,360 18

19 Coastal Erosion USGS Map 1:63,360 19

20 Coastal Erosion 1955 to 1998 JERS-1 vs. USGS Map 1:63,360 20

21 Flood Detection Dual Polarization R,B: HH G: HV 21

22 Hydrology Delineation Amplitude Image Coherence Image Classified Image 22

23 Glacier Delineation Since glacier outlines are optically determined, classification is extremely difficult for debris-covered glaciers. They look like dirt McCarthy, Alaska Optical delineation can be difficult 23

24 Kennicott: Optical Image 24

25 Kennicott: Coherence Plot 25

26 Burn Scar Detection 26

27 Accessing SAR Data 27

28 Alaska Satellite Facility (ASF) Operated by the Geophysical Institute (University of Alaska Fairbanks) Member of the NASA DAAC Alliance ASF operates on a 24x7 schedule 50,000 image products per year U.S. Order Desk for customers of ERS-2 Americas Data Node for customers of ALOS 28

29 ASF Receiving Ground Station ASF operates two, X-band receiving antennas 11m Antenna Currently downlinking two SAR satellites: ERS-2 ALOS 10m Antenna 29

30 R % J % ASF Archive Data E1 15% E2 10% ASF Archive contains: 400 TB of SAR data 30

31 Accessing SAR Data Step 1: Submit a short proposal describing research and data requirements. Proposal must be approved by NASA or government consortium (NASA/USGS/NSF). Step 2: Access SAR data through ASF s URSA user interface. Archive Data: Extensive archive of ERS-1, ERS-2, JERS-1, RADARSAT-1and ALOS PALSAR data exists at ASF. Accessed through the User Remote Sensing Access (URSA). New SAR Data: New acquisitions of ALOS PALSAR and ERS-2. Complete a Data Acquisition Request (DAR) for future satellite tasking. Access data once in the ASF Archive. Visit 31

32 Don Atwood Alaska Satellite Facility Questions? 32