1. 1 Field- And GIS-Based Measurements of Coastal Change for the Southeast Chukchi Sea, Alaska William F. Manley INSTAAR, University of Colorado Diane M. Sanzone Arctic I&M Program, National Park Service James W. Jordan Dept. of Environmental Studies, Antioch University New England Owen K. Mason GeoArch Alaska Eric G. Parrish INSTAAR, University of Colorado Leanne R. Lestak INSTAAR, University of Colorado AGU Presentation -- December 14, 2006 See also: instaar.colorado.edu/QGISL/ARCN/

2. 2 Coastal Erosion  Rapid, observable change to the environment  Multiple impacts on a variety of habitats  Fragile coast is a sensitive indicator of “stressors”: direct human disturbance climate change: longer ice-free season increased permafrost melting change in frequency and intensity of storms sea level rise

3. 3 Goals  Field measurements as test of GIS approach  Preliminary GIS results

4. 4 Study Area C h u k c h i S e a

5. 5 Coastal Monitoring Stations 27 sites first established 1987-1994 revisited in 2006 measured on “bluff top”

6. 6 Field Methods

7. 7 Remote Sensing & GIS Approach  High-resolution base imagery 2003 orthophoto mosaic  Imagery and data useful for other concerns  Historic aerial photographs orthorectified photos for ca. 1980 orthorectified photos for ca. 1950  Comparison of different “time slices” allows us to detect and measure change 2003 ca. 1980 ca. 1950

8. 8 from NOAA & NPS 1:24,000 natural color photos mosaic created by Aero-Metric 0.6 m resolution accuracy: 1.2 m (RMSE) 112 tiles, 98 GB: lots of imagery! highest res. in Alaska for this large of an area available to the public early 2007 valuable for other types of research

9. 9 60 frames Color IR 1.0 m res. 57 frames Color IR 1:64,000 1.0 m resolution 1.5 m accuracy (RMSE)

10. 10 130 frames Black & White 1.0 m res. 108 frames Black and White 1:43,000 1.0 m resolution 2.0 m accuracy (RMSE)

11. 11 Mainland bluff Beach ridge complex Barrier island or spit Shoreline Reference Feature (SRF): “bluff top” (wave-cut scarp)

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22. 22 2003

23. 23 1949

24. 24 1985

25. 25 2003

26. 26 1949

27. 27 1985

28. 28 2003

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30. 30 DSAS Thieler et al. (2005)

31. 31 baseline Baseline

32. 32 Transects

33. 33 Transects 51.4 m ÷ 36 yr = 1.4 m/yr 1949 1985

34. 34 “Early” Period ca. 1950 – ca. 1980 m/yr 1949 1985

35. 35 “Late” Period ca. 1980 – 2003 m/yr 2003 1985

36. 36 accretion

37. 37 GIS Errors ca. 1950ca. 19802003 Orthorectification2.01.5NA Digitizing343 Total (SRSS)3.64.33.0 Shoreline Position (m) “Early”“Late”“Long Term” ca. 1950 – ca. 1980 ca. 1980 - 2003 ca. 1950 - 2003 Position (m)5.65.24.7 Rate (m/yr)± 0.20± 0.23± 0.09 Coastal Change

38. 38 1:1 r 2 = 0.80 n = 21

39. 39 1:1 mean difference: 0.12 m/yr r 2 = 0.80 n = 21

40. 40 GIS Errors ca. 1950ca. 19802003 Orthorectification21.5NA Digitizing343 Total (SRSS)3.64.33.0 Shoreline Position (m) “Early”“Late”“Long Term” ca. 1950 – ca. 1980 ca. 1980 - 2003 ca. 1950 - 2003 Position (m)5.65.24.7 Rate (m/yr)± 0.20± 0.23± 0.09 Coastal Change Rate (m/yr)± 0.12 Field Test (mean difference)

41. 41 spatial variability “early” erosion

42. 42 accretion

43. 43 station eroded “late” erosion

44. 44 xy plot “Early” Period ca. 1950 – ca. 1980 Avg ± SD ca. 1950 – ca. 19800.0 ± 1.1 ca. 1980 – 2003-0.5 ± 0.6 Avg ± SD ca. 1950 – ca. 1980-0.6 ± 0.4 ca. 1980 – 2003-0.2 ± 0.3 CAKR (n = 1628) BELA (n = 1146)

45. 45 xy plot “Late” Period ca. 1980 – 2003 Avg ± SD ca. 1950 – ca. 19800.0 ± 1.1 ca. 1980 – 2003-0.5 ± 0.6 Avg ± SD ca. 1950 – ca. 1980-0.6 ± 0.4 ca. 1980 – 2003-0.2 ± 0.3 CAKR (n = 1628) BELA (n = 1146)

46. 46 xy plot Is coastal erosion increasing with Arctic warming?

47. 47 acceptably low errors comprehensive spatial analysis Conclusions  Field: more precise measurements more often  GIS:  Is global warming responsible?: storm climatology important high spatial and temporal resolution needed