Field And GISBased Measurements of Coastal Change for the Southeast Chukchi Sea, Alaska

1
Field- And GIS-Based Measurements of Coastal
Change for the Southeast Chukchi Sea, Alaska
William F. Manley INSTAAR, University of
Colorado Leanne R. Lestak INSTAAR, University of
Colorado Diane M. Sanzone Arctic IM 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
ESRI International User Conference June 20, 2007
See also instaar.colorado.edu/QGISL/ARCN/
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
Monitoring Objectives for Coastal Ecosystems

• Collect baseline data on the physical, chemical,
  and biological parameters of near-shore waters,
  intertidal and subtidal zones, beaches, coastal
  uplands, lagoons, estuaries, and coastal wetlands
  within the Arctic Network (ARCN).
• Determine long-term trends in the physical,
  chemical, and biological characteristics of
  near-shore waters, subtidal and intertidal zones,
  beaches, coastal uplands, lagoons, estuaries, and
  coastal wetlands within ARCN.
• Understand how landscape components interact at
  various spatial and temporal scales to affect
  these coastal-influenced ecosystems.

4
Goals

• Field measurements as test of GIS approach
• Preliminary GIS results

5
Study Area
C h u k c h i S e a
6
BELA
www.earthslot.org

• gt 330 km (gt200 mi) of shoreline
• lagoons with sandy barrier spits and islands
  active eolian systems narrow sandy beaches with
  low tundra bluffs accretionary dune ridge
  complexes bays and inlets uncommon rocky shore
  and deltaic systems

7
CAKR
www.earthslot.org

• gt 120 km (gt75 mi) of shoreline
• lagoons with sand or gravel barrier spits and
  islands narrow sandy beaches with low tundra
  bluffs accretionary beach ridge complexes bays
  and inlets uncommon rocky shore and deltaic
  systems

8
Coastal Monitoring Stations

• 27 sites
• first established 1987-1994
• revisited in 2006
• measured on bluff top

9
Field Methods
10
Remote Sensing GIS Approach

• High-resolution base imagery

2003

• 2003 orthophoto mosaic

• Historic aerial photographs

ca. 1980

• orthorectified photos for ca. 1980
• orthorectified photos for ca. 1950

ca. 1950

• Comparison of different time slices allows us
  to detect and measure change

• Imagery and data useful for other concerns

11

• from NOAA NPS 124,000 natural color photos
• mosaic created by Aero-Metric
• 0.6 m resolution
• accuracy 1.1 m (RMSE)
• 103 tiles, 94 GB lots of imagery!
• highest res. in Alaska for this large of an
  area
• available to the public
• valuable for other types of research

12
60 frames Color IR 1.0 m res.

• 57 frames
• Color IR
• 164,000
• 1.0 m resolution
• 1.5 m accuracy (RMSE)

13
130 frames Black White 1.0 m res.

• 108 frames
• Black and White
• 143,000
• 1.0 m resolution
• 2.0 m accuracy (RMSE)

14
Shoreline Reference Feature (SRF) bluff
top (wave-cut scarp)
Barrier island or spit
Mainland bluff
Beach ridge complex
15
(No Transcript)
16
(No Transcript)
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
(No Transcript)
25
2003
26
1949
27
1985
28
2003
29
1949
30
1985
31
2003
32
(No Transcript)
33
DSAS
Thieler et al. (2005)
34
Baseline
baseline
35
Transects
36
Transects
1949
1985
51.4 m 36 yr 1.4 m/yr
37
Early Period ca. 1950 ca. 1980m/yr
1949
1985
38
Late Period ca. 1980 2003m/yr
1985
2003
39
accretion
40
GIS Errors
Shoreline Position (m)
Coastal Change
41
r2 0.80 n 21
11
42
mean difference 0.12 m/yr
r2 0.80 n 21
11
43
GIS Errors
Shoreline Position (m)
Coastal Change
Field Test (mean difference)
44

• spatial variability
• early erosion

45

• accretion

46

• station eroded
• late erosion

47
(No Transcript)
48
(No Transcript)
49
(No Transcript)
50
(No Transcript)
51
(No Transcript)
52
(No Transcript)
53
(No Transcript)
54
(No Transcript)
55
(No Transcript)
56
(No Transcript)
57
(No Transcript)
58
(No Transcript)
59
Early Period ca. 1950 ca. 1980
CAKR (n 1628)
BELA (n 1146)
xy plot
60
Early Period ca. 1950 ca. 1980
CAKR (n 1628)
BELA (n 1146)
xy plot
61
Late Period ca. 1980 2003
CAKR (n 1628)
BELA (n 1146)
xy plot
62
Late Period ca. 1980 2003
CAKR (n 1628)
BELA (n 1146)
xy plot
63
Is coastal erosion increasing with Arctic warming?
xy plot
64
Conclusions

• Field

• more precise
• measurements more often

• GIS

• acceptably low errors
• comprehensive spatial analysis

• Most coastlines are eroding

• Is global warming responsible?

• storm climatology important
• high spatial and temporal resolution needed

65
Thank you!
Any questions or concerns Leanne.Lestak_at_colorado.
edu 303-492-5802