GIS in Water Resources Fall 2013Clayton Ernst

Mapping the surface of Imja Glacier, Nepal

What is the Problem?

• Climate Change → Warmer Alpine Temperatures → Melting Glaciers

→ Formation of Glacial Lakes

• Potential for Glacial Lake Outburst Floods & devastating consequences downstream

• Lack of Understanding of Glacial Melting→ Need for more accurate melt models

(to inform disaster planning & preparation)

Focus: Imja Tsho, Nepal

• Analyze recently collected field data of debris cover thickness• Correlate with digital surface model• Infer debris thickness across extent of glacier

GOALS:

Data Summary

DEM from ALOS PRISM by D. Lamsal, 2006

Debris thickness measurements by Dave Rounce of McKinney Research Group (CRWR-EWRE)September 2013

5m spatial resolution (1/6 arcsec)

Interpolation Attempt: Kriging

Note: N = 22

Digital Surface Model

Digital Surface Model

Next:Attempt to find correlations between slope, aspect, or curvature and debris thickness

DSM Correlations

0.0 20.0 40.0 60.0 80.0 100.0 120.00

20

40

60

80

100

120

Slope v. Thickness

Slope (% rise)

Debr

is Th

ickne

ss (c

m)

0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.00

20

40

60

80

100

120

Aspect v. Thickness

Aspect (degrees from N)

Debr

is Th

ickne

ss (c

m)

-15.0 -10.0 -5.0 0.0 5.0 10.0 15.00

20

40

60

80

100

120

Curvature v. Thickness

Surface Curvature

Debr

is Th

ickne

ss (c

m)

Elevation Discrepancy

Elevation DiscrepancyLamsal DEM vs. GPS Tracker Recorded Elevation

-21.8134766900002

-17.9005127991669

-13.9875489083335

-10.0745850175001

-6.16162112666673

-2.24865723583336

1.66430665500002

5.5772705458334

9.49023443666678

13.4031983275002

17.3161622183335

21.22912610916690

20

40

60

80

Elevation Discrepancy Histogram

Elevation Discrepancy (m)

Coun

t

-4 -3 -2 -1 0 1 2 3 4

-4

-3

-2

-1

0

1

2

3

4

Normal Probability Plot: Elevation Discrepancy

Standard Normal Z-VariateEl

evati

on D

iscre

panc

y Z-

Scor

e

0 200 400 600 800 1000 1200 14004850

4900

4950

5000

5050

5100

5150

5200

Lamsal GPS

Trek Progress

Elev

ation

(m) On-glacier

Results & Future Work

• Imja glacier’s surface is complex and dynamicMore comprehensive is data required to make meaningful inferences

• Perform further statistical analyses with elevation discrepancy data: are differences significant? On-glacier vs. Off-glacier?

• Investigate alternative data sources – i.e. ASTER albedo data

ACKNOWLEDGEMENTS: Dave Rounce (PhD candidate) & Dr. Daene McKinney

Questions?