1. Assessing glacier retreat and morphometric change at Kvíárjökull, Iceland Georgie Bennett MSc by research

2. Unrealised potential of aerial photography archive 1964 2003 19451964198019982003

3. a) How much ice has been lost between 1945 and 2003? b) What is the temporal pattern of retreat? Hypothesis 1 Kvíárjökull advanced between 1980 and 1998 in response to increased winter precipitation Hypothesis 2 Glacier retreat accelerated into the 21 st C in response to increased air temperature Research question 1: What is the nature of glacier retreat: 1945 2003

4. Research question 2: How is moraine development ‘controlled’ by glacial dynamics: Hypothesis 3 Moraine linearity is inherited from debris bands in the parent ice  Ice marginal pushing? Transverse margin parallel debris bands ? ProcessForm

5. Stereophotography 58 year period: 1945, 1964, 1980, 1998, 2003 9 ground control points (GCPs) on stable points… not ice!! Methods 1. DEM production and quality assessment  Digitally using Leica Photogrammetry Suite 9.1.  Accuracy assessed against GCPs

6. Methods 2. Volume change analysis  Sequential DEMs subtracted: volume change maps Volume change map 1945 – 2003 - 1945 2003 =

7. Methods 3. Surface change analysis  Down glacier profiles  New innovative visualization technique: Meshed temporal profiles 4. Error assessment  50 checkpoints extracted from 2003 DEM (RMSE of 0.39) from stable points around the glacier  DEMs compared with 2003 DEM. Vertical accuracy of DEMs compared to GCPsVertical accuracy compared to 2003 checkpoints YearRMSEMean error 2003 0.39 0 19980.70.75 19801.382.2 19641.032.36 19457.74-3.11

8. Results

9. Total ice loss 1945 - 2003 = 1.8x10 8 cubic meters from the glacier snout = 75 % of 1945 snout volume Spatially variable Research Question 1a: How much volume loss has there been? Volume change map 1945 – 2003

10. Research Question 1b: What is the temporal pattern of retreat?

11.  Greatest elevation loss from 1998 – 2003  Positive elevation change in 1980 - 1998

12. Volume change map 1945 – 2003  Red area = ice cored moraine complex has increased in elevation and volume  Ice-marginal pushing Glacier advance Volume change map of N snout area 1980 – 1998 1980 – 1998 = increase in volume of glacier snout and ice cored moraine complex

13. Animation of hillshaded DEMs 19451964 1980 1998 2003 19451964 1980 1998 2003

14. 4. Ice-cored moraine complex -Glacier snout has retreated ~500m and surface has lowered by ~70m -Advance between 1980 and 1998 of ~200m -Downwasting particularly rapid from 1998- 2003 -Glacier retreat accelerating 2. Glacier snout gradient has downwasted 1. Glacier surface has lowered 3. Deep moulins have developed between 1998 and 2003 Latero-frontal moraine 1945 1964 1980 1998 2003 Animation of downglacier profiles 4. Ice cored moraine complex has emerged

15. New innovative visual technique: Meshed temporal profiles Transect across ice- cored moraine complex Meshed temporal profile: Large changes in relief across profile between 1945 and 2003 Time 1945 2003 1945 1964 1980 1998 2003

16. Topographic inversion cycles in ice cored moraine  Sediment redistributed from peaks to troughs  Differential melting of ice cores  Topography reversed 1945 1964 1980 1998 2003  Fine linear features destroyed  Larger linear features may survive Evolution of linearity in ice cored moraine Ice marginal pushing  Brings bands of debris to the surface  Ice marginal pushing enhances linearity in moraine

17. Conclusions 1.Use of digital photogrammetry has unlocked the archive of photography enabling quantification of change over a 58 year time period. Visualization techniques have been invaluable in revealing processes of moraine construction 1964 2003 19451964198019982003

18. Conclusions 2. Kvíárjökull retreated between 1945 and 2003 interrupted by an advance between 1980 and 1998

19. 3. Linearity in the outer moraines is the result of a combination of inheritance of former linear debris concentrations in parent ice and ice marginal pushing. Conclusions

20. 3. 75% of the 1945 snout ice volume was lost by 2003 with the most rapid volume loss occurring between 1998 and 2003. ICE LOSS IS ACCELERATING Conclusions

21. Thank you Questions?