1. Photo: Snævarr Guðmundsson
Changes in precipitation patterns associated with retreating glaciers in Iceland
Hálfdán Ágústsson, Haraldur Ólafsson, Helgi Björnsson and Finnur Pálsson
University of Iceland, Icelandic Meteorological Office, Belgingur, Bergen school of Meteorology and Earth science institute
Photo: Snævarr Guðmundsson

2. Photo: Frederick W. W. Howell 1891 Photo: Snævarr Guðmundsson 2011
Glaciers in Iceland have retreated and thinned significantly since the end of the Little Ice Age
Photo: Frederick W. W. Howell 1891
Kotárjökull and Rótar-fjallsjökull in Kotárgil, view from Howells-steinn
Photo: Snævarr Guðmundsson 2011

3. HÉR VANTAR DÆMI/MYND AF ÞVÍ HVERNIG GERT ER RÁÐ FYRIR AÐ JÖKLAR HOPA OG HVERFA NÆSTU 100-200 ÁRIN

4. Philippe Crochet and Tómas Jóhannesson
Annual precipitation in Iceland in a linear model
Study region
Philippe Crochet and Tómas Jóhannesson

5. Philippe Crochet and Tómas Jóhannesson
Annual precipitation in Iceland in a linear model
Extensive harnessing of hydropower
Philippe Crochet and Tómas Jóhannesson

6. Unique measurements have been made of the thickness of the ice caps
Current ice cap elevation
Unique measurements have been made of the thickness of the ice caps
Height change if ice cap disappears
Bedrock below Vatnajökull

7. Current ice cap surface
Control simulation
Current ice cap surface
Two model simulations are compared to estimate the effect of Vatnajökull ice cap on the precip-itation distribution and magnitude in the region and on the ice cap.
Sensitivity simulation
Ice cap removed
Control simulation with current ice cap surface
Sensitivity simulation with ice cap removed
WRF/ARW atmo-spheric model at 2 km
Two years:

8. Annual precipitation decrease without ice cap
Sensitivity - control
Annual precipitation decrease without ice cap

9. (Sensitivity-control) / control
Relative Annual precipitation decrease without ice cap

10. Relative Annual precipitation amounts without ice cap
Sensitivity / control
Relative Annual precipitation amounts without ice cap

11. (Sensitivity-control) / control
SUMMER
(Sensitivity-control) / control
Relative Annual precipitation decrease without ice cap
WINTER

12. (Sensitivity-control) / control
Relative Annual precipitation decrease without ice cap
SUMMER
WINTER

13. Relative Annual precipitation amounts without ice cap

14. Summary
+10% decrease in precipitation on Vatnajökull without the ice cap
Largest changes in the SW and NE
+20% (+25%) decrease in precipitation on some watersheds on the ice cap
Only minor changes in the „precipitation shadow“ to the north
The „background“ runoff will change as the glacier retreats in warming climate