The Global Hydrological Cycle Arctic Hydrology September 20, 2005

Water and the Arctic Grease ice Pancake ice Ice plates Arctic sea ice This figure shows the change in sea ice thickness from 1958-76 and 1993-97. The data is from submarine draft measurements and are located in the Gore triangle…. The data used is for similar location but for different times...We can see that all the open triangles are above the solid squares in all regions of the Arctic. The mean decrease in ice thickness over the entire Arctic is approximately 70cm over this 20 year period... Are these changes in SIC and sea ice thickness of thermodynamic or dynamic origin? We saw from the SLP map how potentially more ice could be exported out of the Arctic in the last 2 decades… later on we will see this thinning is a dynamic rather than a thermodynamic consequence Of course three is submarine data close to the Canadian arctic archipelago and the Eurasian continental shelf, but for political reasons, it is a bit touchy to release such data We have seen earlier how thicker ice might have been displaced towards the Beaufort Sea, we will see later from model results how this how this is causing problem in the interpretation in the observed sea ice thinning.

Arctic Fresh Water Budget Ocean: 60,000 km3 Ice : 30,000 km3 Lake Baikal : 23,600 km3 River runoff 35 Bering Strait Inflow 18 Freezing, melting plus precipitation 9 make sure it is consistent with ice budg Norwegian boundary current 3 Ice outflow 29 Ocean surface current 9 CAA throughflow 10 West Spitsbergen Current 3 Atlantic water input in Barents Sea 6 imbalance of 9 The contribution of the surface currents at Fram Strait is subject of debate, it could be much larger explain how the ocean could give huge contribution to this outflow? Bring slide from arctic commission presentation.

SIC climatology March September SSMI passive microwave This shows the summer SIC climatology, as expected we see the penetration of te North Atlantic Drift responsible the Norwegian Sea clear of ice, we can also clearly see its two branches, one that makes it onto the continental plateau in the Barents Sea and the West Spitsberegn Current that flows west of Svalbard, and also that recirculates soutward in the Greenland Sea. We can also see the east Greenland Current that carries ice out of the Arctic along the coast. The region of violet are more compact ice, which is observed where multi-year ice is present in the Central Arctic, the peripheral seas on the other hand are less compact. A similar east-west assymetry is obsered in the North Pacific. In the summer, we see that all peripheral seas are clear of ice, except for the East Siberian Sea which has thicker accumulation in the winter due to the weterlies This shows the mean, but of course there area large interannual variations. For instance the Barents sea in winter can be completely ice covered or ice free, and the same applies to the summer Interestingly during time of large ice export, the ice extent in the Greenland Sea is small, due to the large recirculation in the Greenland Sea. SSMI passive microwave

Fresh Water Reservoir This figure shows the change in sea ice thickness from 1958-76 and 1993-97. The data is from submarine draft measurements and are located in the Gore triangle…. The data used is for similar location but for different times...We can see that all the open triangles are above the solid squares in all regions of the Arctic. The mean decrease in ice thickness over the entire Arctic is approximately 70cm over this 20 year period... Are these changes in SIC and sea ice thickness of thermodynamic or dynamic origin? We saw from the SLP map how potentially more ice could be exported out of the Arctic in the last 2 decades… later on we will see this thinning is a dynamic rather than a thermodynamic consequence Of course three is submarine data close to the Canadian arctic archipelago and the Eurasian continental shelf, but for political reasons, it is a bit touchy to release such data We have seen earlier how thicker ice might have been displaced towards the Beaufort Sea, we will see later from model results how this how this is causing problem in the interpretation in the observed sea ice thinning.

Fresh Water Reservoir This figure shows the change in sea ice thickness from 1958-76 and 1993-97. The data is from submarine draft measurements and are located in the Gore triangle…. The data used is for similar location but for different times...We can see that all the open triangles are above the solid squares in all regions of the Arctic. The mean decrease in ice thickness over the entire Arctic is approximately 70cm over this 20 year period... Are these changes in SIC and sea ice thickness of thermodynamic or dynamic origin? We saw from the SLP map how potentially more ice could be exported out of the Arctic in the last 2 decades… later on we will see this thinning is a dynamic rather than a thermodynamic consequence Of course three is submarine data close to the Canadian arctic archipelago and the Eurasian continental shelf, but for political reasons, it is a bit touchy to release such data We have seen earlier how thicker ice might have been displaced towards the Beaufort Sea, we will see later from model results how this how this is causing problem in the interpretation in the observed sea ice thinning.

Arctic Fresh Water Budget Ocean: 60,000 km3 Ice : 30,000 km3 Runoff: 2500 km3/year Sea Ice Export: 2500 km3/year River runoff 35 Bering Strait Inflow 18 Freezing, melting plus precipitation 9 make sure it is consistent with ice budg Norwegian boundary current 3 Ice outflow 29 Ocean surface current 9 CAA throughflow 10 West Spitsbergen Current 3 Atlantic water input in Barents Sea 6 imbalance of 9 The contribution of the surface currents at Fram Strait is subject of debate, it could be much larger explain how the ocean could give huge contribution to this outflow? Bring slide from arctic commission presentation. Liquid Export: 2000 km3/year

Arctic Drainage Basin 1.5% of the Total Ocean Volume 10% of the total river runoff

Arctic Fresh Water Budget Bering Strait Inflow : 1300 km3/year Ocean: 60,000 km3 Ice : 30,000 km3 Runoff: 2500 km3/year Ice/Water Export: 3000 km3/year River runoff 35 Bering Strait Inflow 18 Freezing, melting plus precipitation 9 make sure it is consistent with ice budg Norwegian boundary current 3 Ice outflow 29 Ocean surface current 9 CAA throughflow 10 West Spitsbergen Current 3 Atlantic water input in Barents Sea 6 imbalance of 9 The contribution of the surface currents at Fram Strait is subject of debate, it could be much larger explain how the ocean could give huge contribution to this outflow? Bring slide from arctic commission presentation.

Monitoring fresh water This figure shows the change in sea ice thickness from 1958-76 and 1993-97. The data is from submarine draft measurements and are located in the Gore triangle…. The data used is for similar location but for different times...We can see that all the open triangles are above the solid squares in all regions of the Arctic. The mean decrease in ice thickness over the entire Arctic is approximately 70cm over this 20 year period... Are these changes in SIC and sea ice thickness of thermodynamic or dynamic origin? We saw from the SLP map how potentially more ice could be exported out of the Arctic in the last 2 decades… later on we will see this thinning is a dynamic rather than a thermodynamic consequence Of course three is submarine data close to the Canadian arctic archipelago and the Eurasian continental shelf, but for political reasons, it is a bit touchy to release such data We have seen earlier how thicker ice might have been displaced towards the Beaufort Sea, we will see later from model results how this how this is causing problem in the interpretation in the observed sea ice thinning.

Mooring deployment This figure shows the change in sea ice thickness from 1958-76 and 1993-97. The data is from submarine draft measurements and are located in the Gore triangle…. The data used is for similar location but for different times...We can see that all the open triangles are above the solid squares in all regions of the Arctic. The mean decrease in ice thickness over the entire Arctic is approximately 70cm over this 20 year period... Are these changes in SIC and sea ice thickness of thermodynamic or dynamic origin? We saw from the SLP map how potentially more ice could be exported out of the Arctic in the last 2 decades… later on we will see this thinning is a dynamic rather than a thermodynamic consequence Of course three is submarine data close to the Canadian arctic archipelago and the Eurasian continental shelf, but for political reasons, it is a bit touchy to release such data We have seen earlier how thicker ice might have been displaced towards the Beaufort Sea, we will see later from model results how this how this is causing problem in the interpretation in the observed sea ice thinning.

Mooring deployment This figure shows the change in sea ice thickness from 1958-76 and 1993-97. The data is from submarine draft measurements and are located in the Gore triangle…. The data used is for similar location but for different times...We can see that all the open triangles are above the solid squares in all regions of the Arctic. The mean decrease in ice thickness over the entire Arctic is approximately 70cm over this 20 year period... Are these changes in SIC and sea ice thickness of thermodynamic or dynamic origin? We saw from the SLP map how potentially more ice could be exported out of the Arctic in the last 2 decades… later on we will see this thinning is a dynamic rather than a thermodynamic consequence Of course three is submarine data close to the Canadian arctic archipelago and the Eurasian continental shelf, but for political reasons, it is a bit touchy to release such data We have seen earlier how thicker ice might have been displaced towards the Beaufort Sea, we will see later from model results how this how this is causing problem in the interpretation in the observed sea ice thinning.

Grace Gravity Recovery and Climate Experiment 110 km 550 km This figure shows the change in sea ice thickness from 1958-76 and 1993-97. The data is from submarine draft measurements and are located in the Gore triangle…. The data used is for similar location but for different times...We can see that all the open triangles are above the solid squares in all regions of the Arctic. The mean decrease in ice thickness over the entire Arctic is approximately 70cm over this 20 year period... Are these changes in SIC and sea ice thickness of thermodynamic or dynamic origin? We saw from the SLP map how potentially more ice could be exported out of the Arctic in the last 2 decades… later on we will see this thinning is a dynamic rather than a thermodynamic consequence Of course three is submarine data close to the Canadian arctic archipelago and the Eurasian continental shelf, but for political reasons, it is a bit touchy to release such data We have seen earlier how thicker ice might have been displaced towards the Beaufort Sea, we will see later from model results how this how this is causing problem in the interpretation in the observed sea ice thinning. 550 km

Grace Gravity Recovery and Climate Experiment This figure shows the change in sea ice thickness from 1958-76 and 1993-97. The data is from submarine draft measurements and are located in the Gore triangle…. The data used is for similar location but for different times...We can see that all the open triangles are above the solid squares in all regions of the Arctic. The mean decrease in ice thickness over the entire Arctic is approximately 70cm over this 20 year period... Are these changes in SIC and sea ice thickness of thermodynamic or dynamic origin? We saw from the SLP map how potentially more ice could be exported out of the Arctic in the last 2 decades… later on we will see this thinning is a dynamic rather than a thermodynamic consequence Of course three is submarine data close to the Canadian arctic archipelago and the Eurasian continental shelf, but for political reasons, it is a bit touchy to release such data We have seen earlier how thicker ice might have been displaced towards the Beaufort Sea, we will see later from model results how this how this is causing problem in the interpretation in the observed sea ice thinning.