On the Importance of Warm Pacific Water Inflow Along the Alaskan Coast
Abstract
The oceanic heat flux into the Arctic Ocean is one of the main driving forces of environmental Arctic change. Together with the heat and buoyancy fluxes from the atmosphere at the surface, the local river runoff, and dynamic wind forcing it modulates the state of sea ice cover and determines regions of net growth/melt of sea ice and variability in multi-year and first-year ice distribution,. The absolute magnitude and long term variability of oceanic heat flux into the Arctic Ocean are not well known from observations and their representation has posed great challenges to global climate models. For example, the inflow of Pacific Summer Water northward through narrow (100 km) Bering Strait and its circulation over the Chukchi Shelf and in the Beaufort Sea is not realistic in low resolution models, which creates problems in the western Arctic. Some of the challenges there include the representation of narrow (10-100 km) coastal and boundary currents, which constitute the main circulation features in that region. The oceanic heat flux into the Arctic Ocean is especially critical in the marginal ice zone coincident directly downstream of warm Pacific Water advection from the Pacific Ocean. The removal of sea ice along the Alaskan coast for prolonged times increases oceanic effects along the coast, including coastal erosion, air-sea exchange, and biological forcing. The existing studies typically assume the dominant role of external atmospheric forcing in such regions and neglect effects of processes internal to the ocean. Especially overlooked tends to be the oceanic thermodynamic control of sea ice through the lateral melt and under-ice ablation along marginal ice zones. However, such ice-ocean interactions may act to de-correlate atmospheric forcing, which could help explain some of the timing issues between AO/atmospheric forcing and sea ice variability, especially in the last decade. In this talk, we focus on model results and in-situ data related to the dynamics of Pacific Water flow along the Alaskan coast, especially the heat flux associated with the Alaska Coastal Current. Our analyses attempts to quantify the respective contributions from the oceanic circulation variability versus the ice-albedo effect on the heat flux from the Chukchi into the Beaufort Sea.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2006
- Bibcode:
- 2006AGUFM.C44B..02M
- Keywords:
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- 0750 Sea ice (4540);
- 4207 Arctic and Antarctic oceanography (9310;
- 9315);
- 4215 Climate and interannual variability (1616;
- 1635;
- 3305;
- 3309;
- 4513);
- 4217 Coastal processes;
- 4255 Numerical modeling (0545;
- 0560)