Arctic climate sensitivity to changes in North Pacific and North Atlantic ocean heat flux
Abstract
Paleoclimate records indicate abrupt swings in Arctic temperature that were coeval with abrupt changes in sea surface temperature (SST) in both the North Pacific and North Atlantic oceans throughout the late Pleistocene, suggesting a strong coupling between extratropical ocean heat flux and Arctic climate. While the processes that contribute to Arctic amplification, including surface-albedo, cloud, and temperature feedbacks, are generally well-established, the relative impacts of changes in ocean heat flux sourced from different ocean basins on poleward heat transfer and Arctic climate feedbacks are not well understood. We employ simulations with the Community Earth System Model version 1.0.4 using a slab ocean configuration with modified ocean-to-atmosphere heat fluxes sourced from the North Pacific and North Atlantic (30-60°N) to determine the sensitivity of Arctic amplification processes to zonal heterogeneities in northern hemisphere SST patterns. We find that a local heat flux magnitude equivalent to a globally averaged +1 W/m2 sourced from the North Pacific results in greater Arctic surface warming/cooling and sea ice decline/advance than the equivalent heat flux perturbation originating from the North Atlantic. We attribute this response primarily to greater net moisture transfer between the North Pacific and Arctic (relative to the North Atlantic simulations) in response to changes in surface ocean heat flux, with accompanying impacts on cloud, sea ice, and temperature feedbacks that amplify the Arctic surface temperature response. In the case of a positive ocean-to-atmosphere heat flux anomaly from the North Pacific, greater moisture transport into the Arctic results in: 1) enhanced sensible and latent heat transfer to the Arctic 2) enhanced low cloud formation and attendant surface infrared radiation in the Arctic, and 3) enhanced area of sea ice decline, which is promoted by the first two processes and further amplifies surface warming through the ice-albedo feedback. Our findings indicate that Arctic temperatures are more sensitive to changes in heat flux sourced from the North Pacific than they are to changes in heat flux sourced from the North Atlantic, implying that changes in ocean heat flux patterns between regions have the potential to elicit non-linear Arctic climate responses
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.A51C0067P
- Keywords:
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- 3305 Climate change and variability;
- ATMOSPHERIC PROCESSESDE: 3319 General circulation;
- ATMOSPHERIC PROCESSESDE: 3354 Precipitation;
- ATMOSPHERIC PROCESSESDE: 1620 Climate dynamics;
- GLOBAL CHANGE